10 things you need to know about aspirin

You decide if the benefits outweigh the risks

Last updated: August 2008

Generic low-dose aspirin does the job for most people.

Aspirin can be your heart's best friend because it helps prevent the formation of blood clots that can cause heart attacks. Regularly taking a low-dose aspirin (81 milligrams) cuts the risk of such attacks by about 25 to 30 percent. And chewing a standard aspirin tablet at the first sign of chest pain can stop an impending heart attack by preventing blood clots from growing larger. Aspirin's anti-clotting effect also protects against ischemic stroke, the most common kind.

Moreover, research has linked aspirin to a reduced risk of Alzheimer's disease, certain cancers, type 2 diabetes, an enlarged prostate gland in men, and other health problems. No wonder, then, that more than 50 million Americans-36 percent of adults-take aspirin regularly as a preventive measure. And even more could benefit from the therapy. Some 20 percent of women and 14 percent of men who are good candidates for aspirin therapy aren't taking the drug, according to a recent study of about 1,900 people 40 and older published in the Journal of General Internal Medicine.

But aspirin's benefits have to be balanced against its risks. It can irritate the stomach and cause potentially dangerous internal bleeding, including, in rare cases, in the brain. That can lead to hemorrhagic stroke, the more deadly kind. In some people, aspirin can trigger asthma.
And not everyone benefits equally from its effects. Responses differ between men and women, for example. And preliminary but intriguing research suggests that many people have a trait that makes them resistant to aspirin's benefits.

The answers to the following 10 common questions about aspirin can help you decide if you're likely to benefit from it and, if you are, help you make the therapy as effective and safe as possible.

10 common questions

1. How do I know if aspirin is right for me?

Your age, gender, and overall health should be the key factors when deciding if its benefits outweigh the risks.

The answer is almost always yes for people who have the highest cardiovascular risk. That includes those who have:

  • suffered a prior heart attack, stroke, or mini-stroke (a transient ischemic attack), or have diabetes.
  • angina (chest pain that worsens when you exercise and eases when you rest).
  • undergone coronary-bypass surgery or angioplasty.

Men over age 40 generally benefit as well. But the scales don't tip in aspirin's favor for most women until age 65.

Women over that age and men over 40 can assess their heart-attack risk using the calculator at Med-decisions.com. If it shows that your risk of heart attack or death from coronary disease in the next five years is 3 percent or greater risk of heart attack or death from coronary disease in the next five years, then you are a potential candidate for low-dose aspirin therapy. But talk with your doctor first to make sure that you aren't at high risk for gastrointestinal bleeding or other problems.

2. Is a larger aspirin dose better?

No. Numerous studies have shown that standard adult tablets, which contain 325 mg, are no better than 81-mg "baby" aspirin at keeping cardiovascular disease at bay. The larger pills, however, do sharply increase the risk of gastrointestinal bleeding and other complications.

But if you suspect you're having a heart attack, bigger is better. Chew and swallow either one adult tablet or four baby ones. (But make sure that you call 911 first.)

3. Can I make aspirin easier on my stomach?

Research shows that coated or buffered aspirin pills aren't the answer. Instead, people who are vulnerable to ulcers and those who have a history of gastrointestinal reactions to aspirin should talk with their doctor about possibly adding a stomach-protecting drug such as misoprostol (Cytotec and generic) or omeprazole (Prilosec, Prilosec OTC, and generic). If you still can't tolerate aspirin or your risk of gastrointestinal bleeding is too high, talk with your physician about using a different blood-thinning medication.

4. Should I stop taking aspirin before surgery?

Not usually. Stopping abruptly not only eliminates its protective benefits but also might elevate risk beyond original levels by making the platelets in the blood more likely to form clots. For example, in a study of more than 600 stroke and heart-attack survivors, researchers found that those who stopped taking aspirin-because of a pending surgical or dental procedure, bleeding, or because they forgot or simply didn't want to take it anymore-had triple the risk of having a stroke within a month, compared with those who continued taking aspirin.

So consult the doctor who oversees your heart health before stopping the drug. If you do need to stop, do so as briefly as possible. If you want to stop because of troubling side effects, talk to your doctor about possibly switching to another blood thinner. And if you have trouble remembering to take your pill, make a habit of taking it at the same time each day, for example, after you brush your teeth in the morning or right after breakfast.

5. How helpful are the newer forms of aspirin?

Fasprin delivers aspirin in a tablet that dissolves in the mouth and is absorbed directly into the blood, bypassing the stomach. That may make Fasprin less likely than swallowed aspirin to directly irritate the stomach. But there's no proof at this time, and it could still pose some risk since aspirin in the bloodstream blocks production of substances that protect the stomach lining. And all aspirin thins the blood, which increases the risk of bleeding in the gut and elsewhere.

Bayer has two specialized, low-dose aspirin products. Bayer Women's Low Dose Aspirin Plus Calcium combines 81 mg of aspirin with 300 mg of calcium. And Bayer Aspirin With Heart Advantage contains 81 mg of aspirin plus 400 mg of phytosterols, substances found naturally in some nuts and other foods that block the absorption of cholesterol from food. Many women, and men, do indeed need extra calcium. And research does suggest that sterols can help lower cholesterol slightly. But the amount of sterols included in the product may not be high enough to have much effect. And both cost much more than standard generic low-dose aspirin products.

6. Can I take aspirin with other over-the-counter pain relievers?

Yes-as long as you stick mainly with acetaminophen (Tylenol and generic), or creams such as Zostrix that contain capsaicin. But it's not a good idea to combine aspirin with ibuprofen (Advil and generic) or naproxen (Aleve and generic). Unlike acetaminophen, those drugs are chemically similar to aspirin, so taking them together multiplies the risk of gastrointestinal problems.

Moreover, ibuprofen and possibly naproxen can undermine aspirin's blood-thinning effect. If you do take aspirin and ibuprofen or naproxen, take the aspirin at least four hours before. That will give it a chance to do its job without having to compete against the other medications.

7. Should I take aspirin to prevent other diseases?

Not if you're at low risk for heart disease. Several randomized clinical trials have shown that a daily aspirin dose of at least 300 mg substantially reduces the risk of the recurrence of precancerous polyps and possibly colon cancer itself. And researchers hope that a genetic test will eventually help identify people most likely to benefit from aspirin.

But for now the dangers associated with the high doses of aspirin used in those clinical trials make the therapy inappropriate for most people. Instead, it should be reserved mainly for people who are at very high risk of the malignancy because of a condition, called familial adenomatous polyposis, that causes them to develop hundreds of polyps.

Other research suggests that salsalate, a relative of aspirin, may prove effective against type 2 diabetes. But it appears to take dangerously high levels of aspirin itself to achieve comparable results. And while a few population studies have suggested that people who regularly take aspirin have a lower risk of developing Alzheimer's disease, more conclusive randomized clinical trials have failed to show that the drug either wards off the disease or prevents cognitive decline.

Finally, preliminary evidence that aspirin relieves urinary difficulties stemming from an enlarged prostate gland in men needs to be confirmed before it's worth taking the drug for that reason alone.

8. Are prescription blood thinners better for preventing heart attack?

Not for most people. While doctors long assumed that taking the anticlotting drug clopidogrel (Plavix) along with aspirin provided additional coronary protection, a recent large clinical trial has shown that the combination works no better than aspirin alone and may increase the risk of harmful bleeding.

The combination should generally be reserved for people in imminent cardiovascular danger, such as those who are having a heart attack or stroke, or having a stent implanted to prop open a clogged artery. Clopidogrel alone can also be an option for people who can't take aspirin for safety reasons.

9. I have asthma. Can I take aspirin?

Yes, but you need to work carefully with your doctor to make sure that aspirin doesn't worsen it. If it does, you could consider aspirin desensitization, a process in which increasing doses of the drug are given under carefully monitored conditions.

10. Should I be tested for aspirin resistance?

Probably not yet. Recent research does suggest that nearly a third of people have a trait that makes their platelets extra sticky, which means that those individuals are resistant to aspirin's heart benefits. Such individuals appear to have about a fourfold increase in nonfatal and fatal vascular events in the heart, brain, and elsewhere in the body. And several companies have recently developed tests to try to identify people with the trait.

But researchers aren't sure which tests best indicate aspirin resistance. Nor do they know whether it's best to treat aspirin-resistant patients by switching them to a different blood-thinning drug, trying a higher dose, or simply taking them off aspirin. So it probably makes most sense to wait until ongoing research answers those questions before being tested for aspirin resistance.

This article first appeared in the September issue of Consumer Reports On Health.

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