Background: In very young children, H(1 )-receptor antagonists have not been adequately studied, although they are widely used and assumed to be safe.
Objective: Our objective was to test the hypothesis that cetirizine would be as safe as placebo for long-term use in this population.
Methods: In the prospective, double-blind, parallel-group, 18-month-long Early Treatment of the Atopic Child (ETAC) study, 817 children with atopic dermatitis who were 12 to 24 months old at study entry were randomized to receive either cetirizine 0.25 mg/kg or placebo twice daily. Safety was assessed by using the reports of all adverse events, diary cards, physical examinations, developmental assessments, electrocardiograms, blood hematology and chemistry tests, and urinalyses.
Results: The population evaluated for safety consisted of 399 children receiving cetirizine and 396 children receiving placebo. Drop-outs and serious events, including hospitalizations, occurred infrequently and were less common in the children receiving cetirizine than in those children receiving placebo, although the differences were not statistically significant. Most reported symptoms and events were mild and were attributed to intercurrent respiratory or gastrointestinal infections, exacerbations of allergic disorders, or age-related concerns rather than to medication-related adverse effects. There were no clinically relevant differences between the groups for neurologic or cardiovascular symptoms or events, growth, behavioral or developmental assessments, laboratory test results, or electrocardiograms, and no child receiving cetirizine therapy had prolongation of the QTc interval.
Conclusions: The safety of cetirizine has been confirmed in this prospective study, the largest and longest randomized, double-blind, placebo-controlled safety investigation of any H(1 )-antagonist ever conducted in children and the longest prospective safety study of any H(1 )-antagonist ever conducted in any age group.