The effect of L-Deprenyl on on-off phenomena in Parkinson's disease.

L-Deprenyl, a specific monoamine oxidase subtype B inhibitor, has been reported a valuable adjunct to conventional treatment of Parkinsonism. A double-blind cross-over controlled study was performed in 19 parkinsonian patients with on-off type problems. Five mg L-Deprenyl per day reduced the number of on-off episodes. Side effects such as hyperkinesias, vivid dreams, dizziness with diaphoresis were frequent. Severe side effects such as nightmares, postural hypotension, confusion, and dizziness with headaches necessitated discontinuation of the drug in 4 patients. L-Deprenyl was of limited value in this group of patients with longstanding Parkinsonism.