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Lidonnici D, Brambilla P, Ravasio R, Zozulya-Weidenfeller A, Beiderbeck A, van Aswegen M, Oliveira R, Sansone VA. Expert Insights from a Delphi-driven Neurologists' Panel: Real-world Mexiletine use in Patients with Myotonic Disorders in Italy. J Neuromuscul Dis 2024; 11:411-423. [PMID: 38306059 DOI: 10.3233/jnd-230115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Background Myotonic disorders, such as non-dystrophic myotonias (NDMs) and myotonic dystrophies (DMs) are characterized by a delay in muscle relaxation after a contraction stimulus. There is general consensus that protocols to treat myotonia need to be implemented. Objective Mexiletine is the only pharmacological agent approved for the symptomatic treatment of myotonia in adult patients with NDM and is considered to be the first-line treatment for DMs; however, its production in Italy was halted in 2022 making its availability to patients problematic. Methods A panel of 8 Italian neurologists took part in a two-round Delphi panel between June and October 2022, analyzing the current use of mexiletine in Italian clinical practice. Results The panelists assist 1126 patients (69% DM type1, 18% NDM and 13% DM type2). Adult NDM patients receive, on average, 400-600 mg of mexiletine hydrochloride (HCl) while adult DM patients receive 100-600 mg, per day in the long-term. The severity of symptoms is considered the main reason to start mexiletine treatment for both NDM and DM patients. Mexiletine is reckoned to have a clinical impact for both NDM and DM patients, but currently drug access is problematic. Conclusions Mexiletine treatment is recognized to have a role in the reduction of the symptomatic burden for NDM and DM patients. Patient management could be improved by facilitating access to therapy and developing new drug formulations.
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Affiliation(s)
| | | | | | | | | | | | | | - Valeria A Sansone
- The NEMO Center, Neurorehabilitation Unit, University of Milan, ASST Niguarda Hospital, Milan, Italy
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2
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Ali H, Cristiano E, Lupo P, Foresti S, DE Ambroggi G, DE Lucia C, Turturiello D, Paganini EM, Bessi R, Farghaly AA, Nicolì L, Cappato R. Oral mexiletine for ventricular tachyarrhythmias treatment in implantable cardioverter-defibrillator patients: a systematic review of the literature. Minerva Cardiol Angiol 2023; 71:622-630. [PMID: 36305779 DOI: 10.23736/s2724-5683.22.06176-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
INTRODUCTION To evaluate the clinical outcomes of oral mexiletine (oMXT) to treat ventricular tachyarrhythmias (VTAs) in the era of implantable cardioverter-defibrillator (ICD) technology. EVIDENCE ACQUISITION A systematic search was conducted using PubMed, Embase and Cochrane databases following the PRISMA guidelines to collect literature data reporting oMXT efficacy and safety outcomes in treating VTAs in ICD recipients. EVIDENCE SYNTHESIS Final analysis included four studies accounting for a total of 91 patients with recurrent VTAs treated with oMXT. Amiodarone therapy was initially attempted in most patients (91.2%), while catheter ablation was performed in one-third of patients. VTA recurrences were observed in 55/91 patients (60.4%) during oMXT treatment compared to 91/91 (100%) before treatment (P<0.001). Appropriate therapies occurred in 55/88 ICD patients (62.5%) during oMXT treatment compared to 80/88 (90.9%) before treatment (P<0.001). After oMXT introduction, there was a significant reduction of the individual burden of VTA episodes and appropriate ICD therapies per patient, showing Hedges'g values of -1.103 (P=0.002) and -1.474 (P=0.008), respectively. Safety analysis showed a sample-weighted overall side-effect rate of 30%, while 21% of patients required drug reduction or discontinuation. Aggregated meta-regression analysis of the included studies and remote literature revealed a linear correlation between oMXT dosage and the overall side effects rate (r2 = 0.48; P=0.014). CONCLUSIONS Oral mexiletine provides an adjunctive treatment to manage VTAs and reduces appropriate therapies in ICD patients with moderate efficacy and acceptable safety profiles. These observations await confirmation through randomised clinical trials.
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Affiliation(s)
- Hussam Ali
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy -
| | - Ernesto Cristiano
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
- Department of Clinical and Molecular Medicine, School of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Pierpaolo Lupo
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Sara Foresti
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Guido DE Ambroggi
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Carmine DE Lucia
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Dario Turturiello
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Edoardo M Paganini
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Riccardo Bessi
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Ahmad A Farghaly
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
- Department of Cardiovascular Medicine, Faculty of Medicine, University of Assiut, Assiut, Egypt
| | - Leoluca Nicolì
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Riccardo Cappato
- Arrhythmia and Electrophysiology Center, IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
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3
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Szonyi MD, Pap R, Vamos M. Use of mexiletine in therapy-refractory recurrent ventricular tachycardia storm. Herzschrittmacherther Elektrophysiol 2023; 34:326-329. [PMID: 37917362 DOI: 10.1007/s00399-023-00976-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023]
Abstract
Electrical storm due to recurrent ventricular tachycardias (VTs) is a life-threatening arrhythmic emergency. The authors present a case report of a 69-year-old male patient with VT storm of non-ischemic etiology. Despite optimal medical treatment escalated by amiodarone antiarrhythmic drug therapy, the patient experienced multiple implantable cardioverter defibrillator (ICD) shocks. An electrophysiological study revealed an epicardial substrate; however, considering the patient's extreme obesity and active anticoagulant effect, catheter ablation was deemed to be unfeasible. Subsequently, mexiletine was added to the patient's drug regimen, resulting in successful control of arrhythmias during the following 6 months. Although the most recent European guidelines for the management of patients with ventricular arrhythmias mention mexiletine only for the treatment of LQT3 patients, its use for treatment-refractory VT storm seems to also be an important indication area.
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Affiliation(s)
- Mihaly D Szonyi
- Gottsegen National Cardiovascular Center, Budapest, Hungary
- Doctoral School of Clinical Medicine, University of Szeged, Szeged, Hungary
| | - Robert Pap
- Cardiac Electrophysiology Division, Department of Internal Medicine, University of Szeged, Semmelweis u. 8., 6725, Szeged, Hungary
| | - Mate Vamos
- Cardiac Electrophysiology Division, Department of Internal Medicine, University of Szeged, Semmelweis u. 8., 6725, Szeged, Hungary.
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Righi D, Porco L, Di Mambro C, Gnazzo M, Baban A, Paglia S, Silvetti MS, Novelli A, Tozzi AE, Drago F. Autosomal Recessive Long QT Syndrome: Clinical Aspects and Therapy. Pediatr Cardiol 2023; 44:1736-1740. [PMID: 37597120 DOI: 10.1007/s00246-023-03266-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/04/2023] [Indexed: 08/21/2023]
Abstract
The autosomal recessive (AR) form of Long QT Syndrome (LQTS) is described both associated with deafness known as Jervell and Lange-Nielsen (JLN) syndrome, and without deafness (WD). The aim of the study is to report the characteristics of AR LQTS patients and the efficacy of the therapy. Data of all children with AR LQTS referred to the Bambino Gesù Children's Hospital IRCCS from September 2012 to September 2021were included. Three (30%) patients had compound heterozygosity and 7 (70%) had homozygous variants of the KCNQ1 gene, the latter showing deafness. Four patients (40%) presented aborted sudden cardiac death (aSCD): three with previous episodes of syncope (75%), the other without previous symptoms (16.6% of asymptomatic patients). An episode of aSCD occurred in 2/3 (66.7%) of WD and heterozygous patients, while in 2/7 (28%) JLN and homozygous patients and in 2/2 patients with QTC > 600 ms. All patients were treated with Nadolol. In 5 Mexiletine was added, shortening QTc and obtaining the disappearance of the T-wave alternance (TWA) in 3/3. Episodes of aSCD seem to be more frequent in LQTS patients with compound heterozygous variants and WD than in those with JLN and homozygous variants. Episodes of aSCD also appear more frequent in children with syncope or with QTc value > 600 ms, even on beta-blocker therapy, than in patients without syncope or with Qtc < 600 ms. However, our descriptive results should be confirmed by larger studies. Moreover, Mexiletine addition reduced QTc value and eliminated TWA.
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Affiliation(s)
- Daniela Righi
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
| | - Luigina Porco
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Corrado Di Mambro
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Maria Gnazzo
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anwar Baban
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Simone Paglia
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Massimo Stefano Silvetti
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Alberto Eugenio Tozzi
- Predictive and Preventive Medicine Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Fabrizio Drago
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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Olleik F, Kamareddine MH, Spears J, Tse G, Liu T, Yan GX. Mexiletine: Antiarrhythmic mechanisms, emerging clinical applications and mortality. Pacing Clin Electrophysiol 2023; 46:1348-1356. [PMID: 37846818 DOI: 10.1111/pace.14846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 09/19/2023] [Accepted: 10/07/2023] [Indexed: 10/18/2023]
Abstract
Mexiletine, a class Ib antiarrhythmic drug, exhibits its major antiarrhythmic effect via inhibition of the fast and late Na+ currents in myocardial tissues that are dependent on the opening of Na+ channels for their excitation. Through a comprehensive examination of mexiletine's therapeutic benefits and potential risks, we aim to provide valuable insights that reinforce its role as a vital therapeutic option for patients with ventricular arrhythmias, long QT syndrome, and other heart rhythm disorders. This review will highlight the current understandings of the antiarrhythmic effects and rationales for recent off-label use and address the mortality and proarrhythmic effects of mexiletine utilizing published basic and clinical studies over the past five decades.
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Affiliation(s)
- Farah Olleik
- Lankenau Medical Center and Lankenau Institute for Medical Research, Wynnewood, Pennsylvania, USA
| | | | - Jenna Spears
- Lankenau Medical Center and Lankenau Institute for Medical Research, Wynnewood, Pennsylvania, USA
| | - Gary Tse
- Tianjin Key Laboratory of Ion-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, PR China
- Kent and Medway Medical School, Canterbury, Kent, UK
- School of Nursing and Health Studies, Hong Kong Metropolitan University, Hong Kong, PR China
| | - Tong Liu
- Tianjin Key Laboratory of Ion-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, PR China
| | - Gan-Xin Yan
- Lankenau Medical Center and Lankenau Institute for Medical Research, Wynnewood, Pennsylvania, USA
- Fuwai Huazhong Hospital, Chinese Academy of Medical Sciences, Zhengzhou, PR China
- Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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6
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Stutzman MJ, Gao X, Kim M, Ye D, Zhou W, Tester DJ, Giudicessi JR, Shannon K, Ackerman MJ. Functional characterization and identification of a therapeutic for a novel SCN5A-F1760C variant causing type 3 long QT syndrome refractory to all guideline-directed therapies. Heart Rhythm 2023; 20:709-717. [PMID: 36731785 DOI: 10.1016/j.hrthm.2023.01.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023]
Abstract
BACKGROUND Pathogenic variants in the SCN5A-encoded Nav1.5 sodium channel cause type 3 long QT syndrome (LQT3). We present the case of an infant with severe LQT3 who was refractory to multiple pharmacologic therapies as well as bilateral stellate ganglionectomy. The patient's novel variant, p.F1760C-SCN5A, involves a critical residue of the Nav1.5's local anesthetic binding domain. OBJECTIVE The purpose of this study was to characterize functionally the p.F1760C-SCN5A variant using TSA-201 and patient-specific induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). METHODS Whole-cell patch clamp was used to assess p.F1760C-SCN5A associated sodium currents with/without lidocaine (Lido), flecainide, and phenytoin (PHT) in TSA-201 cells. p.F1760C-SCN5A and CRISPR-Cas9 variant-corrected isogenic control (IC) iPSC-CMs were generated. FluoVolt voltage dye was used to measure the action potential duration (APD) with/without mexiletine or PHT. RESULTS V1/2 of inactivation was right-shifted significantly in F1760C cells (-72.2 ± 0.7 mV) compared to wild-type (WT) cells (-86.3 ± 0.9 mV; P <.0001) resulting in a marked increase in window current. F1760C increased sodium late current 2-fold from 0.18% ± 0.04% of peak in WT to 0.49% ± 0.07% of peak in F1760C (P = .0005). Baseline APD to 90% repolarization (APD90) was increased markedly in F1760C iPSC-CMs (601 ± 4 ms) compared to IC iPSC-CMs (423 ± 15 ms; P <.0001). However, 4-hour treatment with 10 μM mexiletine failed to shorten APD90, and treatment with 5μM PHT significantly decreased APD90 of F1760C iPSC-CMs (453 ± 6 ms; P <.0001). CONCLUSION PHT rescued electrophysiological phenotype and APD of a novel p.F1760C-SCN5A variant. The antiepileptic drug PHT may be an effective alternative therapeutic for the treatment of LQT3, especially for variants that disrupt the Lido/mexiletine binding site.
