Corticosteroid therapy in asthma.

Corticosteroids are useful in the treatment of both allergic and idiosyncratic asthma. Although the mechanisms of corticosteroid action in asthma are poorly understood, several possible sites of action have been proposed. Corticosteroids alter the cellular and vascular inflammatory response to bronchial injury, affect catecholamine action on airways, and alter the production of eicosanoids, all of which aid in the resolution of bronchospasm in asthmatic patients. Corticosteroids should only be used for the treatment of asthma after therapeutic levels of methylxanthines and beta agonists have been achieved. Although the optimal doses of corticosteroids in asthma have not been defined, guidelines exist to aid in therapy. In the treatment of status asthmaticus, the intravenous route of administration is preferable. Short courses of corticosteroids may be useful in the treatment of chronic asthma. When long-term corticosteroid therapy is the only option for control of bronchospasm, alternate-day and/or aerosolized corticosteroids are preferable to daily corticosteroids and are associated with fewer side effects. Corticosteroids are useful in the pregnant asthmatic patient when bronchospasm cannot be controlled with bronchodilators. The major risk to the fetus in pregnant asthmatics is hypoxia from uncontrolled bronchospasm, and not from therapy. However, the lowest possible dose of systemic corticosteroids needed to control symptoms, with or without the use of aerosolized corticosteroids, is recommended. All asthmatics who have needed systemic or aerosolized corticosteroids within 6 months prior to surgery should receive preoperative and post-operative corticosteroid therapy. For patients not usually on systemic corticosteroids, conversion to oral prednisone, with a rapid taper is recommended. Side effects from short-term corticosteroid therapy are minimal, with hyperglycemia and psychosis being the major concerns. Long-term steroid therapy has significant side effects, however, and use should be minimized. Suppression of the HPA axis is one of the most potentially dangerous side effects of corticosteroids, and therefore any patient who has been treated with corticosteroids for longer than 4 weeks should be evaluated for possible adrenal suppression.