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Lima-Rogel V, López-López EJ, Medellín-Garibay SE, Gómez-Ruiz LM, Romero-Méndez C, Milán-Segovia RC, Romano-Moreno S. Population pharmacokinetics of levetiracetam in neonates with seizures. J Clin Pharm Ther 2017; 43:422-429. [PMID: 29265480 DOI: 10.1111/jcpt.12658] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 11/21/2017] [Indexed: 01/17/2023]
Abstract
WHAT IS KNOWN AND OBJECTIVE This study developed a population pharmacokinetic (PK) model of levetiracetam (LEV) for treating neonatal seizures (NS) and determined the influence of clinically relevant covariates to explain the interindividual variability and residual error. METHODS Twenty newborns admitted to the Neonatal Intensive Care Unit at the Hospital Central "Dr. Ignacio Morones Prieto" were included. LEV doses were administered by intermittent infusion. Blood samples were drawn 3 times post-infusion. Levetiracetam was quantified by a chromatographic technique. NONMEM software was used to determine the population PK model of LEV in neonates and the influence of clinical covariates on drug disposition. RESULTS AND DISCUSSION The LEV PK in neonates is described by a one-compartment open model with first-order elimination. The influence of creatinine clearance (CRCL) and body weight (BW) on clearance (CL[L/h] = 0.47*CRCL), as well as the volume of the distribution (Vd[L] = 0.65*BW) of LEV, were confirmed, considering interindividual variabilities of 36% and 22%, respectively, and a residual error of 13%. WHAT IS NEW AND CONCLUSION Based on the PK of LEV in neonates and the influence of the final PK model, a priori dosing guidelines are proposed considering CRCL, BW and LEV plasma concentrations between 6 and 20 mg/L for NS treatment.
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Affiliation(s)
- V Lima-Rogel
- Neonatal Intensive Care Unit, Hospital Central "Dr. Ignacio Morones Prieto", San Luis Potosí, México
| | - E J López-López
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - S E Medellín-Garibay
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - L M Gómez-Ruiz
- Neonatology Department, Nuevo Hospital Civil "Dr. Juan I. Menchaca", Guadalajara, Jalisco, México
| | - C Romero-Méndez
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - R C Milán-Segovia
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
| | - S Romano-Moreno
- Facultad de Ciencias Químicas, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México
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Andonie D, Gáll Z, Bosa P, Dogaru MT, Vancea S. Simultaneous Determination of Carbamazepine and Carbamazepine-10,11-epoxide in Different Biological Matrices by LC-MS/MS. JOURNAL OF INTERDISCIPLINARY MEDICINE 2017. [DOI: 10.1515/jim-2017-0075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
An uncomplicated, sensitive liquid chromatography linked to mass spectrometry (LC/MS) for evaluation of carbamazepine and carbamazepine-10,11-epoxide (its metabolite) in human plasma, human saliva, rat plasma, and rabbit plasma was developed. Analyses were conducted on a Zorbax SB-C18, 100 mm × 3 mm ID, 3.5 μm column, at a column temperature of 40 ºC. The mobile phase was comprised of 0.1% formic acid in water and methanol in a 35 : 65 (v/v) ratio, with a flow rate of 0.4 mL/min. Lacosamide was utilized as internal standard. Under these chromatographic conditions, the retention times of lacosamide, carbamazepine-10,11-epoxide, and carbamazepine were 1.4 min, 1.6 min, and 2.2 min, respectively. The quantification of the analytes was performed using multiple reaction monitoring, with the use of a triple quadrupole mass spectrometer with electrospray positive ionization. The monitored ions were m/z 194 derived from m/z 237 for carbamazepine, m/z 180 derived from m/z 253 for carbamazepine-10,11-epoxide, and m/z 108 derived from m/z 251 for lacosamide. The samples were prepared by protein precipitation from 0.2 mL of plasma/saliva using 0.6 mL of internal standard solution in methanol. Calibration curves were constructed over the ranges 1.1–17.6 µg/mL and 0.23–5.47 µg/mL for carbamazepine and carbamazepine-epoxide, respectively. The coefficients of determination obtained by using a weighted (1/x) linear regression were greater than 0.994. The reported LC-MS/MS method was applied to preclinical pharmacokinetic studies and therapeutic drug monitoring.
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Affiliation(s)
- Dan Andonie
- Faculty of Pharmacy , University of Medicine and Pharmacy , Tîrgu Mureş , Romania
| | - Zsolt Gáll
- Faculty of Pharmacy , University of Medicine and Pharmacy , Tîrgu Mureş , Romania
| | - Paul Bosa
- Faculty of Pharmacy , University of Medicine and Pharmacy , Tîrgu Mureş , Romania
| | - Maria Titica Dogaru
- Faculty of Pharmacy , University of Medicine and Pharmacy , Tîrgu Mureş , Romania
| | - Szende Vancea
- Faculty of Pharmacy , University of Medicine and Pharmacy , Tîrgu Mureş , Romania
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Tang F, Hartz AMS, Bauer B. Drug-Resistant Epilepsy: Multiple Hypotheses, Few Answers. Front Neurol 2017; 8:301. [PMID: 28729850 PMCID: PMC5498483 DOI: 10.3389/fneur.2017.00301] [Citation(s) in RCA: 269] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/12/2017] [Indexed: 01/16/2023] Open
Abstract
Epilepsy is a common neurological disorder that affects over 70 million people worldwide. Despite the recent introduction of new antiseizure drugs (ASDs), about one-third of patients with epilepsy have seizures refractory to pharmacotherapy. Early identification of patients who will become refractory to ASDs could help direct such patients to appropriate non-pharmacological treatment, but the complexity in the temporal patterns of epilepsy could make such identification difficult. The target hypothesis and transporter hypothesis are the most cited theories trying to explain refractory epilepsy, but neither theory alone fully explains the neurobiological basis of pharmacoresistance. This review summarizes evidence for and against several major theories, including the pharmacokinetic hypothesis, neural network hypothesis, intrinsic severity hypothesis, gene variant hypothesis, target hypothesis, and transporter hypothesis. The discussion is mainly focused on the transporter hypothesis, where clinical and experimental data are discussed on multidrug transporter overexpression, substrate profiles of ASDs, mechanism of transporter upregulation, polymorphisms of transporters, and the use of transporter inhibitors. Finally, future perspectives are presented for the improvement of current hypotheses and the development of treatment strategies as guided by the current understanding of refractory epilepsy.
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Affiliation(s)
- Fei Tang
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States.,Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, United States
| | - Anika M S Hartz
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States.,Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Björn Bauer
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, United States.,Epilepsy Center, University of Kentucky, Lexington, KY, United States
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Ibrahim H, Oman Z, Schuelke M, Edwards JC. Treatment of Gabapentin Toxicity With Peritoneal Dialysis: Assessment of Gabapentin Clearance. Am J Kidney Dis 2017; 70:878-880. [PMID: 28676198 DOI: 10.1053/j.ajkd.2017.05.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/05/2017] [Indexed: 02/08/2023]
Abstract
Gabapentin is almost exclusively cleared by the kidney and thus presents challenges in patients with kidney failure. Gabapentin is known to be effectively cleared by hemodialysis, but the efficiency of clearance by peritoneal dialysis (PD) has not been previously described. We report a case of gabapentin toxicity in a patient on long-term PD who was treated with continuous automated cycling PD. We find that continuous PD provides significant clearance of gabapentin. With 2-L exchanges every 2 hours, we document an apparent elimination half-life of 41.33 hours, which is substantially shorter than the reported elimination half-life of 132 hours in the absence of kidney function. Further, our patient's symptoms of gabapentin toxicity gradually improved and had fully resolved after about 36 hours of dialysis. Gabapentin clearance by PD was estimated at 94% of urea clearance. We conclude that intensive PD provides gabapentin clearance that approximates that of urea and is an effective but slow method to treat gabapentin overdose and toxicity.