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Affiliation(s)
- Marissa J Stutzman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Xiaozhi Gao
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Maengjo Kim
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Dan Ye
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Wei Zhou
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - David J Tester
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - John R Giudicessi
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota
| | - Kevin Shannon
- Department of Pediatrics, David Geffen UCLA School of Medicine, Los Angeles, California
| | - Michael J Ackerman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, Minnesota; Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, Minnesota; Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota.
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Vamos M, Zsigmond EJ, Hohnloser SH. Indications for mexiletine in the new ESC guidelines and beyond. Expert Opin Pharmacother 2023; 24:1403-1407. [PMID: 37306465 DOI: 10.1080/14656566.2023.2223964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/05/2023] [Indexed: 06/13/2023]
Abstract
INTRODUCTION Mexiletine is a class IB sodium-channel blocker. Unlike class IA or IC antiarrhythmic drugs, mexiletine rather shortens than prolongs action potential duration; therefore, it is less associated with proarrhythmic effects. AREAS COVERED Recently, new European Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death were published, including a reappraisal of some established older antiarrhythmic drugs. EXPERT OPINION Mexiletine offers a first-line, genotype-specific treatment strategy for LQT3 patients as emphasized by the most recent guidelines. Besides this recommendation, current study reports suggest that in therapy-refractory ventricular tachyarrhythmias and electrical storms adjunctive mexiletine treatment may offer the possibility of stabilizing patients with or without concomitant interventional therapy such as catheter ablation.
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Affiliation(s)
- Mate Vamos
- Cardiac Electrophysiology Division, Department of Internal Medicine, University of Szeged, Szeged, Hungary
| | - Elod-Janos Zsigmond
- Doctoral School of Clinical Medicine, University of Szeged, Szeged, Hungary
- Department of Cardiology, Medical Centre, Hungarian Defence Forces, Budapest, Hungary
| | - Stefan H Hohnloser
- Department of Cardiology, J. W. Goethe University, Frankfurt Am Main, Germany
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De Bellis M, Boccanegra B, Cerchiara AG, Imbrici P, De Luca A. Blockers of Skeletal Muscle Na v1.4 Channels: From Therapy of Myotonic Syndrome to Molecular Determinants of Pharmacological Action and Back. Int J Mol Sci 2023; 24:ijms24010857. [PMID: 36614292 PMCID: PMC9821513 DOI: 10.3390/ijms24010857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/28/2022] [Accepted: 12/30/2022] [Indexed: 01/05/2023] Open
Abstract
The voltage-gated sodium channels represent an important target for drug discovery since a large number of physiological processes are regulated by these channels. In several excitability disorders, including epilepsy, cardiac arrhythmias, chronic pain, and non-dystrophic myotonia, blockers of voltage-gated sodium channels are clinically used. Myotonia is a skeletal muscle condition characterized by the over-excitability of the sarcolemma, resulting in delayed relaxation after contraction and muscle stiffness. The therapeutic management of this disorder relies on mexiletine and other sodium channel blockers, which are not selective for the Nav1.4 skeletal muscle sodium channel isoform. Hence, the importance of deepening the knowledge of molecular requirements for developing more potent and use-dependent drugs acting on Nav1.4. Here, we review the available treatment options for non-dystrophic myotonia and the structure-activity relationship studies performed in our laboratory with a focus on new compounds with potential antimyotonic activity.
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Öztürk Z, Aydın O, Bodur İ, Yaradılmış RM, Çelik HA, Tuygun N. Dyskinesia due to mexiletine overdose: a rare presentation. Turk J Pediatr 2023; 65:704-706. [PMID: 37661688 DOI: 10.24953/turkjped.2023.84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
BACKGROUND Mexiletine, a class IB antiarrhythmic, is a structural analog of lidocaine. Our knowledge of mexiletine overdose is based on lidocaine overdose reports. Only a few cases of mexiletine overdose have been reported, including fatal overdoses. Mexiletine toxicity primarily affects the central nervous, cardiovascular, and gastrointestinal systems. CASE A 16-year-old female was brought to our hospital by ambulance after taking an unknown dose of mexiletine in a suicide attempt. Ventricular fibrillation developed while in the ambulance; cardiopulmonary resuscitation was started and spontaneous circulation returned within 1 min. The patient had been taking oral mexiletine for 1 month to treat primary erythromelalgia. Her vital signs were normal, but she was unconscious. Following gastric lavage she was transferred to the pediatric intensive care unit. Midazolam and levetiracetam were required due to uncontrolled seizures. During the first hour of hospitalization, severe dyskinesia characterized by abnormal involuntary large hyperkinetic movements in all 4 extremities was observed and successfully treated with 2 doses of intravenous biperiden. The patient was discharged on day 6 of hospitalization. CONCLUSIONS Mexiletine overdose can be life-threatening. In addition to rapid and effective resuscitation, rapid identification and management of cardiovascular and central nervous system manifestations are key to preventing morbidity and mortality. The presented case had severe dyskinesia that was successfully treated with repeated doses of biperiden. Biperiden did not cause arrhythmia. Based on the presented case, we think biperiden should be considered for the treatment of movement disorders in cases of mexiletine overdose.
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Affiliation(s)
- Zeynelabidin Öztürk
- Department of Pediatric Intensive Care, University of Health Sciences, Dr. Sami Ulus Obstetrics and Gynecology, Pediatric Health and Disease Training and Research Hospital, Ankara
| | - Orkun Aydın
- Department of Pediatric Emergency Medicine, University of Health Sciences, Dr. Sami Ulus Obstetrics and Gynecology, Pediatric Health and Disease Training and Research Hospital, Ankara
| | - İlknur Bodur
- Department of Pediatric Emergency Medicine, University of Health Sciences, Dr. Sami Ulus Obstetrics and Gynecology, Pediatric Health and Disease Training and Research Hospital, Ankara
| | - Raziye Merve Yaradılmış
- Department of Pediatric Emergency Medicine, University of Health Sciences, Dr. Sami Ulus Obstetrics and Gynecology, Pediatric Health and Disease Training and Research Hospital, Ankara
| | - Hale Atalay Çelik
- Department of Pediatric Neurology, University of Health Sciences, Dr. Sami Ulus Obstetrics and Gynecology, Pediatric Health and Disease Training and Research Hospital, Ankara, Türkiye
| | - Nilden Tuygun
- Department of Pediatric Emergency Medicine, University of Health Sciences, Dr. Sami Ulus Obstetrics and Gynecology, Pediatric Health and Disease Training and Research Hospital, Ankara
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Shimizu T, Kawai S, Kawada A, Wakamiya T, Nakano Y, Watanabe S, Iwamoto M. Combined mexiletine and flecainide for severe long QT syndrome type 3. Pediatr Int 2023; 65:e15517. [PMID: 36847291 DOI: 10.1111/ped.15517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/28/2023] [Accepted: 02/16/2023] [Indexed: 03/01/2023]
Affiliation(s)
- Toshiyuki Shimizu
- Department of Pediatric Cardiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan
| | - Shun Kawai
- Department of Pediatric Cardiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan
| | - Aiko Kawada
- Department of Pediatric Cardiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan
| | - Takuya Wakamiya
- Department of Pediatric Cardiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan
| | - Yusuke Nakano
- Department of Pediatric Cardiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan
| | - Shigeo Watanabe
- Department of Pediatric Cardiology, Yokohama City University Hospital, Yokohama, Kanagawa, Japan
| | - Mari Iwamoto
- Department of Pediatrics, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Kanagawa, Japan
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11
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Huang YW, Chen Y, Wang CY, Wu L. [Impact of late sodium current inhibition on cardiac electrophysiology parameters and ventricular arrhythmias in isolated Langendorff perfused rabbit hearts with short QT interval]. Zhonghua Xin Xue Guan Bing Za Zhi 2022; 50:1087-1093. [PMID: 36418277 DOI: 10.3760/cma.j.cn112148-20220705-00518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Objective: To determine the electrophysiological effects and related mechanisms of late sodium current inhibitors on hearts with short QT intervals. Methods: The electrophysiological study was performed on isolated Langendorff perfused rabbit hearts. A total of 80 New Zealand White rabbits were used and 34 hearts without drug treatment were defined as control group A, these hearts were then treated with IKATP opener pinacidil, defined as pinacidil group A. Then, 27 hearts from pinacidil group A were selected to receive combined perfusion with sodium channel inhibitors or quinidine, a traditional drug used to treat short QT syndrome, including ranolazine combined group (n=9), mexiletine combined group (n=9), and quinidine combined group (n=9). Nineteen out of the remaining 46 New Zealand rabbits were selected as control group B (no drug treatments, n=19), and then treated with pinacidil, defined as pinacidil group B (n=19). The remaining 27 rabbits were treated with sodium inhibitors or quinidine alone, including ranolazine alone group (n=9), mexiletine alone group (n=9), and quinidine alone group (n=9). Electrocardiogram (ECG) physiological parameters of control group A and pinacidil group A were collected. In control group B and pinacidil group B, programmed electrical stimulation was used to induce ventricular arrhythmias and ECG was collected. ECG physiological parameters and ventricular arrhythmia status of various groups were analyzed. The concentrations of pinacidil, ranolazine, mexiletine and quinidine used in this study were 30, 10, 30 and 1 μmol/L, respectively. Results: Compared with control group A, the QT interval, 90% of the repolarization in epicardial and endocardial monophasic action potential duration (MAPD90-Epi, MAPD90-Endo) was shortened, the transmural dispersion of repolarization (TDR) was increased, and the effective refractor period (ERP) and post-repolarization refractoriness (PRR) were reduced in pinacidil group A (all P<0.05). Compared with the pinacidil group A, MAPD90-Epi, MAPD90-Endo, QT interval changes were reversed in quinidine combined group and mexiletine combined group (all P<0.05), but not in ranolazine combined group. All these three drugs reversed the pinacidil-induced increases of TDR and the decreases of ERP and PRR. The induced ventricular arrhythmia rate was 0 in control group B, and increased to 10/19 (χ2=13.6, P<0.05) in pinacidil group B during programmed electrical stimulation. Compared with the pinacidil group B, incidences of ventricular arrhythmia decreased to 11% (1/9), 11% (1/9) and 0 (0/9) (χ2=4.5, 4.5, 7.4, P<0.05) respectively in ranolazine group, mexiletine group and quinidine group. Conclusions: Inhibition of late sodium current does not increase but even decreases the risk of malignant arrhythmia in hearts with a shortened QT interval. The antiarrhythmic mechanism might be associated with the reversal of the increase of TDR and the decrease of refractoriness (including both ERP and PRR) of hearts with shortened QT interval.
