Collaborating with Health Canada (HC), Paladin Labs Inc., maker of Darvon-N (dextropropoxyphene, also known as propoxyphene), decided to voluntarily recall and withdraw all lots of the medication from the Canadian market and discontinue sales. Last month, the US Food & Drug Administration (FDA) announced that Xanodyne Pharmaceuticals Inc. agreed to pull Darvon (propoxyphene) and Darvocet (propoxyphene and acetaminophen) from the market.
Those decisions followed an FDA request that all manufacturers of propoxyphene, an opioid pain reliever used to treat mild to moderate pain, withdraw their products from the U.S. market. The request came after a study linked the pain killers to serious, possibly fatal Darvocet and <"https://www.yourlawyer.com/topics/overview/darvon">Darvon side effects including heart rhythm problems (both drugs-are propoxyphene-based).
Both painkillers were on the market for more than 50 years. Even before the Darvocet and Darvon recall, it was already known that propoxyphene could be highly addictive.
Now, Health Canada reports that results of the new study show that, even at doses normally taken to manage pain, dextropropoxyphene can significantly increase the risk of serious abnormal heart rhythms. This is an important concern for elderly patients and those with kidney problems as they may be likelier to experience the heart rhythm effects of dextropropoxyphene.
Health Canada is advising patients to talk to their healthcare professional about discontinuing Darvon-N and switching to an alternative. Unused tablets should be returned to the point of purchase for disposal.
Patients taking Darvon-N are advised to speak to their healthcare professionals about concerns with Darvon-N to contact a healthcare professional right away if an abnormal heart rate or rhythm or oter symptoms including dizziness, lightheadedness, fainting, or heart palpitations are experienced; and to report any side effects with Darvon-N to Paladin Labs or to the Canada Vigilance program.
Paladin Labs Inc. can be reached at 6111 Royalmount Ave., Suite 102, Montreal, Quebec H4P 2T4; Telephone: 1-888-550-6060. The Canadian Vigilance Program can be reached online here; via toll-free telephone at 1-866-234-2345. Completed forms can be returned via toll-free fax to 1-866-678-6789, or by mail to: Canada Vigilance Program
Health Canada, Postal Locator 0701E, Ottawa, Ontario K1A 0K9. Reporting Forms, postage paid labels, and Guidelines can be found on the MedEffect™ Canada Web site in the Adverse Reaction Reporting section.
In the U.S., the FDA was widely criticized for taking too long to act on Darvon and Darvocet. Since 1978, the agency received two requests from the group Public Citizen to ban propoxyphene. The United Kingdom banned propoxyphene in 2005 and the entire European Union followed suit in January of 2009. In January 2009, an FDA advisory panel narrowly voted to recommend the FDA remove Darvon and similar products from the market. Rather than heed this advice, the FDA permitted continued marketing of Darvon, Darvocet, and other propoxyphene products, but required a new boxed warning be added to the drug label alerting patients and health care professionals to the risk of a fatal overdose. While the new warning did not include mention of heart rhythm problems, the agency required Xanodyne Pharmaceuticals, the company that markets Darvon and Darvocet in the U.S., to conduct a new safety study assessing unanswered questions about the cardiac effects of propoxyphene. That study finally prompted the FDA to request the medications be removed from the market.
