Stimulants used to treat attention deficit hyperactivity disorder could increase the risk of sudden death in children who have no underlying heart conditions, researchers reported Monday.
Such drugs have carried warnings since 2006 about an increased risk of sudden death in children or teens known to have serious heart abnormalities. But this is the first study to link the stimulants to sudden death in otherwise healthy young people, say officials of the Food and Drug Administration, which helped pay for the research. Further research is needed to confirm the finding, they said.
Columbia University scientists compared stimulant use in 564 young people who suffered sudden unexplained death with that of 564 killed in car accidents. They ranged in age from 7 to 19 and died between 1985 and 1996.
Researchers excluded subjects with identified heart abnormalities or a family history of sudden unexplained death. They interviewed parents and looked at autopsy reports to determine whether the victim had a heart abnormality or had been taking an ADHD stimulant drug.
Of those who died suddenly for no apparent reason, 10 -- or 1.8% -- had been taking methylphenidate, sold under the brand name Ritalin. Only two, or 0.4%, who died in a car accident had been taking a stimulant, and only one of them had taken methylphenidate.
"It's hard to characterize the results as reassuring," the FDA's Robert Temple said at a news conference. Still, Temple said, it's possible that the study missed stimulant use by the car-accident victims, because the parents of children whose deaths were unexplained might have better recall years later of what drugs they took.
"It's not a robust finding," he said, noting that if only one more automobile victim had been found to have taken an ADHD stimulant, the difference between that group and the sudden unexplained death group would no longer have been statistically significant. But, Temple said, "that doesn't mean that this is off the table and we're not concerned about it anymore."
The FDA is now conducting two studies, one in children and one in adults, whose use of ADHD medications has been increasing, to see whether the drugs are associated with a higher risk of sudden death, heart attack or stroke.
An estimated 2.5 million U.S. children take ADHD stimulants, according to an editorial accompanying the study, published online by the American Journal of Psychiatry.
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