Heart Disease Health Center

Safe Pain Relief With Aspirin Therapy

Aspirin has earned its fame as a pain relief wonder drug. It eases headaches, lowers fevers, and reduces swelling. What's more, studies show that daily doses as low as 81 milligrams -- the amount in a baby aspirin -- can reduce the odds of heart attacks and strokes in people who are at risk. About 25 million Americans take aspirin for heart disease protection every day.

But there's a catch. Like any other drug, aspirin has dangers. When taken regularly, it can cause bleeding of the stomach and intestine -- especially in sensitive people. It can also interact with over-the-counter painkillers, causing unwanted side effects. Yet many people don't know this. Some take aspirin as casually as they pop a daily multivitamin.

"People have this skewed impression that over-the-counter medicines are harmless," says Curtis Barr, PharmD, associate professor of pharmacy practice at the Creighton University School of Pharmacy and Health Professions in Omaha, Neb.

That goes double for daily aspirin. "People think, 'It's just baby aspirin after all,'" says Byron Cryer, MD, a spokesman for the American Gastroenterological Association. "'So how bad could it be?'"

Yet it's a potent drug, and every year low-dose aspirin helps send tens of thousands to the hospital with bleeding.

So you must never start daily aspirin without your doctor's OK. If you have been prescribed daily aspirin, you need to know your risks -- before you next reach for a bottle of pain reliever.

Aspirin: The Pros and Cons

While aspirin may be best known as a painkiller, it also works as a blood thinner. Heart attacks and most strokes are caused by blood clots in the heart or brain. Aspirin decreases the blood's natural tendency to clot, allowing it to flow more easily -- reducing the risks of these complications.

But there's the problem. For the same reason that aspirin helps prevent strokes and heart attacks -- reducing the blood's tendency to clot -- it also raises the risk of bleeding elsewhere in the body. Bleeding that can be caused by the reduced ability of blood to clot.

Aspirin also has a special impact on the gastrointestinal tract. It blocks the effects of certain hormone-like substances called prostaglandins. These chemicals protect the stomach and gastrointestinal tract from damage. Aspirin can strip away this protection. Natural acids and enzymes in the stomach, which help digest food, can then injure the lining of the gastrointestinal tract. This can result in ulcers and bleeding. Whether the aspirin is buffered or coated makes no difference. And because aspirin also prevents clotting, the bleeding is worse than normal.

Unfortunately, even low doses of aspirin have this effect, says Cryer, who is also an associate professor of medicine at the University of Texas Southwestern Medical School in Dallas. He worked on a study that tried to find a dose of aspirin that was low enough to avoid these side effects.

"We found that even just 10 milligrams -- which is too low to have any cardiovascular benefit -- posed the same risk of gastrointestinal damage as doses that were over 30 times higher," Cryer tells WebMD.