Anti-leukotriene agents: a new direction in asthma therapy.

A role for the leukotrienes in asthma has been postulated for many years. These mediators induce potent bronchoconstriction, stimulate mucous secretion and decrease mucus transport, increase vascular permeability (thereby promoting edema formation), and induce migration of eosinophils into the lung. Recent studies with both leukotriene receptor antagonists and leukotriene synthesis inhibitors have demonstrated that these new agents can be effective in asthma induced by exercise, aspirin, and allergen challenges. Further, in patients with mild-to-moderate asthma, these drugs improve pulmonary function, decrease symptoms, and reduce the need for "rescue" bronchodilators. Anti-leukotrienes thus represent an important step forward in asthma management.