Dec. 12, 2011 -- A study of 150,000 adults taking drugs for attention deficit hyperactivity disorder (ADHD) found no conclusive evidence that the medications increase the risk for heart attack, stroke, or sudden death from heart-related causes.
The research, published online Monday in the Journal of the American Medical Association, comes just over a month after the same investigators found that the drugs likely do not raise the risk for serious heart problems in children and young adults, based on their study of more than 1.2 million young users.
Millions of children and adults in the U.S. take stimulants such as Adderall, Concerta, Metadate, Methylin, Ritalin, or the non-stimulant Strattera to treat ADHD symptoms such as hyperactivity, impulse control, and trouble focusing.
The new findings should reassure adult patients who take ADHD drugs, but they do not rule out a modest increase in risk associated with their use, says researcher Laurel A. Habel, PhD, a research scientist with the Kaiser Permanente Division of Research in Oakland, Calif.
“With any drug there are potential risks, and these drugs can increase blood pressure,” she tells WebMD. “But if there is an increase in [heart-related] events, our study suggests that it is slight.”
Use of stimulant and non-stimulant ADHD drugs has increased rapidly among adults over the past decade, with almost one in three prescriptions now written for adults.
The drugs can increase blood pressure and heart rate. In 2006, reports of health issues led the FDA to commission the largest studies ever conducted examining ADHD drug-related heart risks in children and adults.
In the latest study, researchers followed slightly more than 150,000 adults who had been prescribed stimulant or non-stimulant ADHD medication and about 300,000 adults with no history of ADHD drug use.
The study period lasted about two decades, during which time there were 1,357 heart attacks, 296 sudden deaths from cardiac arrest, and 575 strokes recorded.
Use of ADHD drugs was not associated with an increased risk of any of these three outcomes, even among users with prior heart disease.
Although the studies do not support claims that ADHD drugs significantly increase the risk for life-threatening heart events, the researchers conclude that a modest increase in risk associated with their use cannot be ruled out.
“These studies provide an important piece of the puzzle that we have not had,” says Vanderbilt University professor of pediatrics and preventive medicine William O. Cooper, MD, who led the study in children.
ADHD Drugs: Is EKG Needed?
Cooper tells WebMD that the two studies provide the strongest evidence to date calming fears that stimulant and non-stimulant ADHD drugs raise the risk for heart attack, stroke, and sudden cardiac death.
Concerns that they did led to a 2008 recommendation by the American Heart Association that children and teens have electrocardiograms (EKGs) to check for heart problems before going on stimulant medication for treatment of ADHD.
In an editorial published with the study, ADHD researcher Philip Shaw, MD, PhD, of the National Institutes of Health concluded that there is now little evidence to support this recommendation.
American Heart Association past-President Robert Bonow, MD, says the two studies were well designed and well executed and he agrees that the findings are reassuring.
Bonow is a professor of medicine at Northwestern University in Chicago.
“There has been something of a dark cloud over these drugs with regard to their impact on the heart,” he says. “These findings should put many of these fears to rest, but it is still important to know an individual patient’s risk. Patients with heart disease and those who have a high risk for heart disease need to be monitored if they take these drugs.”