Efficacy and tolerability of montelukast alone or in combination with loratadine in seasonal allergic rhinitis: a multicenter, randomized, double-blind, placebo-controlled trial performed in the fall

Background: Histamine and cysteinyl leukotrienes seem to be important mediators of allergic rhinitis. Objective: This multicenter, randomized, double-blind, parallel-group, placebo-controlled trial evaluated the effectiveness and tolerability of montelukast, loratadine, and combination therapy with montelukast and loratadine for treating patients with fall seasonal allergic rhinitis. Methods: After a 1-week, single-blind, placebo run-in period, 907 male and female patients aged 15 to 82 years were randomized to 1 of 4 treatments: montelukast 10 mg (n = 155), loratadine 10 mg (n = 301), combination montelukast 10 mg and loratadine 10 mg (n = 302), or placebo (n = 149), administered once daily at bedtime for 2 weeks. The primary endpoint was the daytime nasal symptoms score (mean of congestion, rhinorrhea, pruritus, and sneezing). Results: Mean symptom scores at baseline were similar for the four treatment groups. For each of the three active treatments, the difference was significant for the mean change from baseline compared with placebo (P less than or equal to 0.001). However, the effect of montelukast/loratadine compared with loratadine alone, the primary comparison, was not significantly different. Differences for each therapy alone compared with placebo were also significant for most secondary endpoints, including nighttime symptom scores, eye symptoms scores, and rhinitis-specific quality of life. Differences for montelukast/loratadine compared with each therapy alone generally showed numerical superiority, and a few endpoints showed differences that were statistically significant. All active treatments showed a safety profile generally similar to placebo. Conclusions: Montelukast alone or in combination with loratadine is well tolerated and provides clinical and quality-of-life benefits for patients with seasonal allergic rhinitis.