Taking stimulant medications to treat symptoms of attention deficit and hyperactivity disorder (ADHD) modestly drives up a child's risk of suffering a sudden fatal heart attack, a new study shows. The Food and Drug Administration helped sponsor the latest effort to clarify the risks of ADHD medication. But the agency cautioned Monday that the study's findings were too weak to justify a change in its safety recommendations for physicians prescribing stimulant drugs to young patients.
"It's not a robust finding," said Dr. Robert Temple, director of the FDA's Office of Drug Evaluation. In a group of 564 children who died of sudden cardiac failure between 1985 and 1996, researchers found that 10 were thought to be taking stimulant medications at the time of their death. Among a matched group of youngsters who were killed in car accidents in the same period, only two were thought to be under treatment with stimulant medications.
Researchers assumed that for the children in car crashes, stimulant use was unlikely to be a contributing factor to death. So when they found a higher rate of stimulant use among children who died of sudden cardiac arrest, the difference suggested that the medications were a factor contributing to death by heart attack. They considered the difference "significant" -- meaning it was highly unlikely to have been a chance event. The study came out Monday online in the American Journal of Psychiatry.
The FDA already has urged physicians to consider a child's personal and family history of cardiovascular disease before prescribing stimulant medications for ADHD and to lean against prescribing stimulants for children with underlying heart disease. But such a condition is difficult to detect in most children. As a result, the American Heart Assn. has proposed that all kids being prescribed ADHD medications should first be screened for heart disease with echo- or electro-cardiogram. The FDA recommends such screening only in cases where a physician suspects heart disease may be present.
ADHD researcher Dr. Benedetto Vitiello of the National Institute of Mental Health acknowledged the study is unlikely to settle the debate over routine heart-disease screening for kids treated with stimulant medications. Instead, physicians and ADHD patients and their parents will probably have to wait for the results of two more studies due to be released next fall and winter. Those studies will look at rates of heart attack and stroke -- whether fatal or not -- in children and adults who take stimulant medication for ADHD and compare them to cardiovascular events in populations not on ADHD medication.
-- Melissa Healy