Concomitant montelukast and loratadine as treatment for seasonal allergic rhinitis: A randomized, placebo-controlled clinical trial

Background: Nasal challenge studies have suggested histamine and cysteinyl leukotrienes are important proinflammatory mediators in allergic rhinitis. This study was designed to determine the efficacy of montelukast, a cystein yl leukotriene receptor antagonist, administered alone or concomitantly wit h loratadine, an H-1-receptor antagonist, in seasonal allergic rhinitis. Objective: The purpose of this study was to determine the effect of concomi tant use of montelukast and loratadine in the treatment of seasonal allergi c rhinitis. Methods: In this multicenter (N = 12) double-blind, randomized, parallel-gr oup, placebo-controlled 2-week trial, 460 men and women, aged 15 to 75 year s, with spring seasonal allergic rhinitis were randomly allocated to receiv e 1 of the following 5 treatments: montelukast 10 or 20 mg, loratadine 10 m g, montelukast 10 mg with loratadine 10 mg, or placebo, once daily in the e vening. The primary end point was daytime nasal symptoms score (average of congestion, rhinorrhea, itching, and sneezing). Other end points were eye s ymptoms, nighttime symptoms, individual daytime nasal symptoms, global eval uations (patient's and physician's), and rhinoconjunctivitis quality-of-lif e scores. Results: Concomitant montelukast with loratadine improved the primary end p oint significantly (P < .001) compared with placebo and each agent alone. C ompared with placebo, montelukast with loratadine also significantly improv ed eye symptoms, nighttime symptoms, individual daytime nasal symptoms, glo bal evaluations, and quality of life. Montelukast alone and loratadine alon e caused modest improvements in rhinitis end points. All treatments were si milarly well tolerated. Conclusions: Concomitant montelukast with loratadine provided effective tre atment for seasonal allergic rhinitis and associated eye symptoms with a sa fety profile comparable with placebo.