The U.S. Food and Drug Administration has announced that Xanodyne Pharmaceuticals, inc., the maker of prescription pain medications Darvon and Darvocet, has agreed to withdraw the medications from the U.S. market. The move comes after the results of an FDA study in which new clinical data shows the drug, which goes by the generic name propoxyphene, puts patients at risk of potentially serious or even fatal heart rhythm abnormalities. The FDA determined the new data shows the risks of the drug outweigh any benefits.
The FDA has informed the generic manufacturers of propoxyphene-containing products of Xanodyne’s decision to remove its medications from the market and has requested they voluntarily remove their products as well. The FDA is advising health care professionals to stop prescribing propoxylene to their patients, and patients who are currently taking the drug should contact their health care professional as soon as possible to discuss switching to another pain medication therapy.
Propoxyphene is an opioid used to treat mild to moderate pain. First approved by the FDA in 1957, propoxophene is sold by prescription under various names both alone (Darvon) or in combination with acetaminophen (Darvocet). After safety concerns were raised in 1978, and again in 2009, the FDA formed an advisory committee to review available data. In July 2009, a boxed warning was added to the drug, alerting patients and health care professionals of the danger of overdose. At that time, the FDA also required Xanodyne to conduct a new safety study assessing unanswered questions about the effect of propoxyphene on the heart.
Results of the study show that even when taken at recommended doses, propoxyphene causes significant changes to the electrical activity of the heart. These changes can increase the risk for serious abnormal heart rhythms that have been linked to serious adverse effects, including sudden death.