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Chiodi D, Ishihara Y. The role of the methoxy group in approved drugs. Eur J Med Chem 2024; 273:116364. [PMID: 38781921 DOI: 10.1016/j.ejmech.2024.116364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 03/12/2024] [Accepted: 03/23/2024] [Indexed: 05/25/2024]
Abstract
The methoxy substituent is prevalent in natural products and, consequently, is present in many natural product-derived drugs. It has also been installed in modern drug molecules with no remnant of natural product features because medicinal chemists have been taking advantage of the benefits that this small functional group can bestow on ligand-target binding, physicochemical properties, and ADME parameters. Herein, over 230 methoxy-containing small-molecule drugs, as well as several fluoromethoxy-containing drugs, are presented from the vantage point of the methoxy group. Biochemical mechanisms of action, medicinal chemistry SAR studies, and numerous X-ray cocrystal structures are analyzed to identify the precise role of the methoxy group for many of the drugs and drug classes. Although the methoxy substituent can be considered as the hybridization of a hydroxy and a methyl group, the combination of these functionalities often results in unique effects that can amount to more than the sum of the individual parts.
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Affiliation(s)
- Debora Chiodi
- Department of Chemistry, Takeda Pharmaceuticals, 9625 Towne Centre Drive, San Diego, CA, 92121, USA
| | - Yoshihiro Ishihara
- Department of Chemistry, Vividion Therapeutics, 5820 Nancy Ridge Drive, San Diego, CA, 92121, USA.
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2
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Majhi P, Sayyad S, Gaur M, Kedar G, Rathod S, Sahu R, Pradhan PK, Tripathy S, Ghosh G, Subudhi BB. Tinospora cordifolia Extract Enhances Dextromethorphan Bioavailability: Implications for Alzheimer's Disease. ACS OMEGA 2024; 9:23634-23648. [PMID: 38854540 PMCID: PMC11154920 DOI: 10.1021/acsomega.4c01219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 06/11/2024]
Abstract
Tinospora cordifolia (Willd.) Miers (Menispermaceae) is a traditional rejuvenator and a conventional medicine used to manage oxidative stress-related diseases, including those associated with the central nervous system. Decreased dextromethorphan (DEM) metabolism is necessary for high bioavailability and application against Alzheimer's disease (AD). Since T. cordifolia stem extract (TCE) can potentially inhibit several metabolic enzymes, it can also enhance dextromethorphan bioavailability. This study investigates the potential of TCE to improve DEM's bioavailability and efficacy for the management of AD. In silico analysis was carried out to find the inhibition potential of phytocomponents of T. cordifolia for CYP2D6 and CYP3A4. The LC-MS method was revalidated for the analysis of DEM and metabolite dextrorphan (DEX) in the presence of quinidine (QN). The ratio of DEM to DEX was estimated with varying doses of TCE following pharmacokinetic analysis. Network pharmacology analysis was carried out to understand the complementary potential of phytocomponents. This was further validated in the scopolamine-induced dementia model through behavioral and histopathological analyses. TCE (100 mg/kg) for 14 days increased the DEM to DEX ratio by 2.8-fold compared to QN treatment. While T max was comparable to that of QN treatment at this dose (100 mg/kg) of TCE, it increased significantly at the higher dose (400 mg/kg) of TCE pretreatment. All other pharmacokinetic parameters were also enhanced at this dose with a 4.7-fold increase in DEM/DEX compared with QN. Network pharmacology analysis indicated the ability of TCE to target multiple factors associated with AD. Furthermore, it improved spatial memory and reduced hyperactivity in rodents better than the combination of QN and DEM.
