The use of cromolyn in the management of hyperreactive airways and exercise.

Cromolyn given a few minutes before exercise significantly protects from exercise-induced asthma in more than 70% of patients, probably through prevention of mediator release and possibly through other mechanisms. Its efficacy is comparable to that of theophylline, alpha-adrenergic blockers, and calcium channel blockers; better than that of atropine and ketotifen; but less than that of inhaled albuterol. Cromolyn seems to be more effective than metaproterenol and theophylline for prevention of late reactions of exercise-induced asthma. The addition of cromolyn markedly improved the results in patients not completely protected by inhaled adrenergic agents. Cromolyn also protects from other triggers like hyperventilation with cold air, ultrasonically nebulized water, and sulfur dioxide. Its prolonged administration causes a reduction in the nonspecific hyperreactivity as shown by tests of histamine inhalation or hyperventilation with cold air. This effect is thought to be a result of cromolyn's protection from allergic-induced increase in nonspecific hyperreactivity, although there is some evidence that it can also occur in nonatopic patients, suggesting a broader protective effect.