Objective measurements of daytime sleepiness and performance comparing quazepam with flurazepam in two adult populations using the Multiple Sleep Latency Test.

Daytime residual drowsiness and psychomotor performance were assessed for two long half-life benzodiazepines, quazepam and flurazepam, in two randomized, parallel, and double-blind studies in insomniacs. Seventeen middle-aged patients took quazepam 15 mg or 30 mg, or flurazepam 30 mg; the 47-night study included 4 placebo baseline nights, 28 consecutive treatment nights, and 15 posttreatment nights. Forty-eight geriatric patients took either flurazepam 15 mg, quazepam 15 mg, or placebo; the 15-night study included 1 placebo baseline night, 7 treatment nights, and 7 posttreatment nights. The Multiple Sleep Latency Test (MSLT), an objective test for measuring daytime sleepiness, and performance tests were administered. In the first study, flurazepam patients were significantly (p less than .05) sleepier after the 7th and 14th treatment nights when compared to baseline, whereas quazepam patients were not. In the second study, flurazepam patients were sleepier at midday (p less than .10) and late afternoon (p less than .05) after 1 treatment week than were quazepam and placebo patients. Performance test results suggested quazepam has a relatively low potential for daytime impairment. Thus, quazepam 15 mg produces less daytime somnolence and fewer psychomotor performance decrements than does flurazepam.