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Affiliation(s)
- Praful
Kumar Majhi
- Drug
Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be
University), Bhubaneswar, Odisha 751029, India
| | - Samir Sayyad
- Vitely
Bio LLP, Ahmedabad , Gujarat 380054, India
| | - Mahendra Gaur
- Drug
Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be
University), Bhubaneswar, Odisha 751029, India
| | | | | | - Rajanikant Sahu
- Drug
Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be
University), Bhubaneswar, Odisha 751029, India
| | | | - Shyamalendu Tripathy
- Drug
Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be
University), Bhubaneswar, Odisha 751029, India
| | - Goutam Ghosh
- Department
of Pharmaceutics, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, Odisha 751029, India
| | - Bharat Bhusan Subudhi
- Drug
Development and Analysis Laboratory, School of Pharmaceutical Sciences, Siksha ‘O’ Anusandhan (Deemed to be
University), Bhubaneswar, Odisha 751029, India
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3
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Shimozawa S, Usuda D, Sasaki T, Tsuge S, Sakurai R, Kawai K, Matsubara S, Tanaka R, Suzuki M, Hotchi Y, Tokunaga S, Osugi I, Katou R, Ito S, Asako S, Mishima K, Kondo A, Mizuno K, Takami H, Komatsu T, Oba J, Nomura T, Sugita M. High doses of dextromethorphan induced shock and convulsions in a 19-year-old female: A case report. World J Clin Cases 2023; 11:3870-3876. [PMID: 37383112 PMCID: PMC10294160 DOI: 10.12998/wjcc.v11.i16.3870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/14/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023] Open
Abstract
BACKGROUND Dextromethorphan is a prevalent antitussive agent that can be easily obtained as an over-the-counter medication. There has been a growing number of reported cases of toxicity in recent years. Generally, there are numerous instances of mild symptoms, with only a limited number of reports of severe cases necessitating intensive care. We presented the case of a female who ingested 111 tablets of dextromethorphan, leading to shock and convulsions and requiring intensive care that ultimately saved her life.
CASE SUMMARY A 19-year-old female was admitted to our hospital via ambulance, having overdosed on 111 tablets of dextromethorphan (15 mg) obtained through an online importer in a suicide attempt. The patient had a history of drug abuse and multiple self-inflicted injuries. At the time of admission, she exhibited symptoms of shock and altered consciousness. However, upon arrival at the hospital, the patient experienced recurrent generalized clonic convulsions and status epilepticus, necessitating tracheal intubation. The convulsions were determined to have been caused by decreased cerebral perfusion pressure secondary to shock, and noradrenaline was administered as a vasopressor. Gastric lavage and activated charcoal were also administered after intubation. Through systemic management in the intensive care unit, the patient’s condition stabilized, and the need for vasopressors ceased. The patient regained consciousness and was extubated. The patient was subsequently transferred to a psychiatric facility, as suicidal ideation persisted.
CONCLUSION We report the first case of shock caused by an overdose of dextromethorphan.
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Affiliation(s)
- Shintaro Shimozawa
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Daisuke Usuda
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Toru Sasaki
- Clinical Training Center, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Shiho Tsuge
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Riki Sakurai
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Kenji Kawai
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Shun Matsubara
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Risa Tanaka
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Makoto Suzuki
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Yuta Hotchi
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Shungo Tokunaga
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Ippei Osugi
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Risa Katou
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Sakurako Ito
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Suguru Asako
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Kentaro Mishima
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Akihiko Kondo
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Keiko Mizuno
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Hiroki Takami
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Takayuki Komatsu
- Department of Sports Medicine, Faculty of Medicine, Juntendo University, Bunkyo-city 113-8421, Tokyo, Japan
| | - Jiro Oba
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Tomohisa Nomura
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
| | - Manabu Sugita
- Department of Emergency and Critical Care Medicine, Juntendo University Nerima Hospital, Nerima-city 177-8521, Tokyo, Japan
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4
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Silva AR, Dinis-Oliveira RJ. Pharmacokinetics and pharmacodynamics of dextromethorphan: clinical and forensic aspects. Drug Metab Rev 2020; 52:258-282. [DOI: 10.1080/03602532.2020.1758712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Ana Rita Silva
- Department of Public Health and Forensic Sciences, and Medical Education, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Ricardo Jorge Dinis-Oliveira
