Selegiline in the treatment of narcolepsy

Abstract

We treated 17 narcolepsy patients in a placebo-controlled, double-blind, crossover trial with 10-, 20-, 30-, and 40-mg daily doses of selegiline, a monoamine oxidase inhibitor widely used in Parkinson's disease. There was a dose-dependent as well as a statistically and clinically significant improvement in narcoleptic symptoms and polygraphic measures. At 40 mg, there was a 36% reduction in the number of daytime sleep episodes and a 34% reduction in their duration (compared with placebo, mean values). The number of excessive sleepiness episodes decreased by 43%, and the duration decreased by 47%. The number of cataplectic attacks was reduced by 89%. On the multiple sleep latency test, the REM sleep latency increased from 5.0 to 13.3 minutes, and the number of sleep-onset REM periods decreased from 3.1 to 0.6. Sleep (SI) latency was not changed. No intolerable adverse events occurred. The effective dose range was 20 to 40 mg, requiring a low-tyramine diet, which was easy to maintain. In conclusion, selegiline alleviates both main symptoms of narcolepsy–the abnormal sleep tendency and cataplexy. Thus, treatment with selegiline makes it possible to avoid polypharmacy and to use a potent stimulant without known addiction risk.