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Affiliation(s)
- Hisham Ibrahim
- Division of Nephrology, Department of Internal Medicine, Saint Louis University, St. Louis, MO
| | - Zachary Oman
- Division of Nephrology, Department of Internal Medicine, Saint Louis University, St. Louis, MO
| | - Matthew Schuelke
- Division of Nephrology, Department of Internal Medicine, Saint Louis University, St. Louis, MO
| | - John C Edwards
- Division of Nephrology, Department of Internal Medicine, Saint Louis University, St. Louis, MO.
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Anderson LL, Hawkins NA, Thompson CH, Kearney JA, George AL. Unexpected Efficacy of a Novel Sodium Channel Modulator in Dravet Syndrome. Sci Rep 2017; 7:1682. [PMID: 28490751 PMCID: PMC5431801 DOI: 10.1038/s41598-017-01851-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 04/04/2017] [Indexed: 01/03/2023] Open
Abstract
Dravet syndrome, an epileptic encephalopathy affecting children, largely results from heterozygous loss-of-function mutations in the brain voltage-gated sodium channel gene SCN1A. Heterozygous Scn1a knockout (Scn1a +/-) mice recapitulate the severe epilepsy phenotype of Dravet syndrome and are an accepted animal model. Because clinical observations suggest conventional sodium channel blocking antiepileptic drugs may worsen the disease, we predicted the phenotype of Scn1a +/- mice would be exacerbated by GS967, a potent, unconventional sodium channel blocker. Unexpectedly, GS967 significantly improved survival of Scn1a +/- mice and suppressed spontaneous seizures. By contrast, lamotrigine exacerbated the seizure phenotype. Electrophysiological recordings of acutely dissociated neurons revealed that chronic GS967-treatment had no impact on evoked action potential firing frequency of interneurons, but did suppress aberrant spontaneous firing of pyramidal neurons and was associated with significantly lower sodium current density. Lamotrigine had no effects on neuronal excitability of either neuron subtype. Additionally, chronically GS967-treated Scn1a +/- mice exhibited normalized pyramidal neuron sodium current density and reduced hippocampal NaV1.6 protein levels, whereas lamotrigine treatment had no effect on either pyramidal neuron sodium current or hippocampal NaV1.6 levels. Our findings demonstrate unexpected efficacy of a novel sodium channel blocker in Dravet syndrome and suggest a potential mechanism involving a secondary change in NaV1.6.
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Affiliation(s)
- Lyndsey L Anderson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Nicole A Hawkins
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Jennifer A Kearney
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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Van Matre ET, Mueller SW, Fish DN, MacLaren R, Cava LF, Neumann RT, Kiser TH. Levetiracetam Pharmacokinetics in a Patient with Intracranial Hemorrhage Undergoing Continuous Veno-Venous Hemofiltration. AMERICAN JOURNAL OF CASE REPORTS 2017; 18:458-462. [PMID: 28446744 PMCID: PMC5414484 DOI: 10.12659/ajcr.902709] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Patient: Male, 78 Final Diagnosis: Right thalamic intraparenchymal hemorrhage with intraventricular extension Symptoms: Altered mental status • left sided weakness Medication: Levetiracetam Clinical Procedure: Continuous renal replacement therapy Specialty: Critical Care Medicine
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Affiliation(s)
- Edward T Van Matre
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Scott W Mueller
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Douglas N Fish
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Robert MacLaren
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
| | - Luis F Cava
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Robert T Neumann
- Department of Neurosurgery, University of Colorado School of Medicine, Aurora, CO, USA
| | - Tyree H Kiser
- Department of Clinical Pharmacy, University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences, Aurora, CO, USA
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Engelbrecht L, Grobler CJ, Rheeders M. A simple and cost-effective HPLC-UV method for the detection of levetiracetam in plasma/serum of patients with epilepsy. Biomed Chromatogr 2017; 31. [PMID: 28294369 DOI: 10.1002/bmc.3969] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 02/21/2017] [Accepted: 03/03/2017] [Indexed: 01/22/2023]
Abstract
A simple, fast and cost-effective method was developed and validated for the determination of levetiracetam (LEV) in plasma/serum of patients using high performance liquid chromatography (HPLC) with ultraviolet detection. The stability of LEV plasma/serum samples over time and in different blood collection tubes was evaluated. Serum/plasma samples were deproteinized by methanol spiked with the internal standard, gabapentin. HPLC was carried out on a Venusil XBP C18 , 250 × 4.6 mm, 5 μm column, at a flow rate of 1.0 mL/min and with mobile phase consisting of 50 mm potassium dihydrogen phosphate-acetonitrile at a pH of 5.5. The UV detector was set at 205 nm and 10 μL was injected. Total runtime was 15 min. Calibration curves were linear (correlation coefficient = 0.999) over a concentration range of 1-60 μg/mL. Relative standard deviation values for both the inter-day and intra-day precision and accuracy were <5% for the concentration range. The influence of different collection tubes and the effect of time on the stability of LEV was investigated. These factors may cause inaccuracies owing to drug-protein binding and interference in the matrix. This method is simple, fast, cost-effective, reliable and accurate with minimal sample preparation for daily routine use in therapeutic drug monitoring.
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Affiliation(s)
- Lynette Engelbrecht
- Clinical Pharmacokinetic Laboratory, School of Pharmacy (Pharmacology), North West University, Potchefstroom, South Africa
| | - C J Grobler
- Department of Health Sciences, Vaal University of Technology, Vanderbijlpark, South Africa
| | - Malie Rheeders
- Clinical Pharmacokinetic Laboratory, School of Pharmacy (Pharmacology), North West University, Potchefstroom, South Africa
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Yu Q, Griss R, Schena A, Johnsson K. Highly Modular Bioluminescent Sensors for Small Molecules and Proteins. Methods Enzymol 2017; 589:365-382. [DOI: 10.1016/bs.mie.2017.01.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Douglas-Hall P, Dzahini O, Gaughran F, Bile A, Taylor D. Variation in dose and plasma level of lamotrigine in patients discharged from a mental health trust. Ther Adv Psychopharmacol 2017; 7:17-24. [PMID: 28101320 PMCID: PMC5228716 DOI: 10.1177/2045125316672573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The objectives of this study were to investigate the dose of lamotrigine when prescribed with an enzyme inhibitor or enzyme inducer in patients discharged from a mental health trust and to determine the corresponding lamotrigine plasma concentrations and the factors that may affect these. METHODS All patients discharged on lamotrigine between October 2007 and September 2012 were identified using the pharmacy dispensing database. We recorded demographic details, lamotrigine dose and plasma levels and coprescribed medication. RESULTS During the designated period, 187 patients were discharged on lamotrigine of whom 117 had their plasma levels recorded. The mean lamotrigine daily dose was 226.1 mg (range 12.5-800 mg) and the mean plasma level 5.9 mg/l (range 0.8-18.1 mg/l). Gender, ethnicity, diagnosis and smoking status had no significant effect on dose or plasma levels. Patients taking an enzyme-inducing drug (n = 6) had significantly lower plasma levels [mean (SD) 3.40 (1.54) mg/l] than those not taking enzyme inducers [n = 111; 6.03 (3.13) mg/l; p = 0.043]. Patients taking an enzyme-inhibiting drug (n = 23) had significantly higher levels [7.47 (3.99) mg/l] than those not taking an inhibitor [n = 94; 5.52 (2.75) mg/l; p = 0.035]. No significant difference was found between the doses of lamotrigine in patients taking an enzyme inhibitor and those not taking one (p = 0.376). No significant difference was found between the doses of lamotrigine in patients taking an enzyme-inducing drug and those not taking any (p = 0.574). CONCLUSIONS Current dosing recommendations indicate that lamotrigine doses should be halved in individuals taking enzyme inhibitors and doubled in those on enzyme inducers. In our survey these recommendations were rarely followed with the consequence that patients received too high or too low a dose of lamotrigine, respectively.
