Levodopa induced dyskinesiae represent a common complication of the chronic treatment of patients with Parkinson’s disease.1 Refining the schedule of levodopa administration and adding controlled release preparations of levodopa, or dopamine agonists, or both often prove insufficient to control these problems. Pharmacological agents which exert a mild antagonism on striatal dopamine receptors or modulate the dopamine systems by interacting with serotoninergic pathways have recently shown beneficial effects in levodopa induced dyskinesiae.2 3

Risperidone is a new, atypical neuroleptic drug with potent serotonin-S2 and secondary dopamine-D2 antagonist properties.4 It has antipsychotic effects with a low incidence of extrapyramidal side effects, a feature which makes this drug a candidate for the treatment of levodopa induced psychosis and dyskinesia in patients with Parkinson’s disease. We have previously obtained beneficial effects with low dosages of risperidone in levodopa induced psychosis in patients with Parkinson’s disease.5 …