Low to moderate-dose off-label use of second-generation antipsychotics seems to be safe in the light of cardiac adverse effects in child psychiatric patients

Second-generation antipsychotics (SGAs) may increase the risk for ventricular arrhythmias by prolonging the rate-corrected QT interval (QTc) on an electrocardiogram (ECG). This prospective study aimed to examine QTc changes in child psychiatric patients during the implementation of an SGA monitoring protocol. QTc was calculated using both Bazett's (QTcB) and Fridericia's (QTcF) formula and categorised as normal (≤ 450 ms), borderline (> 450, < 470 ms), prolonged (≥ 470, < 500 ms), or significantly prolonged (≥ 500 ms). The study patients (n = 55, 76% males, median age 9.9 years) were followed for a median of 9 months. In all of them SGA (risperidone, aripiprazole, quetiapine) treatment was off-label. The median olanzapine equivalent dose was 2.0 mg. Concurrent ADHD medication was used by 40%. A baseline (BL) ECG was available for 78%. A BL and at least one follow-up ECG existed for 75%. The mean change in QTcB was 18.1 ms (p < 0.001) and in QTcF 17.2 ms (p < 0.001). The QTcB change was significantly greater in females (31.7 ms vs 13.2 ms, p = 0.046). During the follow-up, 11% had borderline (n = 5) or significant (n = 1) QTcB prolongation. In 5/6, the prolongation appeared after a change in psychotropic medication. No arrhythmias were detected. Low to moderate-dose SGA treatment in children seems to be safe in the light of cardiac adverse effects. However, individual risk assessments and systematic ECG monitoring are necessary. Particular attention should be paid to medication changes and female patients. • Second-generation antipsychotics (SGAs) may prolong the rate-corrected QT interval (QTc) and increase the risk for ventricular arrhythmias. • The risk seems to be low in healthy children, but data on long-term treatment and patients with risk factors are scarce. • In this clinical sample of 55 children using SGAs, QTc prolongation was seen after changes in psychotropic medication. • Individual cardiac risk assessment including family history and monitoring of SGA treatments is vital. Attention should be paid to medication changes and female patients.