Effect of montelukast added to inhaled corticosteroids on fractional exhaled nitric oxide in asthmatic children.

The aim of this prospective, self-controlled, single-blind study was to assess the effect of montelukast added to maintenance therapy with inhaled corticosteroids (ICS) on fractional exhaled nitric oxide (FENO) in asthmatic children. Thirty-five children (age 11.2+/-0.4 yrs (mean+/-SEM)) with mild-to-moderate persistent asthma treated with low to medium doses of ICS and FENO > 20 parts per billion (ppb) were included. The patients were randomly assigned to two groups: 17 patients continued ICS (group C) and 18 had montelukast added to ICS for 3 weeks (group M). FENO measurements were performed in both groups at baseline (T1) and after 3 weeks (T2), and in group M also after 2 weeks of washout. FENO was measured by a chemiluminescence analyser using an on-line method (50 mL x s(-1)) with nitric oxide-free air. The overall mean daily dose of ICS was equivalent to 530+/-58 microg x day(-1) of beclomethasone in group M and to 564+/-55 microg x day(-1) of beclomethasone in group C. There were no significant differences in baseline FENO and forced expiratory volume in one second (FEV1) between the two groups. After 3 weeks there was a significant reduction of FENO values in patients of group M (T1 52.2+/-7.8 ppb, T2 36.1+/-4.6 ppb) but no significant changes in group C (T1 43.5+/-6.0 ppb, T2 47.8+/-9.4 ppb). In group M after 2 weeks of montelukast withdrawal, FENO rose to baseline values (55.6+/-8.7 ppb). In conclusion, after montelukast treatment there is a fractional exhaled nitric oxide reduction in asthmatic children receiving maintenance therapy with inhaled corticosteroids. This suggests an anti-inflammatory effect of montelukast additive to that of inhaled corticosteroids.