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. Daily morning and evening PEFR and St. George's Respiratory Questionnaire (SGRQ) scoring were recorded respectively. The levels of serum IgE and urine leukotriene E4 before and after treatment were measured using enzyme linked immunosorbent assay and enzyme immunoassay kits. Results: In the zafirlukast treated group, the morning PEFR was significantly improved from 314.4 ± 20.6 to 340.6 ± 18.3 L/min (N = 17, p <0.05) after 4 weeks of treatment, while the control group did not show any significant changes. The zafirlukast group had significant improvement in their symptom scores of SGRQ from 48.6 ± 4.6 to 33.8 ± 4.7 (N = 17, p <0.05). However, the placebo did not improve the symptom scores. Conclusion: Leukotriene receptor antagonists effectively improved symptoms and benefited lung function for moderate persistent asthmatic patients who had received regular treatments with inhaled steroids.