Daily Aspirin: Good Or Bad?

We've long known that aspirin reduces the risk of heart attacks and strokes while increasing your chances of surviving them. But now this household drug may protect you in other ways, too.

Newer evidence indicates that aspirin can also reduce the risk of cancer of the colon, esophagus, stomach, rectum, and prostate. And most recently, the humble aspirin has offered the tantalizing possibility that it may help protect against Alzheimer's disease. With all of these potential benefits, why aren't we dumping aspirin in the water as we do with fluoride?

"Aspirin is the one drug I would take to a desert island with me," says Mark Fendrick, MD, an associate professor of internal medicine at the University of Michigan Medical School in Ann Arbor. "It costs two cents a day and its benefits are amazing. And if it had no side effects at all, we could give it to everybody." But Dr. Fendrick worries that the ever-growing list of diseases and disorders that aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDS) seem to combat drowns out information about the risks of this "wonder" drug.

"When you take aspirin, the level of stomach protection is decreased and you're more likely to bleed. Thus, people who take aspirin regularly -- even in a buffered or coated form -- will have roughly double the likelihood of having a perforated ulcer or bleeding in the GI tract," explains Fendrick. "Relatively little attention is paid to this problem that kills more people in the U.S. each year than asthma or cervical cancer. What we need to do is focus less attention on finding more things that make aspirin look good, we have plenty of those, and think more about focusing on how to minimize risk."

So how do you decide whether or not a regular, preventive dose of aspirin is right for you? And if it is, how do you lower the risk of side effects? There's no simple formula, unfortunately. "When you're deciding whether someone should take blood pressure medication or diabetes medication, there are clear cutoffs. In the case of aspirin, the decision is multifactorial and requires a lot of thought," Fendrick tells WebMD.

Those patients most in need of daily aspirin therapy are easy to identify. If you have a documented personal or family history of heart disease -- including heart attacks, stokes, or angina; if you have diabetes; or if you have multiple risks for the development of heart disease such as have high blood pressure, high cholesterol, or are a smoker, you should most likely take a daily dose of aspirin (but always consult with your physician first). Although the optimal dose of aspirin in prevention of future heart disease is still unclear, doses of 75 milligrams, 100 milligrams, or 325 milligrams have been found to be equally effective.

Studies reviewed by the U.S. Preventive Services Task Force have shown that daily or every-other-day aspirin therapy reduced the risk of coronary heart disease by 28%in persons who had never had a heart attack or stroke, but who were considered high-risk individuals.

It's also pretty easy to identify those individuals who, in all probability, don't need to take aspirin on a daily basis, Fendrick says. Healthy people in their 20s and 30s, for example, with no cardiac risk factors and no major risk factors for developing the other diseases aspirin can prevent, such as certain cancers, should consider the risks of aspirin therapy to outweigh the benefits.

But then there's a large group of people that fall into the middle category -- the "probably-should-take" group. For these people, individuals with a strong family history of colon cancer, for example, or dementia, balancing aspirin's potential benefits against its well-documented risks can be a very complicated equation. "The benefits of aspirin for preventing colon cancer, dementia, and heart attacks need to be carefully weighed by a medical professional against the potential for serious complications," says Dr. Fendrick.

The FDA also provides a fact sheet on deciding whether or not daily aspirin therapy is right for you (it's specific to heart disease) on its web site.

More Isn't Always Better

If you and your doctor decide you should be taking aspirin daily, the next question is, "How much?" In the land of the super-size, is it any wonder that we think that if one pill is good, two must be better, and if 100 milligrams may help prevent cancer, 200 or 300 milligrams must have twice or three times as much cancer-busting power? Stop right there. Medications don't work that way, and especially in the case of aspirin and other NSAIDs, a little goes a long way.

"Low-dose aspirin, a 'baby aspirin' dose of 81 milligrams, is safer and just as effective as the standard adult dose of 325 milligrams," says Dr. Fendrick. "When a drug has serious side effects, as aspirin does, you want to give the lowest effective dose. We know now that you don't need 325 milligrams in a great majority of circumstances."

A patient who's having a heart attack right now, for example, should be given a full 325-milligram dose of aspirin, but the person at elevated risk for a heart attack, who's taking daily aspirin as a preventive measure, should stick with the smaller 81-milligram dose.

Taking low-dose aspirin isn't the only way to maximize the drug's benefits while minimizing its dangers. For people at increased risk of gastrointestinal complications, Fendrick recommends combining any aspirin therapy with a prescribed proton pump inhibitor (PPI) such as Prevacid, Prilosec, or Nexium.

In a study of people with prior gastrointestinal bleeding, whose doctors felt their chance of having a heart attack was high enough to warrant aspirin therapy despite its gastrointestinal risks, a standard dose of Prevacid reduced their risk of further bleeding by about eightfold. Enteric-coated aspirin or buffered aspirin do not appear to have a reduced risk of bleeding or other adverse events in the stomach.

Unfortunately, unlike aspirin, these gastroprotective drugs cost a bit more than a couple of cents a day. "If there were no added cost to taking a PPI with a daily aspirin, every aspirin user could benefit from an added level of GI protection," says Fendrick. "But given the current cost of these agents, I only currently recommend gastroprotective therapy to those aspirin users who are at increased risk for GI complications."

That includes people who have had gastrointestinal complications in the past, people who are using high-dose NSAIDs or combining aspirin with other NSAIDs, and people who are taking anticoagulant drugs, among others. "Many older people take aspirin for their heart and then another NSAID for their arthritis," says Fendrick. "This is one of those cases in which two rights make a wrong; the aspirin is good, the NSAID is good, but together they can be dangerous."