New approaches in the use of selegiline for the treatment of Parkinson's disease.

Selegiline hydrochloride (deprenyl) is a safe, useful adjuvant therapy in patients with Parkinson's disease treated with L-dopa. The optimum time for its introduction into the treatment regimen of a patient remains controversial. A multicentre long-term study being conducted by the Parkinson's Disease Research Group of the United Kingdom to attempt to answer whether selegiline improves the natural history of Parkinson's disease is discussed. In a separate study we have been unable to demonstrate that higher doses of selegiline (up to 40 mg a day) produce additional therapeutic benefit above the conventional dose of 10 mg a day in levodopa-treated patients with motor fluctuations. Preliminary data from a neuropsychological study is also presented which suggests that selegiline may have beneficial effects on the speed of psychomotor responses supporting the anecdotal clinical observations of increased mental energy and alacrity.