ABSENCE OF QT(C) PROLONGATION WITH CETIRIZINE IN CHILDREN AGED 6-YEARS TO 11-YEARS

Background: In previous clinical trials, cetirizine has been shown to be efficacious in the treatment of seasonal allergic rhinitis (SAR), p erennial allergic rhinitis, and chronic idiopathic urticaria when give n once daily. As significant QT prolongation and cardiac arrhythmias h ave been reported with some of the newer antihistamines, the electroca rdiographic effects of cetirizine were evaluated. A previous study in normal, healthy, adult volunteers had demonstrated that cetirizine doe s not prolong the QT interval at up to six times the maximum clinical dose. Objective: The intent of this study was to evaluate the electroc ardiographic effects of cetirizine in children. Methods and Patients: As part of a randomized, 4-week, controlled clinical trial, electrocar diograms (ECGs) were obtained for 119 children aged 6 to 11 years with SAR. Participants in this trial received either a placebo (N = 40), 1 0 mg of cetirizine (N = 44), or 5 mg of cetirizine (N = 35). The QT in terval was measured on a 12-lead ECG at the baseline visit (day 1) and at visit 2 (days 11-17). The QT interval was determined by a digitizi ng method and corrected for heart rate by the Hedges' formula for corr ected QT interval (QT,). Results: Five and 10 mg of cetirizine did not result in changes in the QT, interval that were significantly differe nt statistically from those of a placebo. Furthermore, the number of p atients with a 10% to 20% increase in QT, interval was comparable acro ss all treatment groups. Finally, no patients had a QT, interval incre ase of greater than 20% from baseline. Conclusions: The study demonstr ates that cetirizine, up to 10 mg once daily, did not prolong the QT, interval in pediatric patients with SAR.