For the drug manufacturer Xanodyne, the end of the year was not all celebration. Indeed, the pharmaceutical giant had to take one of its products off the market after clinical reports indicated propoxyphene consumers may be at risk of fatal heart rhythms.

But the drug’s dangers are anything but new. According to reports from the Food and Drug Administration, since 1978, the FDA has received two requests to remove the painkillers, commercially sold as Darvon and Darvocet, from the market. In 2009, the agency also asked Xanodyne to include a boxed warning indicating the risks of overdosing.

However, it was not until now that the medical data available was found to be conclusive enough to lead the FDA to seek withdrawal. As it turns out, even the recommended dose, enough to cause significant changes to the electrical activity of the heart, can be fatal.

So grave are the painkillers’ dangers that the FDA is advising health care professionals to stop prescribing Darvon and Darvocet to their patients. Even those who have been taking the drug for years should contact their physicians as soon as possible to discuss switching to another pain management therapy, as the drug’s adverse events can be triggered by minor changes in the patient’s health, including simple dehydration.

In sum, and as Doctor John Jenkins of the Office of New Drugs in the FDA’s Center for Drug Evaluation and Research said: “The drug’s effectiveness in reducing pain is no longer enough to outweigh the drug’s serious potential heart risks.”

For more information about Propoxyphene and its side effects, visit www.fda.gov.