Darvon, Darvocet Banned Over Heart Risk: Was FDA Too Slow to Act?

CBS/AP) It's curtains for Darvon.

The prescription painkiller is being taken off the market by its maker at the request of U.S. health officials who say the 50-year-old pill can cause deadly heart rhythms.

The FDA said Friday that Xanodyne Pharmaceuticals had agreed to halt all U.S. marketing of Darvon and the related brand Darvocet, which contain the drug propoxyphene. The medications have been subject to safety concerns for decades.

The agency also called on generic drugmakers to stop marketing low-cost drugs containing propoxyphene.

FDA officials said they decided to take action based on a recent study showing Darvon interferes with the electrical activity of the heart.

"This last study, the cardiac study, was sort of the final piece of the puzzle that told us what the complete picture was," said Dr. Gerald Dal Pan, director of FDA's office of surveillance and epidemiology.

Public safety advocates said the agency should have acted sooner to pull a drug with limited benefits and a long history of safety problems.

"The FDA's deadly delay in this case starkly illustrates how one of the most important public health concepts, the precautionary principle, was embraced by the UK and Europe, but was for too long recklessly rejected by the FDA," said Dr. Sidney Wolfe, of the consumer watchdog group Public Citizen.

The group petitioned the FDA to ban the drug in 1978 and again in 2006, pointing to its role in thousands of deaths reported by state medical examiners.

Propoxyphene, which was approved in the 1957, is an opioid narcotic used to treat mild to moderate pain. About 10 million people in the U.S. received prescriptions for Darvon and related drugs in 2009, according to the FDA. The most popular form of the drug currently is Darvocet, which combines propoxyphene with the more common painkiller acetaminophen. At an FDA meeting in 2009, officials cited studies showing most of the pain relief from Darvocet came from the acetaminophen.

Dal Pan said patients should continue taking the medication until their doctor prescribes a replacement therapy. Other commonly prescribed drugs in the same class are oxycodone and codeine.

Watch Dr. Jon LaPook's report on the CBS Evening News: