So what are Cox-2 inhibitors, why were they developed and what are those side effects?

To fully comprehend the functioning of Cox-2 inhibitors, we must first discuss nonsteroidal anti-inflammatory drugs, otherwise known as ?NSAIDs?. These include some very popular pain killers (Aspirin and Motrin) created to treat the inflammation of tendonitis, bursitis and arthritis. NSAIDs block both Cox-1 as well as Cox-2 enzymes. Cox-1 enzymes can be found in inflamed parts of the body as well as in the stomach. Cox-1 enzymes produce prostaglandins, that help maintain the proper health of the stomach's mucus lining. Cox-2 enzymes, although not found in the stomach, also produce prostaglandins, which the body uses to deal with inflammations.

Because of the impeding of Cox-1 enzymes, many people are presented with gastronomical side effects when they take NSAIDs. These side effects may involve diarrhea, pain, heartburn, nausea, vomiting, bloating, dyspepsia, stomach ulcers, as well as bleeding within the stomach. And in the worst cases, liver and kidney failure may be caused.

The drug companies calculated that there would be a very large market for an anti-inflammatory drug that did not include a Cox-1 inhibitor, but selectively only inhibited the Cox-2 enzymes in the inflamed areas of the body. No Cox-1 inhibitors, no more gastronomical side effects, the reasoning went. A drug that only inhibited the Cox-2 enzymes would give relief to countless arthritis sufferers, without causing the stomach problems many had with the NSAIDs.

Around 10 years ago the Cox-2 inhibitor drugs appeared in America's drugstores. The medical establishment hailed these Cox-2 inhibiting drugs as a major breakthrough. Over the following years, drugs including Vioxx, Celebrex and Bextra were taken by many millions of Americans suffering with inflammatory pains including arthritis. The results were generally as expected. These drugs helped diminish the pain, without the gastronomical side effects that NSAIDs sometimes caused.

But late in 2004, despite the reduced incidence of stomach-related problems, Merck (the manufacturer of Vioxx) decided to pull the drug from the shelves of America's drugstores. In doing so, Merck referred to an increased risk of heart attack and stroke amongst people taking Vioxx for more than 18 months. Later that same year, a Texas jury awarded a quarter of a billion dollars in damages to the widow of a Vioxx user. Early in 2006, an expert panel recommended the reintroduction of Vioxx onto the market. The FDA however is still looking at the matter.

Early in 2005, the maker of Bextra took it off the market. The FDA's view is that it offers no advantages over other NSAIDs, but may increase the chances of stroke and heart attack, and also cause serious skin problems. As regards Celebrex, the FDA, while acknowledging an increase in the risk of stroke and heart attack especially with high dosages, concluded that its benefits may outweigh these potential side effects. So Celebrex remains on drugstore shelves.

Additional research is being done to study the possible long-term side effects of each of these Cox-2 inhibitor medications. As an example, researchers in Europe concluded that some popular NSAIDs are just as likely to raise the risk of heart attacks as are the Cox-2 drugs. Another recent study concluded that taking Vioxx had a higher risk of cardiovascular side effects than does the other two drugs.

The research continues on.