Short-term effects of oral theophylline in addition to CPAP in mild to moderate OSAS.

Theophylline is effective in the treatment of central apneas and periodic breathing. In obstructive sleep apnea syndrome (OSAS), results of pharmacological monotherapy with theophylline are inconsistent. The present study investigates whether additional theophylline in patients with OSAS and continuous positive airway pressure (CPAP) therapy might improve ventilation, lower effective CPAP pressure levels or affect sleep architecture. Patients with mild to moderate OSAS (mean apnea index [AI] 12.8+/-11.7) and CPAP therapy (Autoset system; n=16, all male) received either 900 mg of oral sustained-release theophylline (T) or placebo (P) on two separate nights, 3 days apart, using a randomized double-blind crossover study design. There was no change in AI (T: 0.7+/-1.4 vs. P: 0.7+/-0.6/h; P=0.3) or apnea-hypopnea index (AHI; T: 4.3+/-3.3 vs. P: 4.5+/-3.7/h; P=0.84) when theophylline was added to CPAP therapy. We observed no difference in mean CPAP pressure (T: 6.9+/-2.1 vs. P: 6.7+/-1.9 cm H2O; P=0.7) or 95% pressure percentiles (T: 9.7+/-2.7 vs. P: 9.3+/-2.1cm H2O; P=0.3) when nights with theophylline were compared to placebo nights. Theophylline reduced significantly total sleep time (T: 290.6+/-58.9 vs. P: 338.0+/-40.1 min; P=0.02) and thus sleep efficiency (SE; T: 70.5+/-14.9%, P: 82.0+/-70.5%; P=0.005). Rapid eye movement and slow wave sleep were not affected. Oral theophylline did not show any additional effects on ventilation parameters or pressures in patients with mild to moderate OSAS once CPAP therapy has been successfully installed. SE was reduced with theophylline with unchanged sleep architecture. The role of oral theophylline may be in patients with predominately central apneas not eligible for ventilation therapy or severe cases.