Effects of repeated administration of zolpidem on sleep, diurnal and nocturnal respiratory function, vigilance, and physical performance in patients with COPD.

STUDY OBJECTIVE To assess the effects of repeated 10-mg oral doses of zolpidem on diurnal and nocturnal respiratory function, as well as on diurnal vigilance and physical performance in COPD patients with disordered sleep. DESIGN Prospective single-blind placebo-controlled clinical study. SETTING Outpatients of a respiratory medicine department. PATIENTS AND METHODS Patients with stable COPD were enrolled for 10 days (D0 to D10), ie, 9 consecutive nights (N1 to N9). They received placebo on N1 and N9 and zolpidem, 10 mg, from N2 to N8. MEASUREMENTS The following parameters were measured: nocturnal polysomnographic recordings with respiratory signals and arterial blood gas values on retiring and awakening on N0, N1, N2, N8, and N9; subjective evaluation of the quality of sleep and of diurnal vigilance by visual analog scales every day from D0 to D10; pulmonary function test, central control of breathing, and walking test on D0 and D9; biological laboratory tests and theophylline level on D0 and D8. RESULTS Ten COPD patients (PaO2 = 72.7 +/- 7.6 mm Hg; PaCO2 = 47.7 +/- 5.4 mm Hg; FEV1 = 0.84 +/- 0.3 L; FEV1/vital capacity = 42.5 +/- 12.3%), 56.8 +/- 8.3 years old, were studied. Compared with placebo, no significant change was found for the various sleep architecture parameters, except an increase in the duration of stage 2 during the D8/N8 night (p < 0.05). In contrast, the autoevaluation score for the quality of sleep was significantly improved during the D6/N6 night relative to that with placebo (p < 0.05), with no change in the other subjective criteria. No variable of the nocturnal respiratory parameters, pulmonary function test, central control of breathing, and physical performance was altered by zolpidem. Arterial blood gas values on awakening were not altered. Clinical and biological tolerance of zolpidem was correct with no significant variation of the theophylline level. CONCLUSION This study shows that repeated 10-mg oral doses of zolpidem during 8 days does not impair nocturnal respiratory and sleep architecture parameters or diurnal pulmonary function tests, central control of breathing, and physical performances in patients with stable COPD.