Vioxx (Generic: Rofecoxib), an NSAID Drug, is a COX-2 Inhibitor, Possibly Explanation its Adverse Cardiovascular consequences, Blood clots, Heart attack and Stroke.

Approved by the FDA in 1999 for the treatment of osteoarthritis, menstrual pain and the management of acute pain, Vioxx is the trade name of the generic drug rofecoxib.
Vioxx is a COX-2 selective, nonsteroidal anti-inflammatory drug (NSAID). Other COX-2 selective NSAIDs on the market at this time are Celebrex (celecoxib) and Bextra (valdecoxib).
Vioxx was considered to be effective for its indications by the drug's preventing the formation of inflammatory prostaglandins. Inflammatory prostaglandins are produced by the enzyme "cyclooxygenase 2," sometimes shortened to "Cox-2," which are believed to cause inflammation and pain. They are also considered to prevent blood cells from sticking together. This may explain the increased incidence of blood clots, heart attack, stroke and other cardiovascular events.

Celebrex, the trade name for clelcoxib and Bextra, the trade name for valdecoxib are also "Cox-2 inhibitors." It is not yet known whether the increased risks, including for heart attack and stroke associated with Vioxx are specific to Vioxx. Because of the common mechanism of action, it is possible that like Vioxx, Celebrex and Bextra may also be found to be associated with the same adverse reactions.