Obstructive Sleep Apnea and Hypopnea Efficacy and Safety of a Long-Acting [beta]2-Agonist

The effect of inhaled long-acting β^sub 2^-agonists in obstructive sleep apnea syndrome (OSAS) is unknown, although from the pharmacological point of view both therapeutic and adverse effects need to be considered. The purpose of this study was to obtain data on the efficacy and safety of salmeterol in patients with OSAS. In a randomized, double-blind, placebo-controlled, cross-over study, effects of salmeterol on respiration during sleep and sleep quality were investigated in 20 patients with OSAS. Of these, 4 patients were female, 16 male; the average age was 53.0 ± 7.8 years, with average body mass index 28.0 ± 3.0 kg· m^sup -2^ and average apnea hypopnea index 35.6 ± 17.8 h^sup -1^. Patients with asthma, chronic obstructive pulmonary disease (COPD), and left heart failure were excluded. Placebo or verum (50 μg salmeterol) was administered at 7 pm by meter dose inhaler and spacer device. All patients underwent full polysomnography during baseline, placebo, and verum night. Statistical analysis was performed by Student's t-test (p > 0.05). Between the placebo and verum there were no differences in total sleep time, sleep stages, apnea index (AI), apnea hypopnea index (AHI), and nadir oxygen saturation. There was, however, 1) a significant deterioration of mean oxygen saturation (SaO^sub 2^m; placebo 93.1 ± 2.0 vs. verum 92.5 ± 2.2%; p = 0.01), 2) of percent of time spent with an oxygen saturation (SaO^sub 2^) ≤ 90% (placebo 13.1 ± 14.5 vs. verum 19.5 ± 20.8%; p = 0.02), and 3) a significant increase in heart rate (placebo 63.1 ± 9.2 vs. verum 65.6 ± 9.3 h^sup -1^; p = 0.01). In patients with OSAS, salmeterol had no adverse effect on quality of sleep, AI or AHI. The slight increase in heart rate and the deterioration of oxygen saturation probably have no clinical relevance; the latter condition might be due to ventilation-perfusion-mismatch. This study excluded any influence of salmeterol on obstructive sleep apnea and hypopnea; on the other hand, salmeterol turned out to be safe in terms of OSAS. This might be of special importance in patients suffering from both OSAS and obstructive airway disease.[PUBLICATION ABSTRACT]