Topic Overview

Why take low-dose aspirin?

Good old aspirin, the common pain reliever that has been in our medicine cabinets for almost a century, also has a talent for prevention.

For people who have had a heart attack: Aspirin can help prevent a second heart attack.

For people who have had a stroke: Aspirin can help prevent a second stroke or a transient ischemic attack (TIA), which is often a warning sign of an impending stroke.

For people who have never had a heart attack or stroke: Aspirin may reduce your chance of having a heart attack or a stroke if you have certain risk factors, such as diabetes, high blood pressure, high cholesterol, or smoking. If you have a higher risk for a heart attack or stroke, aspirin will have even more benefit for you.

Who should take low-dose aspirin?

If you have had a heart attack or stroke, your doctor has probably already prescribed low-dose aspirin for you.

If you have never had a heart attack or stroke, talk to your doctor before you start taking aspirin every day.

Doctors use different guidelines to decide who should take daily aspirin. But no matter which guideline your doctor follows, he or she will look at your health and at your risk for a heart attack or stroke. Then you and your doctor will balance the benefits and the risks of taking a daily aspirin to see if a daily aspirin is right for you. For help on the decision to take low-dose aspirin, see:

Aspirin: Should I Take Daily Aspirin to Prevent a Heart Attack or Stroke?

If you have a higher risk for a heart attack or stroke, aspirin will have even more benefit for you. If the benefit of aspirin is more than the risk of side effects, you may want to take daily aspirin.

Daily aspirin isn't advised for people who have a low risk of heart attack or stroke.

Your doctor can help you know your risk of having a heart attack or stroke and the risk of bleeding from aspirin. If you know your blood pressure and cholesterol numbers, you can use this Interactive Tool: Are You at Risk for a Heart Attack? to find out your risk.

Low-dose aspirin may be used:

• After a heart attack, to prevent another one.
• By people who have coronary artery disease.
• By people with stable angina.
• By people with unstable angina.
• After bypass surgery or angioplasty.
• By people who have had a stroke or transient ischemic attack (TIA).
• After surgery to prevent a stroke (carotid endarterectomy).
• By healthy men over age 45 when the benefits of aspirin to prevent a heart attack are greater than the risk of stomach bleeding from taking daily aspirin.
• By healthy women over age 55 when the benefits of aspirin to prevent a stroke are greater than the risk of stomach bleeding from taking daily aspirin.

If you have atrial fibrillation and have a low risk of stroke, you might take aspirin to help lower your risk of stroke. Aspirin may be a good choice if you are young and have no other heart or health problems or if you can't take an anticoagulant (also called a blood thinner) safely.

Who should not take low-dose aspirin?

Some people shouldn't take aspirin. These include people who:

• Have a stomach ulcer.
• Have recently had a stroke caused by bleeding in the brain.
• Are allergic to aspirin.
• Have high blood pressure that isn't under control.
• Have asthma that is made worse by aspirin.

Daily aspirin isn't advised for people who have a low risk of heart attack or stroke.

If you think you are having a stroke, do not take aspirin because not all strokes are caused by clots. Aspirin could make some strokes worse.

Gout can become worse or hard to treat for some people who take low-dose aspirin.

If you can't take aspirin, your doctor may have you take clopidogrel (Plavix) to help prevent a heart attack or a stroke.

If you take an anticoagulant, such as warfarin (Coumadin), talk with your doctor before taking aspirin, because taking both medicines can cause bleeding problems.

What should I avoid when taking low-dose aspirin therapy?

Drinking 3 or more alcoholic drinks every day while taking daily aspirin increases your risk for liver damage and stomach bleeding. If your doctor recommends aspirin, limit or stop alcohol usage.

Aspirin should not be taken with many prescription and over-the-counter drugs, vitamins, herbal remedies, and supplements. So before you start aspirin therapy, talk to your doctor about all the drugs and other remedies you take.

Because aspirin reduces your blood's ability to clot, your doctor may want you to stop taking aspirin at least 5 days before any surgery or dental procedure that may cause bleeding. Do not suddenly stop taking aspirin without talking to your doctor first. Talking to your doctor first is especially important if you have had a stent placed in a coronary artery.

Tell your doctor if you notice that you bruise easily, have bloody or black stools, or have prolonged bleeding from cuts or scrapes.

Although nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, relieve pain and inflammation much like aspirin does, they do not affect blood clotting in the same way that aspirin does. Do not substitute NSAIDs for aspirin, because they will not decrease your risk of another heart attack.

If you need both aspirin and a pain reliever every day, talk to your doctor about what pain reliever you should take. If you take uncoated aspirin and ibuprofen at the same time, the aspirin may not work as well to prevent a heart attack. You may be able to use acetaminophen instead of ibuprofen to treat your pain. But if ibuprofen is your only option, avoid taking it during the 8 hours before and the 30 minutes after your aspirin dose. For example, you can take ibuprofen 30 minutes after your aspirin dose. If you take ibuprofen once in a while, it does not seem to cause problems.

Experts do not know if NSAIDs other than ibuprofen interfere with uncoated aspirin. Also, experts do not know if people who take a daily coated aspirin should be concerned about ibuprofen or other NSAIDs interacting with the aspirin. Talk to your doctor if you take these medicines every day.

How do you take low-dose aspirin?

Your doctor will recommend a dose of aspirin and how often to take it. Most people take aspirin every day to help prevent a heart attack or a stroke, but others might take aspirin every other day.

Low-dose aspirin (81 mg) is the most common dose used to prevent a heart attack or a stroke. But the dose for daily aspirin can range from 81 mg to 325 mg. One low-dose aspirin contains 81 mg. One adult-strength aspirin contains about 325 mg.

Low-dose aspirin seems to be as effective in preventing heart attacks and strokes as higher doses.

Take aspirin with food if it bothers your stomach.

For low-dose aspirin therapy, do not take medicines that combine aspirin with other ingredients such as caffeine and sodium.

How does aspirin work to prevent a heart attack or stroke?

Aspirin protects you from having a clot-related stroke in the same way it protects you from having a heart attack.

Aspirin slows the blood's clotting action by reducing the clumping of platelets. Platelets are cells that clump together and help to form blood clots. Aspirin keeps platelets from clumping together, thus helping to prevent or reduce blood clots.

During a heart attack, blood clots form in an already-narrowed artery and block the flow of oxygen-rich blood to the heart muscle (or to part of the brain, in the case of stroke). When taken during a heart attack, aspirin slows clotting and decreases the size of the forming blood clot. Taken daily, aspirin's anti-clotting action helps prevent a first or second heart attack.