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Affiliation(s)
- Petrina Douglas-Hall
- Clinical Pharmacist, South London and Maudsley NHS Foundation Trust, Pharmacy Department, Maudsley Hospital, Denmark Hill, London SE5 8AZ, UK
| | - Olubanke Dzahini
- Research Pharmacist, South London and Maudsley NHS Foundation Trust, Pharmacy Department, Maudsley Hospital, London, UK
| | - Fiona Gaughran
- Consultant Psychiatrist, South London and Maudsley NHS Foundation Trust, National Psychosis Service, Maudsley Hospital, London, UK
| | - Ahmed Bile
- Pharmacist, Hounslow East Pharmacy, Middlesex, UK
| | - David Taylor
- Director of Pharmacy and Pathology, Professor of Psychopharmacology, South London and Maudsley NHS Foundation Trust, Pharmacy Department, Maudsley Hospital, London, UK Institute of Pharmaceutical Science, King's College, London, London, UK
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Sensitive inexpensive HPLC determination of four antiepileptic drugs in human plasma: application to PK studies. Bioanalysis 2016; 8:2219-2234. [PMID: 27678163 DOI: 10.4155/bio-2016-0211] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Aim: Recently, polytherapy regimen has been introduced for the treatment of epileptic patients for better seizure control with lesser side effects and better control of multiple seizure types. Methodology: A simple, sensitive and highly specific reversed-phase HPLC method was developed for simultaneous determination of four antiepileptic drugs (AEDs), levetiracetam, lamotrigine, oxcarbazepine and carbamazepine, in real human plasma without interference from endogenous components of plasma. Conclusion: The method was proved to be linear in the range of 0.5–50 µg/ml for all drugs. It was successfully applied for clinical PK study of the AEDs in healthy volunteers following single administration. Also, this method was applied for simultaneous determination of the studied drugs in volunteers’ plasma receiving synergistic binary combinations from the four AEDs when used as add-on therapy. The good precision and selectivity of the developed method allow it to be used for routine therapeutic drug monitoring of such drugs as a useful tool in epilepsy management.
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Quantifying the Effectiveness of Dose Individualization by Simulation for a Drug With Moderate Pharmacokinetic Variability. Ther Drug Monit 2016; 37:641-8. [PMID: 26378372 DOI: 10.1097/ftd.0000000000000194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Dose individualization can reduce variability in exposure. The objective of this work was to quantify, through pharmacokinetic (PK) simulation, the potential for reducing the variability in exposure by dose individualization for a drug with moderate PK variability between subjects and between occasions within a subject, and a narrow therapeutic window. METHODS Using a population PK model that includes between-subject and between-occasion variability for apparent clearance, individual PK profiles in a trial of 300 subjects after a test dose were simulated. From the simulated data, datasets were created mimicking various sampling regimens (from single predose sample to full profile samples over 12 hours) on 1 or more occasions (1, 2, 3, 5, or 10 visits). Using these datasets, individual apparent clearance values were estimated, which were then used to calculate an individualized dose for a predefined target area under the concentration-time curve (AUC), based on the available formulation strengths. The proportion of people whose mean AUC was within a predefined therapeutic AUC range was calculated for the test (before) and the individualized dose (after), and compared between the different sampling scenarios. RESULTS The maximum increase in proportion of subjects with an AUC within the range was 20%. To achieve this benefit, PK samples over 4 hours from 100 dosing occasions were required. As a result of the dose adjustment, the AUC of 7.3% of the subjects moved from inside the therapeutic range to outside of the range. CONCLUSIONS This work shows how modeling and simulation can help assess the benefit and risk of dose individualization for a compound with variability between subjects and between occasions. The framework can be applied to similar situations with a defined set of conditions (eg, therapeutic window, tablet strengths, and PK and/or pharmacodynamic sampling scheme) to inform dose change and to assess the utility of dose individualization against certain success criteria.
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Abstract
Eight new antiepileptic drugs (AEDs) have been approved for use within the United States within the past decade. They are felbamate, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, tiagabine, topiramate, and zonisamide. These afford clinicians with more options to increase efficacy and tolerability in the treatment of patients with epilepsy. Pharmacokinetic properties and drug interactions with other AEDs and other medications taken for comorbidities are individually discussed for each of these new agents. Drug concentrations are not routinely monitored for these newer agents, and there have been few studies designed to investigate their concentration-effect relationships. For most of these medications, the concentrations observed in responders and nonresponders overlap considerably and levels associated with efficacy are often associated with adverse events, complicating the definition of target ranges. Also, epilepsy manifests itself sporadically causing difficulty in clinically monitoring efficacy of medications. Therapeutic drug monitoring provides for the individualization of treatment for these agents, which is important because they demonstrate significant variability in inter- and intraindividual pharmaco-kinetic properties. Therapeutic drug monitoring also allows for identification of noncompliance, drug interactions, and toxicity. Current knowledge of the relationships between efficacy, toxicity, and drug concentrations is discussed.
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Affiliation(s)
- Michele Y. Splinter
- College of Pharmacy, Department of Pharmacy: Clinical and Administrative Sciences, University of Oklahoma Health Sciences Center, P.O. Box 26901, Oklahoma City, OK 73190Department of Pharmacy, Clinical and Administrative Sciences at the College of Pharmacy, University of Oklahoma Health Sciences Center, Oklahoma City
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Abstract
Therapeutic drug monitoring is widely used in the anticonvulsant treatment of persons with epilepsy. Most monitoring uses serum, but many anticonvulsant drugs can as easily be monitored using saliva, including phenobarbital, phenytoin, carbamazepine, lamotrigine, oxcarbazepine, topiramate, levetiracetam, and gabapentin. For highly protein-bound medications such as phenobarbital, phenytoin, and carbamazepine, saliva has the advantage of providing an approximation of the serum free level, the free level presumably being the active moiety. Salivary therapeutic drug monitoring offers a number of advantages over serum therapeutic drug monitoring, including lack of pain, lower cost, and wide potential acceptability by patients and physicians. It has the potential to open new approaches to treatment with strategic at-home monitoring at the time a seizure or adverse event occurs and to allow the collection of cohort-based, pharmacokinetic, and pharmcodynamic data for populations of persons of varying ages and with different medical conditions who require anticonvulsant medications.
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Affiliation(s)
- Robert J. Baumann
- Department of Neurology, Kentucky Clinic, College of Medicine, University of Kentucky, Lexington, Kentucky, baumann @uky.edu
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Saliva and Plasma Monohydroxycarbamazepine Concentrations in Pediatric Patients With Epilepsy. Ther Drug Monit 2016; 38:365-70. [DOI: 10.1097/ftd.0000000000000278] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Intrapatient variation in antiepileptic drug plasma concentration after generic substitution vs stable brand-name drug regimens. Epilepsy Res 2016; 122:79-83. [PMID: 26987080 DOI: 10.1016/j.eplepsyres.2016.02.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 01/21/2016] [Accepted: 02/28/2016] [Indexed: 11/20/2022]
Abstract
Generic substitution of antiepileptic drugs (AEDs) is still a matter of controversy and concern among clinicians and patients. We aimed to assess intrasubject variation in plasma concentrations of lamotrigine (LTG), levetiracetam (LEV) and topiramate (TPM) after generic substitution compared with a stable brand-name drug regimen in a population of patients with epilepsy. A retrospective analysis was performed on prospectively collected and stored data from our therapeutic drug monitoring (TDM) database for the years 2009-2014. The main outcome variable was the proportion of patients who, after switching from branded to generic formulations, showed a greater than ±20% change in AED plasma concentrations compared to the proportion of control patients showing a change in AED plasma concentrations of the same extent while receiving stable branded formulations over repeated TDM tests. Fifty patients on LTG, 27 on LEV and 16 on TPM showing at least one TDM test while receiving generic products fulfilled the inclusion/exclusion criteria for the analysis and were compared with 200 control patients for LTG, 120 for LEV and 80 for TPM. The proportion of patients showing an intrasubject change greater than ±20% in AED plasma concentrations was similar in the brand name vs generic group compared with the control one for LTG (22% vs 33%) and LEV (44% vs 38%), while it was higher in the control group for TPM (41% vs 6%, p<0.01). These are the first data in the literature about the within-patient variation in steady-state plasma concentrations of a series of stable treatments with brand-name AEDs in a real clinical setting. In conclusion, a significant interday variability in intrapatient LTG, LEV and TPM plasma concentrations can be observed even in patients stabilized with the same brand name product over time. This suggests that any change in plasma AED concentration and possible related clinical effects after generic substitution may be not necessarily related to the switch. Our results should be confirmed by large, prospective, blinded, randomized controlled studies in people with epilepsy.