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Affiliation(s)
- Y W Huang
- Department of Cardiology, Peking University First Hospital, Beijing 100034, China
| | - Y Chen
- Department of Cardiology, Peking University First Hospital, Beijing 100034, China
| | - C Y Wang
- Department of Cardiology, Peking University First Hospital, Beijing 100034, China
| | - L Wu
- Department of Cardiology, Peking University First Hospital, Beijing 100034, China
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12
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Bhai SF, Brown A, Gajewski B, Kimminau KS, Waitman LR, Pasnoor M, Barohn RJ. A secondary analysis of PAIN-CONTRoLS: Pain's impact on sleep, fatigue, and activities of daily living. Muscle Nerve 2022; 66:404-410. [PMID: 35585718 PMCID: PMC10629716 DOI: 10.1002/mus.27637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 05/11/2022] [Accepted: 05/13/2022] [Indexed: 11/06/2022]
Abstract
INTRODUCTION/AIMS Peripheral neuropathies commonly affect quality of life of patients due to pain, sleep disturbances, and fatigue, although trials have not adequately explored these domains of care. The aim of this study was to assess the impact of nortriptyline, duloxetine, pregabalin, and mexiletine on pain, sleep, and fatigue in patients diagnosed with cryptogenic sensory polyneuropathy (CSPN). METHODS We implemented a Bayesian adaptive design to perform a 12-wk multisite, randomized, prospective, open-label comparative effectiveness study in 402 CSPN patients. Participants received either nortriptyline (n = 134), duloxetine (n = 126), pregabalin (n = 73), or mexiletine (n = 69). At prespecified analysis timepoints, secondary outcomes, Patient Reported Outcomes Measurement Information System (PROMIS) surveys including Short Form (SF)-12, pain interference, fatigue, and sleep disturbance, were collected. RESULTS Mexiletine had the highest quit rate (58%) due to gastrointestinal side effects, while nortriptyline (38%) and duloxetine (38%) had the lowest quit rates. If tolerated for the full 12 wk of the study, mexiletine had the highest probability (>90%) of positive outcomes for improvements in pain interference and fatigue. There was no significant difference among the medications for sleep disturbance or SF-12 scores. Adverse events and lack of efficacy were the two most common reasons for cessation of therapy. DISCUSSION Physicians caring for patients with CSPN should consider mexiletine to address pain and fatigue, although nortriptyline and duloxetine are better medications to trial first since they are better tolerated. Future research should compare other commonly used medications for CSPN to determine evidence-based treatment strategies.
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Affiliation(s)
- Salman F Bhai
- Department of Neurology, The University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Neuromuscular Center, Institute for Exercise and Environmental Medicine, Texas Health Presbyterian, Dallas, Texas, USA
| | - Alexandra Brown
- Department of Biostatistics and Data Science, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Byron Gajewski
- Department of Biostatistics and Data Science, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Kim S Kimminau
- Department of Family and Community Medicine, The University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Lemuel R Waitman
- Department of Health Management and Informatics, The University of Missouri School of Medicine, Columbia, Missouri, USA
| | - Mamatha Pasnoor
- Department of Neurology, The University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Richard J Barohn
- Department of Neurology, The University of Missouri School of Medicine, Columbia, Missouri, USA
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Salguero-Bodes R, Ruiz-Curiel A, Palomino-Doza J, Valverde-Gómez M, Domínguez-González C, Arribas-Ynsaurriaga F. Cardiovascular effects of mexiletine for treatment of myotonia in myotonic dystrophy type 1. Rev Esp Cardiol (Engl Ed) 2021; 74:986-987. [PMID: 34120884 DOI: 10.1016/j.rec.2021.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Affiliation(s)
- Rafael Salguero-Bodes
- Servicio de Cardiología, Hospital Universitario 12 de Octubre, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Medicina, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
| | - Aníbal Ruiz-Curiel
- Servicio de Cardiología, Hospital Universitario 12 de Octubre, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain
| | - Julián Palomino-Doza
- Servicio de Cardiología, Hospital Universitario 12 de Octubre, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de enfermedades Cardiovasculares (CIBERCV), Spain
| | - María Valverde-Gómez
- Servicio de Cardiología, Hospital Universitario 12 de Octubre, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Medicina, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Cristina Domínguez-González
- Unidad de Neuromuscular, Servicio de Neurología, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain
| | - Fernando Arribas-Ynsaurriaga
- Servicio de Cardiología, Hospital Universitario 12 de Octubre, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Madrid, Spain; Centro de Investigación Biomédica en Red de enfermedades Cardiovasculares (CIBERCV), Spain; Departamento de Medicina, Facultad de Medicina, Universidad Complutense, Madrid, Spain
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van den Berg S, van der Wel V, de Visser SJ, Stunnenberg BC, Timmers L, van der Ree MH, Postema PG, Hollak CEM. Cost-Based Price Calculation of Mexiletine for Nondystrophic Myotonia. Value Health 2021; 24:925-929. [PMID: 34243835 DOI: 10.1016/j.jval.2021.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/21/2020] [Accepted: 02/07/2021] [Indexed: 06/13/2023]
Abstract
OBJECTIVES Mexiletine is a long-known drug used for the treatment of arrhythmias and repurposed in the 1980s for patients with nondystrophic myotonia (NDM). Recently, the price of mexiletine in Europe increased significantly after registration as an orphan drug for NDM. This led to international discussions on affordability and willingness to reimburse mexiletine in the absence of background information that would justify such a price. Our objective was to calculate a cost-based price for mexiletine for adult patients with NDM based on detailed information on development costs. METHODS We calculated a fair price based on a cost-based pricing model for commercial mexiletine to treat adults with NDM using a recent European drug-pricing model as a framework to include actual costs incurred. Three scenarios were applied: 1 with minimum estimated costs, 1 with maximum estimated costs, and 1 with costs as if mexiletine was innovative. RESULTS The calculated fair price of mexiletine per patient per year (PPPY) is €452 for the minimum scenario and €1996 for the maximum scenario. By using hypothetical R&D costs used for innovative drugs, the price would be €6685 PPPY. In Europe, the list price of mexiletine ranges from €30 707-60 730 PPPY, based on 600 mg daily. CONCLUSIONS The current list price for mexiletine in Europe is manifold higher than any scenario of the cost-based models. Accounting for the reduced costs for clinical development in a repurposing scenario, the cost-based pricing model provides a fair commercial price range, which can be used as benchmark for pricing negotiations and/or reimbursement decisions.
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Affiliation(s)
- Sibren van den Berg
- Medicine for Society, Platform at Amsterdam UMC - University of Amsterdam, The Netherlands; Department of Endocrinology and Metabolism, Amsterdam UMC - University of Amsterdam, The Netherlands.
| | - Vincent van der Wel
- Medicine for Society, Platform at Amsterdam UMC - University of Amsterdam, The Netherlands
| | - Saco J de Visser
- Medicine for Society, Platform at Amsterdam UMC - University of Amsterdam, The Netherlands
| | - Bas C Stunnenberg
- Department of Neurology, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Neurology, Rijnstate Hospital, Arnhem, The Netherlands
| | - Lonneke Timmers
- National Health Care Institute (Zorginstituut Nederland), Diemen, The Netherlands
| | - Martijn H van der Ree
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Pieter G Postema
- Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam UMC, University of Amsterdam, Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Carla E M Hollak
- Medicine for Society, Platform at Amsterdam UMC - University of Amsterdam, The Netherlands; Department of Endocrinology and Metabolism, Amsterdam UMC - University of Amsterdam, The Netherlands
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15
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Heatwole C, Luebbe E, Rosero S, Eichinger K, Martens W, Hilbert J, Dekdebrun J, Dilek N, Zizzi C, Johnson N, Puwanant A, Tawil R, Schifitto G, Beck CA, Richeson JF, Zareba W, Thornton C, McDermott MP, Moxley R. Mexiletine in Myotonic Dystrophy Type 1: A Randomized, Double-Blind, Placebo-Controlled Trial. Neurology 2021; 96:e228-e240. [PMID: 33046619 PMCID: PMC7905778 DOI: 10.1212/wnl.0000000000011002] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 08/24/2020] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE To assess mexiletine's long-term safety and effect on 6-minute walk distance in a well-defined cohort of patients with myotonic dystrophy type 1 (DM1). METHODS We performed a randomized, double-blind, placebo-controlled trial of mexiletine (150 mg 3 times daily) to evaluate its efficacy and safety in a homogenous cohort of adult ambulatory patients with DM1. The primary outcome was change in 6-minute walk distance at 6 months. Secondary outcomes included changes in hand grip myotonia, strength, swallowing, forced vital capacity, lean muscle mass, Myotonic Dystrophy Health Index scores, and 24-hour Holter and ECG results at 3 and 6 months. RESULTS Forty-two participants were randomized and 40 completed the 6-month follow-up (n = 20 in both groups). No significant effects of mexiletine were observed on 6-minute walk distance, but hand grip myotonia was improved with mexiletine treatment. There were no differences between the mexiletine and placebo groups with respect to the frequency or type of adverse events. Changes in PR, QRS, and QTc intervals were similar in mexiletine- and placebo-treated participants. CONCLUSIONS There was no benefit of mexiletine on 6-minute walk distance at 6 months. Although mexiletine had a sustained positive effect on objectively measured hand grip myotonia, this was not seen in measures reflecting participants' perceptions of their myotonia. No effects of mexiletine on cardiac conduction measures were seen over the 6-month follow-up period. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that for ambulatory patients with DM1, mexiletine does not significantly change 6-minute walk distance at 6 months.
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Affiliation(s)
- Chad Heatwole
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC.
| | - Elizabeth Luebbe
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Spencer Rosero
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Katy Eichinger
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - William Martens
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - James Hilbert
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Jeanne Dekdebrun
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Nuran Dilek
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Christine Zizzi
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Nicholas Johnson
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Araya Puwanant
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Rabi Tawil
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Giovanni Schifitto
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Christopher A Beck
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - J Franklin Richeson
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Wojciech Zareba
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Charles Thornton
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Michael P McDermott
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
| | - Richard Moxley
- From the Department of Neurology (C.H., E.L., S.R., K.E., W.M., J.H., J.D., N.D., C.Z., R.T., G.S., C.A.B., J.F.R., W.Z., C.T., M.P.M., R.M.), University of Rochester, MN; Virginia Commonwealth University (N.J.), Richmond; and Wake Forest Baptist Health (A.P.), Winston-Salem, NC
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Desaphy JF, Altamura C, Vicart S, Fontaine B. Targeted Therapies for Skeletal Muscle Ion Channelopathies: Systematic Review and Steps Towards Precision Medicine. J Neuromuscul Dis 2021; 8:357-381. [PMID: 33325393 PMCID: PMC8203248 DOI: 10.3233/jnd-200582] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Skeletal muscle ion channelopathies include non-dystrophic myotonias (NDM), periodic paralyses (PP), congenital myasthenic syndrome, and recently identified congenital myopathies. The treatment of these diseases is mainly symptomatic, aimed at reducing muscle excitability in NDM or modifying triggers of attacks in PP. OBJECTIVE This systematic review collected the evidences regarding effects of pharmacological treatment on muscle ion channelopathies, focusing on the possible link between treatments and genetic background. METHODS We searched databases for randomized clinical trials (RCT) and other human studies reporting pharmacological treatments. Preclinical studies were considered to gain further information regarding mutation-dependent drug effects. All steps were performed by two independent investigators, while two others critically reviewed the entire process. RESULTS For NMD, RCT showed therapeutic benefits of mexiletine and lamotrigine, while other human studies suggest some efficacy of various sodium channel blockers and of the carbonic anhydrase inhibitor (CAI) acetazolamide. Preclinical studies suggest that mutations may alter sensitivity of the channel to sodium channel blockers in vitro, which has been translated to humans in some cases. For hyperkalemic and hypokalemic PP, RCT showed efficacy of the CAI dichlorphenamide in preventing paralysis. However, hypokalemic PP patients carrying sodium channel mutations may have fewer benefits from CAI compared to those carrying calcium channel mutations. Few data are available for treatment of congenital myopathies. CONCLUSIONS These studies provided limited information about the response to treatments of individual mutations or groups of mutations. A major effort is needed to perform human studies for designing a mutation-driven precision medicine in muscle ion channelopathies.
