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Elettreby AM, Elnaga AAA, Alsaied MA, Ewis DK, Sharkawy AM, Fareed R, Alderbi GM. Effectiveness and safety of mexiletine versus placebo in patients with myotonia: a systematic review and meta-analysis. Neurol Sci 2024:10.1007/s10072-024-07412-z. [PMID: 38403671 DOI: 10.1007/s10072-024-07412-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 02/16/2024] [Indexed: 02/27/2024]
Abstract
BACKGROUND The rare nature of dystrophic and non-dystrophic myotonia has limited the available evidence on the efficacy of mexiletine as a potential treatment. To address this gap, we conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of mexiletine for both dystrophic and non-dystrophic myotonic patients. METHODS The search was conducted on various electronic databases up to March 2023, for randomized clinical trials (RCTs) comparing mexiletine versus placebo in myotonic patients. A risk of bias assessment was carried out, and relevant data was extracted manually into an online sheet. RevMan software (version 5.4) was employed for analysis. RESULTS A total of five studies, comprising 186 patients, were included in the meta-analysis. Our findings showed that mexiletine was significantly more effective than placebo in improving stiffness score (SMD = - 1.19, 95% CI [- 1.53, - 0.85]), as well as in reducing hand grip myotonia (MD = - 1.36 s, 95% CI [- 1.83, - 0.89]). Mexiletine also significantly improved SF-36 Physical and Mental Component Score in patients with non-dystrophic myotonia only. Regarding safety, mexiletine did not significantly alter ECG parameters but was associated with greater gastrointestinal symptoms (GIT) compared to placebo (RR 3.7, 95% CI [1.79, 7.64]). Other adverse events showed no significant differences. CONCLUSION The results support that mexiletine is effective and safe in myotonic patients; however, it is associated with a higher risk of GIT symptoms. Due to the scarcity of published RCTs and the prevalence of GIT symptoms, we recommend further well-designed RCTs testing various drug combinations to reduce GIT symptoms.
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Affiliation(s)
- Abdelrahman Mohammed Elettreby
- Faculty of Medicine, Mansoura University, El Gomhouria St, Mansoura, 35511, Egypt.
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA.
| | - Ahmed Abdullah Abo Elnaga
- Faculty of Medicine, Mansoura University, El Gomhouria St, Mansoura, 35511, Egypt
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
| | - Mohamed Ahmed Alsaied
- Faculty of Medicine, Mansoura University, El Gomhouria St, Mansoura, 35511, Egypt
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
| | - Dalia Kamal Ewis
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Medicine, Beni Suef University, Beni Suef, Egypt
| | - Aya Mohammed Sharkawy
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Medicine, South Valley University, Qena, Egypt
| | - Rahma Fareed
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt
| | - Gehad Magdy Alderbi
- Medical Research Group of Egypt, Negida Academy LLC, Arlington, MA, 02474, USA
- Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt
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Matthews E, Hanna MG. Repurposing of sodium channel antagonists as potential new anti-myotonic drugs. Exp Neurol 2014; 261:812-5. [PMID: 25218042 DOI: 10.1016/j.expneurol.2014.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/22/2014] [Accepted: 09/02/2014] [Indexed: 01/08/2023]
Abstract
Myotonia is often a painful and disabling symptom which can interfere with daily motor function resulting in significant morbidity. Since myotonic disorders are rare it has generally proved difficult to obtain class I level evidence for anti-myotonic drug efficacy by performing randomized placebo controlled trials. Current treatment guidance is therefore largely based on anecdotal reports and physician experience. Despite the genetic channel heterogeneity of the myotonic disorders the sodium channel antagonists have become the main focus of pharmacological interest. Mexiletine is currently regarded as the first choice sodium channel blocker based on a recent placebo controlled randomized trial. However, some patients do not respond to mexiletine or have significant side effects limiting its use. There is a clinical need to develop additional antimyotonic agents. The study of Desaphy et al. is therefore important and provides in vitro evidence that a number of existing drugs with sodium channel blocking capability could potentially be repurposed as anti-myotonic drugs. Translation of these potentially important in vitro findings into clinical practice requires carefully designed randomized controlled trials. Here we discuss Desaphy's findings in the wider context of attempts to develop additional therapies for patients with clinically significant myotonia.
