Background Montelukast sodium, a potent, oral, specific leukotriene-receptor antagonist, has demonstrated clinical efficacy in the treatment of chronic asthma. Loratadine, a selective histamine type 1 [H1]-receptor antagonist, has demonstrated antiallergic properties. Leukotriene-receptor antagonists given concomitantly with H1-receptor antagonists have been shown to have additive effects in the prevention of bronchospasm in antigen-challenge models.
Objective To determine whether montelukast plus loratadine provides improved efficacy to montelukast alone in the treatment of chronic asthma.
Methods The efficacy of montelukast alone vs montelukast-loratadine was studied in a 10-week, multicenter, randomized, double-blind, 2 × 2 crossover study. After a 2-week placebo run-in period, patients received montelukast sodium [10 mg] plus loratadine [20 mg], or montelukast sodium [10 mg] plus placebo once daily for 2 weeks. After a 2-week placebo washout period, patients were crossed over to receive 2 weeks of the other active treatment regimen, followed by another 2-week placebo washout period.
Results Montelukast given concomitantly with loratadine caused significant improvement in percentage of change from baseline in forced expiratory volume in 1 second [FEV1] compared with montelukast alone [13.86% vs 9.72%; P = .001]. The average additional effect of loratadine [least square mean difference in percentage of change from baseline in FEV1] was 4.15% [95% confidence interval, 1.65%-6.65%]. Key secondary end points [mean daily β-agonist use, daytime and nighttime symptom scores, morning and evening peak expiratory flow rate, and the Patient Global Evaluation] all showed significant improvement with montelukast-loratadine [P