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Affiliation(s)
- Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Savine Vicart
- Sorbonne Université, INSERM, Assistance Publique Hôpitaux de Paris, Centre de Recherche en Myologie-UMR 974, Reference center in neuro-muscular channelopathies, Institute of Myology, Hôpital Universitaire Pitié-Salpêtrière, Paris, France
| | - Bertrand Fontaine
- Sorbonne Université, INSERM, Assistance Publique Hôpitaux de Paris, Centre de Recherche en Myologie-UMR 974, Reference center in neuro-muscular channelopathies, Institute of Myology, Hôpital Universitaire Pitié-Salpêtrière, Paris, France
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17
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Stunnenberg BC, LoRusso S, Arnold WD, Barohn RJ, Cannon SC, Fontaine B, Griggs RC, Hanna MG, Matthews E, Meola G, Sansone VA, Trivedi JR, van Engelen BG, Vicart S, Statland JM. Guidelines on clinical presentation and management of nondystrophic myotonias. Muscle Nerve 2020; 62:430-444. [PMID: 32270509 PMCID: PMC8117169 DOI: 10.1002/mus.26887] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/01/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.
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Affiliation(s)
- Bas C. Stunnenberg
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Samantha LoRusso
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - W. David Arnold
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Richard J. Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
| | - Stephen C. Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Bertrand Fontaine
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Robert C. Griggs
- Department of Neurology, University of Rochester, Rochester, New York
| | - Michael G. Hanna
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Giovanni Meola
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Valeria A. Sansone
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
- Neurorehabilitation Unit, University of Milan, NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy
| | - Jaya R. Trivedi
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, Texas
| | | | - Savine Vicart
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Jeffrey M. Statland
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
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Portaro S, Biasini F, Bramanti P, Naro A, Calabrò RS. Chronic inflammatory demyelinating polyradiculoneuropathy relapse after mexiletine withdrawal in a patient with concomitant myotonia congenita: A case report on a potential treatment option. Medicine (Baltimore) 2020; 99:e21117. [PMID: 32664137 PMCID: PMC7360317 DOI: 10.1097/md.0000000000021117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
INTRODUCTION we report on the first case of a woman affected by chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and recessive myotonia congenita (MC), treated with mexiletine. We aimed at describing the possible role of mexiletine in CIDP management. PATIENT CONCERNS A 44-year-old female affected by CIDP and MC, gained beneficial effects for CIDP symptoms (muscle weakness, cramps, and fatigue) and relapses, after mexiletine intake (200 mg twice a day). The patient presented with detrimental effects after mexiletine drop out, with a worsening of CIDP symptoms. INTERVENTIONS The patient reported a nearly complete remission of muscle stiffness and weakness up to 3 years since mexiletine intake. Then, she developed an allergic reaction with glottis edema, maybe related to mexiletine intake, as per emergency room doctors' evaluation, who suggested withdrawing the drug. OUTCOMES The patient significantly worsened after the medication drop out concerning both CIDP and MC symptoms. CONCLUSION This is the first report on the association of CIDP and MC in the same patient. Such diseases may share some clinical symptoms related to a persistent sodium currents increase, which maybe due either to the over-expression of sodium channels following axonal damage due to demyelination or to the chloride channel genes mutations. This is the possible reason why mexiletine maybe promising to treat CIDP symptoms.
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Stunnenberg BC, Raaphorst J, Groenewoud HM, Statland JM, Griggs RC, Woertman W, Stegeman DF, Timmermans J, Trivedi J, Matthews E, Saris CGJ, Schouwenberg BJ, Drost G, van Engelen BGM, van der Wilt GJ. Effect of Mexiletine on Muscle Stiffness in Patients With Nondystrophic Myotonia Evaluated Using Aggregated N-of-1 Trials. JAMA 2018; 320:2344-2353. [PMID: 30535218 PMCID: PMC6583079 DOI: 10.1001/jama.2018.18020] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE In rare diseases it is difficult to achieve high-quality evidence of treatment efficacy because of small cohorts and clinical heterogeneity. With emerging treatments for rare diseases, innovative trial designs are needed. OBJECTIVE To investigate the effectiveness of mexiletine in nondystrophic myotonia using an aggregated N-of-1 trials design and compare results between this innovative design and a previously conducted RCT. DESIGN, SETTING, AND PARTICIPANTS A series of aggregated, double-blind, randomized, placebo-controlled N-of-1-trials, performed in a single academic referral center. Thirty Dutch adult patients with genetically confirmed nondystrophic myotonia (38 patients screened) were enrolled between February 2014 and June 2015. Follow-up was completed in September 2016. INTERVENTIONS Mexiletine (600 mg daily) vs placebo during multiple treatment periods of 4 weeks. MAIN OUTCOMES AND MEASURES Reduction in daily-reported muscle stiffness on a scale of 1 to 9, with higher scores indicating more impairment. A Bayesian hierarchical model aggregated individual N-of-1 trial data to determine the posterior probability of reaching a clinically meaningful effect of a greater than 0.75-point difference. RESULTS Among 30 enrolled patients (mean age, 43.4 [SD, 15.24] years; 22% men; 19 CLCN1 and 11 SCN4A genotype), 27 completed the study and 3 dropped out (1 because of a serious adverse event). In 24 of the 27 completers, a clinically meaningful treatment effect was found. In the Bayesian hierarchical model, mexiletine resulted in a 100% posterior probability of reaching a clinically meaningful reduction in self-reported muscle stiffness for the nondystrophic myotonia group overall and the CLCN1 genotype subgroup and 93% posterior probability for the SCN4A genotype subgroup. In the total nondystrophic myotonia group, the median muscle stiffness score was 6.08 (interquartile range, 4.71-6.80) at baseline and was 2.50 (95% credible interval [CrI], 1.77-3.24) during the mexiletine period and 5.56 (95% CrI, 4.73-6.39) during the placebo period; difference in symptom score reduction, 3.06 (95% CrI, 1.96-4.15; n = 27) favoring mexiletine. The most common adverse event was gastrointestinal discomfort (21 mexiletine [70%], 1 placebo [3%]). One serious adverse event occurred (1 mexiletine [3%]; allergic skin reaction). Using frequentist reanalysis, mexiletine compared with placebo resulted in a mean reduction in daily-reported muscle stiffness of 3.12 (95% CI, 2.46-3.78), consistent with the previous RCT treatment effect of 2.69 (95% CI, 2.12-3.26). CONCLUSIONS AND RELEVANCE In a series of N-of-1 trials of mexiletine vs placebo in patients with nondystrophic myotonia, there was a reduction in mean daily-reported muscle stiffness that was consistent with the treatment effect in a previous randomized clinical trial. These findings support the efficacy of mexiletine for treatment of nondystrophic myotonia as well as the feasibility of N-of-1 trials for assessing interventions in some chronic rare diseases. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT02045667.
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Affiliation(s)
- Bas C. Stunnenberg
- Department of Neurology, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Joost Raaphorst
- Department of Neurology, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Neurology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Hans M. Groenewoud
- Department of Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
| | | | - Robert C. Griggs
- Department of Neurology, University of Rochester Medical Center, Rochester, New York
| | - Willem Woertman
- Department of Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Dick F. Stegeman
- Department of Neurology, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Janneke Timmermans
- Department of Cardiology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Jaya Trivedi
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, Texas
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Christiaan G. J. Saris
- Department of Neurology, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Bas J. Schouwenberg
- Department of Pharmacology–Toxicology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Gea Drost
- University of Groningen, Department of Neurology and Neurosurgery, University Medical Center Groningen, Groningen, the Netherlands
| | - Baziel G. M. van Engelen
- Department of Neurology, Donders Institute for Brain Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Gert Jan van der Wilt
- Department of Health Evidence, Radboud University Medical Center, Nijmegen, the Netherlands
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Liu J, Bayer JD, Aschar-Sobbi R, Wauchop M, Spears D, Gollob M, Vigmond EJ, Tsushima R, Backx PH, Chauhan VS. Complex interactions in a novel SCN5A compound mutation associated with long QT and Brugada syndrome: Implications for Na+ channel blocking pharmacotherapy for de novo conduction disease. PLoS One 2018; 13:e0197273. [PMID: 29791480 PMCID: PMC5965851 DOI: 10.1371/journal.pone.0197273] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 04/30/2018] [Indexed: 11/29/2022] Open
Abstract
Background The SCN5A mutation, P1332L, is linked to a malignant form of congenital long QT syndrome, type 3 (LQT3), and affected patients are highly responsive to the Na+ channel blocking drug, mexiletine. In contrast, A647D is an atypical SCN5A mutation causing Brugada syndrome. An asymptomatic male with both P1332L and A647D presented with varying P wave/QRS aberrancy and mild QTc prolongation which did not shorten measurably with mexiletine. Objective We characterized the biophysical properties of P1332L, A647D and wild-type (WT) Na+ channels as well as their combinations in order to understand our proband’s phenotype and to guide mexilitine therapy. Methods Na+ channel biophysics and mexilitine-binding kinetics were assessed using heterologous expression studies in CHO-K1 cells and human ventricular myocyte modeling. Results Compared to WT, P1332L channels displayed a hyperpolarizing shift in inactivation, slower inactivation and prominent late Na+ currents (INa). While A647D had no effect on the biophysical properties of INa, it reduced peak and late INa density when co-expressed with either WT or P1332L. Additionally, while P1332L channels had greater sensitivity to block by mexiletine compared to WT, this was reduced in the presence of A647D. Modelling studies revealed that mixing P1332L with A647D channels, action potential durations were shortened compared to P1332L, while peak INa was reduced compared to either A647D coexpressing with WT or WT alone. Conclusions While A647D mitigates the lethal LQT3 phenotype seen with P1332L, it also reduces mexilitine sensitivity and decreases INa density. These results explain our proband’s mild repolarization abnormality and prominent conduction defect in the atria and ventricles, but also suggest that expression of P1332L with A647D yields a novel disease phenotype for which mexiletine pharmacotherapy is no longer suitable.
