(-)Deprenyl in the treatment of decompensated Parkinson's disease.

Two main forms of declining motor performance are evident in Parkinson's disease: response fluctuations and "loss of benefit", i.e., the progression of the disease without "on-off" symptoms. (-)Deprenyl has a favourable beneficial effect in reducing the mild forms of response fluctuations. The addition of (-)deprenyl in such patients to the continuing substitution therapy prevents the development of more severe "on-off" manifestations. In severely disabled patients with irregular response swings or permanent akinesia the use of (-)deprenyl as an adjuvant drug cannot modify anymore the course of the disease.