Sleep latency is shortened during 4 weeks of treatment with zaleplon a novel nonbenzodiazepine hypnotic

Background: Zaleplon is a short-acting pyrazolopyrimidine hypnotic with a r apid onset of action. This multicenter study compared the efficacy and safe ty of 3 doses of zaleplon with those of placebo in outpatients with DSM-III -R insomnia. Zolpidem, 10 mg, was used as an active comparator. Method: After a 7-night placebo (baseline) period, 615 adult patients were randomly assigned to receive, in double-blind fashion, 1 of 5 treatments (z aleplon, 5, 10, or 20 mg; zolpidem, 10 mg; or placebo) for 28 nights, follo wed by placebo treatment for 3 nights. Sleep latency, sleep maintenance, an d sleep quality were determined from sleep questionnaires that patients com pleted each morning. The occurrence of rebound insomnia and withdrawal effe cts on discontinuation of treatment was also assessed. All levels of signif icance were p less than or equal to .05. Results: Median sleep latency was significantly lower with zaleplon, 10 and 20 mg, than with placebo during all 4 weeks of treatment and with zaleplon , 5 mg, for the first 3 weeks. Zaleplon, 20 mg, also significantly increase d sleep duration compared with placebo in all but week 3 of the study. Ther e was no evidence of rebound insomnia or withdrawal symptoms after disconti nuation of 4 weeks of zaleplon treatment. Zolpidem, 10 mg, significantly de creased sleep latency, increased sleep duration, and improved sleep quality at most timepoints compared with placebo; however, after discontinuation o f zolpidem treatment, the incidence of withdrawal symptoms was significantl y greater than that with placebo and there was an indication of significant rebound insomnia for some patients in the zolpidem group compared with tho se in the placebo group. The frequency of adverse events in the active trea tment groups did not differ significantly from that in the placebo group. Conclusion: Zaleplon is effective in the treatment of insomnia. In addition , zaleplon appears to provide a favorable safety profile, as indicated by t he absence of rebound insomnia and withdrawal symptoms once treatment was d iscontinued.