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Factors that influence the pharmacokinetics of lamotrigine in Japanese patients with epilepsy. Eur J Clin Pharmacol 2016; 72:555-62. [DOI: 10.1007/s00228-016-2008-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/10/2016] [Indexed: 10/22/2022]
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Simultaneous Quantitation of Lamotrigine, Levetiracetam, 10-Hydroxycarbazepine, Topiramate, and Zonisamide in Serum Using HPLC-MS/MS. Methods Mol Biol 2016; 1383:29-37. [PMID: 26660171 DOI: 10.1007/978-1-4939-3252-8_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Antiepileptic drugs (AEDs) are a diverse group of pharmacological agents used in the treatment of epileptic seizures. Over the past several decades some new AEDs, including lamotrigine (LTG), levetiracetam (LVA), oxcarbazepine (OXC), topiramate (TOP), and zonisamide (ZNS), have become widely used. This chapter describes a very simple and rapid liquid chromatography-tandem mass spectrometry method for simultaneous quantitation of LVA, ZNS, LTG, TOP, and MHD in human serum. The method requires a very small amount of serum (50 μL) for multiple drug measurements and has a total analysis time of 4 min that makes it well suited for routine clinical analysis of several drugs simultaneously. The imprecision (CVs) measured at various concentrations across the analytical measurement range (AMR) are less than 7% for all analytes. The AMR for each analyte is as follows: LVA (1-100 μg/mL), ZNS (0.8-80 μg/mL), TOP (0.5-50 μg/mL), and 0.6-60 μg/mL for LTG and MHD.
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Balasubramanian D, Deng AX, Doudney K, Hampton MB, Kennedy MA. Valproic acid exposure leads to upregulation and increased promoter histone acetylation of sepiapterin reductase in a serotonergic cell line. Neuropharmacology 2015; 99:79-88. [DOI: 10.1016/j.neuropharm.2015.06.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 05/22/2015] [Accepted: 06/26/2015] [Indexed: 01/10/2023]
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Chen X, Gu E, Wang S, Zheng X, Chen M, Wang L, Hu G, Cai JP, Zhou H. Evaluation of the Effects of Ketoconazole and Voriconazole on the Pharmacokinetics of Oxcarbazepine and Its Main Metabolite MHD in Rats by UPLC-MS-MS. J Chromatogr Sci 2015; 54:334-42. [PMID: 26499119 DOI: 10.1093/chromsci/bmv146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Indexed: 11/13/2022]
Abstract
Oxcarbazepine (OXC), a second-generation antiepileptic drug, undergoes rapid reduction with formation of the active metabolite 10,11-dihydro-10-hydroxy-carbazepine (MHD) in vivo. In this study, a method for simultaneous determination of OXC and MHD in rat plasma using ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS-MS) was developed and validated. Under given chromatographic conditions, OXC, MHD and internal standard diazepam were separated well and quantified by electrospray positive ionization mass spectrometry in the multiple reaction monitoring transitions mode. The method validation demonstrated good linearity over the range of 10-2,000 ng/mL for OXC and 5-1,000 ng/mL for MHD. The lower limit of quantification was 5 ng/mL for OXC and 2.5 ng/mL for MHD, respectively. The method was successfully applied to the evaluation of the pharmacokinetics of OXC and MHD in rats, with or without pretreatment by ketoconazole (KET) and voriconazole (VOR). Statistics indicated that KET and VOR significantly affected the disposition of OXC and MHD in vivo, whereas VOR predominantly interfered with the disposition of MHD. This method is suitable for pharmacokinetic study in small animals.
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Affiliation(s)
- Xinxin Chen
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Ermin Gu
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Shuanghu Wang
- The Laboratory of Clinical Pharmacy, The People's Hospital of Lishui, Lishui 323000, China
| | - Xiang Zheng
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Mengchun Chen
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Li Wang
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Guoxin Hu
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
| | - Jian-ping Cai
- The Key Laboratory of Geriatrics, Beijing Hospital & Beijing Institute of Geriatrics, Ministry of Health, Beijing 100730, China
| | - Hongyu Zhou
- Pharmacology Department, School of Pharmacy, Wenzhou Medical University, Wenzhou 325035, China
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Bansal AD, Hill CE, Berns JS. Use of Antiepileptic Drugs in Patients with Chronic Kidney Disease and End Stage Renal Disease. Semin Dial 2015; 28:404-12. [PMID: 25929593 DOI: 10.1111/sdi.12385] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Epilepsy is a disorder with an approximate worldwide prevalence of 1%. Due to complexities of metabolism, protein-binding, renal elimination, and other pharmacokinetic parameters, the dosing of antiepileptic drugs (AEDs) in patients with chronic kidney disease (CKD) or end stage renal disease (ESRD) deserves special attention. This is a review of the most commonly prescribed AEDs with special focus on their indication, pharmacokinetics, and unique considerations for use in patients with CKD and ESRD. A review of their renal toxicities is also included.
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Affiliation(s)
- Amar D Bansal
- Renal-Electrolyte and Hypertension Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Chloe E Hill
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jeffrey S Berns
- Renal-Electrolyte and Hypertension Division, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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Lacosamide serum concentrations in adult patients with epilepsy: the influence of gender, age, dose, and concomitant antiepileptic drugs. Ther Drug Monit 2015; 36:494-8. [PMID: 24562047 DOI: 10.1097/ftd.0000000000000051] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Lacosamide (LCM), a new antiepileptic drug (AED) approved as adjunctive therapy for the treatment of patients with partial-onset seizures, has limited pharmacokinetic and drug interaction data. The main objectives of the present study were to investigate the effects of dose, age, gender, and hepatic enzyme-inducing AEDs on the pharmacokinetics of LCM as assessed by steady state serum LCM values. METHODS An LCM AED therapeutic drug monitoring database was analyzed with regard to LCM serum concentrations and other relevant patient and AED drug information. One hundred twenty eight sera were identified. These were collected from 68 women and 61 men aged 19-66 years, who were prescribed a median LCM dose of 300 mg (range 50-600 mg). RESULTS Serum LCM concentrations were observed in the following main groupings: LCM monotherapy (n = 5), LCM with nonenzyme-inducing AEDs (n = 50), LCM with enzyme-inducing AEDs (n = 49), LCM with valproic acid (n = 20), and LCM with enzyme-inducing AEDs plus valproic acid (n = 4). Analysis of variance showed a correlation of dose with LCM concentrations (r = 0.53, P < 0.001), and women had statistically higher mean LCM concentration than did men, 37.2 ± 23.6 versus 26.8 ± 12.9 μmol/L (P = 0.001). Serum LCM concentrations were significantly lower (P = 0.002) in the enzyme-inducing AED group (carbamazepine and phenytoin) compared with the LCM monotherapy group and the nonenzyme-inducing group, 23.5 ± 11.0, 34.5 ± 7.7, and 32.7 ± 17.9 μmol/L, respectively. CONCLUSIONS Serum LCM concentrations increased dose dependently, were age independent, and were higher in women compared with men. Carbamazepine and phenytoin can significantly decrease serum LCM concentrations, probably via induction of LCM metabolism.
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Sanavio B, Krol S. On the Slow Diffusion of Point-of-Care Systems in Therapeutic Drug Monitoring. Front Bioeng Biotechnol 2015; 3:20. [PMID: 25767794 PMCID: PMC4341557 DOI: 10.3389/fbioe.2015.00020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/09/2015] [Indexed: 12/22/2022] Open
Abstract
Recent advancements in point-of-care (PoC) technologies show great transformative promises for personalized preventative and predictive medicine. However, fields like therapeutic drug monitoring (TDM), that first allowed for personalized treatment of patients' disease, still lag behind in the widespread application of PoC devices for monitoring of patients. Surprisingly, very few applications in commonly monitored drugs, such as anti-epileptics, are paving the way for a PoC approach to patient therapy monitoring compared to other fields like intensive care cardiac markers monitoring, glycemic controls in diabetes, or bench-top hematological parameters analysis at the local drug store. Such delay in the development of portable fast clinically effective drug monitoring devices is in our opinion due more to an inertial drag on the pervasiveness of these new devices into the clinical field than a lack of technical capability. At the same time, some very promising technologies failed in the clinical practice for inadequate understanding of the outcome parameters necessary for a relevant technological breakthrough that has superior clinical performance. We hope, by over-viewing both TDM practice and its yet unmet needs and latest advancement in micro- and nanotechnology applications to PoC clinical devices, to help bridging the two communities, the one exploiting analytical technologies and the one mastering the most advanced techniques, into translating existing and forthcoming technologies in effective devices.
