Treatment of hyperkinetic movement disorders with tetrabenazine: a double-blind crossover study.

Tetrabenazine, a presynaptic monoamine depleting agent, has been reported to have an ameliorating effect in a variety of hyperkinetic movement disorders. In a double-blind crossover trial of tetrabenazine versus placebo, 19 patients with a variety of hyperkinetic movement disorders were evaluated. During the evaluation period, all but 4 patients were treated for three or more weeks at a maximum dosage of 200 mg per day. The patients were examined and rated using clinical assessment of hyperkinesia, and movies of their activities were randomized and rated by an independent group of neurologists. A good correlation was found between the clinical examination scale and the film analysis score. Improvement was seen in all 4 patients with tardive dyskinesia, 4 of 6 patients with Meige disease, and 5 of 6 patients with other dystonias. One patient with Huntington disease showed marked improvement and 2 patients with congenital choreoathetosis showed only mild improvement. The most frequent side effects included daytime drowsiness, drooling or sialorrhea, insomnia, restlessness and anxiety, parkinsonian features, and mild postural hypotension. The adverse effects resolved with continued administration or with reduction in dosage. Tetrabenazine is a useful and safe therapeutic agent in some patients with hyperkinetic movement disorders.