L-deprenyl treatment of on-off phenomena in Parkinson's disease.

The effects of L-deprenyl were investigated in 47 parkinsonian patients under chronic levodopa treatment with our without on-off phenomena. During a 1 to 3 months' treatment 5–10 mg of L-deprenyl caused a significant reduction in on-off disabilities in 23 out of 34 patients (68%). The improvement was only moderate (38%) or minimal (30%). All patterns of akinetic on-off disabilities showed improvement. Peak-dose dyskinesias were aggravated in 20 patients.