Millions of Americans were committed users of Cox-2 inhibiting drugs until their previously unknown side effects were uncovered late in 2004.

So what are Cox-2 inhibitors, and what side effects can they produce?

To fully comprehend how Cox-2 inhibitors work, we must first discuss nonsteroidal anti-inflammatory drugs, otherwise known as “NSAIDs”. These include some very popular pain killers (Aspirin and Motrin) intended to relieve the inflammation of bursitis, arthritis and tendonitis. NSAIDs inhibit 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. They produce prostaglandins, which help maintain the proper health of the stomach’s mucus lining. Cox-2 enzymes, although not found in the stomach, also create prostaglandins, which the body uses to deal with inflammations.

Because of the impeding of Cox-1 enzymes, many people suffer gastronomical side effects when using NSAIDs. Such can involve ulcers and stomach bleeding, bloating, heartburn, vomiting and nausea. And in the worst cases, kidney or liver failure may be caused.

So the pharmaceutical companies calculated that there would be a huge market for an anti-inflammatory medication that did not include a Cox-1 inhibitor, but instead specifically 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 Cox-2 enzymes would provide relief to countless arthritis and other sufferers, without causing the stomach problems many had with the common NSAIDs.

About a decade ago the Cox-2 inhibitor drugs appeared in America’s drugstores. The medical and drug industries hailed these Cox-2 inhibiting drugs as a major breakthrough. Over the following years, drugs including Vioxx, Bextra and Celebrex were taken by countless patients suffering with inflammatory pains including arthritis. And the results were generally as expected. These Cox-2 inhibitors helped diminish the pain, without the gastronomical side effects associated with the older NSAIDs.

But in late 2004, despite the fact that patients were reporting fewer stomach-related side effects, Merck (the manufacturer of Vioxx) decided to pull the drug from the shelves of America’s drugstores. At the time, Merck referenced an increased incidence of both strokes and heart attacks amongst people taking the product for more than 18 months. Later in 2004, a Texas jury awarded damages of $1,000,000,000 to the widow of a man who was a user of Vioxx. In February of 2006, an expert panel recommended the reintroduction of Vioxx onto the market. However the Food and Drug Administration is still looking at the matter.

In the spring of 2005, Bextra’s manufacturer took it off the market. The FDA’s view is that Bextra delivers no advantages over other NSAIDs, but may increase the risk of stroke and heart attack, as well as serious skin problems. As regards Celebrex, the Food and Drug Administration, while confirming an increase in heart attacks and strokes especially with high doses, believes its benefits outweigh these potential side effects. As a result Celebrex remains on drugstore shelves.

Additional research is being undertaken to study the potential long-term side effects of all three of these Cox-2 inhibitor medications. For 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 using Vioxx resulted in a higher risk of cardiovascular side effects than Celebrex and Bextra.

The research is ongoing.