How Vioxx Increases Heart Attack Risk

FDA to Study Other Cox-2 Inhibitors

Following the withdrawal of Vioxx from the market in September 2004, FDA officials said in October 2004 that they would begin a study of three other painkillers in the same drug class as Vioxx because it is unclear whether all Cox-2 inhibitors have the same effect.

Researchers have a general idea of how Vioxx could be raising the risk of heart attack, but not whether the heart attack risk is unique to Vioxx or applies to other Cox-2 inhibitor drugs. The event that triggers heart attacks and many strokes is the formation of a blood clot in an artery. Clotting is controlled by a delicate balance between compounds with opposite effects, such as prostacyclin, which inhibits clotting, and thromboxane, which promotes clotting. Prostacyclin is made in cells lining the blood vessel wall by an enzyme called Cox-2. Vioxx blocks Cox-2 while trying to stop inflammation in joints and other tissue, which might have the result of upsetting the balance between prostacyclin and thromboxane, which promotes clotting.

Cox-2 inhibitor drugs, which also include Celebrex, Mobic, Bextra, Dynastat and Arcoxia, are relatively new and designed to ease pain and inflammation without damaging the stomach. So far, only Vioxx has been shown to have an increased heart attack risk.

Read more on our Vioxx Information Page >>