Additive bronchoprotective and bronchodilator effects with single doses of salmeterol and montelukast in asthmatic patients receiving inhaled corticosteroids

Abstract

Objective: We wished to evaluate whether the combination of a leukotriene receptor antagonist and long-acting beta(2)-agonist might confer additive beneficial effects in terms of bronchoprotection and bronchodilatation, in mild to moderate asthmatic patients who were suboptimally controlled on inhaled corticosteroids alone.

Methods: Twelve asthmatic patients were enrolled into a single-blind, placebo-controlled, crossover study, receiving additive therapy as either of the following: (1) montelukast alone, 10 mg (ML(10)); (2) inhaled salmeterol alone, 50 microg (SM(50)); (3) ML(10) and SM(50); (4) ML(10) and inhaled salmeterol, 100 microg (SM(100)); or (5) placebo inhaler and tablet. Trough measurements were made of adenosine monophosphate (AMP) bronchial challenge (the provocative concentration of a drug [AMP] causing a fall of >/= 20% in FEV(1) [PC(20)]) as the primary end point, and spirometry, following single doses of either placebo or active treatments (12 h after salmeterol, and 24 h after monteleukast, respectively).

Results: Compared to placebo, all active treatments led to significant improvements (p < 0.05) in geometric mean AMP-PC(20): placebo, 42 mg/mL; ML(10), 106 mg/mL; SM(50), 115 mg/mL; ML(10) and SM(50), 183 mg/mL; and ML(10) and SM(100), 247 mg/mL. The effects of montelukast and salmeterol were numerically additive, with ML(10) and SM(100) being significantly different (p < 0.05) from ML(10) alone. For mean FEV(1) and forced expiratory flow rate between 25% and 75% of vital capacity, there were significant differences (p < 0.05) between both combination therapies vs ML(10) alone.

Conclusions: Our results suggest additive benefits of a single dose of a long-acting beta(2)-agonist and leukotriene antagonist, in terms of bronchoprotection and bronchodilation. Further studies in more severe asthmatics are required to evaluate long-term clinical effects.