Sept. 30, 2004 -- Pharmaceutical giant Merck & Co. pulled its anti-inflammatory drug Vioxx off the shelves today in a voluntary recall after a clinical trial found patients using the drug had an increased risk of heart attacks and strokes. The following are some facts on the once-popular medication.
Vioxx is the name Merck & Co. gave to rofecoxib, a non-steroidal anti-inflammatory drug (NSAID) developed by the company in the 1990s.
Vioxx is classified as a COX-2 inhibitor, a type of pain relief that works by inhibiting an enzyme (cyclooxygenase) involved in inflammation.
In 1999, Merck received FDA approval for Vioxx as a treatment for pain from osteoarthritis, acute pain in adults, and menstrual pain.
Twelve percent of adults in the United States (about 25 million people) reported taking prescription drugs for arthritis, according to a July 2000 Kaiser poll.
Vioxx was seen by industry analysts as a direct competitor to Celebrex, a COX-2 inhibitor manufactured by rival Pharmacia.
The most common side effects from Vioxx were listed as upper-respiratory infections, diarrhea, nausea and high blood pressure.
Since its introduction, more than 91 million prescriptions for Vioxx have been written in the United States alone.
Advertising to consumers and physicians helped fuel the growth of COX-2 inhibitors. In 2002, Merck spent $171 million to promote Vioxx to physicians, while Pharmacia spent $133 million on Celebrex and another $120 million on Bextra.
Total U.S. sales of COX-2 inhibitors (including Vioxx and Celebrex) were $4.5 billion in 2003.
Merck reported worldwide sales of Vioxx reached $661 million for the first quarter of 2004, an increase of 30 percent from the comparable prior year period. In markets outside of the United States, Vioxx continues to be the best-selling arthritis and pain medicine.
In 2000, while studying Vioxx's gastrointestinal effect, Merck researchers noted the patients taking Vioxx had a greater number of heart attacks than those taking naproxen, another NSAID.
In September 2001, the FDA issued a warning to Merck for misrepresenting the safety of Vioxx by downplaying the cardiovascular risks associated with the drug's use. The following year, new safety information was added to Vioxx labeling.
A Canadian study from May 2004 investigated the safety of COX-2 inhibitors. Patients in the study using Vioxx had an 80 percent increased risk of hospital admission for congestive heart failure compared to those taking Celebrex.
In August 2004, an FDA-sponsored study reported patients taking the recommended starting dose of Vioxx (12.5 mg) had a 50 percent greater risk of heart attacks and sudden cardiac death than patients taking Celebrex. The same study found patients taking the highest recommended dose (50 mg) had three times the risk of heart attacks and sudden cardiac death.
Most patients using Vioxx take daily doses of 12.5 or 25 mg for arthritis. A 50 mg dose has been approved by the FDA for the treatment of pain, but not for more than five days.
Following the release of the FDA study, Merck issued a statement that "strongly disagrees" with the study's findings.
In September 2004, the FDA approved Vioxx for juvenile rheumatoid arthritis, the first COX-2 inhibitor to be approved for JRA.
Sources: Merck & Co., www.merck.com, www.fda.gov, British Medical Journal, Cleveland Clinic Journal of Medicine, ABC News Medical Unit