THE AIRWAY EFFECTS OF STOPPING REGULAR ORAL THEOPHYLLINE PATIENTS WITH ASTHMA

Aims We investigated whether the deterioration in asthma control repor ted Following cessation of theophylline was due to tolerance to theoph ylline. Methods Eighteen subjects with mild stable asthma were given o ral theophylline 10 mg kg(-1) day(-1) or placebo for 2 weeks in a doub le-blind crossover study. FEV1 and PD20 histamine were measured before and 8 h after the first dose of treatment and 8, 32 and 56 h after th e final dose. PD20 AMP was measured before treatment and 9 h after the final dose. Results Six patients did not tolerate theophylline. In th e other 12 subjects there were no differences between treatments in da ily PEF, symptom scores, rescue bronchodilator use, PD20 histamine or FEV1 up to 8 h post treatment. Following withdrawal of theophylline th ere were significantly lower values for mean FEV1 (mean difference 0.1 51, 95% CI 0.03, 026) and PD20 AMP compared to placebo but no differen ce in other end points. Conclusions The small rebound deterioration in lung function following regular treatment with therapeutic doses of o ral theophylline is consistent with the development of tolerance.