An open trial of clozapine for dystonia.
Pharmacologic treatment of severe dystonia is often unsatisfactory. The atypical antipsychotic medication clozapine appears to improve tardive dystonia associated with conventional neuroleptic use. We studied the efficacy of clozapine for severe dystonia in five patients in an open trial. The patient cohort included four with generalized dystonia and one with Meige syndrome. All patients were evaluated at baseline and at least weekly while on medication with subjective assessment of response by the patient and physician rating using the Burke-Fahn-Marsden Evaluation Scale for Dystonia. All five subjects had significant improvement detected by the Burke-Fahn-Marsden Evaluation Scale as well as subjective improvement while on clozapine. Side effects, such as sedation and orthostatic hypotension, developed in all patients but was only treatment-limiting in one subject who developed persistent symptomatic orthostatic hypotension and tachycardia. Two of the four remaining patients continued clozapine after completion of the study; an additional patient was uncertain if the benefit outweighed the side effects. One patient discontinued treatment because of difficulty obtaining the FDA-required weekly white blood cell counts for patients on clozapine. We conclude that clozapine appears to be effective for generalized and refractory focal dystonia although its use may be limited by the side effects and need for hematologic monitoring.