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Affiliation(s)
- E Matthews
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK
| | - M G Hanna
- MRC Centre for Neuromuscular Diseases, Department of Molecular Neuroscience, UCL Institute of Neurology and National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.
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Heatwole CR, Statland JM, Logigian EL. The diagnosis and treatment of myotonic disorders. Muscle Nerve 2013; 47:632-48. [PMID: 23536309 DOI: 10.1002/mus.23683] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2012] [Indexed: 12/12/2022]
Abstract
Myotonia is a defining clinical symptom and sign common to a relatively small group of muscle diseases, including the myotonic dystrophies and the nondystrophic myotonic disorders. Myotonia can be observed on clinical examination, as can its electrical correlate, myotonic discharges, on electrodiagnostic testing. Research interest in the myotonic disorders continues to expand rapidly, which justifies a review of the scientific bases, clinical manifestations, and numerous therapeutic approaches associated with these disorders. We review the pathomechanisms of myotonia, the clinical features of the dystrophic and nondystrophic myotonic disorders, and the diagnostic approach and treatment options for patients with symptomatic myotonia.
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Affiliation(s)
- Chad R Heatwole
- Department of Neurology, Box 673, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, New York, New York 14642, USA.
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Conravey A, Santana-Gould L. Myotonia congenita and myotonic dystrophy: surveillance and management. Curr Treat Options Neurol 2011; 12:16-28. [PMID: 20842486 DOI: 10.1007/s11940-009-0055-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OPINION STATEMENT Myotonia can be treated both pharmacologically and by lifestyle modifications. Cell membrane stabilizers are the medications most commonly used for symptomatic treatment of myotonia. Most patients do not require treatment for the myotonia itself, unless it is severe, but physicians must be aware of anesthesia risks in both myotonia congenita and myotonic dystrophy. A mainstay of management of myotonic dystrophy is the surveillance and treatment of its various systemic complications.
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Affiliation(s)
- Allison Conravey
- Department of Pediatrics, Tulane University, 1430 Tulane Avenue, SL-37, New Orleans, LA, 70112, USA,
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Logigian EL, Martens WB, Moxley RT, McDermott MP, Dilek N, Wiegner AW, Pearson AT, Barbieri CA, Annis CL, Thornton CA, Moxley RT. Mexiletine is an effective antimyotonia treatment in myotonic dystrophy type 1. Neurology 2010; 74:1441-8. [PMID: 20439846 DOI: 10.1212/wnl.0b013e3181dc1a3a] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVE To determine if mexiletine is safe and effective in reducing myotonia in myotonic dystrophy type 1 (DM1). BACKGROUND Myotonia is an early, prominent symptom in DM1 and contributes to decreased dexterity, gait instability, difficulty with speech/swallowing, and muscle pain. A few preliminary trials have suggested that the antiarrhythmic drug mexiletine is useful, symptomatic treatment for nondystrophic myotonic disorders and DM1. METHODS We performed 2 randomized, double-blind, placebo-controlled crossover trials, each involving 20 ambulatory DM1 participants with grip or percussion myotonia on examination. The initial trial compared 150 mg of mexiletine 3 times daily to placebo, and the second trial compared 200 mg of mexiletine 3 times daily to placebo. Treatment periods were 7 weeks in duration separated by a 4- to 8-week washout period. The primary measure of myotonia was time for isometric grip force to relax from 90% to 5% of peak force after a 3-second maximum grip contraction. EKG measurements and adverse events were monitored in both trials. RESULTS There was a significant reduction in grip relaxation time with both 150 and 200 mg dosages of mexiletine. Treatment with mexiletine at either dosage was not associated with any serious adverse events, or with prolongation of the PR or QTc intervals or of QRS duration. Mild adverse events were observed with both placebo and mexiletine treatment. CONCLUSIONS Mexiletine at dosages of 150 and 200 mg 3 times daily is effective, safe, and well-tolerated over 7 weeks as an antimyotonia treatment in DM1. CLASSIFICATION OF EVIDENCE This study provides Class I evidence that mexiletine at dosages of 150 and 200 mg 3 times daily over 7 weeks is well-tolerated and effective in reducing handgrip relaxation time in DM1.