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Affiliation(s)
- Barbara Sanavio
- IRCCS Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
| | - Silke Krol
- IRCCS Fondazione Istituto Neurologico Carlo Besta, Milan, Italy
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Population pharmacokinetic modeling of oxcarbazepine active metabolite in Chinese patients with epilepsy. Eur J Drug Metab Pharmacokinet 2015; 41:345-51. [DOI: 10.1007/s13318-015-0266-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 02/09/2015] [Indexed: 12/20/2022]
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Becchetti A, Aracri P, Meneghini S, Brusco S, Amadeo A. The role of nicotinic acetylcholine receptors in autosomal dominant nocturnal frontal lobe epilepsy. Front Physiol 2015; 6:22. [PMID: 25717303 PMCID: PMC4324070 DOI: 10.3389/fphys.2015.00022] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 01/14/2015] [Indexed: 11/22/2022] Open
Abstract
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a focal epilepsy with attacks typically arising in the frontal lobe during non-rapid eye movement (NREM) sleep. It is characterized by clusters of complex and stereotyped hypermotor seizures, frequently accompanied by sudden arousals. Cognitive and psychiatric symptoms may be also observed. Approximately 12% of the ADNFLE families carry mutations on genes coding for subunits of the heteromeric neuronal nicotinic receptors (nAChRs). This is consistent with the widespread expression of these receptors, particularly the α4β2* subtype, in the neocortex and thalamus. However, understanding how mutant nAChRs lead to partial frontal epilepsy is far from being straightforward because of the complexity of the cholinergic regulation in both developing and mature brains. The relation with the sleep-waking cycle must be also explained. We discuss some possible pathogenetic mechanisms in the light of recent advances about the nAChR role in prefrontal regions as well as the studies carried out in murine models of ADNFLE. Functional evidence points to alterations in prefrontal GABA release, and the synaptic unbalance probably arises during the cortical circuit maturation. Although most of the available functional evidence concerns mutations on nAChR subunit genes, other genes have been recently implicated in the disease, such as KCNT1 (coding for a Na+-dependent K+ channel), DEPD5 (Disheveled, Egl-10 and Pleckstrin Domain-containing protein 5), and CRH (Corticotropin-Releasing Hormone). Overall, the uncertainties about both the etiology and the pathogenesis of ADNFLE point to the current gaps in our knowledge the regulation of neuronal networks in the cerebral cortex.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Patrizia Aracri
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Simone Meneghini
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Simone Brusco
- Department of Biotechnology and Biosciences and NeuroMi-Milan Center for Neuroscience, University of Milano-Bicocca Milano, Italy
| | - Alida Amadeo
- Department of Biosciences, University of Milano Milano, Italy
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Biggs JE, Boakye PA, Ganesan N, Stemkowski PL, Lantero A, Ballanyi K, Smith PA. Analysis of the long-term actions of gabapentin and pregabalin in dorsal root ganglia and substantia gelatinosa. J Neurophysiol 2014; 112:2398-412. [DOI: 10.1152/jn.00168.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The α2δ-ligands pregabalin (PGB) and gabapentin (GBP) are used to treat neuropathic pain. We used whole cell recording to study their long-term effects on substantia gelatinosa and dorsal root ganglion (DRG) neurons. Spinal cord slices were prepared from embryonic day 13 rat embryos and maintained in organotypic culture for >5 wk (neuronal age equivalent to young adult rats). Exposure of similarly aged DRG neurons (dissociated and cultured from postnatal day 19 rats) to GBP or PGB for 5–6 days attenuated high-voltage-activated calcium channel currents (HVA ICa). Strong effects were seen in medium-sized and in small isolectin B4-negative (IB4−) DRG neurons, whereas large neurons and small neurons that bound isolectin B4 (IB4+) were hardly affected. GBP (100 μM) or PGB (10 μM) were less effective than 20 μM Mn2+ in suppression of HVA ICa in small DRG neurons. By contrast, 5–6 days of exposure to these α2δ-ligands was more effective than 20 μM Mn2+ in reducing spontaneous excitatory postsynaptic currents at synapses in substantia gelatinosa. Spinal actions of gabapentinoids cannot therefore be ascribed to decreased expression of HVA Ca2+ channels in primary afferent nerve terminals. In substantia gelatinosa, 5–6 days of exposure to PGB was more effective in inhibiting excitatory synaptic drive to putative excitatory neurons than to putative inhibitory neurons. Although spontaneous inhibitory postsynaptic currents were also attenuated, the overall long-term effect of α2δ-ligands was to decrease network excitability as monitored by confocal Ca2+ imaging. We suggest that selective actions of α2δ-ligands on populations of DRG neurons may predict their selective attenuation of excitatory transmission onto excitatory vs. inhibitory neurons in substantia gelatinosa.
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Affiliation(s)
- James E. Biggs
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
| | - Paul A. Boakye
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Naren Ganesan
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | | | - Aquilino Lantero
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
| | - Klaus Ballanyi
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Physiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada
| | - Peter A. Smith
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Canada; and
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Heyman E, Levin N, Lahat E, Epstein O, Gandelman-Marton R. Efficacy and safety of felbamate in children with refractory epilepsy. Eur J Paediatr Neurol 2014; 18:658-62. [PMID: 24906615 DOI: 10.1016/j.ejpn.2014.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2013] [Revised: 04/03/2014] [Accepted: 05/07/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Despite the introduction of multiple new antiepileptic drugs in the past two decades, many patients with epilepsy continue to experience uncontrolled seizures or significant side effects. AIM To present our experience with felbamate therapy in children with drug-resistant epilepsy. METHODS We retrospectively reviewed the medical charts and video-EEG recordings of all patients receiving felbamate until May 2012. Efficacy was determined according to seizure frequency during the week prior to treatment initiation and the week after the maximal dosage of felbamate was reached. RESULTS Fifty patients (34 boys) aged 4 months to 17 years (mean--5.5 years) were identified. Nearly third of the patients had Lennox-Gastaut syndrome. Mean epilepsy duration was 3.4 years (range--1 month to 13 years). The mean number of previous antiepileptic drugs was 7.5. The mean duration of follow-up was 1.1 years. Seizure frequency decreased by at least 50% in 29 (58%) patients. Side effects were reported in 22 (44%) patients, none of them included aplastic anemia or liver failure. In the responder group, the maximal dose of felbamate was lower and the patients were older compared to non-responders. CONCLUSIONS Despite current recommendations, felbamate is initiated following multiple AEDs. Based on its efficacy and safety data, earlier initiation of felbamate is recommended in children with refractory epilepsy.
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Affiliation(s)
- Eli Heyman
- Department of Pediatric Neurology, Assaf Harofeh Medical Center, Zerifin, Israel; Sackler School of Medicine, Tel Aviv University, Israel
| | - Noa Levin
- Department of Pediatric Neurology, Assaf Harofeh Medical Center, Zerifin, Israel
| | - Eli Lahat
- Department of Pediatric Neurology, Assaf Harofeh Medical Center, Zerifin, Israel; Sackler School of Medicine, Tel Aviv University, Israel
| | - Orna Epstein
- Department of Pediatric Neurology, Assaf Harofeh Medical Center, Zerifin, Israel
| | - Revital Gandelman-Marton
- EEG and Epilepsy Unit, Department of Neurology, Assaf Harofeh Medical Center, Zerifin, Israel; Sackler School of Medicine, Tel Aviv University, Israel.
