Painkiller Vioxx Often Taken at Too High Dose

Evidence continues to grow that the popular pain reliever Vioxx may cause high blood pressure, swelling, and other health problems. And with the latest study, there's a new concern: High rates of misuse of the popular arthritis remedy, with many patients taking daily doses at twice the usual recommended level.

And it's not that they are necessarily "doubling up" their prescribed doses for better pain relief. Researchers at Vanderbilt University Medical Center say that patients are often being prescribed the highest 50 milligram dose by their doctors for daily pain relief.

"That's a cause for concern, because no one should be taking 50 milligram doses for more than five days, but we're finding that many people are taking it for [everyday] problems," says study researcher Marie R. Griffin, MD, MPH, professor of medicine and preventive medicine.

"There is no proof that the higher dose is more effective than the 25 milligram dose recommended for chronic pain, and there is pretty good evidence that the higher dose can be more harmful," she tells WebMD. "Just about all the nonsteroidal medications can cause increases in blood pressure, so this is something that needs to be watched, considering about 10% of the U.S. population takes some type of NSAID. However, there have now been a number of studies showing that especially at 50 milligrams, Vioxx seems to do this more than the others."

Higher Doses, Higher Risks

Vioxx is a Cox-2 inhibitor, a group of anti-inflammatory medications used to treat arthritis and other painful conditions. These drugs, which also include Bextra and Celebrex, were developed as alternatives to traditional anti-inflammatory drugs like ibuprofen. In general, Cox-2 inhibitors cause less stomach irritation and ulcers. Anti-inflammatory drugs, both old and new, are together known as NSAIDs (non-steroidal anti-inflammatory drugs).

In Griffin's study, tracking prescription records of 40,000 people taking any type of NSAID, her team found that about one in six patients getting Vioxx were prescribed a monthly course at a dose higher than the recommended 25 mg. About 15% of Vioxx users were taking at least 50 mg a day. However, this 50 mg dose is recommended only for short-term use of sudden, severe pain; daily doses should be prescribed at either 25 mg or 12.5 mg doses, Griffin says.

Her study appears in the June issue of Pharmacoepidemiology and Drug Safety.

Pre-licensing Vioxx studies compared the effects of various doses of Vioxx to other NSAIDs - 2,400 mg of ibuprofen and 150 mg of Voltaren. About twice as many patients taking 50 mg doses of Vioxx - 10% - developed high blood pressure during the first six months of use compared with lower doses of or other NSAIDs. They were also about 1 1/2 times more likely to develop leg swelling caused by fluid retention.