Montelukast

Montelukast is a selective antagonist of the leukotriene D4 (LTD4) receptor. In patients with asthma, montelukast 5 to 250 mg/day attenuated LTD4-induced bronchoconstriction and, at a dosage of 10 mg, significantly reduced early and late airway response to allergen (dust mite extract) relative to placebo. In studies evaluating the effects of various dosages of montelukast on exercise-induced bronchoconstriction the optimal dose of the drug was found to be 10 mg. Montelukast 10 mg/day controlled asthma significantly more effectively than placebo in a 3-month randomised double-blind study. In a 9-month open extension of this trial, during which patients were randomised to treatment with montelukast 10 mg/day or beclomethasone (approximately 400 micrograms/day), daytime symptom score and beta-agonist use decreased to a similar extent in each group. In a further study, treatment with montelukast 10 mg/day permitted clinically significant tapering of corticosteroid dosage in patients with stable asthma. Montelukast (5 mg/day) has also demonstrated efficacy in childhood asthma. The tolerability profile of montelukast was similar to that of placebo in placebo-controlled clinical trials in adults and children; the most common adverse event was headache.