Abstract
1. Peak saccade velocity provides a valuable means of assessing the sedative effect of drugs in humans. The present study investigated the effects of zolpidem, an imidazopyridine hypnotic, on saccade velocity in healthy volunteers after single and repeated administration. 2. Zolpidem 5 mg, 10 mg and 20 mg significantly and dose dependently depressed peak saccade velocity during the 1.5 h after a single administration. On the morning after zolpidem administration, peak saccade velocity had returned towards pretreatment levels. Nitrazepam 10 mg also significantly depressed peak saccade velocity but the effect was maintained the following morning. The saccade response to zolpidem (5 and 10 mg) was undiminished after the seven nightly doses. 3. Nightly administration of zolpidem improved subjective sleep quality and there was no evidence of rebound insomnia following cessation of drug treatment.