Leukotriene pathway inhibitors in asthma and chronic obstructive pulmonarydisease

Leukotrienes can be generated from a wide variety of cells including mast c ells and eosinophils. The biological properties of these products include b ronchial smooth muscle contraction, stimulation of mucous production, enhan cement of vascular permeability, and recruitment of eosinophils. These prop erties can contribute significantly to the pathobiology of asthma. Recently , zafirlukast and montelukast, and zileuton, leukotriene D-4 receptor antag onists and 5-lipoxygenase inhibitors, respectively, have been developed and are available for treating asthma. Studies have found these compounds modi fy bronchospasm with exercise, the pulmonary reaction to aspirin in sensiti ve subjects, and the airway response to inhaled antigen. Furthermore, in pa tients with chronic asthma, leukotriene modifiers improve airflow obstructi on, decrease the need fur rescue medication, and diminish symptoms. Moreove r, these drugs can prevent asthma exacerbations. However, there is little e vidence that these medications have potent anti-inflammatory activity. None theless, leukotriene modifiers represent new, and effective, therapeutics i n the treatment of asthma; at present, the positioning of these products in relationship to inhaled corticosteroids, for example, in the treatment of asthma has not been fully defined but will emerge with further study and us e in the clinic setting.