Verofylline, a methylxanthine bronchodilator, in asthma.

Verofylline, a long-acting polysubstituted methylxanthine bronchodilator, was taken orally by eight adult patients with asthma in a double-blind, crossover tolerance study. Peak expiratory flow, forced vital capacity, and its subdivisions were measured weekly 2, 4, and 6 hr after oral dosing with drug or placebo. Peak drug activity developed between 4 and 6 hr after dosing. Subject tolerance was good at the doses used. Dose-response curves for mean forced expiratory volume in one second, peak expiratory flow rate, and forced expiratory flow at the end of 4 hr were greater after 0.05 mg/kg verofylline than after placebo or higher doses of verofylline. Mean percent change in forced vital capacity remained increased as long as 6 hr after 0.15 mg/kg active drug. Verofylline was not very effective as a bronchodilator at the doses used.