Management of asthma. 2. Antiasthmatic drugs

Asthma is a complex disease characterized by hyperreactive airways, with a wide spectrum of severity and presentation. Management requires confirmation of the diagnosis; characterization of the severity, chronicity, and precipitating factors; and development of an appropriate treatment plan based on the established efficacy of the various pharmacologic and nonpharmacologic modes of therapy. For acute symptoms, treatment with sympathomimetic amines appears to be the most appropriate initial measure. Corticosteroids are the most potent drugs available for dealing with acute symptoms that are unresponsive to bronchodilators. For the control of chronic asthma, either theophylline or cromolyn can be used initially. Chronic therapy may also require corticosteroids, in which case toxic effects of long-term therapy can be minimized by use of alternate-day dosage of prednisone or daily inhalation of beclomethasone dipropionate. Concurrent with drug therapy, environmental control measures can be used to minimize exposure to avoidable precipitants, and injection therapy with allergenic extracts can be considered if inhalant allergy can be convincingly demonstrated to play a major role. Failure of airway obstruction to respond to corticosteroids and the other measures should raise serious questions regarding the diagnosis.