A long-term study has confirmed the risks associated with the arthritis drug Vioxx.
The study, an analysis of people who took the arthritis drug carried out by Dr. Robert Bresalier of the M.D. Anderson Cancer Center at the University of Texas, has found Vioxx doubles the risk of strokes and heart attacks.
Dr. Bresalier says other drugs in the same class of painkillers known as Cox-2 inhibitors may also cause similar harm, but the data suggests that the risk is not permanent and does not persist.
In 2004 preliminary safety data from this same study raised concern that Vioxx increased the risks of heart attacks and stroke, prompting drug maker Merck to withdraw the popular painkiller from the market - the research initially set out to determine whether Vioxx could prevent polyps that raise the risk of colon cancer.
At the time, before it was withdrawn from the market, Vioxx had generated sales of $2.5 billion a year.
Last year Merck agreed to a $4.85 billion deal to settle 50,000 pending lawsuits concerning claims of heart attacks, strokes and deaths allegedly caused by the drug.
An analysis in 2005 by the same researchers published in the New England Journal of Medicine suggested that it took 18 months for the drug to increase the risk of heart attacks and strokes, which became an important issue in Merck's legal defense of Vioxx.
The new analysis, by independent statisticians, however suggests the risk occurs early and persists, and Dr. Bresalier says this data shows that precisely determining the timing of the risk cannot be done, but he suggest it appears to start relatively early.
The study, 'Approve' tracked 84% of the more than 2,500 patients from the trial who had been divided into two groups, one taking daily doses of rofecoxib, and the other dummy pills with no active ingredients and it examined the effects of three years of treatment.
It looked particularly for any signs of "cardiovascular toxicity" such as non-fatal or fatal heart attacks or strokes occurring during the year after treatment stopped.