Randomized, placebo-controlled study of cetirizine and loratadine in children with seasonal allergic rhinitis

Background: Pharmacologic treatment is a mainstay of allergy therapy and many caregivers use over-the-counter antihistamines for the treatment of seasonal allergic rhinitis (SAR) symptoms in children. Objective: To assess the efficacy and safety of cetirizine 10 mg syrup versus loratadine 10 mg syrup versus placebo syrup in a randomized double-blind study of children, ages 6-11 years, with SAR. Methods: This randomized, double-blind, parallel-group, placebo-controlled study was conducted at 71 U.S. centers during the spring tree and grass pollen season. After a 1-week placebo run-in period, qualified subjects were randomized to once-daily cetirizine 10 mg (n = 231), loratadine 10 mg (n = 221), and placebo (n = 231) for 2 weeks. The primary efficacy end point was change from baseline in the subject's mean reflective total symptom severity complex (TSSC) score over 14 days. Results: Children treated with cetirizine experienced significantly greater TSSC score reductions versus children treated with placebo over 14 days (least square mean change, -2.1 versus -1.6; p = 0.006). The differences in TSSC score improvement over 14 days between the cetirizine versus loratadine groups (-2.1 versus -1.8; p = 0.124) and between the loratadine versus placebo groups (-1.8 versus -1.6; p = 0.230) were not statistically significant. Predominant adverse events in the cetirizine, loratadine, and placebo groups were headache (3.5, 3.6, and 3.1%, respectively) and pharyngitis (3.5, 2.7, and 3.5%, respectively). Somnolence was reported in three subjects (1.3%) treated with cetirizine and in none of the other subjects. Conclusion: Cetirizine 10 mg was statistically significantly more efficacious than placebo in the treatment of SAR symptoms in children ages 6-11 years. Symptom improvement was not significantly different between the loratadine 10 mg and placebo groups.