Quazepam and temazepam: effects of short- and intermediate-term use and withdrawal.

Two benzodiazepine hypnotics, one with an intermediate elimination t1/2 (temazepam, 15 mg) and the other with a long t1/2 (quazepam, 15 mg), were evaluated in 22- night sleep laboratory studies. The effectiveness and side effects of these benzodiazepines were assessed during short- and intermediate term use. Subjects were also assessed for the presence of rebound insomnia after abrupt withdrawal. Quazepam, 15 mg, was significantly effective in improving sleep both with short- and intermediate-term use, but the effectiveness of temazepam was considerably less. Although temazepam was effective for maintaining sleep with short-term use, there was rapid development of tolerance for this effect with intermediate-term use. Temazepam did not produce any behavioral side effects during either drug condition. The only side effect associated with quazepam was a significant degree of daytime sleepiness. After its withdrawal, temazepam was associated with some sleep and mood disturbance on the first withdrawal night, whereas quazepam had carryover effectiveness.