FDA has approved Vioxx (rofecoxib), a new drug for treatment of osteoarthritis, menstrual pain and for the management of acute pain in adults. Vioxx is a non-steroidal anti-inflammatory drug or NSAID, and is the second approved version in a class of drugs commonly referred to as a “Cox-2 inhibitor”. (Celebrex, the first, was approved in December l998.) The following may be used to respond to questions.
NSAID drugs temporarily relieve pain by blocking the body’s production of prostaglandins, chemicals which are believed to be associated with the pain and inflammation of injuries and immune reactions.
An enzyme called cyclo-oxygenase is needed for the production of prostaglandins. People have two such enzymes, called cyclo-oxygenase 1 (Cox 1) and cyclo-oxygenase-2 (Cox-2). Most NSAIDS inhibit both these enzymes, but Vioxx and other selective Cox-2 inhibitors do not inhibit cyclo-oxygenase-1. Based on what is known about the role of Cox-1 and Cox-2, it is hoped that NSAIDS that selectively inhibit Cox-2 will have a lower incidence of some side effects (particularly certain adverse effects on the gastrointestinal system such as ulcers and bleeding), while still providing effective treatment for conditions such as pain and osteoarthritis.
In clinical trials of about 3600 people, Vioxx was found to be an effective treatment for the signs and symptoms of osteoarthritis — the most common form of arthritis — which is also known as a degenerative joint disease and tends to affect older people. Vioxx was also found effective for management of acute pain in adults, in studies conducted in people with post-operative pain following dental extractions or post-operative pain following orthopedic surgery; and for the management of pain related to the menstrual cycle.
Vioxx was compared to ibuprofen (a commonly used NSAID) and to placebo in two clinical trials by using endoscopes (devices to examine the upper gastrointestinal tract) to determine the incidence of stomach and upper intestinal ulcerations following use of these products. Treatment with 25 to 50 mg of Vioxx daily was associated with a significantly lower percentage of patients with endoscopic gastroduodenal ulcers than treatment with ibuprofen 2400 mg daily.
However, NSAID products can cause a range of gastrointestinal problems; and patients with asymptomatic ulcers found with endoscopy often recover without special treatment and without experiencing any serious symptoms or complications. A few cases of serious gastrointestinal bleeding and one case of obstruction occurred among patients taking Vioxx in clinical studies. Additional studies in a larger population would be needed to see whether Vioxx actually causes fewer serious gastrointestinal complications than older NSAID products. Until such studies are done, the drug labeling for Vioxx will include a warning for doctors and their patients about the risks associated with all NSAIDS, including risks of GI ulceration, bleeding and perforation. Patients are advised to promptly report signs and symptoms of gastrointestinal ulceration or bleeding, skin rash, unexplained weight gain, or swelling to their physicians.
In addition, Vioxx does not affect the platelet aggregation (clumping), an important part of the blood clotting process. Many other NSAID products can interfere with this platelet function, which may increase the risk of bleeding complications in some patients. However, like other NSAIDS, Vioxx appears to have some potential for causing adverse effects on the kidney, particularly at higher doses.
Source: The Food and Drug Administration