Comparative efficacy of newer hypnotic drugs for the short-term management of insomnia: a systematic review and meta-analysis.

OBJECTIVES: To compare the clinical effectiveness of zaleplon, zolpidem or zopiclone (Z-drugs) with either benzodiazepines licensed and approved for use in the UK for the short-term management of insomnia (diazepam, loprazolam, lorazepam, lormetazepam, nitrazepam, temazepam) or with each other.

METHODS: MEDLINE, EMBASE, PsycINFO, Science Citation Index/Web of Science were searched from 1966 to March 2003 and The Cochrane Library, reference lists of included studies and a number of psychopharmacology journals. Randomized controlled trials comparing either benzodiazepines with the Z-drugs or any two of the Z-drugs in patients with insomnia were included. Outcome measures included: sleep onset latency, total sleep duration, number of awakenings, quality of sleep, adverse events, tolerance, rebound insomnia and daytime alertness.

RESULTS AND CONCLUSIONS: Twenty four eligible studies were identified with a total study population of 3,909 (17 studies comparing a Z-drug with a benzodiazepine and 7 comparing a Z-drug). Insufficient or inappropriately reported data meant that meta-analysis was possible only for a small number of outcomes. There are few clear, consistent differences between the drugs. Some evidence suggests that zaleplon gives shorter sleep latency but shorter duration of sleep than zolpidem, reflecting the pharmacological profiles of the drugs.