Effect of montelukast on exhaled Leukotrienes and quality of life in asthmatic patients

Study objectives: In some patients with asthma treated with inhaled corticosteroids, suppression of inflammation is incomplete. This may be because the effect of corticosteroids on cysteinylleukotriene (cys-LT) biosynthesis is limited. Montelukast is a cys-LT antagonist that significantly improves asthma control in corticosteroid-treated asthmatic patients. However, not all patients treated with cys-LT antagonists show a clinical improvement. Design: We have studied the effect of treatment for 4 weeks with montelukast (10 mg/d) on exhaled cys-LTs and leukotriene B-4 (LTB4), exhaled nitric oxide, asthma quality of life (AQL), and respiratory function in patients with stable asthma. Setting: Asthma clinics in general practice. Patients: We studied 50 patients (30 men; mean +/- SEM age, 53 +/- 2 years) who were treated with inhaled corticosteroids. Measurements and results: We detected cys-LTs in exhaled breath condensate in 25 of 50 patients; however, in the normal nonasthmatic subjects, cys-LTs were below the limit of detection. After treatment with montelukast, there was a fall in cys-LT concentrations from 14.6 +/- 3.3 to 8.5 +/- 2.6 pg/mL after 2 weeks (p > 0.05) and to 3.9 +/- 1.3 pg/mL after 4 weeks (p < 0.01). Exhaled LTB4 levels were also elevated. After treatment with montelukast, LTB4 levels fell from 33.0 +/- 3.9 to 20.4 +/- 2.5 pg/mL after 2 weeks of treatment (p < 0.05), and to 17.0 +/- 2.2 pg/mL after 4 weeks of treatment (p < 0.01). These changes in exhaled cys-LT and LTB4 were associated with significant improvements in AQL scores. Conclusions: It appears that in some patients with stable asthma treated with inhaled corticosteroids, the suppression of inflammation is incomplete. Adding a leukotriene receptor antagonist can provide a complementary effect of controlling inflammation, with a significant improvement in quality of life.