Biperiden administration in normal sleep and after rapid eye movement sleep deprivation in healthy volunteers.

Twenty-six healthy volunteers were randomly assigned to one of four groups. Groups Bip-4 and Bip-6, each with six subjects, received 4 and 6 mg of biperiden, respectively, and were studied on acclimatization, baseline, biperiden, and follow-up nights. Group REM-P (n = 7) and Group REM-Bip (n = 7) were studied on acclimatization, baseline, six nights of REM sleep deprivation, and one recovery (treatment) night with either placebo (group REM-P) or biperiden (group REM-Bip), and one follow-up night. Biperiden 4 and 6 mg increased REM sleep latency and biperiden 6 mg reduced REM sleep time. On the recovery night following REM sleep deprivation Group REM-P and REM-Bip showed an increase in sleep continuity. REM sleep time in the REM-P group was increased during the recovery (treatment) night (REM sleep recovery), while the REM-Bip group did not show a significant REM sleep increase during recovery (treatment) night. It was not until the follow-up night that REM sleep increased in the REM-Bip group.