- Department of Public Health and Forensic Sciences, and Medical Education, Faculty of Medicine, University of Porto, Porto, Portugal
- Department of Sciences, IINFACTS – Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS), CESPU, CRL, Gandra, Portugal
- Department of Biological Sciences, Faculty of Pharmacy, Laboratory of Toxicology, UCIBIO, REQUIMTE, University of Porto, Porto, Portugal
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5
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Rogasch NC, Zipser C, Darmani G, Mutanen TP, Biabani M, Zrenner C, Desideri D, Belardinelli P, Müller-Dahlhaus F, Ziemann U. The effects of NMDA receptor blockade on TMS-evoked EEG potentials from prefrontal and parietal cortex. Sci Rep 2020; 10:3168. [PMID: 32081901 PMCID: PMC7035341 DOI: 10.1038/s41598-020-59911-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 01/21/2020] [Indexed: 12/24/2022] Open
Abstract
Measuring the brain’s response to transcranial magnetic stimulation (TMS) with electroencephalography (EEG) offers unique insights into the cortical circuits activated following stimulation, particularly in non-motor regions where less is known about TMS physiology. However, the mechanisms underlying TMS-evoked EEG potentials (TEPs) remain largely unknown. We assessed TEP sensitivity to changes in excitatory neurotransmission mediated by n-methyl-d-aspartate (NMDA) receptors following stimulation of non-motor regions. In fourteen male volunteers, resting EEG and TEPs from prefrontal (PFC) and parietal (PAR) cortex were measured before and after administration of either dextromethorphan (NMDA receptor antagonist) or placebo across two sessions in a double-blinded pseudo-randomised crossover design. At baseline, there were amplitude differences between PFC and PAR TEPs across a wide time range (15–250 ms), however the signals were correlated after ~80 ms, suggesting early peaks reflect site-specific activity, whereas late peaks reflect activity patterns less dependent on the stimulated sites. Early TEP peaks were not reliably altered following dextromethorphan compared to placebo, although findings were less clear for later peaks, and low frequency resting oscillations were reduced in power. Our findings suggest that early TEP peaks (<80 ms) from PFC and PAR reflect stimulation site specific activity that is largely insensitive to changes in NMDA receptor-mediated neurotransmission.
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Affiliation(s)
- Nigel C Rogasch
- Brain, Mind and Society Research Hub, School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Australia. .,Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, Australia. .,Discipline of Psychiatry, Adelaide Medical School, University of Adelaide, Adelaide, Australia.
| | - Carl Zipser
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Ghazaleh Darmani
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Tuomas P Mutanen
- Centre for Cognitive Neuroimaging, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom
| | - Mana Biabani
- Brain, Mind and Society Research Hub, School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Australia
| | - Christoph Zrenner
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Debora Desideri
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Paolo Belardinelli
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Florian Müller-Dahlhaus
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany.,Department of Psychiatry and Psychotherapy, University Medical Center Mainz, Mainz, Germany
| | - Ulf Ziemann
- Department of Neurology and Stroke, and Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
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6
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Taylor CP, Traynelis SF, Siffert J, Pope LE, Matsumoto RR. Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical use. Pharmacol Ther 2016; 164:170-82. [PMID: 27139517 DOI: 10.1016/j.pharmthera.2016.04.010] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Dextromethorphan (DM) has been used for more than 50years as an over-the-counter antitussive. Studies have revealed a complex pharmacology of DM with mechanisms beyond blockade of N-methyl-d-aspartate (NMDA) receptors and inhibition of glutamate excitotoxicity, likely contributing to its pharmacological activity and clinical potential. DM is rapidly metabolized to dextrorphan, which has hampered the exploration of DM therapy separate from its metabolites. Coadministration of DM with a low dose of quinidine inhibits DM metabolism, yields greater bioavailability and enables more specific testing of the therapeutic properties of DM apart from its metabolites. The development of the drug combination DM hydrobromide and quinidine sulfate (DM/Q), with subsequent approval by the US Food and Drug Administration for pseudobulbar affect, led to renewed interest in understanding DM pharmacology. This review summarizes the interactions of DM with brain receptors and transporters and also considers its metabolic and pharmacokinetic properties. To assess the potential clinical relevance of these interactions, we provide an analysis comparing DM activity from in vitro functional assays with the estimated free drug DM concentrations in the brain following oral DM/Q administration. The findings suggest that DM/Q likely inhibits serotonin and norepinephrine reuptake and also blocks NMDA receptors with rapid kinetics. Use of DM/Q may also antagonize nicotinic acetylcholine receptors, particularly those composed of α3β4 subunits, and cause agonist activity at sigma-1 receptors.
