Auditory P300 after taking hypnotic zolpidem

Objective: Although the hypnotic, zolpidem, is known to be free of any detrimental residual effects, its residual effects on cognitive function after its elimination half-life have not been sufficiently investigated. This study was designed to examine the residual effects of zolpidem on cognitive function using event-related potentials (ERPs). Methods: Twelve healthy right-handed men participated in this study. ERP recordings were conducted at baseline and 5 hours after taking 10 mg of zolpidem. The auditory oddball task included the presentation of a series of standard (1,000 Hz, 75 dB, 80%) and target tones (2,000 Hz, 75 dB, 20%) in a predetermined quasi-random order. The data were analyzed using analysis of variance (ANOVA). Results: On the behavioral task, the reaction time was significantly delayed in the post-drug condition compared to the baseline. The P300 amplitude was significantly decreased in the post-drug condition compared to the baseline. However, the P300 latency showed no difference between the pre- and post-drug conditions. Conclusions: The residual effects of zolpidem on cognitive function may persist after its elimination half-life. Further large placebo-controlled trials are needed to confirm the findings of this study.