Effects of cromolyn sodium on the response to respiratory heat loss in normal subjects.

To investigate whether premedication with cromolyn sodium blunts the bronchoconstrictor response that occurs in normal subjects after extreme degrees of airway cooling, we had 9 adult male inhale either cromolyn or placebo on separate days, in a random, double-blind fashion, before challenges with cold air. The latter consisted of eucapnic hyperventilation to levels in excess of 85% of the indirect maximal breathing capacity while the subjects breathed air at -13 degrees C. Partial and maximal expiratory flow-volume curves were measured before and after medication and after hyperventilation. Neither cromolyn nor placebo inhalation per se significantly affected pulmonary function. The cold-air challenges caused significant decreases in expiratory flows, and these changes were significantly attenuated by cromolyn but not placebo. Thus, in normal subjects, cromolyn has the ability to modify the airway response to respiratory tract heat loss. Because the subjects were free of sensitized airway mast cells, we interpret these findings as further evidence that cromolyn sodium has immunologic and nonimmunologic modes of action.