Low-dose theophylline in childhood asthma: a placebo-controlled, double-blind study

Regular anti-inflammatory treatment is essential in treating persistent asthma. Most commonly, inhaled corticosteroids (ICS) are used. However, especially in children, there is concern about the long-term safety of ICS such that doses should be kept to a minimum. The use of theophylline has decreased because of frequent side-effects in therapeutic doses. In adults, there have been reports about an immunomodulatory effect of low-dose theophylline. To study the clinical and immunomodulatory effect in children, 36 patients (mean age 12.5 SD 2.4 years) with moderate, persistent asthma on regular ICS were recruited into a placebo-controlled, double-blind study. After a 6-week run-in period, patients received either theophylline 10 mg/kg bodyweight or placebo for 12 weeks. Diary cards, lung function, peripheral blood lymphocyte subpopulations and serum eosinophil cationic protein (sECP) were assessed. In the treatment group, mean serum theophylline was 7.1 mg/l. There was no change in symptoms or use of rescue medication. Mean (SD) peak expiratory flow (PEF) increased from 86% (24) to 95% (18) predicted. sECP decreased from 43.2 microg/l (32.5) to 26.5 microg/l (16.9) (p = 0.02). Lymphocyte subpopulations did not change. The study failed to show a beneficial clinical or an immunomodulatory effect of theophylline when used in low doses. These results do not support a more important role of theophylline in the long-term treatment of moderate childhood asthma.