Abstract

Theophylline and its derivatives dilate the bronchi of asthmatic subjects when given in high enough doses. They may relieve Cheyne-Stokes respiration, and they may increase cardiac output and cause a diuresis in patients with cardiac failure. Since theophylline is not very soluble and irritates the stomach, the more soluble aminophylline, a loose combination of theophylline with ethylene diamine, has been used. Unfortunately in the stomach this readily breaks down to the parent substance and gastric irritation occurs. In practice effective doses of aminophylline can be given only intravenously or by suppositories. If theophylline derivatives could be taken by mouth it would be much more convenient, and for this reason other preparations have been developed.