To study the efficacy of zolpidem in inducing daytime sleep and maintaining mental alertness subsequent to awakening

In operational environment, naps in the daytime could help in maintaining alertness and hence performance. However, due to operational constraints and circadian effect, an aircrew may not get good quantity and quality sleep during the day, even though adequate sleep window is available. In such situations, zolpidem could be effectively utilized to induce sleep. This study intended to examine the beneficial effects of zolpidem 5 mg and 10 mg in inducing daytime sleep and maintaining mental alertness in the subsequent awake period. Material and Methods: In a double-blind, placebo-controlled, repetitive measure design, 20 healthy male volunteers were longitudinally evaluated for their mental alertness and subjective perception of quality of sleep, sleepiness, and fatigue for a period of 12 h following zolpidem-induced daytime sleep. In addition, feedback was obtained on known untoward effects of zolpidem. Results: Zolpidem, in doses of both 5 mg and 10 mg, could induce daytime sleep in all participants. Quality of sleep induced by zolpidem was similar to that of night sleep quality. With 5 mg zolpidem, the alertness was maintained soon after awake from daytime sleep, whereas participants perceived sleepiness for a period of 1–2 h with 10 mg zolpidem. Following awakening, there was a significant increase in the number of lapses with time in the placebo group, which was not found significant with administration of zolpidem. The occurrence of untoward effects with 10 mg zolpidem was more than 5 mg zolpidem. Conclusion: Zolpidem 5 mg and 10 mg were found to be effective in inducing daytime sleep and maintaining performance subsequent to arousal. The sleepiness following arousal as well as adverse effects was found to be more for zolpidem 10 mg as compared to 5 mg. A mandatory ground observation of minimum of 8 h should be ensured following intake of zolpidem before undertaking any flying duties.