Psychophysiological effects and dose equivalence of zopiclone and triazolam administered to healthy volunteers. Methodological considerations

1. Dose-equivalence studies of zopiclone and triazolam were out. 2. Zopiclone (6.25, 8.75 and 11.25 mg), triazolam (0.1875, 0.275 and 0.5 mg) and placebo were given in the morining to 14 healty male volinteers aged 20-25 years under double-blind conditions according to an incomplete block design. Each patient received three of the seven possible treatment at intervals of at least 1 week. Subjects were evaluated using physiological measures, rating scales and memory taskes before and 1.5h after drug administration. 3. The sedative and amnestic effects of zopiclone were qualitatively similar to those of triazolam, with the highest dose of each havin the greatest effect. 4. On the basis of the digit symbol substitution test, 10 mg of zopiclone is equivalent to 0.5 mg of triazolam. Methodological problems of the experimetnal design of dose-equivalence studies are discussed