Effects of a single dose of flurazepam on the sleep of healthy volunteers.

We compared the effects of a single dose of flurazepam (Dalmane) 45 mg with placebo on the sleep of twelve young, healthy male volunteers. A double-blind random-order cross-over design was used. Flurazepam 45 mg had no effect on sleep latency to stage 1 or to stage 2 sleep and no effect on percent stages 3 and 4 sleep. Total sleep time and percent stage 2 sleep significantly increased on the drug night, while wake time, percent stage 1, and percent REM decreased. It is hypothesized that decreases in stages 3 and 4 that are generally seen on second administration or withdrawal of flurazepam are due to the major metabolite, N-desalkyl-flurazepam. In addition, respiration was recorded in six subjects. The number of NREM apneas increased from 15 on the placebo night to 29 on the drug night, although this was not statistically significant. The effect of flurazepam and other benzodiazepines on respiration deserves further study.