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Affiliation(s)
- Jie Liu
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Jason D. Bayer
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University Foundation, Pessac, France
- University of Bordeaux, IMB, UMR 5251, Talance, France
| | | | - Marianne Wauchop
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Danna Spears
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Michael Gollob
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Edward J. Vigmond
- Electrophysiology and Heart Modeling Institute (LIRYC), Bordeaux University Foundation, Pessac, France
- University of Bordeaux, IMB, UMR 5251, Talance, France
| | - Robert Tsushima
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Peter H. Backx
- Department of Biology, York University, Toronto, Ontario, Canada
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
- * E-mail: (PB); (VC)
| | - Vijay S. Chauhan
- Peter Munk Cardiac Center, Division of Cardiology, University Health Network, Toronto, Ontario, Canada
- * E-mail: (PB); (VC)
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Ginanneschi F, Mignarri A, Lucchiari S, Ulzi G, Comi GP, Rossi A, Dotti MT. Neuromuscular excitability changes produced by sustained voluntary contraction and response to mexiletine in myotonia congenita. Neurophysiol Clin 2017; 47:247-252. [PMID: 28153715 DOI: 10.1016/j.neucli.2017.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/03/2017] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE To investigate the cause of transient weakness in myotonia congenita (MC) and the mechanism of action of mexiletine in reducing weakness. METHODS The changes in neuromuscular excitability produced by 1min of maximal voluntary contractions (MVC) were measured on the amplitude of compound muscle action potentials (CMAP) in two patients with either recessive or dominant MC, compared to control values obtained in 20 healthy subjects. Measurements were performed again in MC patients after mexiletine therapy. RESULTS Transient reduction in maximal CMAP amplitude lasting several minutes after MVC was evident in MC patients, whereas no change was observed in controls. Mexiletine efficiently reduced this transient CMAP depression in both patients. DISCUSSION Transient CMAP depression following sustained MVC may represent the electrophysiological correlate of the weakness clinically experienced by the patients. In MC, the low chloride conductance could induce self-sustaining action potentials after MVC, determining progressive membrane depolarization and a loss of excitability of muscle fibers, thus resulting in transient paresis. Mexiletine may prevent conduction block due to excessive membrane depolarization, thus reducing the transient CMAP depression following sustained MVC.
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Affiliation(s)
- Federica Ginanneschi
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy.
| | - Andrea Mignarri
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy
| | - Sabrina Lucchiari
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Gianna Ulzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessandro Rossi
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy
| | - Maria Teresa Dotti
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy
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Abstract
BACKGROUND Chronic pain can often occur after surgery, substantially impairing patients' health and quality of life. It is caused by complex mechanisms that are not yet well understood. The predictable nature of most surgical procedures has allowed for the conduct of randomized controlled trials of pharmacological interventions aimed at preventing chronic postsurgical pain. OBJECTIVES The primary objective was to evaluate the efficacy of systemic drugs for the prevention of chronic pain after surgery by examining the proportion of patients reporting pain three months or more after surgery. The secondary objective was to evaluate the safety of drugs administered for the prevention of chronic pain after surgery. SEARCH METHODS We identified randomized controlled trials (RCTs) of various systemically administered drugs for the prevention of chronic pain after surgery from CENTRAL, MEDLINE, EMBASE and handsearches of other reviews and trial registries. The most recent search was performed on 17 July 2013. SELECTION CRITERIA Included studies were double-blind, placebo-controlled, randomized trials involving adults and evaluating one or more drugs administered systemically before, during or after surgery, or both, which measured pain three months or more after surgery. DATA COLLECTION AND ANALYSIS Data collected from each study included the study drug name, dose, route, timing and duration of dosing; surgical procedure; proportion of patients reporting any pain three months or more after surgery, reporting at least 4/10 or moderate to severe pain three months or more after surgery; and proportion of participants dropping out of the study due to treatment-emergent adverse effects. MAIN RESULTS We identified 40 RCTs of various pharmacological interventions including intravenous ketamine (14 RCTs), oral gabapentin (10 RCTs), oral pregabalin (5 RCTs), non-steroidal anti-inflammatories (3 RCTs), intravenous steroids (3 RCTs), oral N-methyl-D-aspartate (NMDA) blockers (3 RCTs), oral mexiletine (2 RCTs), intravenous fentanyl (1 RCT), intravenous lidocaine (1 RCT), oral venlafaxine (1 RCT) and inhaled nitrous oxide (1 RCT). Meta-analysis suggested a modest but statistically significant reduction in the incidence of chronic pain after surgery following treatment with ketamine but not gabapentin or pregabalin. Results with ketamine should be viewed with caution since most of the included trials were small (that is < 100 participants per treatment arm), which could lead to the overestimation of treatment effect. AUTHORS' CONCLUSIONS Additional evidence from better, well designed, large-scale trials is needed in order to more rigorously evaluate pharmacological interventions for the prevention of chronic pain after surgery. Furthermore, available evidence does not support the efficacy of gabapentin, pregabalin, non-steroidal anti-inflammatories, intravenous steroids, oral NMDA blockers, oral mexiletine, intravenous fentanyl, intravenous lidocaine, oral venlafaxine or inhaled nitrous oxide for the prevention of chronic postoperative pain.
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Gao Y, Xue X, Hu D, Liu W, Yuan Y, Sun H, Li L, Timothy KW, Zhang L, Li C, Yan GX. Inhibition of Late Sodium Current by Mexiletine. Circ Arrhythm Electrophysiol 2013; 6:614-22. [PMID: 23580742 DOI: 10.1161/circep.113.000092] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yuanfeng Gao
- Heart Center, Peking University People's Hospital, Beijing, People's Republic of China
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Abstract
Long QT syndrome (LQTs) is an uncommon genetic disease causing sudden cardiac death with Torsade de Pointes (TdP). The first line drug treatment has been known to be β-blocker. We encountered a 15-year-old female student with LQTs who had prolonged QTc and multiple episodes of syncope or agonal respiration during sleep. Although her T wave morphology in surface electrocardiography resembled LQTs type 1, her clinical presentation was unusual. During the epinephrine test, TdP was aggravated during β-blocker medication, but alleviated by sodium channel blocker (mexiletine). Therefore, she underwent implantable cardioverter defibrillator implantation.
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Affiliation(s)
- Junbeom Park
- Department of Cardiology, Yonsei University Health System, Seoul, Korea
| | - Sook Kyoung Kim
- Department of Cardiology, Yonsei University Health System, Seoul, Korea
| | - Hui-Nam Pak
- Department of Cardiology, Yonsei University Health System, Seoul, Korea
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Statland JM, Bundy BN, Wang Y, Rayan DR, Trivedi JR, Sansone VA, Salajegheh MK, Venance SL, Ciafaloni E, Matthews E, Meola G, Herbelin L, Griggs RC, Barohn RJ, Hanna MG. Mexiletine for symptoms and signs of myotonia in nondystrophic myotonia: a randomized controlled trial. JAMA 2012; 308:1357-65. [PMID: 23032552 PMCID: PMC3564227 DOI: 10.1001/jama.2012.12607] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
CONTEXT Nondystrophic myotonias (NDMs) are rare diseases caused by mutations in skeletal muscle ion channels. Patients experience delayed muscle relaxation causing functionally limiting stiffness and pain. Mexiletine-induced sodium channel blockade reduced myotonia in small studies; however, as is common in rare diseases, larger studies of safety and efficacy have not previously been considered feasible. OBJECTIVE To determine the effects of mexiletine for symptoms and signs of myotonia in patients with NDMs. DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blind, placebo-controlled 2-period crossover study at 7 neuromuscular referral centers in 4 countries of 59 patients with NDMs conducted between December 23, 2008, and March 30, 2011, as part of the National Institutes of Health-funded Rare Disease Clinical Research Network. INTERVENTION Oral 200-mg mexiletine or placebo capsules 3 times daily for 4 weeks, followed by the opposite intervention for 4 weeks, with 1-week washout in between. MAIN OUTCOME MEASURES Patient-reported severity score of stiffness recorded on an interactive voice response (IVR) diary (scale of 1 = minimal to 9 = worst ever experienced). Secondary end points included IVR-reported changes in pain, weakness, and tiredness; clinical myotonia assessment; quantitative measure of handgrip myotonia; and Individualized Neuromuscular Quality of Life summary quality of life score (INQOL-QOL, percentage of maximal detrimental impact). RESULTS Mexiletine significantly improved patient-reported severity score stiffness on the IVR diary. Because of a statistically significant interaction between treatment and period for this outcome, primary end point is presented by period (period 1 means were 2.53 for mexiletine and 4.21 for placebo; difference, -1.68; 95% CI, -2.66 to -0.706; P < .001; period 2 means were 1.60 for mexiletine and 5.27 for placebo; difference, -3.68; 95% CI, -3.85 to -0.139; P = .04). Mexiletine improved the INQOL-QOL score (mexiletine, 14.0 vs placebo, 16.7; difference, -2.69; 95% CI, -4.07 to -1.30; P < .001) and decreased handgrip myotonia on clinical examination (mexiletine, 0.164 seconds vs placebo, 0.494 seconds; difference, -0.330; 95% CI, -0.633 to -0.142; P < .001). The most common adverse effect was gastrointestinal (9 mexiletine and 1 placebo). Two participants experienced transient cardiac effects that did not require stopping the study (1 in each group). One serious adverse event was determined to be not study related. CONCLUSION In this preliminary study of patients with NDMs, the use of mexiletine compared with placebo resulted in improved patient-reported stiffness over 4 weeks of treatment, despite some concern about the maintenance of blinding. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00832000.
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Affiliation(s)
- Jeffrey M Statland
- Department of Neurology, University of Rochester Medical Center, Rochester, NY
| | - Brian N Bundy
- Pediatrics Epidemiology Center, University of South Florida, Tampa, FL
| | - Yunxia Wang
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS
| | - Dipa Raja Rayan
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Jaya R Trivedi
- Department of Neurology, University of Texas Southwestern, Dallas, TX
| | - Valeria A Sansone
- Department of Neurology, University of Milan, IRCCS Policlinico San Donato, Milan, Italy
| | - Mohammad K Salajegheh
- Department of Neurology, Neuromuscular Division, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA
| | - Shannon L. Venance
- Department of Clinical Neurological Sciences, London Health Sciences Centre, London, ON Canada
| | - Emma Ciafaloni
- Department of Neurology, University of Rochester Medical Center, Rochester, NY
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - Giovanni Meola
- Department of Neurology, University of Milan, IRCCS Policlinico San Donato, Milan, Italy
| | - Laura Herbelin
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS
| | - Robert C Griggs
- Department of Neurology, University of Rochester Medical Center, Rochester, NY
| | - Richard J Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, UK
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Abstract
Erythromelalgia is a rare condition characterized by burning pain, erythema, swelling, and increased temperature usually in the extremities. We present an unusual presentation of erythromelalgia of the ears in a patient who has been refractory to multiple therapies and in whom relief of symptoms was achieved with the use of mexiletine. A review of clinical presentation, pathophysiology, and therapeutic options are presented.
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Affiliation(s)
- Alejandra C Vivas
- Department of Dermatology and Cutaneous Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
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Berninger E, Nordmark J, Alván G, Karlsson KK, Idrizbegovic E, Meurling L, Al-Shurbaji A. The effect of intravenously administered mexiletine on tinnitus-a pilot study. Int J Audiol 2009; 45:689-96. [PMID: 17132557 DOI: 10.1080/14992020600765209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The effect of intravenously administered mexiletine on subjective tinnitus and hearing was studied in six patients, who initially responded positively to lidocaine. Distinct mexiletine-induced decreases in tinnitus loudness were demonstrated in three subjects, as reflected by maximum VAS (visual analogue scale) level reduction of 34%, 95%, and 100%, respectively. One subject reported change in tinnitus pitch, another one showed a slight (18% on VAS) tinnitus reduction, and one subject disclosed no effect. Side effects were seen only during one of seven infusions. Mexiletine induced shifts in pure-tone threshold, transient evoked otoacoustic emission, and acoustic reflex threshold, probably reflecting a reversible interference in the function of organ of Corti. The concentration effect relationship remained unclear and no general 'therapeutic' level could be identified. This study confirms the effect of mexiletine on the auditory function and its potential as a possible therapeutic agent or a model for further development in tinnitus pharmacotherapy.
