title: Treatment of myotonia with antiarrhythmic drugs.
abstract: The effects of disopyramide, phenytoin, mexiletine, and tocainide were compared in 30 patients with myotonic disorders. The severity of myotonia was assessed by clinical and electromyographic criteria at the end of each treatment phase lasting four weeks. Mexiletine (MXT) and tocainide (TCD) were found to be the most potent antimyotonic agents. The antimyotonic efficacy of MXT and TCD is explained by their fast-blocking effect on voltage-dependent sodium channels in the muscle membrane. The benefits of myotonia control with pharmacological agents must be weight against the risk of therapy in the individual patient. Because of the risks of hematologic problems, TCD is not recommended by us for the treatment of myotonia.
authors.affiliation: Department of Neurology, Warsaw Medical Academy, Poland.
authors.forename: H
authors.initials: H
authors.lastname: Kwieciński
authors.forename: B
authors.initials: B
authors.lastname: Ryniewicz
authors.forename: A
authors.initials: A
authors.lastname: Ostrzycki
mesh_terms: D000293:Adolescent; D000328:Adult; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004206:Disopyramide / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008801:Mexiletine / Q000627:therapeutic use; D008875:Middle Aged; D009222:Myotonia / Q000188:drug therapy*; D009224:Myotonia Congenita / Q000188:drug therapy; D009223:Myotonic Dystrophy / Q000188:drug therapy; D009460:Neurologic Examination / Q000187:drug effects; D010672:Phenytoin / Q000627:therapeutic use; D011446:Prospective Studies; D016037:Single-Blind Method; D016677:Tocainide / Q000627:therapeutic use
chemical_list: D000889:Anti-Arrhythmia Agents; D008801:Mexiletine; D016677:Tocainide; D010672:Phenytoin; D004206:Disopyramide