COX-2 Inhibitors More Likely to Raise Heart Risks Than Other NSAIDsNov 5, 2008 | Parker Waichman LLP
A new study that confirms the heart risks associated with a class of drugs called NSAIDs has found that the increased risk correlates to the specific pain-causing molecule they act against. According to the study, NSAIDS that are cox-2 inhibitors are more likely to increase the risks of heart attacks and strokes.
NSAIDs are the most prescribed medications for treating conditions such as arthritis. Most people are familiar with over-the-counter, nonprescription NSAIDs, such as aspirin and ibuprofen. NSAIDs also include prescription drugs like Celebrex, as well as the now-banned Vioxx.
NSAIDS target different forms of cyclooxygenase, an enzyme whose activity increases inflammation and pain. Older NSAIDs, such as ibuprofen and naproxen, act primarily against cox-1. Celebrex, Vioxx and Bextra act against cox-2. While cox-2 inhibitors reduce the gastrointestinal bleeding, pain and inflammation that are major side effects of the cox-1 drugs, they have been found to increase the risk of heart attack and stroke.
This latest study, conducted by researchers in Spain and Italy, looked at 8,852 people who had heart attacks. The increase was related to both the dosage and the length of time the drugs were taken. But the risk was increased by 18 percent by NSAIDS that acted against cox-1, compared to a 60 percent increase for those with the greatest cox-2 activity.
"We found a significant correlation between the degree of inhibition in vitro [in the laboratory] of whole blood cox-2, but not whole blood cox-1," said the report by researchers in Spain and Italy.
The Food & Drug Administration (FDA) now requires all COX-2 inhibitors and NSAIDs to bear a black box warning regarding heart attack and stroke risks. The warnings were added to the drugs after Vioxx was recalled in 2004.
Vioxx was approved for use in 1999, and quickly became a blockbuster for Merck, with annual sales of $2.5 billion. But the FDA ordered Vioxx off the market in 2004 after studies showed that people who took the drug had a higher risk for heart attack. The recall came after an analysis of patients using Vioxx linked the defective drug to more than 27,000 heart attacks or sudden cardiac deaths in the U.S. from 1999 through 2003. Since then, Vioxx the subject of thousands of drug injury law suits.
Late last year, Merck announced that it would a $4.85 billion settlement with Vioxx plaintiffs. Under the terms of the Vioxx settlement, Merck set up $4 billion fund for people who claim they suffered heart attacks as a result of Vioxx, and another $850 million fund for those who suffered ischemic strokes. Initial payments for the Vioxx settlement started going out to some plaintiffs last month.