FINDINGS SHOW ADDITIONAL RISKS FOR VIOXX

More trouble is emerging for Merck over its painkiller Vioxx, as researchers say they have found "increased renal and arrhythmia risks" from the drug and have confirmed cardiovascular risks. The company withdrew the drug from the market in 2004, due to evidence that it increased the risk of heart attacks, and faces more than 16,000 ongoing lawsuits.

The renal and arrhythmia risk is apparently limited to Vioxx (rofecoxib), as "a Cox-2 inhibitor class effect was not evident," according to an article in the September issue of the Journal of the American Medical Association. Researchers Jingjing Zhang, Eric Ding and Yiqing Song conducted an analysis of 114 randomized trials with 116,094 participants for Vioxx and five other Cox-2 inhibitors, including Pfizer's Celebrex (celecoxib).

"Compared with controls, rofecoxib was associated with increased risk of arrhythmia and composite renal events," such as peripheral edema, hypertension and renal dysfunction, the researchers said. Some risks were evident as early as the end of 2000 and all increased with dosage and duration.

According to the article, Celebrex was associated with lower risk of both renal dysfunction and hypertension. The study was conducted through a systematic search of EMBASE and MEDLINE through June 2006, bibliographies, FDA reports and pharmaceutical industry clinical trial databases.

Merck issued a statement denying that the information presented in the article was really new. "It is important to recognize that since Vioxx was first marketed, the product label has included precautionary information about the risk of peripheral edema and hypertension in certain individuals, which are well-documented adverse effects associated with [nonsteroidal anti-inflammatory drugs]."