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Affiliation(s)
- E L Logigian
- Department of Neurology, University of Rochester, Rochester, NY, USA.
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Abstract
BACKGROUND Abnormal delayed relaxation of skeletal muscles, known as myotonia, can cause disability in myotonic disorders. Sodium channel blockers, tricyclic antidepressive drugs, benzodiazepines, calcium-antagonists, taurine and prednisone may be of use in reducing myotonia. OBJECTIVES To consider the evidence from randomised controlled trials on the efficacy and tolerability of drug treatment in patients with clinical myotonia due to a myotonic disorder. SEARCH STRATEGY We searched the Cochrane Neuromuscular Disease Group trials register (April 2004), MEDLINE (January 1966 to December 2003) and EMBASE (January 1980 to December 2003). Grey literature was handsearched and reference lists of identified studies and reviews were examined. Authors, disease experts and manufacturers of anti-myotonic drugs were contacted. SELECTION CRITERIA We considered all (quasi) randomised trials of participants with myotonia treated with any drug treatment versus no therapy, placebo or any other active drug treatment. The primary outcome measure was:reduced clinical myotonia using two categories: (1) no residual myotonia or improvement of myotonia or (2) No change or worsening of myotonia. Secondary outcome measures were:(1) clinical relaxation time; (2) electromyographic relaxation time; (3) stair test; (4) presence of percussion myotonia; and (5) proportion of adverse events. DATA COLLECTION AND ANALYSIS Two authors extracted the data independently onto standardised extraction forms and disagreements were resolved by discussion. MAIN RESULTS Nine randomised controlled trials were found comparing active drug treatment versus placebo or another active drug treatment in patients with myotonia due to a myotonic disorder. Included trials were double-blind or single-blind crossover studies involving a total of 137 patients of which 109 had myotonic dystrophy type 1 and 28 had myotonia congenita. The studies were of poor quality. Therefore, we were not able to analyse the results of all identified studies. Two small crossover studies without a washout period demonstrated a significant effect of imipramine and taurine in myotonic dystrophy. One small crossover study with a washout period demonstrated a significant effect of clomipramine in myotonic dystrophy. Meta-analysis was not possible. AUTHORS' CONCLUSIONS Due to insufficient good quality data and lack of randomised studies, it is impossible to determine whether drug treatment is safe and effective in the treatment of myotonia. Small single studies give an indication that clomipramine and imipramine have a short-term beneficial effect and that taurine has a long-term beneficial effect on myotonia. Larger, well-designed randomised controlled trials are needed to assess the efficacy and tolerability of drug treatment for myotonia.
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Affiliation(s)
- J Trip
- Academisch Ziekenhuis Maastricht (AZM), Department of Neurology, P. Debyelaan 25 Postbus5800, Maastricht, Limburg, Netherlands, 6202 AZ.
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Abstract
The myotonic disorders, including the myotonic dystrophies (myotonic dystrophy type 1, DM1; myotonic dystrophy type 2, DM2/PROMM/PDM), the muscle channelopathies or non-dystrophic myotonias (chloride, sodium, calcium and potassium channelopathies) are all characterized by myotonia and muscle weakness despite different pathophysiology involved in these disorders. Myotonia may affect the eye, facial and jaw muscles as well as the hands and legs. It may be painful and disabling. Muscle weakness may be episodical as in the paralytic attacks of the sodium and calcium channelopathies or culminate in permanent muscle weakness as in the calcium channelopathies and some sodium channelopathies associated to specific point mutations. The severity of myotonia may fluctuate in the myotonic dystrophies, but weakness is usually fixed, affecting neck flexors, facial and jaw muscles as well as proximal and distal muscles of the limbs. Despite the recent progress in molecular genetics the precise mechanisms responsible for myotonia and weakness are not fully understood and there is no standardized treatment strategy. We present a review of selected treatment trials in the myotonic disorders and the muscle channelopathies, and discuss our experience in the treatment of myotonia and muscle weakness, with reference to the limits and advantages of treatment trials in this field.
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Affiliation(s)
- G Meola
- Department of Neurology, University of Milan, Istituto Policlinico San Donato, Italy
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