How safe are ADHD drugs for children?

Washington: A new study now suggests that drugs for attention deficit hyperactivity disorder (ADHD) are unlikely to cause cardiac damage in children who take them.

The study, conducted at the University at Buffalo, has been published in the journal Pediatric Research.

The authors, however, caution that because the study was conducted on primates, the finding is not automatically applicable to humans.

Nonetheless, they have previously published that this primate model reliably shows other side effects similar to what is found in children receiving these medications.

The new findings conclude that chronic exposure to methylphenidate (MPH), a commonly prescribed ADHD drug, is unlikely to increase cardiovascular risks in healthy children.

“The findings are very reassuring in that even high-dose chronic MPH stimulant therapy did not result in any evidence of abnormal structures or function in the hearts of the monkeys,” said Steven E. Lipshultz, the study’s principal investigator.

-Sudden cardiac death controversy

The results contribute important evidence to an ongoing controversy about whether or not MPH is associated with sudden cardiac death. A number of studies have reported an increase in sudden cardiac death or other damage to the heart in some children taking the drug or other stimulant therapy for ADHD.

-Long-term testing

Lipshultz and his colleagues spent several years developing infrastructure to test how the therapy affected the hearts of the monkeys over the long term.

For five years, the monkeys were continuously treated with therapeutic, super-therapeutic (high doses) or a placebo, using a randomised design, starting when they were about 2 years old. The duration of the study corresponds to what would be a child to adulthood span, the researchers said.

“For ethical reasons, this study could not have been done in children,” Lipshultz added.

After a comprehensive cardiovascular assessment in all the monkeys, there were no statistical differences between the three groups on serum cardiovascular and inflammatory biomarkers, electrocardiograms, echocardiograms, cardiac pathology from endomyocardial biopsies and other clinical parameters.

In addition to the large population of children being treated with this therapy for ADHD and related disorders, Lipshultz noted that the findings also are good news for child survivors of cancer.

“On a personal level, I have cared for children and adolescents who have survived childhood cancer, who now are experiencing severe learning disabilities as a result of their cancer therapies,” he said. “They become my patients because their hearts have been damaged, an unfortunate effect of the successful treatment of their childhood cancer.

“Current recommendations state that children, such as these, with underlying heart disease, should avoid chronic stimulant therapy because of the concern that it could further damage their hearts. However, these prescription stimulants often allow these children to do much better with their learning progress, and denying such a useful therapy for theoretical reasons is difficult. The findings that we are reporting demonstrate that these useful medications, in many cases, can be prescribed to these children as well.”