FDA Considers Citizen Petition to Remove Darvon From Market

Darvon
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On Friday, January 30, 2009, government medical advisers recommended a ban on Darvon by a narrow 14-12 vote. Darvocet is a prescription medicine that's been used for pain treatment for more than 50 years.

The advisory panel meeting was prompted by a petition filed on February 28, 2006 by Public Citizen, a public-advocacy organization. They asked the agency to remove the products from the market because there's little evidence the drugs are effective and they carry risks of death from heart problems.

Public Citizen does not contend that Darvon or Darvon containing products represent an "imminent hazard." This means that these products may be removed by the FDA only upon a determination that they are unsafe or ineffective. The FDA is not required to follow the recommendations of its advisers, but often does so.

Darvon (propoxyphene) was first approved in 1957. It is mainly marketed as Darvocet, which includes a dose of acetaminophen. It remains one of the top 25 most commonly prescribed medications. Darvon was developed by Eli Lilly & Co. (LLY). Later, the company combined propoxyphene with acetaminophen, and sold as Darvocet.

Both drugs are now marketed by private, generic-drug makers including Xanodyne Pharmaceuticals Inc. of Newport, Ky., and Qualitest/Vintage Pharmaceuticals, of Huntsville, Ala. More than 20 million prescriptions were written for the products containing Darvon in 2007, according to the FDA. The companies said the products were safe and effective when used as directed.

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The products are approved to treat mild to moderate pain. But like certain other classes of pain medications, Darvon products can be addictive and have been linked to deaths in patients, especially when used with alcohol and other drugs. The drug labels' currently warn of those risks.

Darvon underwent a second evaluation in 1962 (Kefauver-Harris Drug Amendments). That evaluation found Darvon to be efficacious in the treatment of mild to moderate pain. Each time a new Darvon drug product was reviewed and approved by the FDA, the product's safety and efficacy was reaffirmed. The most recent reviews were in 2003 (Darvocet A500) and in 2006 for it's generic version.

Public Citizen's Petition does not raise any new safety or efficacy issues that have not already been considered by FDA. In its petition, Public Citizen cited data from the Drug Abuse Warning Network, which uses a sample of nationwide autopsy information from medical examiners - implicating propoxyphene in 5.6% of drug-related deaths from 1981 to 1999. Public Citizen also said the network reported 2,110 accidental deaths related to propoxyphene over the same period.

Since its first approval 50 years ago, it is estimated that more than 600 million prescriptions for Darvon drugs have been dispensed. In 2005, over 26 million prescriptions were filled, making it one of the twenty-five most commonly prescribed drugs.

Propoxyphene drugs are also used throughout the world, including in South America, Europe, Africa, Australia, and Asia. In 2005, U.K. health authorities said the benefits of the drugs didn't outweigh the risks and announced a phased withdrawal of the products over a three-year period.

The FDA said a review of its adverse-event reporting data base showed 3,028 serious and non-serious reports from 1957 through Sept. 24, 2008, associated with Darvon. Of those, 2,136 reports were considered serious and included 1,452 deaths. Many of the serious-event reports included reports of suicides, intentional drug overdoses, heart attacks and unintentional drug overdoses, the FDA said. The agency said some of the serious adverse-event reports also listed more than one type of drug.

Source
FDA Briefing Document

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