Treatment of the "on-off" phenomenon in Parkinsonism with lithium carbonate

Six patients with severe parkinsonism complicated by the "on-off" phenomenon were treated with lithium carbonate in addition to regular antiparkinson medications. A randomized double-blind crossover trial of lithium versus placebo was conducted, followed by an open trial of lithium therapy. Five patients had markedly reductions in akinesia (mean, 70%) and improved by one grade in Parkinson staging. This result was more striking in male than in female patients, and in all responders benefit has been maintained during the open phase of lithium treatment (mean follow-up of 36 weeks). In no patient was a reduction in akinesia observed during placebo treatment. Lithium carbonate appears to offer a new and potentially effective approach to treatment of the on-off phenomenon.