Phase II Therapeutic Trial of Mexiletine in Non-Dystrophic Myotonia (IND #77,021) CINCH 5306. Phase II Therapeutic Trial of Mexiletine in Non-Dystrophic Myotonia (IND #77,021) CINCH 5306

Non-dystrophic myotonias are a group of rare muscle disorders caused by abnormalities in different muscle cell membrane proteins. Patients experience delayed muscle relaxation that causes impaired physical activity, stiffness, and pain. Mexiletine has been shown to be beneficial for symptoms of myotonia in case reports of patients with non-dystrophic myotonia, however, current management of these patients primarily depends on individual practitioners' preference. This study is a placebo-controlled, double-blind, cross-over treatment trial using mexiletine in non-dystrophic myotonias. The results, if positive, will permit the identification of mexiletine as an effective therapy for myotonia, making it a first-line therapy for patients with non-dystrophic myotonia. The specific aim of this proposal is to perform a randomized, double-blind, placebo-controlled cross-over study to assess whether mexiletine improves both quantitative and qualitative measures... (for more see dbGaP study page.)