Controlled-release theophylline in the treatment of nocturnal asthma.

A total of 104 asthmatic patients with symptoms of asthma and/or a 'morning dip' in the peak expiratory flow rate (PEFR) who were receiving multiple therapies, including inhaled or oral steroids, were treated in addition once nightly with controlled-release theophylline in an 8-week double-blind, placebo-controlled cross-over study. Theophylline produced an improvement in symptoms of cough, wheeze, sleep disturbance and PEFR in the 73 completing patients compared to run-in and placebo treatment. Theophylline also produced an improvement in the forced expiratory volume in 1 s and forced vital capacity relative to baseline, and in the difference between actual and predicted PEFR values. Nausea was the most frequent side-effect but both patients' and investigator's global impressions of the effect of study medication were in favour of theophylline.