Effect of various disease states on theophylline plasma levels and on pulmonary function in patients with chronic airway obstruction treated with a sustained release theophylline preparation.

Theophylline plasma levels and FEV1 were measured in patients affected by chronic obstructive pulmonary disease and a concomitant disease state (congestive heart failure, chronic cor pulmonale, obesity, peptic disease, hepatic cirrhosis, chronic renal failure) and treated with a sustained release theophylline preparation. Our results indicate that, only in patients affected by congestive heart failure and chronic cor pulmonale, is there a decreased plasma clearance of the drug. Low levels of plasma theophylline were measured in obese patients probably because they received an inadequate posology.