Selegiline in Narcolepsy
We examined the effect of the specific monoamine oxidase-B (MAO-B) inhibitor selegiline (deprenyl, Eldepry!), 20-30 mg p.o. daily, in 21 subjects with the narcoleptic syndrome for 4 weeks. Selegiline was compared to no treatment (7 subjects) or conventional central stimulant drugs, including dexamphetamine or mazindol (14 subjects). Severity and frequency of narcolepsy, accessory symptoms, and effects of selegiline on mood were measured. Selegiline, as well as causing MAO-B inhibition, is
... nhibition, is interconverted to amphetamine. Urinary amphetamine and methamphetamine excretion were determined in 18 subjects after 4 weeks on selegiline and the results were compared with amphetamine excretion in subjects on dexamphetamine. The effect of seiegiline, 20-30 mg p.o., on alertness and mood was similar to that of dexamphetamine in the same dosage, with comparable sympathomimetic side effects. Selegiline, 20 mg p.O., caused a subjective increase in alertness for 4-8 h. Mean urinary amphetamine excretion on dexamphetamine, 15-70 mg daily (mean 29 mg) at pH 5.6-6.6, was 5,184 f.1g!24 h, and on selegiline, 20-30 mg daily (mean 22.5), was 4,127 f.1g!24 h. We conclude that selegiline, 20-30 mg daily, requires further evaluation in narcolepsy. Key Words: Amphetamine interconversion-MAO-B inhibition-Narcolepsy -Seiegiline. Two different isozymes of monoamine oxidase (MAO), types A and B, have been identified. These have different substrate specificities and can be inhibited selectively (1). Selegiline in lO-mg daily oral dosage causes selective MAO type B inhibition in the brain of greater than 90% (2,3). Unlike conventional MAO-A inhibitors, selegiline does not produce the beer, cheese, and wine type of hypertensive crisis, as tyramine, which is absorbed from the gastrointestinal tract, can still be effectively metabolised. Wyatt et al. (4) showed that the nonspecific MAO inhibitor phenylzine, 60-90 mg124 h, caused a reduction in narcolepsy, cataplexy, sleep paralysis, and hypnagogic hallucinations, with suppression of rapid eye movement (REM) sleep, and had a continued effect for over a year in seven subjects with narcolepsy. However, hypotension, oedema, and impaired sexual function were bothersome, and side effects, together with severe dietary restrictions, have prevented the widespread investigation of MAO inhibitors in narcolepsy. We report the effects of selegiline, 20-30 mg daily, given over a 4-week period to 21 subjects with narcolepsy-cataplexy.