Mortality: In the National Heart, Lung and Blood Institute's Cardiac Arrhythmia Suppression Trial (CAST), a long-term, multicentered, randomized, double-blind study in patients with asymptomatic non-life-threatening ventricular arrhythmias who had a myocardial infarction more than six days but less than two years previously, an excessive mortality or non-fatal cardiac arrest rate (7.7%) was seen in patients treated with encainide or flecainide compared with that seen in patients assigned to carefully matched placebo-treated groups (3.0%). The average duration of treatment with encainide or flecainide in this study was ten months.
The applicability of the CAST results to other populations (e.g., those without recent myocardial infarction) is uncertain. Considering the known proarrhythmic properties of MEXITIL and the lack of evidence of improved survival for any antiarrhythmic drug in patients without life-threatening arrhythmias, the use of MEXITIL as well as other antiarrhythmic agents should be reserved for patients with life-threatening ventricular arrhythmia.
(mexiletine hydrochloride, USP)
MEXITIL® (mexiletine hydrochloride, USP) is an orally active antiarrhythmic agent available as 150 mg, 200 mg and 250 mg capsules. 100 mg of mexiletine hydrochloride is equivalent to 83.31 mg of mexiletine base. It is a white to off-white crystalline powder with slightly bitter taste, freely soluble in water and in alcohol. MEXITIL has a pKa of 9.2.
MEXITIL (mexiletine hydrochloride, USP)is indicated for the treatment of documented ventricular arrhythmias, such as sustained ventricular tachycardia, that, in the judgement of the physician, are life-threatening. Because of the proarrhythmic effects of MEXITIL, its use with lesser arrhythmias is generally not recommended. Treatment of patients with asymptomatic ventricular premature contractions should be avoided.
Initiation of MEXITIL treatment, as with other antiarrhythmic agents used to treat life-threatening arrhythmias, should be carried out in the hospital.
Antiarrhythmic drugs have not been shown to enhance survival in patients with ventricular arrhythmias.
Published Studies Related to Mexitil (Mexiletine)
Mexiletine for symptoms and signs of myotonia in nondystrophic myotonia: a
randomized controlled trial. 
myotonia in patients with NDMs... CONCLUSION: In this preliminary study of patients with NDMs, the use of
Mexiletine is an effective antimyotonia treatment in myotonic dystrophy type 1. [2010.05.04]
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... 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.
Morphine versus mexiletine for treatment of postamputation pain: a randomized, placebo-controlled, crossover trial. [2008.08]
BACKGROUND: Stump and phantom pains are debilitating sequelae of amputations that are often resistant to treatment. The efficacy of pharmacologic therapies, including opioids and sodium channel blockers, for postamputation pain is uncertain... CONCLUSIONS: Therapy with morphine, but not mexiletine, resulted in a decrease in intensity of postamputation pain but was associated with a higher rate of side effects and no improvement in self-reported levels of overall functional activity and pain-related interference in daily activities.
Translation of flecainide- and mexiletine-induced cardiac sodium channel inhibition and ventricular conduction slowing from nonclinical models to clinical. [2011.05]
INTRODUCTION: Nonclinical in vivo models used for cardiovascular safety testing have not previously been studied for their sensitivity for detection of conduction slowing resulting from cardiac sodium channel block. The goal of this study was to examine the sensitivity of in vivo models to cardiac sodium channel block, and translation of the effect from in vitro to in vivo models using sodium channel inhibitors flecainide and mexiletine; flecainide, but not mexiletine is commonly associated with QRS complex prolongation in humans...
Refractory erythromelalgia of the ears: response to mexiletine. [2011.03]
Erythromelalgia is a rare condition characterized by burning pain, erythema, swelling, and increased temperature usually in the extremities. We present an unusual presentation of erythromelalgia of the ears in a patient who has been refractory to multiple therapies and in whom relief of symptoms was achieved with the use of mexiletine.
Clinical Trials Related to Mexitil (Mexiletine)
Mexiletine in Sporadic Amyotrophic Lateral Sclerosis (SALS) [Active, not recruiting]
The purpose of this research is to find out if mexiletine is safe and effective in people
with Amyotrophic Lateral Sclerosis (ALS). In this trial, participants will be taking either
300 milligrams per day of mexiletine, 900 milligrams per day of mexiletine or placebo
(non-active study drug). The safety and efficacy of these doses will be compared to see if
one dose is better than the other.
Combined N-of-1 Trials Mexiletine vs Placebo in Patients With Non-Dystrophic Myotonia (NDM) [Recruiting]
The main objective of this study is to explore whether multiple trials with individual
patients (N-of-1 trials) can produce a reliable evidence base for coverage decisions on
clinical and cost-effectiveness of drug treatment for patients with rare diseases. As a case
study, we will study the clinical and cost-effectiveness of Mexiletine in patients with
Non-Dystrophic myotonia. The results of this analysis will be compared with the results
obtained from a recently published international, multi-centre, randomized,
placebo-controlled trial of Mexiletine in patients with Non-Dystrophic Myotonia
(clinicaltrials. gov Identifier: NCT00832000).
The secondary objective of this proposal is to assess whether mexiletine improves myotonia
measured (both quantitatively and qualitative) in patients with non-dystrophic myotonia.
Clinical Efficacy Trial of Mexiletine for Myotonic Dystrophy Type 1 [Recruiting]
Mexiletine and Non Dystrophic Myotonias [Completed]
Treatment strategies in non-dystrophic myotonias are based on selective case reports,
clinical experience and theoretical benefit. Presently, the most promising antimyotonic
medication is mexiletine (MEX) but its manufacturing was stopped. The proposed randomized,
double-blind, placebo-controlled, crossover trial is designed to:
1. study the safety and efficacy of mexiletine for the treatment of non-dystrophic
2. validate electromyographic tests as a standardized outcome measure of myotonia
3. assess the reliability and validity of a new clinical rating scale for myotonia
Ability of Late Sodium or Calcium Current Block to Balance the ECG Effects of Potassium Current Block [Completed]
The primary objective of this research study is to test the hypothesis that late sodium
current blocking drugs (mexiletine or lidocaine) can attenuate the effect of hERG potassium
channel blocking drugs (dofetilide) on ventricular repolarization (QTc) by shortening early
repolarization (J-Tpeakc). The secondary object is to assess the ability of calcium channel
block (diltiazem) to reduce the QTc prolongation associated with hERG block (moxifloxacin).
Page last updated: 2013-02-10