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Affiliation(s)
| | - Stephen F Traynelis
- Dept. of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Joao Siffert
- Avanir Pharmaceuticals, Inc., Aliso Viejo, CA, USA
| | - Laura E Pope
- Avanir Pharmaceuticals, Inc., Aliso Viejo, CA, USA
| | - Rae R Matsumoto
- College of Pharmacy, Touro University California, Vallejo, CA, USA
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7
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Nguyen L, Thomas KL, Lucke-Wold BP, Cavendish JZ, Crowe MS, Matsumoto RR. Dextromethorphan: An update on its utility for neurological and neuropsychiatric disorders. Pharmacol Ther 2016; 159:1-22. [PMID: 26826604 DOI: 10.1016/j.pharmthera.2016.01.016] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Dextromethorphan (DM) is a commonly used antitussive and is currently the only FDA-approved pharmaceutical treatment for pseudobulbar affect. Its safety profile and diverse pharmacologic actions in the central nervous system have stimulated new interest for repurposing it. Numerous preclinical investigations and many open-label or blinded clinical studies have demonstrated its beneficial effects across a variety of neurological and psychiatric disorders. However, the optimal dose and safety of chronic dosing are not fully known. This review summarizes the preclinical and clinical effects of DM and its putative mechanisms of action, focusing on depression, stroke, traumatic brain injury, seizure, pain, methotrexate neurotoxicity, Parkinson's disease and autism. Moreover, we offer suggestions for future research with DM to advance the treatment for these and other neurological and psychiatric disorders.
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Affiliation(s)
- Linda Nguyen
- Department of Behavioral Medicine and Psychiatry, School of Medicine, West Virginia University, Morgantown, WV 26506, USA; Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, WV 26506, USA
| | - Kelan L Thomas
- College of Pharmacy, Touro University California, Vallejo, CA 94592, USA
| | - Brandon P Lucke-Wold
- Graduate Program in Neuroscience, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - John Z Cavendish
- Graduate Program in Neuroscience, School of Medicine, West Virginia University, Morgantown, WV 26506, USA
| | - Molly S Crowe
- Department of Psychology, West Virginia University, Morgantown, WV 26506, USA
| | - Rae R Matsumoto
- Department of Behavioral Medicine and Psychiatry, School of Medicine, West Virginia University, Morgantown, WV 26506, USA; College of Pharmacy, Touro University California, Vallejo, CA 94592, USA.
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8
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Schoedel KA, Morrow SA, Sellers EM. Evaluating the safety and efficacy of dextromethorphan/quinidine in the treatment of pseudobulbar affect. Neuropsychiatr Dis Treat 2014; 10:1161-74. [PMID: 25061302 PMCID: PMC4079824 DOI: 10.2147/ndt.s30713] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Pseudobulbar affect (PBA) is a common manifestation of brain pathology associated with many neurological diseases, including amyotrophic lateral sclerosis, Alzheimer's disease, stroke, multiple sclerosis, Parkinson's disease, and traumatic brain injury. PBA is defined by involuntary and uncontrollable expressed emotion that is exaggerated and inappropriate, and also incongruent with the underlying emotional state. Dextromethorphan/quinidine (DM/Q) is a combination product indicated for the treatment of PBA. The quinidine component of DM/Q inhibits the cytochrome P450 2D6-mediated metabolic conversion of dextromethorphan to its active metabolite dextrorphan, thereby increasing dextromethorphan systemic bioavailability and driving the pharmacology toward that of the parent drug and away from adverse effects of the dextrorphan metabolite. Three published efficacy and safety studies support the use of DM/Q in the treatment of PBA; significant effects were seen on the primary end point, the Center for Neurologic Study-Lability Scale, as well as secondary efficacy end points and quality of life. While concentration-effect relationships appear relatively weak for efficacy parameters, concentrations of DM/Q may have an impact on safety. Some special safety concerns exist with DM/Q, primarily because of the drug interaction and QT prolongation potential of the quinidine component. However, because concentrations of dextrorphan (which is responsible for many of the parent drug's side effects) and quinidine are lower than those observed in clinical practice with these drugs administered alone, some of the perceived safety issues may not be as relevant with this low dose combination product. However, since patients with PBA have a variety of other medical problems and are on numerous other medications, they may not tolerate DM/Q adverse effects, or may be at risk for drug interactions. Some caution is warranted when initiating DM/Q treatment, particularly in patients with underlying risk factors for torsade de pointes and in those receiving medications that may interact with DM/Q.
