Antileukotriene agents in asthma: the dart that kills the elephant?

THE PERSISTENCE OF AIRWAY INFLAMMATION is believed to cause the mechanical changes and symptoms of asthma. After decades of research, a new class of medication has emerged that focuses on leukotrienes, mediators of inflammation. These substances are potent inducers of bronchoconstriction, increased vascular permeability and mucus production, and they potentiate the influx of inflammatory cells in the airways of patients with asthma. In this article the author reviews the development, mechanism of action, and clinical and toxic effects of the leukotriene synthesis inhibitors and receptor antagonists that are entering the North American market. These agents can decrease airway response to antigen, airway hyperresponsiveness and exercise-induced asthma. They are also effective inhibitors of ASA-induced symptoms. Although few published studies are available, the antileukotrienes seem almost as effective in the management of chronic asthma as low-dose inhaled corticosteroids, and their use permits a decrease in the frequency of use or dose of corticosteroids. Further evaluation and clinical experience will determine the position of targeted inhibition of the leukotriene pathway in the treatment of asthma.