Zafirlukast improves pulmonary function in patients with moderate persistent asthma receiving regular inhaled steroids: a prospective randomized control study.

Background: Zafirlukast is a leukotriene receptor antagonist that was invented to treat patients with chronic asthma.

Methods: To evaluate whether the zafirlukast improved the peak expiratory flow rate (PEFR) and clinical symptoms, 31 asthmatic patients with moderate persistent asthma who received regular inhaled corticosteroid were randomly divided into the study group (N = 17). They received the zafirlukast 20 mg bid for 4 weeks, and the control group (N = 14) received a placebo.