Double-blind trial of R-(-)-deprenyl for the "on-off" effect complicating Parkinson's disease.

We performed a double-blind parallel study of deprenyl 5 mg BID vs. placebo in treatment of "on-off" oscillations complicating Parkinson's disease. After a 2-week baseline period, treatment was given for 6 weeks with weekly evaluations using the Northwestern Disability Scale and patients' hourly self-assessment of "on-off" status performed at home. Patients on deprenyl experienced significant improvement in time spent in the "on" state. They were also more likely than patients on placebo to experience improvement of severity of tremor and hypomimia during the "on" state. No other areas of disability improved in quality. Side effects such as hallucinations and worsening of choreoathetosis were frequent among the deprenyl group but generally responded to reduction in concomitant levodopa/carbidopa dosage. We conclude that deprenyl is moderately useful in ameliorating "on-off" in a majority of patients.