NSAIDs -- or nonsteroidal anti-inflammatory drugs -- are among the most common pain relief medicines in the world. Every day more than 30 million Americans use them to soothe headaches, sprains, arthritis symptoms, and other daily discomforts, according to the American Gastroenterological Association. And as if that wasn't enough, in addition to dulling pain NSAIDs also lower fever and reduce swelling.
But how do those little pills do so much? And if they're so good in some ways, why do they also raise the risk of heart problems in some people? The answer is complicated. Even researchers don't fully understand how NSAIDs work.
If your mother or grandmother had a knee or hip replacement, the odds are good she was in her late 60s or 70s when she opted for the surgery, and it was a "last resort" decision -- either get a new knee or start using a cane or a wheelchair.
That's not today's joint replacement surgery. With the baby boom generation hitting their 60s -- the age at which joints start to hurt and ultimately give out -- more and more people are seeking knee and hip replacements to maintain their active lifestyle.
Nonetheless, with the benefits and risks of NSAIDs in the headlines frequently, WebMD turned to four experts for a rundown of what researchers do know. Our panel consisted of:
Byron Cryer, MD, a spokesman for the American Gastroenterological Association and an associate professor of medicine at the University of Texas Southwestern Medical Center in Dallas.
Nieca Goldberg, MD, a spokeswoman for the American Heart Association and chief of Women's Cardiac Care at Lennox Hill Hospital in New York.
John Klippel, MD, president and CEO of the Arthritis Foundation in Atlanta.
Scott Zashin, MD, clinical assistant professor at the University of Texas Southwestern Medical Center in Dallas and author of Arthritis Without Pain.
Here is their explanation of how NSAIDs help ease your pain -- and sometimes cause side effects in the process.
What Is Pain?
First, it helps to understand what pain is. On a basic level, pain is the result of an electrical signal being sent from your nerves to your brain.
But the process is not only electrical. When you get injured -- say with a sprain -- the damaged tissue releases chemicals called prostaglandins, which are like hormones. These prostaglandins cause the tissue to swell. They also amplify the electrical signal coming from the nerves. Basically, they increase the pain you feel.
How Do NSAIDs Help Relieve Pain?
NSAIDs work on a chemical level. They block the effects of special enzymes -- specifically Cox-1 and Cox-2 enzymes. These enzymes play a key role in making prostaglandins. By blocking the Cox enzymes, NSAIDs stop your body from making as many prostaglandins. This means less swelling and less pain.
Most NSAIDs block both Cox-1 and Cox-2 enzymes. They include the over-the-counter drugs:
Aspirin (Bufferin, Bayer, and Excedrin)
Ibuprofen (Advil, Motrin, Nuprin)
Ketoprofen (Actron, Orudis)
Other NSAIDs are available by prescription. They include:
Aspirin has some benefits that other NSAIDs do not. The biggest is that aspirin works against the formation of blood clots. As a result, you are less likely to form the clots that can cause heart attacks and strokes. Other NSAIDs do not have this effect.
Cox-2 inhibitors are a newer form of prescription NSAID. As you might guess, they only affect Cox-2 enzymes and not Cox-1. Two of them -- Bextra and Vioxx -- are no longer sold because of concerns about their side effects. The third, Celebrex, is still available.