Clinical Studies of Combination Montelukast and Loratadine in Patients with Seasonal Allergic Rhinitis

BACKGROUND: Concomitant use of montelukast and loratadine may improve symptoms of seasonal allergic rhinitis (SAR) more than treatment with either drug alone. OBJECTIVE: We compared the efficacy of this combination versus placebo, nasal beclomethasone, montelukast, and loratadine in study 1 and versus placebo, montelukast, and loratadine in study 2. METHODS: Patients were randomly allocated to double-blind treatment with intranasal beclomethasone 200 mu g/twice daily (study 1 only), placebo, montelukast 10 mg+loratadine 10 mg, montelukast 10 mg, or loratadine 10 mg once daily. The primary endpoint was the Composite Symptom Score (CSS): average of daily diary scores for Daytime Nasal Symptoms and Nighttime Symptoms. RESULTS: In study 1, improvements in the change from baseline in CSS were seen for montelukast+loratadine (least-squares means [95% CI] = -0.43 [-0.51, -0.35]), beclomethasone (-0.57 [-0.64, -0.49]), montelukast, and loratadine. All treatments were significantly better than placebo; montelukast+loratadine had a significantly greater effect on CSS than montelukast alone but no difference compared to loratadine was detected. Beclomethasone provided significantly greater improvement versus montelukast+loratadine on the primary and secondary endpoints except for the rhinoconjunctivitis quality-of-life score. In study 2, the combination treatment was similar to montelukast, loratadine, and placebo for the primary and secondary endpoints. CONCLUSION: In study 1, montelukast+loratadine had a significantly greater effect on CSS than placebo and montelukast alone; however, in all comparisons, nasal beclomethasone had a greater effect on daily symptoms. In contrast, the combination of montelukast+loratadine in study 2 did not provide greater improvement compared with placebo, montelukast, or loratadine monotherapy, perhaps due to a large placebo effect.