CHICAGO (Reuters) - A long-term analysis of people who took the arthritis drug Vioxx confirms it doubles the risk of strokes and heart attacks, researchers said on Monday, but this risk goes away a year after people stop taking it.
And other drugs in the same class of painkillers known as Cox-2 inhibitors may cause similar harm, they said.
"The good news is the data suggests that the risk doesn't persist forever. The risk goes back toward normal after a year of follow up," said Dr. Robert Bresalier of the M.D. Anderson Cancer Center at the University of Texas, whose study appears in the journal Lancet.
Safety data from this same study in 2004 set off alarms that Vioxx increased the risks of heart attacks and stroke, prompting drug maker Merck & Co Inc to withdraw the popular painkiller from the market.
Merck last year inked a $4.85 billion deal to settle thousands of claims for heart attacks, strokes and deaths allegedly caused by the drug. The original study, funded by Merck, was meant to determine whether Vioxx could prevent polyps that raise the risk of colon cancer.
A 2005 analysis by Bresalier and colleagues 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, a time frame that played a prominent role in Merck's legal defense of Vioxx.
The journal later posted a correction on its Web site, saying the difference was not statistically significant. The new analysis, done with independent statisticians, suggests the risk occurs early and persists, Bresalier said.
"This data shows you can't precisely determine the timing of the risk. It does appear to start relatively early," he said in a telephone interview.
The study, dubbed Approve, looked at the effects of three years of treatment with Vioxx, or rofecoxib, in 2,587 patients. Patients were checked for side effects while on the drug and two weeks after they stopped.
It includes one-year follow-up data on patients who stopped taking the drug because of heart side effects.
