Public Citizen renews call for FDA to ban Serzone, cites Canadian action and new adverse event data
WASHINGTON, D.C., October 29, 2003 -- Citing new reports of deaths and severe injuries from liver failure in patients taking the antidepressant Serzone (nefazodone), consumer advocacy group Public Citizen submitted to the FDA a supplement to its March 2003 petition requesting the withdrawal of Serzone from the market.
Earlier in October, Canada announced it would remove Serzone from the market, effective November 27, 2003, due to the drug's association with "hepatic adverse events such as jaundice, hepatitis and hepatocellular necrosis". Serzone had already been taken off the markets in Europe and Scandinavia.
Bristol-Myers Squibb manufactures and markets Serzone. More than 2.8 million prescriptions were filled for the drug in the United States in 2002. The company is reported as saying that cases of liver failure among Serzone users are very rare and side-effect rates have not changed.
Nafazodone lost patent protection in September this year. Approval for generic versions of Serzone was received by Dr. Reddy's Laboratories, Ranbaxy Pharmaceuticals, Teva Pharmaceutical Industries, EON Labs, Ivax Corp, Mylan Laboratories, and Watson Pharmaceuticals.
In its original petition, Public Citizen cited 21 cases of liver failure and 11 deaths from 1994, when nefazodone was first marketed, to the spring of 2002. A new analysis of the FDA Adverse Event Reports Database found that, just from April 1, 2002, through May 12, 2003, there were 33 additional reports of liver failure -- including nine deaths -- for a total of 55 patients with liver failure, including 20 deaths.
"Typically, it is estimated that only about 10 percent of cases are reported, meaning that potentially hundreds of people have died from this drug and hundreds more have been injured," said Dr. Sidney Wolfe, director of Public Citizen's Health Research Group. "This drug is no more effective than other antidepressants, but is uniquely and unpredictably toxic."
Public Citizen maintains that the liver toxicity dangers of nefazodone are compounded by the fact that it inhibits a key enzyme that is involved in the metabolism of about half of all prescribed drugs, so nefazodone increases the toxicity dangers of other drugs a patient may be taking. Also, by inhibiting this enzyme, nefazodone can increase its own concentration with potentially toxic results.
The FDA in December 2001 notified Bristol-Myers Squibb that it must add a "Black Box" warning to the package insert for nefazodone warning of life-threatening liver damage and recommending that physicians advise their patients to be aware of signs of liver problems.
According to Public Citizen, the "Dear Health Care Professional" letter posted on the Health Canada Web site makes it clear that it is not possible to manage this drug safely, saying, "To date, no risk factor to predict patients who will develop irreversible liver failure with nefazodone [Serzone] has been identified. Also, no clinical strategy, such as routine liver function tests, could be identified to reduce the risk of liver failure".
Sources: Public Citizen, news reports
Posted: October 2003