The effects of doxofylline versus theophylline on sleep architecture in COPD patients

Theophylline is known to alter sleep architecture because of its affinity to adenosine receptors. One of the consequences of disrupted sleep is impaired cognitive performance. A single-blind, randomized cross-over study of eight male chronic obstructive pulmonary disease (COPD) patients was undertaken to evaluate the effects of theophylline versus doxofylline on sleep architecture. The patients, who were all ex-smokers, had been treated with theophylline. Mean age was 53 +/- 12 yrs, forced expiratory volume in one second (FEV1) 50 +/- 22% predicted and forced vital capacity (FVC) 70 +/- 18% predicted. Following a wash-out period, four patients were given oral slow-release theophylline (T) (300 mg b.i.d.) for one week, followed by a cross-over to doxofylline (D) (400 mg t.i.d.) for a second week. The other four patients were given the drugs in the reverse order. All patients underwent polysomnography at baseline and at the end of each week of treatment. The number of arousals per hour was 5.5 +/- 2.9 at baseline, 9.4 +/- 5.2 during T treatment and 5.4 +/- 4.4 during D treatment. During T treatment, sleep efficiency was 60 +/- 19% vs 75 +/- 13% recorded at baseline trial and 68 +/- 25 recorded during D treatment. Sleep quality, during T treatment, was poorer than at baseline, with a greater increase in the percentage of wakefulness and more stage 2 sleep than at baseline. Slow wave sleep was reduced with both treatments, particularly D. Neither drug affected the arterial oxygen saturation (Sao2) or respiratory rate during sleep.(ABSTRACT TRUNCATED AT 250 WORDS)