[Cardiovascular risks and management during Attention Deficit Hyperactivity Disorder treatment with methylphenidate]

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common of the pediatric neuropsychiatric disorders. Methylphenidate is an important element of therapeutic strategies for ADHD. Clinicians are interested in the safety of methylphenidate. Because this drug raises heart rate and blood pressure, concerns have been raised about its cardiovascular safety. Concerns were based on case reports of sudden cardiac death in methylphenidate users, plausible pharmacological pathways involving well-established stimulant effects on heart rate and blood pressure. Until recently, data were limited to a number of observational studies too small to examine serious cardiac events. In the past two years, large retrospective, population-based cohort studies were performed. These studies did not show any evidence that methylphenidate was associated with an increase in risk of myocardial infarction, sudden cardiac death, or stroke. Treatment of children with methylphenidate is not significantly associated with an increase in the short term or mid-term risk of severe cardiac events. For many, available data now will be seen as reassuring. But gaps persist in the methodical and comprehensive assessments of the safety of methylphenidate. Analyses cannot be generalized to children with long-term use of stimulants. Furthermore, long-term effects of slight increases in heart rate or blood pressure are unknown. Stimulant administration continues to have a detectable adrenergic effect even after years of treatment. In the MTA study, greater cumulative stimulant exposure was associated with a higher heart rate at years 3 and 8. Although less severe, such adverse cardiac events are nonetheless alarming to patients. This adrenergic effect may have clinical implications, especially for individual patients with underlying heart abnormalities and it deserves further investigation. More research is necessary to optimize a safe use of methylphenidate regarding its cardiovascular effects. In light of the controversies surrounding the increase in the number of children being diagnosed with ADHD, the broad use of methylphenidate in these patients, and cardiovascular concerns about it, this article addresses topics of clinical significance. For ease of use by practitioners, the article summarizes the guidelines stated by the European Medicines Agency over the appropriate pretreatment evaluation and cardiovascular assessment. It advocates a thorough history and physical examination before initiating methylphenidate to treat patients with ADHD, with an emphasis on the identification of risk factors for sudden death. A cardiac sub-specialist consultation is mandatory in case of history or physical examination findings. In other cases, an electrocardiographic screening is recommended in order to check out previously unrecognized heart disease.