Corticosteroids and cromolyn sodium as modulators of airway inflammation.

Heightened airway reactivity is a cardinal feature of asthma and correlates with many clinical features of the illness, such as the acute response to bronchodilator drugs, the magnitude of diurnal fluctuations in lung function, and the amount of therapy required to control symptoms. Data have accumulated indicating that a reduction in airway reactivity can decrease asthma morbidity, and many advocate treating asthmatic patients prophylactically to prevent acute exacerbations from developing, rather than responding to them after they have occurred. This approach is particularly effective if it is used when the airways are being exposed to stimuli to which they are sensitive. A number of drugs have been purported to reduce airway reactivity, but the most convincing evidence supports the effects of cromolyn and inhaled and oral steroids. Although each type of drug has its own advantages and disadvantages and different modes of action, the common denominator is believed to be a reduction in the state of airway inflammation.