The effects of zolpidem in obstructive sleep apnea - An open-label pilot study

New knowledge on hypnotics and their effects on the phenotypic causes of obstructive sleep apnea indicate that zolpidem has therapeutic potential for certain patients. Specifically, zolpidem increases the threshold for arousal threshold and pharyngeal dilator muscle responsiveness. However, the effects of a standard dose of zolpidem (10 mg) on obstructive sleep apnea severity and symptoms have not been investigated. In an open-label pilot study, 12 unselected people with obstructive sleep apnea were recruited following a diagnostic in-laboratory sleep study. Participants then returned for a single-night sleep study in which 10 mg of zolpidem was given just prior to sleep. Tolerability, next-day sleepiness and the effects of zolpidem on polysomnography variables were assessed. Zolpidem was well tolerated and significantly improved the sleep efficiency compared with the no-drug night (77 ± 12% versus 84 ± 9%, p = 0.005). Individual responses on obstructive sleep apnea severity to zolpidem in this unselected obstructive sleep apnea patient population were variable with no overall systematic difference in apnea-hypopnea index (29 ± 18.2 events per hr versus 33 ± 28 events per hr, p = 0.45) or other key respiratory parameters (e.g. event duration or hypoxemia). Next-day sleepiness assessed via the Karolinska Sleepiness Scale was not different between visits (4 ± 1 versus 4 ± 2, p = 0.85). These findings provide the first insight into the effects of a standard dose of zolpidem in obstructive sleep apnea, and highlight its tolerability and potential to improve sleep quality. The variable effects on obstructive sleep apnea severity observed in this pilot also underscore the need for larger trials that incorporate phenotypic characterisation (e.g. arousal threshold, Pcrit and muscle responsiveness) to understand inter-individual heterogeneity and the therapeutic potential of zolpidem for certain people with obstructive sleep apnea.