Heterocyclic amphetamine derivatives and caffeine on sleep in man.

Effects of the heterocyclic amphetamine derivatives, pemoline (20 and 40 mg), prolintane hydrochloride (5 and 10 mg), methylphenidate hydrochloride (10 and 20 mg) and fencamfamine hydrochloride (10 and 20 mg), and of caffeine anhydrous (100, 200 and 300 mg) on sleep, were compared with placebo in six young adults (20-31 years) using electroencephalography for sleep measures and analogue scales for subjective assessments of well-being and sleep quality. The study was double-blind. No consistent effect was found with pemoline. With prolintane there were no changes in sleep latencies, or in slow wave sleep (SWS). Rapid eye movement (REM) sleep was reduced during the first 2 h after sleep onset. With methylphenidate and fencamfamine latencies to sleep onset and to stage 3 sleep were unchanged. The higher dose of each drug delayed the first and subsequent REM periods. Both drugs reduced the duration of REM sleep, and the higher dose of each drug reduced the percentage REM sleep. Methylphenidate also reduced total sleep time (TST). There was no evidence of reduced SWS with either drug. Impairment of sleep was reported with each drug. With caffeine there were no changes in latencies to sleep onset or to the first REM period, though in one study with 300 mg subsequent REM periods were delayed. Awake activity and drowsy sleep were increased and TST and SWS were decreased. With 300 mg only, REM sleep was decreased though percentage REM sleep was not altered. Impaired sleep was reported with all doses of caffeine.