Cromolyn therapy in patients with bronchial asthma. Effect on inhalation challenge with allergen, histamine, and methacholine.

The action mechanism of cromolyn sodium and its effect on bronchial sensitivity to allergen, methacholine chloride, and histamine inhalations were studied in 17 asthmatic subjects. Cromolyn capsules or placebo was administered by an inhaler (Spinhaler) randomly on alternate days 30 minutes before aerosol challenge. Cromolyn and placebo did not differ in their effect on bronchial response to histamine or methacholine. However, the degree of decrease in forced vital capacity and forced expiratory volume in one second after allergen challenge was significantly reduced by cromolyn in 15 of 17 subjects. Immediate and delayed reactions of itching, tightness, or wheezing developed in 14 subjects after allergen challenges following placebo intake and were prevented or substantially inhibited by cromolyn.