Cardiovascular Effects of Mixed Amphetamine Salts Extended Release in the Treatment of School-Aged Children with Attention-Deficit/Hyperactivity Disorder

BackgroundThe cardiovascular safety of mixed amphetamine salts extended release (MAS XR) was evaluated in 2968 children 6–12 years of age with attention-deficit/hyperactivity disorder (ADHD).MethodsIn this prospective, open-label, noncomparative, community-based study, subjects whose symptoms of ADHD were well controlled with stimulant medication maintained their established treatment regimens for 2 weeks before enrollment into the current study. Subjects’ regimens were then converted to an approximately equivalent once-daily dose of MAS XR 10, 20, or 30 mg/d according to a medication-conversion algorithm, which could be adjusted to 40 mg/d for optimal efficacy and tolerability. Systolic blood pressure (SBP), diastolic BP (DBP), and pulse were measured at each study visit. Twelve-lead electrocardiography was performed at screening and at the end of the extension phase or early termination.ResultsNo clinically significant changes in BP or pulse were observed. Although one subject experienced a QT-prolongation interval > 25%, no clinically significant prolongation in the mean QT interval was seen. Approximately 2.5% of subjects demonstrated two consecutive SBP or DBP values > 95th percentile for age, sex, and height, and 3.6% of subjects’ pulse increased by ≥ 25 to ≥ 110 beats per minute. No serious cardiovascular adverse events or deaths occurred.ConclusionsIn addition to demonstrated efficacy and safety, the cardiovascular profile of MAS XR showed generally small divergences from age-specific population norms that pose very limited risk in this patient population.