Effects of nedocromil sodium on the bronchomotor response to sulfur dioxide in asthmatic patients

It is known that cromolym sodium and nedocromil sodium share similar antiallergic properties. This study examined whether nedocromil sodium, a pyranoquinoline dicarboxylic acid, could inhibit sulfur dioxide (SO2) bronchoconstriction in a dose-dependent manner in 10 men with mild asthma. Previous studies have shown that cromolyn sodium produces such inhibition in allergic monkeys and asthmatic subjects. Subjects in this double-blind, placebo-controlled study were nonsmoking men between the ages of 23 and 40 years (mean age, 30.7 years). The study took place over 5 days within a 3-week period. On the first of 5 days, each subject had a history taken and physical examination, SO2 baseline test, laboratory testing, and a methacoline dose-response test. On each of 4 test days, the subjects received pretreatment with either placebo or a 2, 4, or 8 mg dose of nedocromil sodium in a randomized, double-blind sequence, followed after 30 minutes by an SO2 dose-response test. Results showed that maximum bronchoconstriction response to SO2 was significantly attenuated (p < 0.01) by all three doses of nedocromil sodium, with small differences noted between dose levels. We concluded that nedocromil sodium inhibited SO2-induced bronchospasm at dose levels as low as 2 mg.