Assessment of Cardiovascular Risks due to Methylphenidate in Six Months of Treatment in Children with Attention Deficit and Hyperactivity Disorder

Objectives: Cardiovascular adverse effects can be seen rarely in patients receiving methylphenidate for attention deficit and hyperactivity disorder (ADHD). In this study, we planned to investigate the effects of methylphenidate on the cardiovascular system in ADHD patients.Methods: One hundred and forty-one patients, who were diagnosed with ADHD and started on methylphenidate treatment between May 2011 and May 2012, were investigated. A cardiologic evaluation was performed on all of the patients before the methylphenidate treatment was begun. Subsequently, the patients were invited for regular visits at three months intervals for assessment of cardiovascular and electrocardiographic (ECG) changes during this treatment. The data of all these patients at the beginning of treatment and within the first 6 months were evaluated. Thirty-five patients (24.8%) suffered from various cardiovascular symptoms in the first 6 months. Demographic characteristics, heart rate, systolic and diastolic blood pressures, QTc duration on ECG, rhythm Holter and 24-hour blood pressure monitoring results of these patients were evaluated.Results: Thirty-five patients (10 girls and 25 boys) had cardiovascular symptoms in the first 6 months. The mean age of patients was 9.2±2.8 years. Although QTc duration significantly increased after methylphenidate treatment (p<0.05), this increase was within normal ranges. Similarly, systolic and diastolic blood pressures of patients increased significantly. This increase was between the 90–95th percentiles in only 5 patients. Twenty-four-hour blood pressure monitoring results were normal, and the methylphenidate treatment of these patients was not stopped. The mean heart rate of patients was also increased, but this increase was not statistically significant. The symptoms with respect to the cardiovascular system were palpitations in 16 patients (45.8%), chest pain in 11 patients (31.5%), palpitations with chest pain in 5 patients (14.2%) and dyspnea in 3 patients (8.5%). All patients' ECG and rhythm Holter results were within normal limits. Two patients discontinued treatment because of their parent's unwillingness for the drug to be continued.Conclusions: In ADHD patients, the elongation of QTc duration and increase in the systolic and diastolic blood pressures were statistically significant during 6 months of methylphenidate treatment. However, all these changes remained within normal limits. All patients receiving this drug should be monitored carefully for cardiovascular side effects.