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Nair AB, Kumria R, Al-Dhubiab BE, Attimarad M, Harsha S. Noninvasive Sampling of Gabapentin by Reverse Iontophoresis. Pharm Res 2014; 32:1417-24. [DOI: 10.1007/s11095-014-1546-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/06/2014] [Indexed: 01/06/2023]
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Lee CH, Liou HH. Pregabalin activates ROMK1 channels via cAMP-dependent protein kinase and protein kinase C. Eur J Pharmacol 2014; 740:35-44. [DOI: 10.1016/j.ejphar.2014.06.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 05/21/2014] [Accepted: 06/16/2014] [Indexed: 02/01/2023]
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Deeb S, McKeown DA, Torrance HJ, Wylie FM, Logan BK, Scott KS. Simultaneous Analysis of 22 Antiepileptic Drugs in Postmortem Blood, Serum and Plasma Using LC–MS-MS with a Focus on Their Role in Forensic Cases. J Anal Toxicol 2014; 38:485-94. [DOI: 10.1093/jat/bku070] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Krasowski MD, McMillin GA. Advances in anti-epileptic drug testing. Clin Chim Acta 2014; 436:224-36. [PMID: 24925169 DOI: 10.1016/j.cca.2014.06.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/29/2014] [Accepted: 06/03/2014] [Indexed: 12/12/2022]
Abstract
In the past twenty-one years, 17 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are clobazam, ezogabine (retigabine), eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. Therapeutic drug monitoring is often used in the clinical dosing of the newer anti-epileptic drugs. The drugs with the best justifications for drug monitoring are lamotrigine, levetiracetam, oxcarbazepine, stiripentol, and zonisamide. Perampanel, stiripentol and tiagabine are strongly bound to serum proteins and are candidates for monitoring of the free drug fractions. Alternative specimens for therapeutic drug monitoring are saliva and dried blood spots. Therapeutic drug monitoring of the new antiepileptic drugs is discussed here for managing patients with epilepsy.
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Affiliation(s)
- Matthew D Krasowski
- Department of Pathology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States.
| | - Gwendolyn A McMillin
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT, United States; ARUP Institute for Clinical and Experimental Pathology, ARUP Laboratories Inc., Salt Lake City, UT, United States
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Stockis A, Lu S, Tonner F, Otoul C. Clinical pharmacology of levetiracetam for the treatment of epilepsy. Expert Rev Clin Pharmacol 2014; 2:339-50. [DOI: 10.1586/ecp.09.16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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83
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Johannessen Landmark C, Patsalos PN. Methodologies used to identify and characterize interactions among antiepileptic drugs. Expert Rev Clin Pharmacol 2014; 5:281-92. [DOI: 10.1586/ecp.12.10] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Generic products of antiepileptic drugs: a perspective on bioequivalence, bioavailability, and formulation switches using Monte Carlo simulations. CNS Drugs 2014; 28:69-77. [PMID: 24092569 DOI: 10.1007/s40263-013-0112-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
INTRODUCTION Generic products of antiepileptic drugs (AEDs) are currently a controversial topic as neurologists and patients are reluctant to switch from brand products to generics and to switch between generics. OBJECTIVE The aim of this study was to provide enlightenment on issues of bioequivalence (BE) and interchangeability of AED products. METHODS Monte Carlo simulations of the classic 2 × 2 BE studies were performed to study the effect of sample size, within-subject variability, and the true difference in pharmacokinetic values of the products under comparison on BE acceptance of generic AED products. Simulations were extended to study the comparative performance of two generic AED products against the same innovative product. The simulated results are compared with literature data on AEDs. RESULTS The question with regard to bioavailability (BA) is whether two formulations are different, while for BE the question is whether two formulations are sufficiently similar in terms of extent and rate of absorption. Therefore, the criteria for BA and BE and the statistical analysis involved in their analysis are different. Two generic formulations that meet regulatory approval requirements for generics by being bioequivalent to the same innovative AED may not be bioequivalent to one another and therefore should not be regarded as equal or as therapeutically equivalent products. A switch from a standard or an immediate-release formulation to a modified-release product, which comprises extended-release or delayed-release formulations, should not be regarded as a switch between generics, but rather as a switch between different formulation types. DISCUSSION Switches between bioequivalent generic AED products could potentially lead to larger changes in plasma levels and exposure than the brand-to-generic switch. The simulation work verified the clinical findings that not all generic AED products bioequivalent to the same innovative product are bioequivalent to one another. CONCLUSIONS Two generic formulations that meet regulatory approval requirements for generics, by being bioequivalent to the innovative AED, may not be bioequivalent to one another. Additional BE criteria are needed for a formulation switch, particularly in epilepsy, where a breakthrough seizure may change a patient's status from seizure-free to refractory.
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Andres-Mach M, Zadrożniak A, Haratym-Maj A, Florek-Luszczki M, Raszewski G, Antkiewicz-Michaluk L, Luszczki JJ. Effect of 1-methyl-1,2,3,4-tetrahydroisoquinoline on the protective action of various antiepileptic drugs in the maximal electroshock-induced seizure model: a type II isobolographic analysis. J Neural Transm (Vienna) 2013; 120:1651-63. [PMID: 23744255 PMCID: PMC3834176 DOI: 10.1007/s00702-013-1047-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/22/2013] [Indexed: 12/02/2022]
Abstract
The aim of this study was to characterize the interaction between 1-methyl-1,2,3,4-tetrahydroisoquinoline (1-MeTHIQ-an endogenous parkinsonism-preventing substance) and various antiepileptic drugs [AEDs: clonazepam (CZP), ethosuximide (ETS), gabapentin (GBP), levetiracetam (LEV), tiagabine (TGB) and vigabatrin (VGB)] in the mouse maximal electroshock (MES)-induced seizure model. Results indicate that 1-MeTHIQ in combination with CZP (at the fixed ratios of 50:1 and 25:1), ETS (1:10) and GBP (1:1, 1:2, 1:5 and 1:10) exerted supra-additive (synergistic) interactions in the mouse MES model. In contrast, 1-MeTHIQ in combination with CZP (200:1 and 100:1), ETS (1:1, 1:2 and 1:5), LEV and VGB (1:1, 1:2, 1:5 and 1:10), and TGB (200:1, 100:1, 50:1 and 25:1) produced additive interaction in the mouse MES model. Total brain AED concentrations were unaffected by 1-MeTHIQ, and inversely, CZP, ETS and GBP had no impact on total brain concentrations of 1-MeTHIQ, indicating pharmacodynamic nature of synergistic interactions between 1-MeTHIQ and the tested AEDs in the mouse MES model. In conclusion, the supra-additive interactions of 1-MeTHIQ with CZP (at the fixed ratios of 50:1 and 25:1), ETS (1:10) and GBP (1:1, 1:2, 1:5 and 1:10) in the mouse MES model appear to be particularly favorable combinations from a clinical viewpoint. The additive combinations of 1-MeTHIQ with CZP (100:1, 50:1), ETS (1:1, 1:2 and 1:5), LEV and VGB (1:1, 1:2, 1:5, and 1:10), and TGB (200:1, 100:1, 50:1 and 25:1) seem to be neutral and worthy of consideration in further clinical practice.