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Affiliation(s)
| | | | - Edward M Sellers
- DL Global Partners, Inc., Toronto, Canada ; University of Toronto, Toronto, Ontario, Canada
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9
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Ghasemi M, Schachter SC. The NMDA receptor complex as a therapeutic target in epilepsy: a review. Epilepsy Behav 2011; 22:617-40. [PMID: 22056342 DOI: 10.1016/j.yebeh.2011.07.024] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 07/01/2011] [Accepted: 07/18/2011] [Indexed: 01/02/2023]
Abstract
A substantial amount of research has shown that N-methyl-D-aspartate receptors (NMDARs) may play a key role in the pathophysiology of several neurological diseases, including epilepsy. Animal models of epilepsy and clinical studies demonstrate that NMDAR activity and expression can be altered in association with epilepsy and particularly in some specific seizure types. NMDAR antagonists have been shown to have antiepileptic effects in both clinical and preclinical studies. There is some evidence that conventional antiepileptic drugs may also affect NMDAR function. In this review, we describe the evidence for the involvement of NMDARs in the pathophysiology of epilepsy and provide an overview of NMDAR antagonists that have been investigated in clinical trials and animal models of epilepsy.
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Affiliation(s)
- Mehdi Ghasemi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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10
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Akerele E, Bisaga A, Sullivan MA, Garawi F, Comer SD, Thomas AA, Nunes EV, Kleber HD. Dextromethorphan and quinidine combination for heroin detoxification. Am J Addict 2008; 17:176-80. [PMID: 18463993 DOI: 10.1080/10550490802019543] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Dextromethorphan (DM) is a low-affinity, non-competitive NMDA receptor antagonist that has shown promise in preclinical and preliminary clinical studies for the reduction of opioid withdrawal symptoms, but when used at higher doses, it is associated with deleterious side effects attributed to its metabolite, dextrorphan. A clinical trial was therefore conducted to test the withdrawal-suppressant effect of a combination of dextromethorphan with quinidine (DM/Q). Quinidine inhibits the metabolism of dextromethorphan, reducing dextrorphan levels. Opioid-dependent patients were admitted to an inpatient unit, stabilized for three days on morphine (25 mg, sc, every six hours), and randomly assigned on day 2 to DM/Q (30 mg/30 mg, twice a day) (n = 22) or matching placebo (n = 9) prior to the discontinuation of morphine on day 4. Withdrawal symptoms, measured with the Modified Himmelsbach Opioid Withdrawal Scale (MHOWS), increased significantly on days 4 and 5 (Z = 3.70, p = .0002), and by day 6, 90% of the sample (28/31) had dropped out of the study. There were no differences between treatment groups on either outcome measure. The combination of dextromethorphan and quinidine appears ineffective as a primary treatment for opioid withdrawal. Future studies should examine dextromethorphan as an adjunct to other anti-withdrawal medications and focus more on the relationship between dextrorphan levels and withdrawal suppression.
