True about zafirlukast is

Refer KDT 6/e p 222 Zafirlukast and Montelukast are cysteinyl Leukotriene receptor antagonist They cause modest improvement in lung function and reduction in asthma symptoms and lessen the need for beta agonists rescue therapy These drugs can be considered in patients with persistent asthma Zafirlukast is long acting and can be given twice to once daily orally It is a modest bronchodilator