Hypnotic residual effects of benzodiazepines with repeated administration

Performance measures were compared to the multiple sleep latency test (MSLT) as indices to assess tolerance to the residual effects of benzodiazepine hypnotics during repeated nightly administration. Twelve healthy, normal sleepers received flurazepam 30 mg, temazepam 30 mg, and placebo for nine nights in a repeated measures, Latin-square design with 19 nights of recovery separating the treatments. As compared to placebo, both drugs altered sleep stage parameters in the early (nights 1-2) and late (nights 8-9) phases of the study. Hypnotic effects were found for both drugs in the early phase, but diminished for both in the late phase. The subjects' performance the next day was disrupted following treatment with flurazepam, but not with temazepam, during the early phase. Mean sleep latency on the MSLT was reduced by both drugs during the early phase. During the late phase, flurazepam did not disrupt performance but still affected the MSLT. Temazepam affected neither index the next day during the late phase.