Effect of baclofen on tardive dyskinesia

Abstract
Eighteen chronic psychiatric patients with neuroleptic-induced tardive dyskinesia of 1/2–9 years duration participated in a double-blind crossover study on the effect and side effects of baclofen and placebo in the treatment of tardive dyskinesia. Each treatment phase lasted 3 weeks. Evaluation of the results included an assessment of video-tape recording. Baclofen (20–120 mg daily) reduced the hyperkinesias (median score from 5 to 3, PP<0.01). The effect on the oral movement pattern of tardive dyskinesia was characterized by a reduced frequency, an unchanged or slightly reduced amplitude, and an increased duration of each separate mouth opening and tongue protrusion, a response pattern very similar to the response pattern of α-methyl-p-tyrosine, an inhibitor of the catecholamine synthesis. Sedation, muscular weakness, and confusion were observed in 50% of the patients. These side effects, appearing mainly in elderly patients, sometimes set in before the anti-hyperkinetic effect, thus limiting the practical usefulness of baclofen in the treatment of tardive dyskinesia.