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Affiliation(s)
- Marta Andres-Mach
- Isobolographic Analysis Laboratory, Institute of Rural Health, Jaczewskiego 2, 20-950 Lublin, Poland
| | - Anna Zadrożniak
- Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8, 20-090 Lublin, Poland
| | - Agnieszka Haratym-Maj
- Department of Physiopathology, Institute of Rural Health, Jaczewskiego 2, 20-950 Lublin, Poland
| | | | - Grzegorz Raszewski
- Department of Physiopathology, Institute of Rural Health, Jaczewskiego 2, 20-950 Lublin, Poland
| | - Lucyna Antkiewicz-Michaluk
- Department of Neurochemistry, Institute of Pharmacology, Polish Academy of Science, Smetna 12, 31-343 Krakow, Poland
| | - Jarogniew J. Luszczki
- Isobolographic Analysis Laboratory, Institute of Rural Health, Jaczewskiego 2, 20-950 Lublin, Poland
- Department of Pathophysiology, Medical University of Lublin, Jaczewskiego 8, 20-090 Lublin, Poland
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Brzaković B, Vučićević K, Kovačević SV, Miljković B, Prostran M, Martinović Ž, Pokrajac M. Pharmacokinetics of lamotrigine in paediatric and young adult epileptic patients--nonlinear mixed effects modelling approach. Eur J Clin Pharmacol 2013; 70:179-85. [PMID: 24240511 DOI: 10.1007/s00228-013-1606-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 10/23/2013] [Indexed: 11/28/2022]
Abstract
PURPOSE The purpose of the study was to examine and describe adjunctive lamotrigine (LTG) pharmacokinetics in paediatric and young adult patients using a nonlinear mixed effects modelling (NONMEM) approach. METHODS The study included 53 patients (age range 3-35 years) who were concomitantly treated with carbamazepine (CBZ) and/or valproic acid (VPA). A total of 70 blood samples corresponding to trough levels were available for analysis. Data were modelled, and the final model was evaluated using NONMEM and auxiliary software tools. RESULTS The final LTG population model included the effects of concomitant drugs and patient's weight (WT) which stratified the population into three groups: ≤25 kg, >25 to <60 kg and ≥60 kg. Based on the final model, the estimated LTG oral clearance (CL/F) for a typical patient weighing ≤25 kg, >25 to <60 kg or ≥60 kg who was concomitantly treated with CBZ was estimated to be 3.28, 4.23, or 7.15 l/h, respectively. If a patient was concomitantly treated with CBZ + VPA, the CL/F decreased on average by 69.5 % relative to LTG + CBZ co-therapy. VPA was found to decrease the LTG CL/F by 87.6 % compared to co-therapy with only CBZ. CONCLUSION The LTG population pharmacokinetic model developed in this study may be a reliable method for individualising the LTG dosing regimen in paediatric and young adult patients on combination therapy during therapeutic drug monitoring.
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Affiliation(s)
- Branka Brzaković
- Medicines and Medical Devices Agency of Serbia, Belgrade, Serbia
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87
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Abstract
Blood (serum/plasma) antiepileptic drug (AED) therapeutic drug monitoring (TDM) has proven to be an invaluable surrogate marker for individualizing and optimizing the drug management of patients with epilepsy. Since 1989, there has been an exponential increase in AEDs with 23 currently licensed for clinical use, and recently, there has been renewed and extensive interest in the use of saliva as an alternative matrix for AED TDM. The advantages of saliva include the fact that for many AEDs it reflects the free (pharmacologically active) concentration in serum; it is readily sampled, can be sampled repetitively, and sampling is noninvasive; does not require the expertise of a phlebotomist; and is preferred by many patients, particularly children and the elderly. For each AED, this review summarizes the key pharmacokinetic characteristics relevant to the practice of TDM, discusses the use of other biological matrices with particular emphasis on saliva and the evidence that saliva concentration reflects those in serum. Also discussed are the indications for salivary AED TDM, the key factors to consider when saliva sampling is to be undertaken, and finally, a practical protocol is described so as to enable AED TDM to be applied optimally and effectively in the clinical setting. Overall, there is compelling evidence that salivary TDM can be usefully applied so as to optimize the treatment of epilepsy with carbamazepine, clobazam, ethosuximide, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin, primidone, topiramate, and zonisamide. Salivary TDM of valproic acid is probably not helpful, whereas for clonazepam, eslicarbazepine acetate, felbamate, pregabalin, retigabine, rufinamide, stiripentol, tiagabine, and vigabatrin, the data are sparse or nonexistent.
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88
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Behbahani M, Najafi F, Bagheri S, Bojdi MK, Salarian M, Bagheri A. Application of surfactant assisted dispersive liquid–liquid microextraction as an efficient sample treatment technique for preconcentration and trace detection of zonisamide and carbamazepine in urine and plasma samples. J Chromatogr A 2013; 1308:25-31. [DOI: 10.1016/j.chroma.2013.07.088] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 07/22/2013] [Accepted: 07/23/2013] [Indexed: 11/28/2022]
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89
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Ahmed ABA, Rao AS, Rao MV, Taha RM. HPTLC/HPLC and gravimetric methodology for the identification and quantification of gymnemic acid fromGymnema sylvestremethanolic extracts. ACTA CHROMATOGR 2013. [DOI: 10.1556/achrom.25.2013.2.10] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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90
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Reimers A, Brodtkorb E. Second-generation antiepileptic drugs and pregnancy: a guide for clinicians. Expert Rev Neurother 2013; 12:707-17. [PMID: 22650173 DOI: 10.1586/ern.12.32] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
When treating pregnant women with antiepileptic drugs (AEDs), clinicians have to balance potential fetal adverse effects against the risks of uncontrolled maternal disease. Only recently have emerging scientic data provided a rational basis for treatment decisions considering both aspects. The focus of research is currently moving from the first to the second AED generation. Lamotrigine is relatively well studied, and data on other novel AEDs, such as levetiracetam, oxcarbazepine, topiramate, zonisamide, gabapentin and pregabalin, are in progress. Safety issues appear to be favorable for lamotrigine, and preliminary results are also promising for levetiracetam and oxcarbazepine. Drugs metabolized by uridine-diphospate glucuronosyl transferase or excreted unchanged by the kidneys are particularly susceptible to increased body clearance during pregnancy. Lamotrigine is subject to both mechanisms, and therapeutic serum levels may sometimes be difficult to maintain. The authors review the recommendations and clinical research on modern AED treatment during pregnancy, highlighting current experience with second-generation drugs.
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Affiliation(s)
- Arne Reimers
- Department of Clinical Pharmacology, St. Olavs University Hospital, 7006 Trondheim, Norway
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91
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Factors Influencing Serum Topiramate Concentrations in Routine Therapeutic Drug Monitoring in Korean Adult Patients With Epilepsy. Ther Drug Monit 2013; 35:177-82. [DOI: 10.1097/ftd.0b013e31827efe1d] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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92
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Neuroprotective effects of the mood stabilizer lamotrigine against glutamate excitotoxicity: roles of chromatin remodelling and Bcl-2 induction. Int J Neuropsychopharmacol 2013; 16:607-20. [PMID: 22564541 PMCID: PMC6324934 DOI: 10.1017/s1461145712000429] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Lamotrigine (LTG), a phenyltriazine derivative and anti-epileptic drug, has emerged as an effective first-line treatment for bipolar mood disorder. Like the other mood stabilizers lithium and valproate, LTG also has neuroprotective properties but its exact mechanisms remain poorly defined. The present study utilized rat cerebellar granule cells (CGCs) to examine the neuroprotective effects of LTG against glutamate-induced excitotoxicity and to investigate potential underlying mechanisms. CGCs pretreated with LTG were challenged with an excitotoxic dose of glutamate. Pretreatment caused a time- and concentration-dependent inhibition of glutamate excitotoxicity with nearly full protection at higher doses (≥ 100 μm), as revealed by cell viability assays and morphology. LTG treatment increased levels of acetylated histone H3 and H4 as well as dose- and time-dependently enhanced B-cell lymphoma-2 (Bcl-2) mRNA and protein levels; these changes were associated with up-regulation of the histone acetylation and activity of the Bcl-2 promoter. Importantly, lentiviral-mediated Bcl-2 silencing by shRNA reduced both LTG-induced Bcl-2 mRNA up-regulation and neuroprotection against glutamate excitotoxicity. Finally, the co-presence of a sub-effective concentration of LTG (10 μm) with lithium or valproate produced synergistic neuroprotection. Together, our results demonstrate that the neuroprotective effects of LTG against glutamate excitotoxicity likely involve histone deacetylase inhibition and downstream up-regulation of anti-apoptotic protein Bcl-2. These underlying mechanisms may contribute to the clinical efficacy of LTG in treating bipolar disorder and warrant further investigation.
