PT  - JOURNAL ARTICLE
AU  - Weiss, Michael D.
AU  - Macklin, Eric A.
AU  - Simmons, Zachary
AU  - Knox, Angela S.
AU  - Greenblatt, David J.
AU  - Atassi, Nazem
AU  - Graves, Michael
AU  - Parziale, Nicholas
AU  - Salameh, Johnny S.
AU  - Quinn, Colin
AU  - Brown, Robert H.
AU  - Distad, Jane B.
AU  - Trivedi, Jaya
AU  - Shefner, Jeremy M.
AU  - Barohn, Richard J.
AU  - Pestronk, Alan
AU  - Swenson, Andrea
AU  - Cudkowicz, Merit E.
AU  - For the Mexiletine ALS Study Group
TI  - A randomized trial of mexiletine in ALS
AID  - 10.1212/WNL.0000000000002507
DP  - 2016 Apr 19
TA  - Neurology
PG  - 1474--1481
VI  - 86
IP  - 16
4099  - http://n.neurology.org/content/86/16/1474.short
4100  - http://n.neurology.org/content/86/16/1474.full
SO  - Neurology2016 Apr 19; 86
AB  - Objective: To determine the safety and tolerability of mexiletine in a phase II double-blind randomized controlled trial of sporadic amyotrophic lateral sclerosis (SALS).Methods: Sixty participants with SALS from 10 centers were randomized 1:1:1 to placebo, mexiletine 300 mg/d, or mexiletine 900 mg/d and followed for 12 weeks. The primary endpoints were safety and tolerability. Secondary endpoints were pharmacokinetic study from plasma and CSF, ALS Functional Rating Scale–Revised (ALSFRS-R) score, slow vital capacity (SVC), and muscle cramp frequency and severity.Results: The only serious adverse event among active arm participants was one episode of imbalance. Thirty-two percent of participants receiving 900 mg of mexiletine discontinued study drug vs 5% on placebo (p = 0.026). Pharmacokinetic study demonstrated a peak plasma concentration 2 hours postdose and strong correlation between plasma and CSF (p < 0.001). Rates of decline of ALSFRS-R and SVC did not differ from placebo. Analysis of all randomized patients demonstrated significant reductions of muscle cramp frequency (300 mg: rate = 31% of placebo, p = 0.047; 900 mg: 16% of placebo, p = 0.002) and cramp intensity (300 mg: mean = 45% of placebo, p = 0.08; 900 mg: 25% of placebo, p = 0.005).Conclusions: Mexiletine was safe at both doses and well-tolerated at 300 mg/d but adverse effects at 900 mg/d led to a high rate of discontinuation. Mexiletine treatment resulted in large dose-dependent reductions in muscle cramp frequency and severity. No effect on rate of progression was detected, but clinically important differences could not be excluded in this small and short-duration study.Classification of evidence: This study provides Class I evidence that mexiletine is safe when given daily to patients with amyotrophic lateral sclerosis at 300 and 900 mg and well-tolerated at the lower dose.AE=adverse event; ALS=amyotrophic lateral sclerosis; ALSFRS-R=revised ALS Functional Rating Scale; AUC=area under the concentration curve; DSMB=data safety monitoring board; SAE=serious adverse event; SALS=sporadic amyotrophic lateral sclerosis; SF-36=Short Form–36 Health Survey; SVC=slow vital capacity