[Medication for ADHD and the risk of cardiovascular mortality]

Recently, the FDA recommended a black-box warning describing the increased risk of cardiovascular events associated with the use of stimulant drugs (amphetamines; in the Netherlands: dexamphetamine, methylphenidate) in the treatment of attention deficit hyperactivity disorder (ADHD). The recommendation was based largely on the increased use of these drugs in children and adults in the USA, voluntary reporting of adverse events, and the pharmacological analogy with other sympathomimetic amines, such as ephedrine, pseudoephedrine and phenylpropanolamine, for which similarwarnings have been given previously. The Adverse Event Reporting System documented 25 cases of sudden death based on WHO criteria with the use of amphetamines and methylphenidate; most of the cases were children aged less than 18 years. Sudden death in children is most often caused by fatal arrhythmias due to congenital heart diseases, such as long QT syndrome and hypertrophic cardiomyopathy. An increase in heart rate can potentially provoke life-threatening arrhythmias when the QT interval does not compensate for the increase. In adults, increased blood pressure and heart rate are well-documented risk factors for cardiovascular events. The use of methylphenidate is increasing in the Netherlands, indicating that greater caution is warranted when prescribing these drugs.