A dose response study of the hypnotic effectiveness of alprazolam and diazepam in normal subjects.

One group of eight normal young males was administered three doses of alprazolam (0.25, 0.5 and 1.0 mg) and placebo, while a second group of eight normal young males was given three doses of diazepam (2, 5, and 10 mg) and placebo in the same design. All subjects slept in the sleep laboratory for 10 nights, 2 consecutive nights each week for 5 consecutive weeks. The first 2 nights served as adaptation. During the next 4 weeks subjects received a random dose of alprazolam (or placebo) or a random dose of diazepam (or placebo) each week. Similar dose-related benzodiazepine effects were found on sleep with both medications. Alprazolam reduced percent stage 4 and REM sleep and increased stage 2 sleep and latency to REM. Diazepam decreased percent stage 1 and increased percent stage 2 sleep. No drug by dose interactions were found. It was concluded that, while both drugs had similar effects on sleep, alprazolam showed significant effects on REM sleep parameters and might be evaluated for possible antidepressant effect.