Reuters announced that the American Heart Association journal Circulation published an article showing Pfizer Inc.?s Bextra, a COX-2 inhibitor, can triple the risk of heart attack and stroke in certain patients.
In the study, the researchers studied mice genetically prone to hardening of the arteries or atherosclerosis and found that a compound called thromboxane or TxA2, produced by COX-1, accelerates atherosclerosis. While low-dose aspirin prevents heart attack and stroke by blocking COX-1 formation of TxA2 in platelets, the addition of a COX-2 inhibitor caused changes that would result in a loss of stability of the plaque, making it more likely to rupture and activate clotting, causing heart attack or stroke.
Merck & Co. Inc. pulled its COX-2 inhibitor Vioxx from the market after clear evidence its use could raise the risk of heart attacks and in December, the National Institutes of Health halted a study involving Pfizer?s COX-2 inhibitor Celebrex.
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