ECG parameters in children and adolescents treated with aripiprazole and risperidone

Atypical antipsychotics (AP) are increasingly being used in children and adolescents for the treatment of psychiatric disorders. Atypical AP may cause QT prolongation on the electrocardiogram (ECG), which predisposes patients to an increased risk of developing threatening ventricular arrhythmias. Although this phenomenon has been exhaustively reported in adults, few studies investigated the safety of these drugs in pediatric patients. We performed an open-label, prospective study to assess the arrhythmic risk of aripiprazole and risperidone in a pediatric population. A total of 60 patients (55 M/5F, mean age 10.2+2.6 years, range 4-15 years), receiving a new prescription of aripiprazole or risperidone in monotherapy underwent a standard ECG before and after two months from the beginning of antipsychotic treatment. Basal and post-treatment ECG parameters, including mean QT (QTc) and QT dispersion (QTd), were compared within treatment groups. Twenty-nine patients were treated with aripiprazole (mean dosage 7.4+3.1mg/day) and 31 with risperidone (mean dosage 1.5+1mg/day). In our series, no patient exhibited pathological values of QTc or QTd before and after treatment for both drugs. However, treatment with risperidone was associated with a slight increase of both mean QTc and QTd values (407.4+11.9 ms vs 411.2+13.0 ms, p<0.05; and 40.0+4.4 ms vs 44.7+5.5 ms, p<0.001, respectively). Treatment with aripiprazole was associated with no changes of mean QTc, even if a small increase of QTd, (40.6+6.5 ms vs 46.3+7.2 ms, p<0.01) was observed. Although our data suggest a slight effect of aripiprazole and risperidone on ventricular repolarization, it is unlikely that such a change results in clinically relevant effects. The treatment with risperidone and aripiprazole in children with psychiatric disorders is not associated with clinically relevant modifications of QT interval. Caution in prescribing these drugs, however, is necessary in patients with family history of a genetic predisposition to arrhythmias in order to warrant a reliable assessment of drug-induced QT prolongation.