Cromolyn sodium in the treatment of asthma: coming of age in the United States.

Cromolyn sodium has matured as a first-line drug in the management of asthma in the United States. New pharmacokinetic assays reveal that it exerts classic dose-response effects both in vitro and in vivo. The protective effect of cromolyn sodium is due chiefly to its ability to inhibit mediator release from mast cells, but there is considerable evidence that it may affect reflex-induced asthma and bronchial hyperreactivity. It may also reduce the number of inflammatory effector cells such as eosinophils and decrease the IgE-mediated local immune response. Two formulations are currently available in the United States: the powdered Spinhaler apparatus and a solution that can be aerosolized by a nebulizer. A metered-dose aerosol preparation containing 1 mg/drug per activation is being investigated in other parts of the world and appears to be equally as effective as the powdered and nebulized forms of cromolyn. Recent controlled studies reveal that cromolyn sodium and theophylline have equal efficacy in the first-line management of asthma, but troublesome cardiovascular and psychoneurologic side effects are often observed after theophylline therapy. If used properly, cromolyn sodium is a valuable agent in the pharmacologic treatment of asthma.