Residual effects of zopiclone and benzodiazepine hypnotics on psychomotor performance related to car driving.

A double-blind, randomized, cross-over study was carried out in 10 normal healthy volunteers to investigate the residual effects of 7.5 mg zopiclone, 1 mg lormetazepam, 0.25 mg triazolam, 1 mg flunitrazepam and placebo. Tests of psychomotor performance and analogues of car driving ability were administered the morning following night-time medication. Changes with respect to placebo in an information-processing task one hour after taking the medications confirmed the hypnotic efficacy of zopiclone, triazolam and flunitrazepam. Flunitrazepam also produced a significant depression of the Critical Flicker Fusion Threshold (CFF) and increased subjective ratings of sedation one hour after nocturnal dosing. Flunitrazepam impaired the reaction time on the information-processing test the morning following doses of 1 mg.