The Effects of Methylphenidate on Ventricular Repolarization Parameters in Children with Attention-Deficit Hyperactivity Disorder.

Background: Long-acting methylphenidate (MPH), a psychostimulant agent, is widely used in the treatment of attention-deficit hyperactivity disorder (ADHD). Methylphenidate might cause an increment in the risk of lethal arrhythmias by deteriorating ventricular repolarization. QT intervals, the corrected QT (QTc), QT dispersion, T-peak to T-end (TpTe), and the TpTe/QTc ratio are the most utilized indicators of ventricular repolarization in electrocardiogram (ECG). The present study was conducted to examine the effects of long-term MPH use on the ECG in pediatric patients. Methods: A total of 52 children with ADHD and 51 age- and gender-matched controls were enrolled in the study. The children had been using MPH regularly for at least 6 months. Comparisons were made regarding ECG parameters, including the mean intervals of QT, QTc, QTc dispersion interval duration, TpTe intervals, TpTe/QT, and TpTe/QTc ratio. Results: The median duration of treatment with MPH was 30 months (minimum-maximum: 6-120), and the median MPH dose was 30 mg/day (minimum-maximum: 18-54). The main findings showed significantly prolonged P-wave dispersion, TpTe interval, TpTe dispersion, and TpTe/QT and TpTe/QTc ratios in the ADHD group compared to the healthy controls ( Conclusion: Methylphenidate may have proarrhythmogenic effects in children with ADHD, which may not be adversely affected by long-term use and treatment dose. Considering the extensive use of MPH, cardiac monitoring of these children is important.