Improvements in distal lung function correlate with asthma symptoms after treatment with oral montelukast.

STUDY OBJECTIVES The distal airways are likely to contribute to asthma pathobiology and symptoms but have rarely been specifically evaluated in relation to systemic oral therapy. We hypothesized that treatment with montelukast, an oral cysteinyl-leukotriene receptor antagonist, would improve both proximal and distal lung physiology in patients with mild asthma. DESIGN Randomized, double-blind, crossover design. SETTING Academic referral center. PATIENTS Subjects with mild asthma limited to using short-acting inhaled beta(2)-agonists. INTERVENTIONS Nineteen subjects with mild asthma underwent a baseline assessment of lung function, lung mechanics, and symptoms, followed by randomization to therapy with montelukast, 10 mg taken in the evening, or placebo in a crossover, double-blind fashion. Each treatment phase lasted 4 weeks, with a 2-week washout period. A repeat evaluation was performed during the last week of each treatment phase. MEASUREMENTS AND RESULTS Montelukast resulted in improvement in (mean +/- SD) proximal and distal lung function parameters (change in FEV(1): montelukast, 0.16 +/- 0.06 L; placebo, -0.05 +/- 0.05 L; p = 0.008); change in specific conductance: montelukast, 7.2 +/- 2.9% predicted; placebo, -17 +/- 8% predicted; p = 0.007; change in % predicted residual volume [RV]: montelukast, 18.4 +/- 8.3% predicted; placebo, 3.0 +/- 2.9% predicted; p = 0.05). Improvement in symptoms (ie, wheeze and chest tightness) correlated with improvements in RV while receiving montelukast, but not while receiving placebo (Pearson coefficients: 0.55 and 0.66, respectively; p < 0.008 and 0.04, respectively). CONCLUSIONS The systemically acting oral agent montelukast improves proximal and distal lung physiology. Improvements in distal lung function correlate with improvements in asthma symptoms.