In recent years, the number of children diagnosed with attention-deficit/hyperactivity disorder or ADHD has increased. A recent report estimates ADHD prevalence among children and adolescence at 8%.
Pharmacological treatment is most commonly prescribed for ADHD, particularly stimulant medications such as methylphenidate (MPH) and mixed-amphetamine-salt (MAS) formulations. However, there have been concerns on the side effects of these drugs, particularly adverse effects on the heart. However, health experts could not agree about the cardiotoxicity risks involved. As early as 2008, the American Heart Association (AHA) recommends screening pediatric patients for heart problems before starting ADHD treatments. However, the American Academy of Pediatrics was not convinced of the risks and rejected the AHA guidelines.
According to Dr. Raul Silva the New York University Langone Medical Center:
“There has been a big brouhaha about the safety, particularly the cardiovascular safety, of stimulant medications for ADHD in kids, and at one point, the cardiac folks put a very big scare into people.”
This motivated him and his team of researchers to conduct a comprehensive review of data available from clinical trials conducted during the last 10 years on the safety of MPH and MAS.
Their results presented at the National Institute of Mental Health and American Society of Clinical Psychopharmacology New Clinical Drug Evaluation Unit (NCDEU) 2010 Annual Meeting clarified some questions but also brought some reassurances. The findings basically show that ADHD medications, MPH as well as MAS, can increase heart rate, blood pressure, both systolic and diastolic and QT interval of children and adolescents. These increases however are mild to moderate and may not be clinically relevant to ADHD patients without initial cardiovascular problems. However, for those with underlying heart conditions that may not have diagnosed, these side effects can be dangerous. There were no deaths due to cardiovascular problems reported in the studies analyzed. The authors support the recommendations of the AHA to screen patients for heart abnormalities before starting them on these medications – but only if screening is possible. Withholding ADHD treatment from patients without access to an ECG is not warranted, according to the authors.
Dr. Silva believes in erring on the side of caution and performs cardiac screening for all his pediatric patients:
“The parents appreciate my doing this, and I have found some very interesting things, such as arrhythmias. When I go back to the pediatric cardiologist, they often tell me that it’s nothing to worry about. So the take-home message here is monitor when you can, ask baseline questions, but also be reassured, because the data really don’t show a heck of a lot of problems with cardiovascular side effects.”
Many drugs previously thought to be safe turned out to have adverse effects on heart health – rofecixib and rosiglitazone, to name a few. No wonder AHA is being cautious.