Airway mechanics after withdrawal of a leukotriene receptor antagonist in children with mild persistent asthma: Double-blind, randomized, cross-over study

Background: To determine the response of airway mechanics and the changes in asthma symptoms to stepping down of leukotriene receptor antagonist (LTRA) therapy. Methods: Thirty children (mean age: 7.1 years) with mild, well-controlled, and persistent asthma who took LTRA as maintenance treatment were randomized into a double-blind, placebo-controlled, cross-over study. Each group received an LTRA (montelukast) or placebo daily for 2 weeks, followed by a 1-week washout period, and then the alternate treatment for 2 weeks. Spirometry and impulse oscillation system (IOS) measurements before and after four puffs of salbutamol inhalation, fractional exhaled nitric oxide (FeNO), and the childhood asthma control test (C-ACT) were evaluated at baseline, the end of placebo treatment, and the end of LTRA treatment. Results: Changes of FEV₁/FVC (p =.113) and FEV₁ (p =.109) from baseline to posttreatment did not differ significantly between the placebo and montelukast groups. In the placebo group, prebronchodilator (pre-) FEV₁/FVC was decreased (83% vs. 86%) and bronchodilator response (BDR) in FEV₁ was diminished (10.7% vs. 6.4%) at posttreatment compared with baseline. However, the montelukast group had no significant changes in pre-FEV₁/FVC (p =.865) and BDR in FEV₁ (p =.461). In addition, compared with the montelukast group, the placebo group showed no significant changes in Rrs5 (total airway resistance), Rrs5–20 (peripheral airway resistance), FeNO, and symptoms by the C-ACT. Conclusion: In children with well-controlled mild persistent asthma, changes in spirometry, IOS, FeNO, and C-ACT results did not differ between the placebo and montelukast groups within 2 weeks.