Cardiovascular measures in children and adolescents with attention-deficit/hyperactivity disorder who are new users of methylphenidate and atomoxetine

Objective: The purpose of this study was to assess the cardiovascular effects of drugs used for attention-deficit/hyperactivity disorder (ADHD) in children and adolescents treated in community care centers in Italy. Methods: This study was an open, prospective, observational study of youth with ADHD treated with atomoxetine (ATX) and methylphenidate (MPH). Measurements of blood pressure and heart rate, and electrocardiogram (ECG) assessment were performed at baseline and at regular intervals up to 24 months. Results: By June 2010, 1758 youth were enrolled in the Italian ADHD National Registry. Statistically significant increases were observed in cardiovascular measures: in the MPH group after 6 months in heart rate (+2.01, p=0.01); in the ATX group after 6 months in diastolic pressure (+1.60, p=0.01) and in heart rate (+2.93, p=0.001), and after 12 months in heart rate (+3.26, p=0.003). Compared with the baseline, 59 patients had an alteration of ECG during the follow-up period. Although at 12 months, the probability of detecting an abnormal ECG was higher in the MPH group than in the ATX group, only 2 out of 30 cases at 6 months with altered ECG were considered to have experienced serious adverse events. One case was treated with ATX and one with MPH, and arrhythmia was the detected abnormality. Conclusions: Treatment with MPH and ATX in youth appears to have a small but significant impact on the cardiovascular system. The long-term impact of these medications is unknown. Several clinically meaningless ECG alterations were observed mostly in MPH-treated youth. We therefore suggest evaluating cardiovascular risks at baseline.