Zaleplon improves sleep without producing rebound effects in outpatients with insomnia

The efficacy and safety of three doses of zaleplon, a novel non-henzodiazep ine hypnotic, were compared with those of placebo in outpatients with insom nia in this l-week study, using zolpidem 10 mg as active comparator. Postsl eep questionnaires were used to determine treatment effects on the patient' s perception of sleep, as well as any development of pharmacological tolera nce during therapy or rebound insomnia or withdrawal symptoms upon disconti nuation of therapy. During week 1, sleep latency was significantly shorter with zaleplon 5, 10, and 20 mg compared to placebo. The significant decreas e in sleep latency persisted through week 4 with zaleplon 20 mg, and was ag ain evident with zaleplon 10 mg at week 3. Zaleplon 20 mg also had signific ant effects on sleep duration, number of awakenings, and sleep quality comp ared to placebo. No pharmacological tolerance developed during treatment wi th zaleplon and there were no indications of rebound insomnia or withdrawal symptoms after treatment discontinuation. Zolpidem 10 mg had significant e ffects on sleep latency, sleep duration, and sleep quality compared to plac ebo. However, a significantly greater incidence of withdrawal symptoms and a suggestion of sleep difficulty after treatment discontinuation (rebound i nsomnia) for all sleep measures was seen with zolpidem compared to placebo. There was no significant difference in the frequency of adverse events wit h active treatment compared to placebo. These results show that zaleplon pr ovides effective treatment of insomnia with a favourable safety profile. (C ) 2000 Lippincott Williams & Wilkins.