The Ritalin study: Research raises concerns about safety of popular drug

 HOUSTON -- Most of us know it as Ritalin: the brand name for the drug methylphenidate.

For a nearly a half-century, doctors have been writing millions of prescriptions for it, mostly to kids diagnosed with attention deficit disorder.

That’s why we were intrigued to learn about some controversial findings from a study done five years ago on methylphenidate.

The study was a joint project of Houston’s MD Anderson, the nation’s biggest cancer center, and UTMB on Galveston Island.

It all began when a UTMB researcher was struck by something so basic it seems almost unbelievable: with all those kids taking the drug, little was known about the long-term health effects. Could there be an increased risk of cancer?

The researcher was Marvin Legator, known nationally for his work on environmental risks to human health. Before his death in 2005, he’d come across studies showing high doses of methylphenidate caused tumors in the livers of mice.

"Legator was a close friend of mine," said Dr. Samuel Epstein a professor of Environmental and Occupational Medicine at the University of Illinois School of Public Health in Chicago. Dr. Epstein is a national critic of how drugs are approved for use.

"These were very, very important findings and warnings of a cancer risks that were clearly evident," Epstein said of the mice studies Legator reviewed. But what about humans?

Legator found little data. So he and researchers at UTMB launched their own, small project. With the cooperation of a pediatrician and parents at a pediatrics clinic run by UTMB in Texas City, a dozen children with hyperactivity disorder were put on methylphenidate.

But first, researchers took blood samples from the 12 kids. After three months on the drug, their blood was taken again. The before-and-after samples were then sent to MD Anderson. There, another group of researchers analyzed them for chromosome damage -- damage that could raise the risk of cancer later in life.

What they found was startling: all 12 kids had triple the amount of chromosome damage compared to before they started taking the drug. What the researchers had discovered sent shock waves through the pharmaceutical industry.

It wasn’t long before federal health investigators descended on MD Anderson. They quizzed the local researchers, scrutinizing the blood samples and how they were tested. In the end, we’re told the investigators made some technical criticisms, but overall they found nothing that discredited the dramatic findings.

Then, scientists the world over tried to duplicate what had been found at UTMB and at MD Anderson. Bottom line: they couldn’t do it.

A German study of 38 children found no "significant" genetic damage from taking methylphenidate.

A federal study on monkeys also failed to find "significant" damage.

A study in California looked at medical records of adults who’d taken the drug as kids and found an increased rate of leukemia but said further study was needed and concluded there was no "strong" link to cancer.

Then, earlier this year, a study paid for by the makers of Ritalin also failed to duplicate the findings of the study done in Texas.

So was MD Anderson’s blood analysis wrong? Was there really no genetic damage in the Texas City kids? Or if there was, was it from something they all just all happened to be exposed to other than the methylphenidate? No one has tried to answer those questions.

We do know by talking to the pediatrician at that clinic that to the best of his knowledge, today the kids in the study are doing fine. The pediatrician says the study never diminished his confidence. He says he continues to prescribe the methylphenidate drugs like Ritalin.

What might UTMB researcher Marvin Legator have done had he not died shortly after his study was published?

"There is no question that Legator would have preceded on a large scale study of Ritalin on human populations," Dr. Epstein said.