Vioxx taken off the market

Vioxx is a type of non-steroidal anti-inflammatory drug (NSAID). It goes by the generic name rofecoxib and is a relative of more familiar NSAIDs such as ibuprofen and naproxen. Drugs like ibuprofen and naproxen work by blocking an enzyme which helps produce pain and inflammation called COX-1. Medications like Vioxx work by inhibiting the similar COX-2 enzyme.

The COX-2 drugs are effective pain-killers. Most studies suggest that, compared to other NSAIDs, they are also easier on the stomach. For this reason, COX-2 drugs are a boon for people at high risk of gastritis, peptic ulcers, and upper intestinal bleeding who also need strong pain relief. So you can see why COX-2 medicines were a welcome addition to the arsenal of pain relief medicines. But, like all drugs, NSAIDs have side effects.

We have known that most NSAIDs, including the COX-2 drugs, may increase blood pressure, alter kidney function, and cause swelling from fluid retention. Doctors also have known that COX-2 drugs in particular could potentially increase the risk of blood clots, heart attacks, and strokes. That's because the COX-2 drugs can cause blood vessels to constrict and increase the tendency of blood to clot — unlike the older NSAIDs, which tend to decrease blood clotting.

Even before Merck (the company that makes Vioxx) voluntarily withdrew the drug from the market, there were reports that patients taking Vioxx had higher rates of cardiovascular events than patients taking the COX-1 drug naproxen (Naprosyn). But other studies comparing Vioxx to placebo did not show a clear risk. Then last month, an observational study showed that patients on doses of Vioxx higher than 25 milligrams per day were especially at risk for heart attack.

Observational studies can hint at a possible "cause and effect," but randomized, controlled trials are the gold standard in medical research. It was the results of just such a randomized trial that led to the withdrawal of Vioxx. Last week, Merck announced that a still-unpublished 18-month study revealed that there were more heart attacks in people taking the 25mg pill of Vioxx than in people taking a placebo sugar pill. Merck has advised that patients currently taking Vioxx contact their doctors. Here is some general advice that may be useful, although patients taking Vioxx should talk with their doctors before making changes.

If you are taking Vioxx only for pain relief and have not had a gastrointestinal bleed in the past and are under age 65, it might be wise to try taking acetaminophen or other antiinflammatory agents such as ibuprofen or naproxen.

For anyone with a risk factor for atherosclerosis (the cause of heart attacks and strokes), it is especially important for you to check with your doctor. Risk factors for atherosclerosis include smoking, high blood pressure, diabetes, being overweight, and having parents or siblings known to have atherosclerosis.

If you need an anti-inflammatory drug, and have had bleeding from the upper intestinal tract or peptic ulcer disease, talk to your doctor about switching to another COX-2 drug, such as Celebrex (celecoxib), valdecoxib (Bextra) or Prexige (lumiracoxib). Prexige is approved for use in the United Kingdom and some other countries, but not in the United States . If you are allergic to sulfa drugs, you should not take Celebrex or Bextra, so that limits the options for U.S. citizens.

Of the older NSAIDs, Mobic (meloxicam) and Relafen (nabumetone) may irritate the stomach less than other NSAIDs.

Understandably, the potential risk of Vioxx raises concern about all COX-2 inhibitors. So if you are taking Celebrex, Bextra or Prexige you may wonder if you are at risk. As of this time, no published studies or reports by the manufacturers show strong evidence of a similar risk from these drugs, nor has the U.S. Food and Drug Administration raised a warning flag about any of them.

December 2004 Update

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