RESUMEN
BACKGROUND: Patients with bronchial asthma frequently have exercise-induced bronchocon striction. Exercise-induced bronchoconstriction limits the activities important for physical and social development in children. Leukotriene receptor antagonist has been shown to protect against exercise-induced bronchoconstriction. The purpose of this study is to determine the effect of montelukast in protecting or controlling exercise-induced asthma. METHOD: 22 patients were enrolled and received montelukast(5 mg/day) for 2 months. Exercise challenges were performed before and after treatment and medication was not given for at least 48 hours before follow-up test. The form of exercise was free running for 8 minutes. The respiratory symptom scores, maximum percent fall in FEV1 from pre-exercise baseline and time to recovery of FEV1 to within 10% of pre-exercise baseline were evaluated. RESULTS: The respiratory symptoms score was siginificantly improved after 2 months of therapy(p<0.05). The maximum percent fall in FEV1 after exercise and the time from maximum percent fall in FEV1 to return to within 10 precent of pre-exercise FEV1 were also siginificantly improved after 2 months of therapy(p<0.05). In 3 patients with exercise-induced asthma, the maximum percent fall in FEV1 was decreased after 2 months of therapy, but was increased after follow-up 2 months without therapy. CONCLUSION: Montelukast, a leukotriene-receptor antagonist, is effective for protection and control of exercise-induced asthma in children.