Study Objective: To compare the hypnotic effects of a bedtime dose of zolpidem, triazolam, and placebo. Design: Double-blind, randomized, placebo- and active-controlled, parallel-group trial. Setting: Six Canadian hospitals. Patients: 357 patients (aged 19 to 71 years) hospitalized the night before a surgical procedure. Interventions: At bedtime, each patient received either zolpidem 10 mg, triazolam 0.25 mg, or placebo, and was allowed to sleep for a maximum of 8 hours. Measurements: Outcome measures were subjective in nature and included a morning questionnaire, visual analog scales, and observation for-ms by study personnel. All continuous variables were analyzed by analysis of variance. All categorical data were compared using the Cochran-Mantel-Haenszel (CMH) test, and the percentage of patients asleep was compared using a CMH chi-square analysis. When significant overall treatment effects were observed, pairwise comparisons were undertaken. Compared with the Placebo group, the following parameters were significantly (p < 0.001) different in the zolpidem and triazolam groups: sleep latency was shorter, total sleep time was longer, patients fell asleep more easily, and the number of patients awake 2 hours after drug administration was lower. There were no difference between any groups in next-morning somnolence or ability to concentrate. Both drugs were well tolerated, with adverse arent incidence rates nearly identical to placebo. Conclusions: In patients suffering from transient insomnia, a single dose of zolpidem 10 mg was as effective as triazolam 0.25 mg; and both were more effective than Placebo and were well tolerated. (C) 1997 by Elsevier Science Inc.