A multicenter trial of the prophylactic effect of ketotifen, theophylline, and placebo in atopic asthma.

Three hundred seventy-four patients with asthma were entered into a year-long, double-blind, double-placebo controlled study comparing the prophylactic effect of ketotifen (229 patients), theophylline (73 patients), and placebo (72 patients). The ketotifen group was larger to allow the accumulation of additional long-term safety data. The primary measure of therapeutic effect was a decrease in concomitant medication without a significant increase in symptomatology or a decrement in pulmonary functions.