A double-blind placebo-controlled trial of theophylline in general practice

Patients with moderate to severe asthma, from two urban general practices, entered a double-blind randomised placebo-controlled crossover trial of sustained-release theophylline versus placebo. Theophylline was given in therapeutic dosage (to ensure serum levels of between 10 and 20 micrograms/ml) for two months, followed by two months of placebo or vice versa. The results from the 24 patients who entered both theophylline and placebo treatment arms were compared, using outcome measures relevant to general practice care. Theophylline is shown to be of value in the management of asthma in general practice.