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Affiliation(s)
- Erik Berninger
- Department of Audiology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
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Eroğlu S, Ozin B, Ozbiçer S, Müderrisoğlu H. A case of myotonic dystrophy presenting with ventricular tachycardia and atrial fibrillation. Turk Kardiyol Dern Ars 2009; 37:337-340. [PMID: 19875908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Myotonic dystrophy type 1 (MD1) is an autosomal dominant disorder characterized by myotonia, progressive muscular weakness, cataract, and cardiac involvement. Cardiac involvement is common and includes conduction system abnormalities, supraventricular and ventricular arrhythmias, and less frequently, myocardial dysfunction and ischemic heart disease. A 54-year-old woman with a previous diagnosis of MD1 was admitted with palpitation, blood pressure of 157/118 mmHg, and a heart rate of 220 beats/min. Electrocardiography (ECG) showed ventricular tachycardia. Within minutes, hemodynamic collapse developed and electrical cardioversion was performed. Immediately following cardioversion, ECG showed atrial fibrillation, a slightly prolonged QT interval, and intraventricular conduction delay. After intravenous infusion of amiodarone, the rhythm converted to sinus. Transthoracic echocardiography showed significantly depressed left ventricular function, an ejection fraction of 25%, and normal coronary arteries. During electrophysiological study, atrium-His interval and His-ventricle interval were 120 msec was 54 msec, respectively, and monomorphic ventricular flutter was induced. An implantable cardioverter-defibrillator was placed. She was discharged in sinus rhythm.
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Affiliation(s)
- Serpil Eroğlu
- Department of Cardiology, Medicine Faculty of Başkent University, Ankara, Turkey.
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Abstract
Maxiletine, a new drug effective in the treatment of ventricular arrhythmias, was given to 20 patients for approximately 2 years. The study was designed to investigate the nature and prevalence of side-effects during long-term therapy, and the degree of correlation between such effects and the serum levels of the drug. The methodology used to determine the serum level is described. Mexiletine was well tolerated and serious side-effects were not seen. In particular, antinuclear factor was not detected during the treatment period. The serum level of mexiletine was easily maintained within the therapeutic range, and most side-effects correlated closely with the drug level. Mexiletine appears to be an effective alternative to currently available antiarrhythmic agents.
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Abstract
BACKGROUND Mexiletine (Mex) has been proposed as a gene-specific therapy for patients with long-QT syndrome type 3 (LQT3) caused by mutations in the cardiac sodium channel gene (SCN5A). The degree of QT shortening and the protection from arrhythmias vary among patients harboring different mutations. We tested whether the clinical response to Mex in LQT3 could be predicted by the biophysical properties of the different mutations. METHODS AND RESULTS We identified 4 SCN5A mutations in 5 symptomatic LQT3 patients with different responses to Mex (6 to 8 mg . kg(-1) . d(-1)). We classified the mutations as sensitive to Mex (P1332L, R1626P; >/=10% of QTc shortening and QTc <500 ms or no arrhythmias) or insensitive to Mex (S941N, M1652R; negligible or no QTc shortening and sudden death). We measured Na(+) current from HEK 293 cells transfected with wild-type (WT) or mutant Nav1.5. All mutations showed impaired inactivation of Na(+) current, but the mutations identified in patient responders to Mex (P1332L, R1626P) showed a hyperpolarizing shift of V(1/2) of steady-state inactivation. Furthermore, Mex produced use-dependent block with the order R1626P=P1332L>S941N=WT>M1652R, suggesting that Mex-sensitive mutants present prolonged recovery from Mex block. CONCLUSIONS We propose that voltage dependence of channel availability and shifts of V(1/2) of steady-state inactivation correlate with the clinical response observed in LQT3 patients. This supports the view that the response to Mex is mutation specific and that in vitro testing may help to predict the response to therapy in LQT3.
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Affiliation(s)
- Yanfei Ruan
- Molecular Cardiology, Fondazione Salvatore Maugeri, Via Maugeri 10/10A, 27100 Pavia, Italy
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Ates O, Cayli SR, Gurses I, Turkoz Y, Tarim O, Cakir CO, Kocak A. Comparative neuroprotective effect of sodium channel blockers after experimental spinal cord injury. J Clin Neurosci 2007; 14:658-65. [PMID: 17532502 DOI: 10.1016/j.jocn.2006.03.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2006] [Accepted: 03/27/2006] [Indexed: 10/23/2022]
Abstract
Spinal cord injury (SCI) results in loss of function below the lesion. Secondary injury following the primary impact includes a number of biochemical and cellular alterations leading to tissue necrosis and cell death. Influx of Na(+) ions into cells has been postulated to be a key early event in the pathogenesis of secondary traumatic and ischemic central nervous system injury. Previous studies have shown that some voltage-sensitive sodium channel blockers provide powerful neuroprotection. The purpose of the present study was to compare the neuroprotective effect of three sodium channel blockers-mexiletine, phenytoin and riluzole--after SCI. Ninety rats were randomly and blindly divided into five groups of 18 rats each: sham-operated group, trauma group (bolus injection of 1 mL physiological saline intraperiteonally [i.p.]), mexiletine treatment group (80 mg/kg, i.p.), phenytoin treatment group (200 mg/kg, i.p.) and riluzole treatment group (8 mg/kg, i.p.). Twenty-four hours after injury, the rats were killed for determination of spinal cord water content and malondialdehyde (MDA) levels. Motor function scores of six rats from each group were evaluated weekly for six weeks. Then the rats were killed for histopathological assessment. Although all the treatment groups revealed significantly lower MDA levels and spinal cord edema than the trauma group (p<0.05), the riluzole and mexiletine treatment groups were better than the phenytoin treatment group. In the chronic stage, riluzole and mexiletine treatment achieved better results for neurobehavioral and histopathological recovery than phenytoin treatment. In conclusion, all the tested Na(+) blockers had a neuroprotective effect after SCI; riluzole and mexiletine were superior to phenytoin.
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Affiliation(s)
- Ozkan Ates
- Inonu University, School of Medicine, Department of Neurosurgery, Turgut Ozal Medical Center, 44069 Malatya, Turkey.
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Garcia-Touchard A, Somers VK, Kara T, Nykodym J, Shamsuzzaman A, Lanfranchi P, Ackerman MJ. Ventricular ectopy during REM sleep: implications for nocturnal sudden cardiac death. ACTA ACUST UNITED AC 2007; 4:284-8. [PMID: 17457352 PMCID: PMC3332547 DOI: 10.1038/ncpcardio0877] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Accepted: 01/05/2007] [Indexed: 11/09/2022]
Abstract
BACKGROUND A young adult female presented with syncope and periodic weakness. A 12-lead electrocardiogram showed frequent premature ventricular contractions and prolonged QU interval. Repetitive runs of nonsustained ventricular tachycardia were recorded at night. INVESTIGATIONS Electromyography, muscle biopsy, MRI, echocardiography, exercise stress testing using Bruce protocol with microvolt T-wave alternans testing, 24 h Holter monitoring, electrophysiological testing and examination of the effects of sleep and sleep stage on the patient's ventricular arrhythmias. DIAGNOSIS Type 1 Andersen-Tawil syndrome, (also known as type 7 long QT syndrome). Severe ventricular arrhythmia was observed, predominantly during rapid eye movement sleep. We speculate that the autonomic instability present during rapid eye movement sleep precipitates increasing vulnerability to sleep-related ventricular tachycardia. MANAGEMENT Beta-blocker therapy alone, subsequently combined with mexiletine treatment.
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Affiliation(s)
| | | | | | | | | | | | - Michael J Ackerman
- Correspondence Mayo Clinic College of Medicine, Mayo Clinic Windland Smith Rice Sudden Death Genomics Laboratory, Guggenheim 501, 200 First Street SW, Rochester, MN 55905, USA
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Abstract
"Burning mouth syndrome" (BMS) refers to a chronic orofacial pain disorder usually unaccompanied by mucosal lesions or other clinical signs of organic disease. BMS is typically characterized by a continuous, spontaneous, and often intense burning sensation as if the mouth or tongue were scalded or on fire. Burning mouth syndrome is a relatively common condition. The estimated prevalence of BMS reported in recent studies ranges between 0.7 and 4.6% of the general population. About 1.3 million American adults, mostly women in the postmenopausal period, are afflicted with BMS. The etiology of this disorder is poorly understood even though new evidence for a possible neuropathic pathogenesis of idiopathic BMS is emerging. Burning mouth syndrome may present as an idiopathic condition (primary BMS type) distinct from the symptom of oral burning that can potentially arise from various local or systemic abnormalities (secondary BMS type), including nutritional deficiencies, hormonal changes associated with menopause, local oral infections, denture-related lesions, xerostomia, hypersensitivity reactions, medications, and systemic diseases including diabetes mellitus. In more than a third of patients, multiple, concurrent causes of BMS may be identified. It is important to note that the diagnosis of BMS should be established only after all other possible causes have been ruled out. Professional delay in diagnosing, referring, and appropriately managing of BMS patients occurs frequently. Treatment should be tailored to each patient and it is recommended to practice the treatment in a multidisciplinary facility. This article discusses our current understanding of the etiology and pathogenesis of BMS. The authors have tried to emphasize new pharmacological approaches to manage this challenging disorder.
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Affiliation(s)
- Alexander Maltsman-Tseikhin
- Center for Pain Medicine, Tel-Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
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Abstract
Lidocaine is a use-dependent sodium channel blocker that produces analgesia when administered intravenously to patients with neuropathic pain. This article reviews the role and limitations of intravenous lidocaine infusions for neuropathic pain. Lidocaine infusions rarely provide relief that persists significantly beyond the duration of the infusion. Diagnostically, systemic lidocaine may help establish the presence of neuropathic pain and the responsivity to oral sodium channel blockade. However, the data supporting diagnostic infusions remain sparse. Therapeutically, infusions should generally be restricted to patients with neuropathic pain who are unable to take oral medication.
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Affiliation(s)
- Ian Carroll
- Stanford University School of Medicine, 780 Welch Road, Suite 208E, Palo Alto, CA 94034, USA.
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Sen O, Caner H, Aydin MV, Ozen O, Atalay B, Altinors N, Bavbek M. The effect of mexiletine on the level of lipid peroxidation and apoptosis of endothelium following experimental subarachnoid hemorrhage. Neurol Res 2007; 28:859-63. [PMID: 17288746 DOI: 10.1179/016164106x115099] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVE The role of apoptosis in etiopathogenesis of vasospasm is not clearly understood yet. It is widely accepted that protection of the endothelial cells from the process of apoptosis could have beneficial effects on cerebral vasospasm after subarachnoid hemorrhage (SAH). Mexiletine blocks sodium and calcium channels and activates ATP-sensitive K(+) channels. Moreover, mexiletine is known to have potent antioxidant effects through inhibiting free-radical production. METHODS Twenty-one rabbits were allocated into three groups randomly. Group I was sham operated group (n=7). SAH occurred but no medication was given to the Group II rabbits (SAH only group) (n=7). Mexiletine (50 mg/kg, b.i.d., i.p.) was administered just before SAH and continued until 48 hours following SAH to the Group III rabbits (Mexiletine treated group) (n=7). The ApopTag peroxidase in situ apoptosis detection kit (Serologicals Corporation, former Intergen) was used to demonstrate apoptosis in a cross section of basillary arteries. Thiobarbituric acid reactive material was used to determine the lipid peroxidation levels. RESULTS There was a statistically significant difference between lipid peroxidation product levels of the control and SAH only groups (p<0.05). The level of lipid peroxidation production in Mexiletine treated group was significantly lower compared with SAH only group (p<0.05) but not significantly higher than the control group (p>0.05). DISCUSSION In the present study we investigated the antioxidant action of mexiletine on apoptosis of endothelium following a rabbit SAH model. This experimental study directly suggested that lipid peroxidation is an important step in development of apoptosis in endothelial cells and prevention of structural integrity of endothelial cell should play a beneficial role in attenuation of cerebral vasospasm. Mexiletine treatment prevented the increase in lipid peroxidation and cerebral vasospasm. Examination of endothelial cells by staining specific for apoptosis demonstrated significant protection of cell integrity in the treated group.
