A comparative assessment of the risks and benefits of zopiclone - A reviewof 15 years' clinical experience

Zopiclone is a cyclopyrrolone hypnosedative that is chemically unrelated to the benzodiazepines but nevertheless potentiates gamma-aminobutyric acid-m ediated neuronal inhibition, and has demonstrated proven efficacy and good tolerability in the treatment of insomnia over 15 years of use, Zopiclone i s indicated for short term use, and should not be prescribed for more than 4 weeks. This review compares the efficacy of zopiclone with that of a number of com monly used short-, medium- and long-acting benzodiazepines. Zopiclone at do sages of 7.5 mg/day has demonstrated efficacy equivalent and in some cases greater to that of flurazepam 30 mg/day, nitrazepam 5 mg/day, flunitrazepam 1 to 2 mg/day, temazepam 20 mg/day, triazolam 0.125 to 0.5 mg/day and mida zolam 15 mg/day. Zopiclone-treated patients reported themselves to be less impaired by daytime sedation than patients treated with the medium- and lon g-acting hypnosedatives flurazepam, nitrazepam and flunitrazepam. Zopiclone and temazepam showed similar effects on daytime behaviour while zopiclone appeared to have somwhat better effects on daytime well-being than the shor t-acting triazolam and midazolam, There has been no clinical comparison wit h the frequently used medium-acting benzodiazepines lormetazepam and brotiz olam and the imidazopyridine hypnosedative zolpidem. Data from clinical tri als, pooled analyses and postmarketing surveillance including over 30 000 p atients showed that with the exception of bitter taste (reported by <10% of zopiclone recipients), the tolerability profile of zopiclone is similar to that of placebo, Clinical trials found no evidence for significant rebound insomnia and indicated that the risk of withdrawal reactions with therapeu tic doses of zopiclone is very low. In addition, to date, dependency appear s very low, although abuse potential should be considered following a histo ry of addiction or psychiatric illness. Evaluation of the accumulated evide nce from over 2.5 billion units dispensed in more than 30 countries indicat es that zopiclone is effective, well tolerated and an excellent alternative to benzodiazepines in the short term treatment of insomnia.