Heart attack, stroke, and sudden death were no more common in children on the drugs than in other kids, the federally funded study showed. That was true even for kids and young adults at high risk for heart trouble - a group doctors have long worried about when prescribing these drugs.
"Parents should be very reassured," said Dr. Laurel Leslie, a Tufts University pediatrician who had no role in the study but served on a FDA advisory panel examining drugs for ADHD.
The study was sponsored by the FDA and the federal Agency for Healthcare Research and Quality. Results were published online Tuesday by the New England Journal of Medicine. Results from similar studies of these medicines in adults are expected soon.
More than 5 million children in the U.S. have been diagnosed with ADHD, which interferes with the ability to pay attention and control behavior. Although it seems counterintuitive, stimulant drugs like Ritalin, Adderall, Concerta and Strattera can help these children. And about 2.7 million kids are prescribed such drugs each year.
Isolated reports of heart attacks and strokes in kids taking the drugs had caused worry, and the Canadian government curbed use of one drug in 2006. The FDA added a black box warning to some ADHD drugs, and the American Heart Association gave the controversial advice in 2008 that it was reasonable to screen a child starting on such a drug with a heart EKG test.
"There's such strong feelings around these drugs" and whether they are overused in children who might be helped by behavioral therapy alone, said study author Dr. William Cooper, a pediatrics and preventive medicine professor at Vanderbilt University. "The potential safety questions have added another layer of concern."
His study was aimed at resolving the safety question. Researchers used medical records from four big health plans covering more than 1.2 million people two to 24 years of age. They found 81 cases of serious heart problems from 1998 through 2005 among all people in the study.
Those on ADHD meds were no more likely to suffer a heart attack, stroke or sudden death than were non-users or former users of such drugs. More than half of kids and young adults taking ADHD drugs used methylphenidate (generic Ritalin), and researchers saw no increased risk from that specific drug either.
"The good news is that it doesn't look like overall there's an increase in cardiovascular events in kids who are on ADHD drugs," said Dr. Gordon Tomaselli, a Johns Hopkins University heart specialist and president of the American Heart Association. "The question parents should be asking themselves is, `Does my child really need this?"'
Cooper, the study's leader, and Leslie, the Boston pediatrician, defended the drugs' use, especially with careful medical monitoring and behavioral therapy.
"I take care of kids all the time who are helped by these drugs," Cooper said.
FDA spokeswoman Sandy Walsh said stimulants "should generally not be used in patients with serious heart problems, or for whom an increase in blood pressure or heart rate would be problematic." Patients on ADHD meds should be watched for changes in heart rate or blood pressure, she said.
The National Institute of Mental Health has more on ADHD.