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Affiliation(s)
- Orhan Sen
- Department of Neurosurgery, Baskent University, Ankara, Turkey.
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Tian XL, Cheng Y, Zhang T, Liao MLC, Yong SL, Wang QK. Optical mapping of ventricular arrhythmias in LQTS mice with SCN5A mutation N1325S. Biochem Biophys Res Commun 2006; 352:879-83. [PMID: 17157817 PMCID: PMC2699586 DOI: 10.1016/j.bbrc.2006.11.106] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Accepted: 11/17/2006] [Indexed: 10/23/2022]
Abstract
Transgenic expression of SCN5A mutation N1325S creates a mouse model for type-3 long QT syndrome (LQT3), TG-NS/LQT3. Optical mapping is a high temporal and spatial resolution fluorescence mapping system that records 256 action potentials simultaneously in a Langendorff-perfused heart. Here for the first-time, we provide a spatial view of VT in a genetic LQT3 model using optical mapping. Spontaneous VT was detected in TG-NS/LQT3 hearts, but not in littermate control hearts. VT was initiated primarily by activation of a new firing focus as well as functional conduction block of new activation waves. New firing was initiated at many different Loci in the heart, suggesting that "increased automaticity" is a key mechanism for initiation of VT. The sustained VT was maintained by a reentry mechanism. Nifedipine, an L-type calcium channel blocker, decreased the frequency of VT, indicating the involvement of abnormalities of the calcium homeostasis in the genesis of VT in TG-NS/LQT3 mice.
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Affiliation(s)
- Xiao-Li Tian
- Department of Molecular Cardiology, Lerner Research Institute and Center for Cardiovascular Genetics, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
| | - Yuanna Cheng
- Department of Cardiovascular Medicine, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
| | - Teng Zhang
- Department of Molecular Cardiology, Lerner Research Institute and Center for Cardiovascular Genetics, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
| | - Mei-Ling Chang Liao
- Department of Cardiovascular Medicine, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
| | - Sandro L. Yong
- Department of Molecular Cardiology, Lerner Research Institute and Center for Cardiovascular Genetics, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
| | - Qing K. Wang
- Department of Molecular Cardiology, Lerner Research Institute and Center for Cardiovascular Genetics, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
- Department of Cardiovascular Medicine, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195, USA
- Corresponding author. Tel.: +1 216 445 5070; Fax: +1 216 636-1231. E-mail address: (Q.K. Wang)
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Ozen IO, Vural IM, Moralioğlu S, Barun S, Ercan ZS, Sarioğlu Y. Effects of Mexiletine on Electrical Field Stimulation-Induced Contractile Responses in the Ipsilateral and Contralateral Vasa Deferentia after Unilateral Testicular Torsion/Detorsion. Eur Surg Res 2006; 38:423-9. [PMID: 16902305 DOI: 10.1159/000094980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2006] [Accepted: 06/26/2006] [Indexed: 11/19/2022]
Abstract
AIM To investigate testicular torsion-induced changes on the electrical field stimulation (EFS)-induced contractions in rabbit vasa deferentia and to evaluate the effect of mexiletine. METHODS 18 male New Zealand albino rabbits were used in this experiment. Rabbits were divided into three groups: (1) control group (n = 6); (2) torsion group (n = 6), and (3) mexiletine group (n = 6). In the control group, vasa deferentia on both sides were harvested. In the torsion and mexiletine groups, the left testes of the rabbits were subjected to 720 degrees of clockwise torsion for 2 h and then detorsion was performed. In the mexiletine group, 50 mg/kg i.p. mexiletine was administered 1 h before detorsion. Following 24 h of the torsion, vasa deferentia on both sides were harvested and 2-cm strips including both the prostatic and epididymal portions were prepared to record EFS-induced contractions. RESULTS Testicular torsion caused a significant inhibition in both phases of EFS-induced biphasic contractions of the ipsi- and contralateral vasa deferentia. Mexiletine treatment did not affect these inhibitory responses. Torsion/detorsion of the spermatic cord did not alter exogenously applied noradrenaline-induced contractions in both vasa deferentia. However, KCl-induced contractions diminished significantly in ipsilateral vas deferens of the torsion group and mexiletine restored this inhibition. CONCLUSIONS Unilateral testicular torsion/detorsion leads to inhibition in both phases of EFS-induced biphasic contractions of the ipsi- and contralateral vasa deferentia by causing a defect in presynaptic nerve transmission. However, mexiletine has no effect on this inhibition. Inhibition of the KCl-induced contractions in the ipsilateral vas deferens, which indicates postsynaptic tissue damage, is restored by administering mexiletine 1 h prior to detorsion.
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Affiliation(s)
- Ibrahim Onur Ozen
- Department of Pediatric Surgery, Faculty of Medicine, Gazi University, Beşevler Ankara, Turkey.
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Chrestian N, Puymirat J, Bouchard JP, Dupré N. Myotonia congenita--a cause of muscle weakness and stiffness. ACTA ACUST UNITED AC 2006; 2:393-9; quiz following 399. [PMID: 16932590 DOI: 10.1038/ncpneuro0239] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Accepted: 04/25/2006] [Indexed: 11/08/2022]
Abstract
BACKGROUND A 56-year-old woman was referred to a neurogenetic clinic with a history of stiffness and transient weakness. A previous needle electromyogram had confirmed the presence of myotonia, but a muscle biopsy had revealed no evidence of dystrophy. INVESTIGATIONS Neurological examination, electrophysiological studies and genetic testing. DIAGNOSIS Recessive myotonia congenita (Becker's disease). MANAGEMENT Explanation of the nature of the disease and treatment with mexiletine 200 mg twice daily.
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Abstract
Congenital long-QT syndrome with 2:1 atrioventricular block presenting in the perinatal period is rare, has a poor prognosis, and leads to high risk for lethal ventricular arrhythmic events. An implantable cardioverter-defibrillator seems to be the most effective treatment in the prevention of arrhythmic sudden cardiac death in patients with long-QT syndrome. Technical limitations and risks associated with implantable cardioverter-defibrillators in asymptomatic infants is considered too great to justify use for primary prophylaxis against sudden cardiac death. In this case report we describe the first successful parental use of an automated external defibrillator prescribed for primary prophylaxis against sudden cardiac death in an infant with long-QT syndrome.
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Affiliation(s)
- Abhay Divekar
- Section of Pediatric Cardiology, Department of Pediatrics, Health Sciences Center, University of Manitoba, FE-241, 685 William Ave, Winnipeg, Manitoba, Canada R3E 0Z2.
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Ebell MH. Systemic lidocaine or mexiletine for neuropathic pain. Am Fam Physician 2006; 74:79. [PMID: 16848381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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Abstract
HISTORY AND CLINICAL FINDINGS A 63-year-old woman was admitted because of abdominal pain for 12 months, associated with an increasing abdominal distension. One month before a gastroscopy had revealed mild gastritis. The taking of proton pump inhibitors did not improve her symptoms. There was no relevant neurological or psychiatric past history. INVESTIGATIONS Ultrasound and laboratory tests demonstrated a fatty liver and increased serum levels of lipoproteins. Magnetic resonance imaging revealed an increase in subcutaneous and intraperitoneal adipose tissue. Endoscopy did not show any additional significant findings. DIAGNOSIS AND TREATMENT The patient had adiposis dolorosa. Initially she was given daily a combination of mexiletine 400 mg and 75 mg Amitriptyline. After a few days the ailment decreased and had disappeared completely after one week. Three months later the dosage was reduced to 100 mg mexiletine and 25 mg Amitriptyline daily. After another two months all medication was discontinued. At follow-up after 12 months the symptoms had not recurred. CONCLUSION This case demonstrates that abdominal pain is not always caused by diseases of the visceral hollow organs. It must also be borne in mind that abdominal pain may be associated with adipose tissue, as is the case in adiposis dolorosa. The disease can be successfully treated, as in this case, using a combination of mexiletine and Amitriptyline.
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Affiliation(s)
- J Tiesmeier
- Medizinische Klinik II, Krankenhaus Bad Oeynhausen
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Head CE, Balasubramaniam R, Thomas G, Goddard CA, Lei M, Colledge WH, Grace AA, Huang CLH. Paced electrogram fractionation analysis of arrhythmogenic tendency in DeltaKPQ Scn5a mice. J Cardiovasc Electrophysiol 2006; 16:1329-40. [PMID: 16403066 DOI: 10.1111/j.1540-8167.2005.00200.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Gain-of-function mutations within Scn5a, including the DeltaKPQ 1505-1507 deletion in the inactivation domain compromising myocardial repolarization, are implicated in human long QT 3 syndrome (LQT3), associated with ventricular arrhythmogenesis and sudden death. METHODS AND RESULTS Patch clamp studies on isolated ventricular Scn5a+/Delta myocytes from DeltaKPQ mice produced by homologous recombination in embryonic stem (ES) cells confirmed such altered electrophysiological properties of the mutant channel. Programmed electrical stimulation (PES) with decremental pacing from the basal right ventricular epicardial surface and paced electrogram fractionation analysis (PEFA) of electrograms recorded from the basal left ventricular epicardial surface of Langendorff-perfused whole heart preparations demonstrated ventricular tachycardia (VT) in 8 of 9 Scn5a+/Delta mutant (but no Scn5a+/+ (wild-type (WT)) controls; n = 17), with increased electrogram durations (EGD) and more dispersed conduction curves. Isoproterenol (100 nM) was without effect on tachycardic Scn5a+/Delta hearts (n = 9) yet propranolol (1 microM) prevented VT in all isoproterenol-infused WT control (n = 4) but no Scn5a+/Delta hearts (n = 4). Furthermore propranolol itself increased EGD and dispersion in Scn5a+/Delta hearts. In contrast, mexiletine (10 microM) suppressed VTs in 4 of 5 Scn5a+/Delta hearts without altering EGD or dispersion. CONCLUSION Beta-adrenoreceptor blockade does not confer an antiarrhythmic effect and may even enhance arrhythmogenesis by increasing reentrant substrate in Scn5a+/Delta hearts while mexiletine protects against VT without modifying conduction characteristics. Together these findings permit a scheme where VT in LQT3 is initiated by triggered mechanisms but propagated by reentry.
