Effects of Montelukast in Children With Asthma

Inclusion Criteria: * Children 6 to 14 yrs old, step 1 and step 2 GINA (Global INitiative for Asthma) guidelines * exhaled nitric oxide (NO) \>20 PPB at visit 2 * symptoms more often than twice a day, FEV1 equal or higher than 80% of predicted value and reversibility equal or higher than 12% to salbutamol, or a positive provocation test with methacholine, or exercise * no regular medication, inhaled short-acting beta-2 agonists for symptom relief Exclusion Criteria: * Patient is hospitalized * Patient has FEV1 \< 80% predicted on visit 1 * Patient has 2 or more nighttime awakenings for asthma per week or pef variability 30% or more * upper respiratory infection in the previous 3 weeks * treatment with glucocorticoids or LTRAs in the previous 4 weeks * treatment with inhaled glucocorticoids for more than 4 weeks in the previous year