Darvon, a 53-year-old pain pill, will be pulled from the U.S. market after a study found potentially fatal heart risks in healthy people who take the medicine at the recommended dose.
Xanodyne Pharmaceuticals Inc., the drug’s owner since 2005, will withdraw Darvon and Darvocet, a product that combines Darvon’s active ingredient with acetaminophen, Food and Drug Administration officials said today in a statement. The agency requested the move after evaluating study data, and asked makers of generic versions to take them off the market as well. Darvon’s active ingredient, the opioid propoxyphene, had been approved in 1957 for treating mild to moderate pain.
The U.K. announced in 2005 that it would pull propoxyphene- containing drugs from the market, citing reports of as many of 400 fatal overdoses a year. The European Medicines Agency recommended a ban last year. Also last year, the FDA rejected an advisory panel’s recommendation to withdraw the drug, opting instead to require a new safety study and a black-box warning label about the risks of excessive use.
Xanodyne’s new clinical research, combined with new epidemiological data, led the FDA to conclude that propoxyphene’s benefits no longer outweigh its risks, said John Jenkins, director of the agency’s Office of New Drugs.
All Users at Risk
The data “suggested that the heart risk of propoxyphene could apply to all users, not just those who took excessive doses or those with medical conditions,” such as reduced kidney function, Jenkins said today during a conference call.
Xanodyne, a closely held drugmaker in Newport, Kentucky, that doesn’t disclose sales figures, acquired Darvon and Darvocet in July 2005 from a company that had bought the rights from Indianapolis-based Eli Lilly & Co., the developer of the medicines.
Xanodyne removed the drug as “part of a market-wide withdrawal applying to all propoxyphene-containing products, affecting branded and generic pharmaceutical companies,” the company said today in a statement. Darvon and Darvocet represent less than 1 percent of the propoxyphene market in total prescriptions, Natasha Giordano, Xanodyne’s chief executive officer, said today in a separate e-mail.
Those two brands “have never been promoted in any way by Xanodyne, neither through personal promotion by sales representatives nor direct-to-consumer or direct-to-doctor advertising or promotions,” Giordano said.
About 10 million people in the U.S. received prescriptions for propoxyphene-containing products in 2009, said Gerald Dal Pan, director of the FDA’s Office of Surveillance and Epidemiology, on the conference call.
“For the first time, we now have data showing that the standard therapeutic dose of propoxyphene can be harmful to the heart,” he said in the statement.
Users of the drug “need to know that these changes to the heart’s electrical activity are not cumulative,” he said. “Once patients stop taking propoxyphene, the risk will go away.”
Public Citizen will ask Congress to investigate why the FDA didn’t take propoxyphene off the market years ago, said Sidney Wolfe, the Washington-based consumer group’s director of health research.
“Evidence going back more than 30 years indicates that propoxyphene is not very effective, is toxic at doses not much higher than the recommend dose,” and is “somewhat addictive,” Wolfe said today in a statement. “Due to FDA negligence, at least 1,000 to 2,000 or more people in the U.S. have died from using propoxyphene since the time the U.K. ban was announced” in 2005, he said.
Wolfe’s group petitioned the FDA in 1978 and in 2006 to ban the drug.
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