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Affiliation(s)
- Catherine E Head
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, UK
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Lindia JA, Köhler MG, Martin WJ, Abbadie C. Relationship between sodium channel NaV1.3 expression and neuropathic pain behavior in rats. Pain 2006; 117:145-53. [PMID: 16061326 DOI: 10.1016/j.pain.2005.05.027] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 05/09/2005] [Accepted: 05/27/2005] [Indexed: 11/21/2022]
Abstract
A multitude of voltage-gated sodium channel subtypes (NaV1) are expressed in primary sensory neurons where they influence excitability via their role in the generation and propagation of action potentials. Peripheral nerve injury alters the expression of several NaV1subtypes, but among these only NaV1.3 is up-regulated in dorsal root ganglia (DRG) neurons. The increased expression of NaV1.3 implicates this subtype in the development and maintenance of neuropathic pain, but its contribution to neuropathic pain behavior has not been examined. Using the spared nerve injury (SNI) model, we found that peripheral nerve lesion increased NaV1.3-like immunoreactivity (-LI) in DRG neurons and that mechanical allodynia was partially alleviated following oral administration of two NaV1 blockers, mexiletine (30 and 100 mg/kg, p.o.) and lamotrigine (30 and 100 mg/kg, p.o.). Intrathecal administration of antisense oligonucleotides (4 days) selective for NaV1.3 decreased NaV1.3 immunostaining in the DRG by 50% in the SNI model, but did not attenuate mechanical or cold allodynia. Moreover, we found that only 18% of NaV1.3 positive neurons also expressed activated transcription factor-3 (ATF3), a marker of injured neurons. We then selectively axotomized a cutaneous nerve (sural) and a muscle nerve (gastrocnemius) in order to identify if NaV1.3 up-regulation is dependent on cutaneous and/or muscle afferent activation and found that the numbers of neurons expressing NaV1.3 was proportional to the magnitude of the injury, but independent of the nature of innervation. These results suggest that NaV1.3 increases in primary sensory neurons that are not directly damaged in response to injury. Thus, although NaV1.3 is up-regulated in a subpopulation of DRG neurons after injury, reduction in the expression of NaV1.3 subtype alone is not sufficient to influence the NaV1-dependent behavioral hypersensitivity associated with nerve injury.
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Affiliation(s)
- Jill A Lindia
- Merck Research Laboratories, Department of Pharmacology, P.O. Box 2000, Rahway, NJ 07065, USA
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Abstract
OBJECTIVE The goal of this study was to evaluate the influence of congestive heart failure (CHF) on the clearance of mexiletine. METHODS The mexiletine clearance/bioavailability (CL/F) ratio was estimated in 584 inpatients receiving mexiletine therapy. The study population consisted of 210 patients with CHF [CHF group; 116 inpatients with New York Heart Association (NYHA) class I-II (group NYHA I-II) CHF and 94 inpatients with NYHA class III-IV (group NYHA III-IV) CHF] and 374 inpatients without CHF (Non-CHF group). Serum levels of mexiletine were determined by high performance liquid chromatography (HPLC). RESULTS Mexiletine clearance was significantly lower in the CHF group when compared with the Non-CHF group (0.264+/-0.093 vs. 0.393+/-0.082 l/h/kg, mean+/-S.D., p<0.05). Further, the CL/F ratio was 50% lower in group NYHA III-IV when compared with the Non-CHF group, and the CL/F ratio tended to change in inverse proportion to NYHA class. CONCLUSION CHF status significantly affects mexiletine clearance. Therefore, dose adjustments and careful monitoring are likely required in CHF patients receiving mexiletine.
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Affiliation(s)
- Mariko Kobayashi
- Department of Pharmaceutical Sciences, Niigata University of Pharmacy and Applied Life Sciences, Japan
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Tremont-Lukats IW, Challapalli V, McNicol ED, Lau J, Carr DB. Systemic administration of local anesthetics to relieve neuropathic pain: a systematic review and meta-analysis. Anesth Analg 2005; 101:1738-1749. [PMID: 16301253 DOI: 10.1213/01.ane.0000186348.86792.38] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We reviewed randomized controlled trials to determine the efficacy and safety of systemically administered local anesthetics compared with placebo or active drugs. Of 41 retrieved studies, 27 trials of diverse quality were included in the systematic review. Ten lidocaine and nine mexiletine trials had data suitable for meta-analysis (n = 706 patients total). Lidocaine (most commonly 5 mg/kg IV over 30-60 min) and mexiletine (median dose, 600 mg daily) were superior to placebo (weighted mean difference on a 0-100 mm pain intensity visual analog scale = -10.60; 95% confidence interval: -14.52 to -6.68; P < 0.00001) and equal to morphine, gabapentin, amitriptyline, and amantadine (weighted mean difference = -0.60; 95% confidence interval: -6.96 to 5.75) for neuropathic pain. The therapeutic benefit was more consistent for peripheral pain (trauma, diabetes) and central pain. The most common adverse effects of lidocaine and mexiletine were drowsiness, fatigue, nausea, and dizziness. The adverse event rate for systemically administered local anesthetics was more than for placebo but equivalent to morphine, amitriptyline, or gabapentin (odds ratio: 1.23; 95% confidence interval: 0.22 to 6.90). Lidocaine and mexiletine produced no major adverse events in controlled clinical trials, were superior to placebo to relieve neuropathic pain, and were as effective as other analgesics used for this condition.
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Affiliation(s)
- Ivo W Tremont-Lukats
- *Department of Neurology, Medical University of South Carolina, Charleston, SC; †Department of Anesthesiology and Critical Care, University of Chicago Hospitals, Chicago, IL; ‡Department of Anesthesiology, and §Institute for Clinical Research and Health Policy Studies Tufts-New England Medical Center, Boston, MA
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Yamauchi M, Watanabe E, Yasui K, Takeuchi H, Terasawa T, Sawada K, Hishida H, Kodama I. Prevention of ventricular extrasystole by mexiletine in patients with normal QT intervals is associated with a reduction of transmural dispersion of repolarization. Int J Cardiol 2005; 103:92-7. [PMID: 16061129 DOI: 10.1016/j.ijcard.2004.09.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2004] [Accepted: 09/04/2004] [Indexed: 11/21/2022]
Abstract
BACKGROUND Antiarrhythmic potential of mexiletine in patients with congenital and acquired long-QT syndrome (LQTS) has been attributed to a reduction of transmural dispersion of repolarization (TDR). A similar mechanism could be involved in the antiarrhythmic activity of the drug in patients with normal QT intervals, but the issue remains to be investigated. METHODS AND RESULTS We analyzed 24-h Holter ECG recordings from 17 patients in sinus rhythm showing premature ventricular complexes (PVCs) with normal QT intervals (age, 62+/-10 years, mean+/-S.D.). Treatment of the patients with oral mexiletine (300 mg/day for 21-40 days) resulted in a significant reduction of PVCs (from 13899+/-18887 to 6949+/-12822 beats/24 h, p<0.01). Rate-dependent behavior of ventricular repolarization was analyzed by plotting QT intervals (QT(peak), QT(end)), and the interval from T-wave peak to T-wave end (TPE) against preceding respective RR intervals of sinus beats. Both the QT(peak) and QT(end) tended to be shortened by mexiletine at RR intervals from 600 ms to 1000 ms, although the changes did not reach statistical significances. TPE, which reflects TDR, was shortened significantly at relatively long RR intervals (by 14+/-9% at RR of 900 ms, p<0.05). There was a linear relationship between the percentage shortening of TPE and the percentage reduction of PVCs (r=0.86, p<0.04). TPE> or =70 ms was significantly associated with PVC suppression >75% with an odds ratio of 0.60 (95% confidence interval 0.36-0.98, per 1 ms increment). CONCLUSION Inhibitory effect of mexiletine against PVCs in patients with normal QT intervals is mediated at least in part by a reduction of TDR. Mexiletine may be effective in patients exhibiting longer baseline TPE.
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Affiliation(s)
- Masaki Yamauchi
- Department of Cardiology, Gifu Shakai Hoken Hospital, Kani, Japan
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Garry EM, Delaney A, Anderson HA, Sirinathsinghji EC, Clapp RH, Martin WJ, Kinchington PR, Krah DL, Abbadie C, Fleetwood-Walker SM. Varicella zoster virus induces neuropathic changes in rat dorsal root ganglia and behavioral reflex sensitisation that is attenuated by gabapentin or sodium channel blocking drugs. Pain 2005; 118:97-111. [PMID: 16213091 DOI: 10.1016/j.pain.2005.08.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 07/22/2005] [Accepted: 08/01/2005] [Indexed: 11/25/2022]
Abstract
Reactivation of latent varicella zoster virus (VZV) within sensory trigeminal and dorsal root ganglia (DRG) neurons produces shingles (zoster), often accompanied by a chronic neuropathic pain state, post-herpetic neuralgia (PHN). PHN persists despite latency of the virus within human sensory ganglia and is often unresponsive to current analgesic or antiviral agents. To study the basis of varicella zoster-induced pain, we have utilised a recently developed model of chronic VZV infection in rodents. Immunohistochemical analysis of DRG following VZV infection showed the presence of a viral immediate early gene protein (IE62) co-expressed with markers of A- (neurofilament-200; NF-200) and C- (peripherin) afferent sensory neurons. There was increased expression of neuropeptide Y (NPY) in neurons co-expressing NF-200. In addition, there was an increased expression of alpha2delta1 calcium channel, Na(v)1.3 and Na(v)1.8 sodium channels, the neuropeptide galanin and the nerve injury marker, Activating Transcription Factor-3 (ATF-3) as determined by Western blotting in DRG of VZV-infected rats. VZV infection induced increased behavioral reflex responsiveness to both noxious thermal and mechanical stimuli ipsilateral to injection (lasting up to 10 weeks post-infection) that is mediated by spinal NMDA receptors. These changes were reversed by systemic administration of gabapentin or the sodium channel blockers, mexiletine and lamotrigine, but not by the non-steroidal anti-inflammatory agent, diclofenac. This is the first time that the profile of VZV infection-induced phenotypic changes in DRG has been shown in rodents and reveals that this profile appears to be broadly similar (but not identical) to changes in other neuropathic pain models.
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MESH Headings
- Amines/pharmacology
- Amines/therapeutic use
- Animals
- Anticonvulsants/pharmacology
- Anticonvulsants/therapeutic use
- Behavior, Animal/drug effects
- Behavior, Animal/physiology
- Cyclohexanecarboxylic Acids/pharmacology
- Cyclohexanecarboxylic Acids/therapeutic use
- Disease Models, Animal
- Fluorescent Antibody Technique
- Gabapentin
- Galanin/metabolism
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/physiopathology
- Ganglia, Spinal/virology
- Herpes Zoster/metabolism
- Herpes Zoster/prevention & control
- Herpes Zoster/virology
- Herpesvirus 3, Human/drug effects
- Herpesvirus 3, Human/physiology
- Immediate-Early Proteins/metabolism
- Immunohistochemistry
- Lamotrigine
- Mexiletine/pharmacology
- Mexiletine/therapeutic use
- Neuralgia/etiology
- Neuralgia/prevention & control
- Neuralgia, Postherpetic/prevention & control
- Neuralgia, Postherpetic/virology
- Neurons, Afferent/metabolism
- Neuropeptide Y/metabolism
- Rats
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/physiology
- Reflex/drug effects
- Reflex/physiology
- Sodium Channels/drug effects
- Sodium Channels/metabolism
- Trans-Activators/metabolism
- Triazines/pharmacology
- Triazines/therapeutic use
- Viral Envelope Proteins/metabolism
- Virus Latency/physiology
- gamma-Aminobutyric Acid/pharmacology
- gamma-Aminobutyric Acid/therapeutic use
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Affiliation(s)
- Emer M Garry
- Division of Veterinary Biomedical Sciences, Centre for Neuroscience Research, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, UK
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Abstract
Sudden cardiac death in healthy individuals with structurally normal hearts and a characteristic morphology of the QRS complex resembling a right bundle branch block with elevation of the ST segment in V1 to V3 is known as Brugada syndrome (BrS). Although placement of an implantable cardioverter-defibrillator is considered the only effective therapy for symptomatic patients, some authors have repeatedly reported a beneficial effect of quinidine and isoproterenol in patients with BrS. Also, isolated case reports on the usefulness of cilostazol, sotalol, and mexiletine have been described. The present article reviews the mechanisms by which these drugs may act and their role in the pharmacotherapy of BrS. Other possible agents, mainly I(2) blockers, are also reviewed.
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Affiliation(s)
- Manlio F Márquez
- Department of Electrocardiology, Instituto Nacional de Cardiología Ignacio Chávez, México.
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