LEXINGTON, Mass.--(BUSINESS WIRE)--Critical Therapeutics, Inc. (Nasdaq: CRTX) today announced enrollment of the first patient in its Phase IV clinical study designed to evaluate the efficacy of ZYFLO CR™ (zileuton) extended-release tablets in asthma patients whose symptoms are poorly controlled despite taking moderate dose inhaled corticosteroids (ICS). ZYFLO CR and the immediate release formulation of zileuton, ZYFLO® (zileuton tablets), are the only FDA-approved leukotriene synthesis inhibitors for the prophylaxis and chronic treatment of asthma in adults and children 12 years of age and older. ZYFLO CR and ZYFLO are not indicated for use in the reversal of bronchospasm in acute asthma attacks, but can be continued during acute exacerbations of asthma.