RESUMO
Attention-deficit hyperactivity disorder is a frequent condition in children and often extends into adulthood. Use of immediate-release methylphenidate (MPH) has raised concerns about potential cardiovascular adverse effects within a few hours after administration. This study was carried out to investigate acute effects of MPH on electrocardiogram (ECG) in a pediatric population. A total of 54 consecutive patients with attention-deficit hyperactivity disorder (51 males and 3 females; mean age =12.14±2.6 years, range 6-19 years), receiving a new prescription of MPH, underwent a standard ECG 2 hours before and after the administration of MPH 10 mg per os. Basal and posttreatment ECG parameters, including mean QT (QT interval when corrected for heart rate [QTc]), QTc dispersion (QTd) interval duration, T-peak to T-end (TpTe) intervals, and TpTe/QT ratio were compared. Significant modifications of both QTc and QTd values were not found after drug administration. QTd fluctuated slightly from 25.7±9.3 milliseconds to 25.1±8.4 milliseconds; QTc varied from 407.6±12.4 milliseconds to 409.8±12.7 milliseconds. A significant variation in blood pressure (systolic blood pressure 105.4±10.3 vs 109.6±11.5; P<0.05; diastolic blood pressure 59.2±7.1 vs 63.1±7.9; P<0.05) was observed, but all the data were within normal range. Heart rate moved from 80.5±15.5 bpm to 87.7±18.8 bpm. No change in TpTe values was found, but a statistically significant increase in TpTe/QTc intervals was found with respect to basal values (0.207±0.02 milliseconds vs 0.214±0.02 milliseconds; P<0.01). The findings of this study show no significant changes in ECG parameters. TpTe values can be an additional parameter to evaluate borderline cases.
RESUMO
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.