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93
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Pharmacokinetic variability of four newer antiepileptic drugs, lamotrigine, levetiracetam, oxcarbazepine, and topiramate: a comparison of the impact of age and comedication. Ther Drug Monit 2013; 34:440-5. [PMID: 22777154 DOI: 10.1097/ftd.0b013e31825ee389] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Newer antiepileptic drugs (AEDs) are widely used in patients with epilepsy. There is still insufficient documentation regarding pharmacokinetic variability of these AEDs in different patient groups. PURPOSE The purpose of this study was to compare age and comedication as factors contributing to pharmacokinetic variability between 4 newer AEDs (lamotrigine, levetiracetam, oxcarbazepine, and topiramate) among patients with refractory epilepsy. METHODS Data regarding age, gender, use of AEDs, daily doses, and serum concentration measurements were retrieved from a therapeutic drug monitoring database, from patients admitted to the National Center for Epilepsy, Norway, 2007-2008. RESULTS In total, 1050 patients were included, 111 younger children (2-9 years), 137 older children (10-17 years), 720 adults (18-64 years), 82 elderly (65-93 years). Fifty percent of the patients were prescribed polytherapy, in 88 different combinations. The interindividual pharmacokinetic variability was extensive, as illustrated by a 10-fold variability in serum concentration compared with dose. Age affected the apparent clearance of levetiracetam to the largest extent, as shown by a 60% increase in younger children and a 40% reduction in the elderly, respectively, compared with adults. Comedication altered the clearance of lamotrigine to the greatest extent ±70% because it is affected by both enzyme inducers and inhibitors. Hepatic enzyme inducers increased the clearance of levetiracetam and topiramate by 25% and oxcarbazepine by 75%. Valproic acid reduced the clearance of topiramate by 25%. CONCLUSION Age and comedication are important contributors to pharmacokinetic variability. Age had the greatest impact on levetiracetam, and comedication affected the clearance of each of the 4 AEDs investigated in this study. Pharmacokinetic drug interactions must be carefully considered when multidrug therapies are prescribed. Therapeutic drug monitoring is a valuable tool for individualizing AED therapy.
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Storer RJ, Goadsby PJ. Topiramate is likely to act outside of the trigeminocervical complex. Cephalalgia 2013; 33:291-300. [PMID: 23314783 DOI: 10.1177/0333102412472069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND To facilitate understanding the locus and mechanism of action of antimigraine preventives, we examined the effect of topiramate on trigeminocervical activation in the cat. METHODS Cats were anesthetized and physiologically monitored. Electrical stimulation of the superior sagittal sinus activated nociceptive trigeminovascular afferents. Extracellular recordings were made from neurons in the trigeminocervical complex. RESULTS Microiontophoretically delivered topiramate, applied locally at the second order synapse of the trigeminovascular system in the trigeminocervical complex, produced significant inhibition of L-glutamate-evoked firing of neurons only at the highest microiontophoretic currents (27 ± 7% at -160 nA; P < 0.05, N = 14 cells), but did not inhibit firing of these neurons evoked by stimulation of the craniovascular afferents (2 ± 5%, P = 0.762, N = 13 cells). In contrast, systemically administered topiramate (30 mg/kg intravenously) partly inhibited this firing (32 ± 10% at 15 min; F 5,35 = 3.5, P < 0.05, N = 8 cats). After this systemic administration, profound inhibition (70 ± 10%, P < 0.001, N = 7) of L-glutamate-evoked firing of cells in the trigeminocervical complex at the second order synapse of the trigeminovascular system was observed. CONCLUSIONS These data suggest that topiramate acts outside of the trigeminocervical complex in the cat. Determining the sites of action of preventive antimigraine treatments is crucial to developing laboratory models for the development of new therapeutics, and may vary between species.
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Affiliation(s)
- Robin J Storer
- Headache Group, Department of Neurology, UCSF Headache Center, 1701 Divisadero St., San Francisco, CA 94115, USA.
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Becchetti A. Neuronal nicotinic receptors in sleep-related epilepsy: studies in integrative biology. ISRN BIOCHEMISTRY 2012; 2012:262941. [PMID: 25969754 PMCID: PMC4392997 DOI: 10.5402/2012/262941] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 10/21/2012] [Indexed: 11/23/2022]
Abstract
Although Mendelian diseases are rare, when considered one by one, overall they constitute a significant social burden. Besides the medical aspects, they propose us one of the most general biological problems. Given the simplest physiological perturbation of an organism, that is, a single gene mutation, how do its effects percolate through the hierarchical biological levels to determine the pathogenesis? And how robust is the physiological system to this perturbation? To solve these problems, the study of genetic epilepsies caused by mutant ion channels presents special advantages, as it can exploit the full range of modern experimental methods. These allow to extend the functional analysis from single channels to whole brains. An instructive example is autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), which can be caused by mutations in neuronal nicotinic acetylcholine receptors. In vitro, such mutations often produce hyperfunctional receptors, at least in heterozygous condition. However, understanding how this leads to sleep-related frontal epilepsy is all but straightforward. Several available animal models are helping us to determine the effects of ADNFLE mutations on the mammalian brain. Because of the complexity of the cholinergic regulation in both developing and mature brains, several pathogenic mechanisms are possible, which also present different therapeutic implications.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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Aghighi SA, Tipold A, Piechotta M, Lewczuk P, Kästner SB. Assessment of the effects of adjunctive gabapentin on postoperative pain after intervertebral disc surgery in dogs. Vet Anaesth Analg 2012; 39:636-46. [DOI: 10.1111/j.1467-2995.2012.00769.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Johannessen Landmark C, Johannessen SI, Tomson T. Host factors affecting antiepileptic drug delivery-pharmacokinetic variability. Adv Drug Deliv Rev 2012; 64:896-910. [PMID: 22063021 DOI: 10.1016/j.addr.2011.10.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 10/11/2011] [Accepted: 10/14/2011] [Indexed: 01/16/2023]
Abstract
Antiepileptic drugs (AEDs) are the mainstay in the treatment of epilepsy, one of the most common serious chronic neurological disorders. AEDs display extensive pharmacological variability between and within patients, and a major determinant of differences in response to treatment is pharmacokinetic variability. Host factors affecting AED delivery may be defined as the pharmacokinetic characteristics that determine the AED delivery to the site of action, the epileptic focus. Individual differences may occur in absorption, distribution, metabolism and excretion. These differences can be determined by genetic factors including gender and ethnicity, but the pharmacokinetics of AEDs can also be affected by age, specific physiological states in life, such as pregnancy, or pathological conditions including hepatic and renal insufficiency. Pharmacokinetic interactions with other drugs are another important source of variability in response to AEDs. Pharmacokinetic characteristics of the presently available AEDs are discussed in this review as well as their clinical implications.
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98
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Mallaysamy S, Johnson MG, Rao PGM, Rajakannan T, Bathala L, Arumugam K, van Hasselt JGC, Ramakrishna D. Population pharmacokinetics of lamotrigine in Indian epileptic patients. Eur J Clin Pharmacol 2012; 69:43-52. [DOI: 10.1007/s00228-012-1311-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 05/09/2012] [Indexed: 11/28/2022]
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Shibata M, Hashi S, Nakanishi H, Masuda S, Katsura T, Yano I. Detection of 22 antiepileptic drugs by ultra-performance liquid chromatography coupled with tandem mass spectrometry applicable to routine therapeutic drug monitoring. Biomed Chromatogr 2012; 26:1519-28. [DOI: 10.1002/bmc.2726] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2011] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 11/08/2022]
Affiliation(s)
- Mai Shibata
- Department of Clinical Pharmacy and Education, Graduate School of Pharmaceutical Sciences; Kyoto University; Kyoto; Japan
| | - Sachiyo Hashi
- Department of Pharmacy; Kyoto University Hospital; Kyoto; Japan
| | - Haruka Nakanishi
- Department of Clinical Pharmacy and Education, Graduate School of Pharmaceutical Sciences; Kyoto University; Kyoto; Japan
| | - Satohiro Masuda
- Department of Pharmacy; Kyoto University Hospital; Kyoto; Japan
| | - Toshiya Katsura
- Department of Pharmacy; Kyoto University Hospital; Kyoto; Japan
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Drust A, Luchtmann M, Firsching R, Tröger U, Martens-Lobenhoffer J, Bode-Böger SM. Recurrent seizures in a levetiracetam-treated patient after subarachnoid hemorrhage: a matter of enhanced renal function? Epilepsy Behav 2012; 23:394-5. [PMID: 22342435 DOI: 10.1016/j.yebeh.2011.12.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 12/13/2011] [Accepted: 12/18/2011] [Indexed: 11/17/2022]
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