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Affiliation(s)
- Evaristo Akerele
- Department of Psychiatry, Columbia University College of Physicians & Surgeons, New York, New York, USA
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11
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Pope LE, Khalil MH, Berg JE, Stiles M, Yakatan GJ, Sellers EM. Pharmacokinetics of dextromethorphan after single or multiple dosing in combination with quinidine in extensive and poor metabolizers. J Clin Pharmacol 2005; 44:1132-42. [PMID: 15342614 DOI: 10.1177/0091270004269521] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Dextromethorphan (DM) pharmacological properties predict that the widely used cough suppressant could be used to treat several neuronal disorders, but it is rapidly metabolized after oral dosing. To find out whether quinidine (Q), a CYP2D6 inhibitor, could elevate and prolong DM plasma profiles, 2 multiple-dose studies identified the lowest oral dose of Q that could be used in a fixed combination with 3 doses of DM. A multiple-dose study in healthy subjects with an extensive or a poor enzyme metabolizer phenotype evaluated the safety and pharmacokinetic profile of a selected fixed-dose combination (AVP-923). Study 1 randomized 46 healthy subjects, who were extensive CYP2D6 metabolizers, to receive 0, 2.5, 10, 25, 50, or 75 mg Q twice daily in combination with 30 mg DM for 7 days. Plasma and urine samples were collected after the first and last doses for the assay of DM, dextrorphan (DX), and Q. Study 2 randomized 65 healthy extensive CYP2D6 metabolizers to 8 groups given twice-daily 45- or 60-mg DM doses combined with 0, 30, 45, or 60 mg Q for 7 days. The effects of increasing Q were not different with doses greater than 25 mg, whereas lower doses showed a dose-related increase in plasma DM concentrations. Urinary ratios of DM/DX showed a Q dose- and time-related increase in the number of subjects converted to the poor metabolizer phenotype that reached 100% on day 3 of dosing with 25 mg Q. Results from both studies indicated that 25 to 30 mg Q is adequate to maximally suppress O-demethylation of DM. Study 3 evaluated 7 extensive metabolizers and 2 poor metabolizers given an oral capsule every 12 hours containing 30 mg Q combined with 30 mg DM. DM plasma AUC values increased in both groups of subjects during the 8-day study. The mean urinary metabolic ratio (DM/DX) increased at least 27-fold in extensive metabolizers by day 8. There was no effect of Q on urinary metabolic ratios in poor metabolizers. Safety evaluations, including electrocardiograms, indicated that the combination was well tolerated, with no difference between extensive and poor metabolizer phenotypes.
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Affiliation(s)
- Laura E Pope
- Avanir Pharmaceuticals, 11388 Sorrento Valley Road, Suite 200, San Diego, CA 92121, USA
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12
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Oliveto A, Poling J, Kosten TR, Gonsai K. Isradipine and dextromethorphan in methadone-maintained humans under a naloxone discrimination procedure. Eur J Pharmacol 2004; 491:157-68. [PMID: 15140632 DOI: 10.1016/j.ejphar.2004.03.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 03/04/2004] [Accepted: 03/10/2004] [Indexed: 10/26/2022]
Abstract
In seven methadone-maintained human participants trained to distinguish between a low dose of naloxone (0.15 mg/70 kg, i.m.; i.e., Drug A) and placebo (i.e., Drug B) under an instructed novel-response drug discrimination procedure, the calcium channel blocker isradipine (0-10 mg/70 kg, p.o.; N=7) and the N-methyl-D-aspartic acid (NMDA) receptor antagonist dextromethorphan (0-60 mg/70 kg, p.o.; N=6) were tested each alone and in combination with the training dose of naloxone. Isradipine alone produced some naloxone- and novel-appropriate responding, minimal changes in self-reports and decreases in blood pressure. Dextromethorphan alone produced some novel-appropriate responding and minimal changes in self-reports and vital signs. When combined with naloxone, isradipine significantly attenuated naloxone-occasioned responding, without increasing novel-appropriate responding, and attenuated naloxone-induced increases in opioid receptor antagonist ratings and ratings measuring sedation. Dextromethorphan significantly attenuated naloxone-appropriate responding, increased novel-appropriate responding, and enhanced naloxone's effects on ratings of dysphoric effects. These results suggest that isradipine attenuates and dextromethorphan enhances some of the behavioral effects of naloxone in opioid-dependent humans.
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Affiliation(s)
- Alison Oliveto
- CT and VA Connecticut Healthcare System, Yale University, New Haven, 950 Campbell Avenue, Psychiatry 116A-4, Building 36, West Haven, CT 06516, USA.
