Evaluate the additive role of zileuton 600mg qid to clinically stable asthmatics on Advair
250/50 bid. Since asthma is an endogenous inflammatory disease there usually is increased
total exhaled, bronchial and alveolar nitric oxide which are markers of eosinophilic driven
pathways of inflammation. The addition of zileuton which is a leukotriene synthesis inhibitor
by itself or together with inhaled corticosteroids should reduce nitric oxide gas exchange.