The efficacy of montelukast in the treatment of cat allergen-induced asthma in children

Background: Montelukast is a leukotriene antagonist approved for the treatment of childhood asthma in children age 2 years and older. There are limited studies on its effects on allergic asthma in children. Objective: We sought to evaluate montelukast's effects on upper and lower airway responses to intense cat allergen exposure. Methods: In a double-blind, placebo-controlled, cross-over trial 18 subjects aged 6 to 14 years with cat-induced asthma were randomly assigned to receive 1 week each of either montelukast or placebo, followed by a 1-hour cat challenge in an environmental exposure unit. Upper and lower respiratory tract symptoms were rated, and spirometry and acoustic rhinometry were performed. Challenges were stopped early if the subject became too uncomfortable or had a greater than 50% decrease in FEV₁. Results: Overall changes in FEV₁ were significantly different with montelukast treatment and remained significant after adjusting for allergen level (P = .02; adjusted P = .01). Lower respiratory tract symptom scores were significantly reduced with montelukast versus placebo (P = .007) but lost significance after adjusting for allergen level (P = .16). Challenge length was significantly longer with montelukast versus placebo (P < .001) and remained significant after adjusting for allergen level (P = .019). Montelukast did not significantly affect upper respiratory responses, as measured by means of symptom scores (P = .43) and changes in acoustic rhinometry (P = .078). Conclusions: Montelukast was significantly more effective than placebo in attenuating lower respiratory responses and extending challenge length when cat-sensitive children with mild persistent asthma were exposed to high levels of cat allergen.