The effects of theophylline on metabolic rate in chronic obstructive lung disease patients.

OBJECTIVE: To study the effect of theophylline and an alternative bronchodilator, ipratropium, on resting energy expenditure (REE) and thermic effect of food (TEF). DESIGN: 5-week randomized, repeated measures, double-blind, cross-over design, comparing the effects of theophylline and ipratropium drug treatments on metabolic measurements made during a baseline period. SETTING: Ambulatory Clinical Trials Center at University of California, San Diego. SUBJECTS: 14 patients at least 65 years old with a clinical diagnosis of chronic obstructive pulmonary disease. MEASUREMENTS: Resting energy expenditure and thermic effect of food were measured by indirect calorimetry. Body composition was determined using bioimpedance. RESULTS: Resting energy expenditure did not differ between baseline and either of the two drug treatments. In men, the thermic effect of food increased significantly during theophylline and ipratropium drug treatment periods (p < 0.03). CONCLUSIONS: Theophylline or ipratropium does not appear to increase resting energy expenditure in patients with chronic obstructive lung disease. The elevated values for thermic effect of food in men need further study.