Comparative study of zopiclone, a novel hypnotic, and three benzodiazepines

The hypnotic effect and tolerance of zopiclone 7.5 mg, nitrazepam 5 mg, flurazepam 30 mg, flunitrazepam 2 mg and placebo were compared in a one-night double blind study in 414 hospitalised patients who were to undergo an operation on the following day. Zopiclone was slightly superior to nitrazepam but was inferior both to flurazepam and flunitrazepam. All the active drugs differed clearly from placebo. The results from a subset of patients, excluding those who felt anxious either before treatment on the evening prior to the operation or on the following morning, were analysed separately. All the active products differed significantly from placebo; zopiclone was slightly less effective than the three benzodiazepines. All the benzodiazepines decreased the percentage of patients feeling anxious about the operation by about 25%, zopiclone by about 10% and placebo did not change it at all.