Double blind crossover study of cromolyn sodium inhibition of aerosol antigen challenge.

Six men patients, with type I hypersensitivity to pollen antigens, were studied during four separate periods approximately one week apart. During the first and fourth periods, aqueous extracts of ragweed or grass pollen were administered via a nebulizer. During the second and third periods the patients were treated with a single capsule of cromolyn sodium or placebo in a double blind fashion, delivered as a powder 30 minutes prior to antigen bronchial challenge. The test doses of antigen resulted in a decrease of FEy, ranging from 20.3 to 61.3 percent with a mean of 35.5 percent. Pretreatment with cromolyn sodium resulted in 21.9 to 100 percent protection with a mean of 65.3 percent which contrasts with the -12.4 ±24 percent protection following placebo (P<0.005). The FVC measurements paralleled these changes. This double blind study demonstrates the ability of cromolyn sodium to provide protection against polleninduced obstruction in sensitive asthmatic subjects.