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Lyszkiewicz DA, Einarson A, Koren G. Dextromethorphan in Pregnancy. Chest 2001. [DOI: 10.1016/s0012-3692(15)50203-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Liu ST, Wu CT, Yeh CC, Ho ST, Wong CS, Jao SW, Wu CC, Kang JC. Premedication with dextromethorphan provides posthemorrhoidectomy pain relief. Dis Colon Rectum 2000; 43:507-10. [PMID: 10789747 DOI: 10.1007/bf02237195] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
PURPOSE Previous studies have shown that N-methyl-D-aspartate receptor antagonists provide a preemptive analgesic effect in humans. This study was designed to examine whether premedication with dextromethorphan, an N-methyl-D-aspartate antagonist, also provided a preemptive analgesic effect that improved postoperative pain management. METHODS Sixty patients who were American Society of Anesthesiologists status I and II scheduled for hemorrhoidectomy (modified Whitehead procedure) were included in the study. Patients were randomly assigned to the control and study groups. For the control group patients received chlorpheniramine maleate (20 mg), a component of the injection form of dextromethorphan, intramuscular injection 30 minutes before skin incision. In the study group dextromethorphan 40 mg containing 20 mg chlorpheniramine maleate (intramuscular) was given as premedication 30 minutes before skin incision. Pethidine (1 mg/kg, intramuscular) was given for pain relief as required postoperatively. The time to first pethidine injection, total pethidine consumption, worst pain score, and pethidine-related side effects were recorded for 48 hours postoperatively. RESULTS The times to first pethidine injection (mean +/- standard error of the mean) were 5.2 +/- 3 and 19.6 +/- 6 hours in the control and study groups, respectively. Total pethidine consumption was 140 +/- 11.3 and 63.5 +/- 11.8 mg in the control and study groups. The worst visual analog scale pain scores were 7.4 +/- 0.2 and 5.6 +/- 0.3 in the control and study groups during the two-day observation. The numbers of patients who required pethidine injection were 29 and 20 in the control and study groups, respectively. Two patients suffered pethidine-related side effects, such as nausea, vomiting, dizziness, and headache, in the control group, and no patient complained of any side effect in the study group. CONCLUSION We found that dextromethorphan premedication provided a preemptive analgesic effect, thus producing reduced postoperative pain and pethidine requirement and improved recovery from hemorrhoidectomy.
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Affiliation(s)
- S T Liu
- Section of Anesthesia, Armed Forces Sung-Shang Hospital, Taipei, Taiwan, Republic of China
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Andaloro VJ, Monaghan DT, Rosenquist TH. Dextromethorphan and other N-methyl-D-aspartate receptor antagonists are teratogenic in the avian embryo model. Pediatr Res 1998; 43:1-7. [PMID: 9432105 DOI: 10.1203/00006450-199801000-00001] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
N-Methyl-D-aspartate (NMDA) receptors are a calcium-conducting class of excitatory amino acid receptors that are involved in neuronal development and migration. Certain well known teratogens (e.g. homocysteine, ethanol, and chloroform) that induce congenital neural tube and neural crest defects also have the capacity to act as NMDA receptor antagonists. We hypothesized that teratogenicity was a general property of NMDA receptor antagonists, and that high affinity NMDA receptor antagonists would induce neural tube and neural crest defects. Chicken embryos were given 5, 50, or 500 nmol/d of selected NMDA receptor antagonists for 3 consecutive days during the process of neural tube closure, beginning 4 h after the beginning of incubation. Selected NMDA receptor antagonists represented three classes of antagonists: ion channel blockers, glycine site antagonists, and glutamate site agonists and antagonists. All classes of NMDA receptor antagonists induced embryonic death and congenital defects of the neural crest and neural tube; however, the channel blockers were the most potent teratogens. Dextromethorphan at 500 nmol/embryo/d killed more than half the embryos and induced congenital defects in about one-eighth of the survivors; dextromethorphan was also highly lethal at 50 nmol/embryo/d. Glutamate site NMDA receptor agonists (NMDA and homoquinolinic acid) displayed weak toxicity relative to their known NMDA receptor potency. Taken together, these data indicate that NMDA receptor antagonists, particularly channel blockers, are potent teratogens in the chicken embryo model. Because dextromethorphan is a widely used nonprescription antitussive, its strong teratogeneticity using this model is particularly noteworthy.
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Affiliation(s)
- V J Andaloro
- Department of Pharmacology, College of Medicine, University of Nebraska Medical Center, Omaha 68198-6260, USA
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