The efficacy of isoproterenol inhalation for predicting the response to orally administered theophylline in chronic obstructive pulmonary disease.

Orally administered theophylline is commonly prescribed for patients with chronic obstructive pulmonary disease (COPD). It would be advantageous to predict those patients who will or will not respond to this methylxanthine. Forty men with COPD received placebo and theophylline orally, each for 1 month in a double-blind, single cross-over fashion. The acute response of the forced expiratory volume in one second (FEV1) to isoproterenol inhalation (015 mg) during placebo therapy was determined. The subjective and objective responses after 1 month of therapeutic theophylline concentrations (15.1 +/- 4.2 microgram/ml), mean +/- SD) in these clinically stable subjects also were measured. The sensitivity and specificity of isoproterenol aerosolization for predicting an objective response to theophylline was 75 and 96%, respectively. We conclude that isoproterenol inhalation can predict the response to orally administered theophylline in patients with COPD.