Effects of enhancing slow-wave sleep by gamma-hydroxybutyrate on obstructive sleep apnea.

Sleep apneas are rarely observed during slow-wave sleep (SWS), which is poorly represented in patients with obstructive sleep apnea (OSA). Gamma-hydroxybutyrate (gamma OH), a natural metabolite of the brainstem, increases the percentage of total sleep time (TST) spent in SWS. We evaluated the effects of gamma OH on sleep and breathing disorders in eight patients with OSA (age, 45 +/- 2 yr; body mass index, 35.0 +/- 1.5 kg/m2; mean +/- SEM). Three conventional sleep studies were done within a week; the first and third were control studies, and the second was the gamma OH study (30 mg/kg at bedtime and 3 h later). Because the effects of the drug last only 3 h, we analyzed and compared the results of the first 6 h of sleep recording. The percentage of TST spent in SWS increased with gamma OH (30.7 +/- 3.9%) compared with that in the control studies (12.5 +/- 1.1 and 11.0 +/- 2.1%) at the expense of stages I and II. There was no difference between apnea index obtained during the control studies (26.3 +/- 5.3 and 25.4 +/- 6.2/h) and that obtained during the gamma OH study (29.6 +/- 4.9/h). Most apneic events occurred during Stages I and II, and REM, but this proportion was less during the gamma OH study (77.9 +/- 8.9%) than during the control studies (92.3 +/- 1.9 and 95.9 +/- 2.2%), apneas occurring even during SWS with gamma OH.(ABSTRACT TRUNCATED AT 250 WORDS)