Vioxx

Vioxx is the brand name for the drug rofecoxib, which is a nonsteroidal anti-inflammatory drug (NSAID) that was commonly used for the treatment of osteoarthritis, dysmenorrhea, and other acute pain conditions. It was developed and patented by the pharmaceutical corporation Merck & Company, and was marketed in the beginning of the 2000s. In September of 2004, Merck voluntarily withdrew Vioxx from the market due to a study that showed the drug increased the risk of heart attack and stroke.

Vioxx is in the class of NSAIDs referred to as COX-2 selective inhibitors. COX-1 and COX-2 are forms of the cyclooxygenase enzyme, which make biological mediators called prostanoids. Prostanoids are involved in inflammatory reactions, and if they are inhibited inflammation is significantly reduced. Other anti-inflammatory drugs such as aspirin, naproxen and ibuprofen, are nonselective, and inhibit both COX-1 and COX-2 enzymes. These nonselective NSAIDs are known to have harmful effects on the gastrointestinal tract, such as peptic ulcers, and Vioxx was popular because it did not share this adverse effect.

Vioxx was determined to be much less harmful on the stomach in a series of studies known collectively as the Vioxx GI Outcomes Research, or VIGOR study, in which the side effects of Vioxx were compared to a conventional NSAID, naproxen. During the same VIGOR studies it was also discovered that the use of Vioxx increased the risk of heart attack by four times more than naproxen. At the end of the studies it was thought that the difference in the incidence of heart problems was due to a protective effect of naproxen rather than an increase risk caused by Vioxx. However, after a second series of studies, Merck determined that prolonged use of Vioxx did indeed increase the risk of heart attack compared to a placebo.

On September 23rd of 2004, the FDA estimated that during its five