[Comparison of the effects of zopiclone and triazolam on the sleep of normal subjects].

Zopiclone 7.5 mg and triazolam 0.50 mg have been compared in a double-blind randomized cross-over sleep laboratory study. After a 6-day placebo, 12 healthy male volunteers aged 20-35 years received 2 active treatment sequences of 6 days separated by a 8-day placebo period and followed by a withdrawal period with placebo for 8 days. 22 polygraphic sleep recordings have been performed. The duration of nocturnal awakenings decreases at the beginning of treatment. Sleep onset latency is significantly decreased as well as the number of awakenings during sleep at the end of treatment. Both drugs improve the sleep efficiency index. Zopiclone increases total sleep time at the beginning and at the end of treatment. Triazolam increases this parameter at the end of the study only. Zopiclone, unlike triazolam increases the duration of deep NREM sleep-stages 3 and 4--at the beginning of treatment. No significant changes in sleep parameters were seen with zopiclone nor triazolam at the end of treatment. In sleep questionnaires, sleep onset latency is shorter under zopiclone than under triazolam and daytime drowsiness is less frequent with zopiclone.