Background: Zafirlukast is an oral leukotriene receptor antagonist used in the treatment of patients with mild to moderate asthma. To investigate its effects in a clinical practice setting, we evaluated zafirlukast in a heterogeneous group of patients who had asthma of different degrees of severity and who were receiving concomitant asthma medications.
Methods: A total of 3759 patients were enrolled at 924 sites. Patients received zafirlukast 20 mg twice a day for 4 weeks. Pulmonary function was measured twice a day, and overall asthma symptom scores, number of nighttime awakenings, severity of morning asthma symptoms, and beta2-agonist use were recorded daily.
Results: In the efficacy analysis (3207 evaluable patients), all parameters showed statistically significant improvement that continued throughout the 4 weeks of the trial. A total of 71% of patients had improved pulmonary function and 72% had improved asthma symptoms. Improvement was consistent regardless of asthma severity category and regardless of concomitant asthma medication category. More than 70% of both physicians and patients indicated there was clinical improvement in pulmonary measures as well as in asthma symptoms. Common adverse events reported were headache (3.7%), nausea (1.4%), pharyngitis (1.4%), and sinusitis (1.1%).
Conclusions: Zafirlukast 20 mg twice a day is well tolerated and improves pulmonary function and asthma symptoms, regardless of asthma severity category and regardless of concomitant asthma medication category.