A proposed alternate mechanism of action for theophylline

The methylxanthines; caffeine, theophylline, and theobromine have several pharmacological actions, of which, their ability to relax bronhcial smooth muscle has great value in the treatment of chronic obstructive pulmonary disease. Theophylline is the most effective of the methylxanthines in this regard. Clinically, it is either used alone or in combination with beta-adrenergic agonists. The pharacological basis of this combination depends on the ability of these two classes of drugs to increase the intracellular concentration of 3', 5' cyclic-AMP. The objectives of this study were to evaluate whether theophylline causes a substantial increase of plasma E and NE to justify this evaluation as an alternate mechanism of action for theophylline. Speically, this study was designed to; 1.) Quantify the release of plasma catecholamines after theophylline challenge in normal subjects; 2.) Compare this rise in plasma catecholamines after theophylline of placebo administration and; 3.) Document relationships between plasma theophylline levels and plasma catecholamines.