Mexiletine in the treatment of torticollis and generalized dystonia

Mexiletine is an antiarrhythmic drug that has been reported to exert antidy stonic properties. We performed an open-label study to collect further evid ence of the antidystonic effect of mexiletine in spasmodic torticollis (ST) and to evaluate its possible use in generalized dystonia. We administered mexiletine to six patients with dystonia (three with generalized dystonia a nd three with ST) who had failed to respond to previous pharmacotherapy. Th e drug was started at a dose of 200 mg/d by mouth and increased up to a max imum dose of 800 mg/d. Patients were evaluated at regular intervals over a 6-week period with use of the Fahn & Marsden Dystonia Scale and the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and videotaped. At the end of the trial, the videotapes were reviewed and scored by a blind obser ver. Patients were then followed for at least 1 year and evaluated every 3 months at the dose reached during the study period. No adverse effects were reported in Five patients; in one patient, dizziness developed at the dosa ge of 800 mg/d, requiring a reduction of the dose. At the end of a 6-week p eriod, a significant improvement in the rating scale for dystonia and in vi deotape ratings was observed after mexiletine treatment (p < 0.01). Our dat a indicate that mexiletine is a useful drug in dystonia treatment.