Effectiveness of zopiclone as a preoperative hypnotic.

A controlled, double-blind study was made of the efficacy and safety of a new hypnotic, zopiclone, on the preoperative night's sleep by a Joint Study Unit Group of the anesthesiology departments in 6 national hospitals. The following results were found: (1) zopiclone 7.5 and 10 mg and nitrazepam 10 mg were significantly superior to placebo both on the quality of sleep and the mental state of the patient, while no significant differences were observed among these three active drugs; (2) a significantly higher incidence of side-effects was observed for nitrazepam 10 mg than for zopiclone 7.5 and 10 mg and placebo; (3) zopiclone 7.5 and 10 mg and also nitrazepam 10 mg were significantly more useful than placebo, and (4) the above results show that 7.5 and 10 mg of zopiclone are of great benefit to the preoperative night's sleep and have less side-effects than 10 mg of nitrazepam.