Aspirin for heart attack and unstable angina

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	Why It Is Used
	How Well It Works
	Side Effects
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Aspirin works quickly (within 15 minutes) to prevent the formation of blood clots, decreasing the risk for heart attack or stroke.

Generic or store brands are as effective as brand-name aspirin.

It has been well documented that aspirin reduces the risk of heart attack in people with known coronary artery disease (CAD). It is also now understood that aspirin lowers the risk of having symptoms for people who have a higher risk for the disease. People who are at high risk for coronary artery disease or who already have coronary artery disease benefit the most from aspirin therapy.

You can take aspirin to help you during a heart attack. After you call 911 or other emergency services, chew 1 adult-strength aspirin (325 mg) if you are not allergic to aspirin and if there is no other reason that you can't take aspirin. Aspirin slows blood clotting, so a blood clot that is causing the heart attack stays smaller.

You may also take low-dose aspirin (81 mg) every day to help lower the risk of a heart attack or stroke. 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 40 who have one or more risk factors for heart disease, as long as their blood pressure is controlled and the benefits of aspirin are greater than the risks.
• By healthy women over age 65, or women under 65 who have one or more risk factors for heart disease as long as their blood pressure is controlled and the benefits of aspirin are greater than the risks.

If you have atrial fibrillation and cannot take or choose not to take warfarin, you may take an adult-strength aspirin (325 mg) every day to help lower the risk of a stroke.

Studies show that people who are at high risk for coronary artery disease or who have established coronary artery disease benefit the most from aspirin therapy. One large study showed that people ages 65 and older with both heart failure and coronary artery disease had a significantly lower death rate when they took aspirin on a regular basis.¹

• Aspirin decreases the risk of a first heart attack and recurrent heart attacks.²
• Aspirin may reduce the severity of a heart attack when taken immediately after symptoms begin. One study showed that those who took aspirin during their heart attack and for 1 month after were less likely to die from a subsequent heart attack or stroke than those who did not take aspirin.³
• Aspirin may help improve the symptoms of unstable angina.

However, in people with a relatively low risk of developing cardiovascular disease, the benefits of preventive aspirin therapy may be outweighed by the increased risk of bleeding problems.²

Side effects of aspirin include:

• Stomach inflammation (gastritis).
• Gastrointestinal bleeding.
• Allergic reaction.
• Increased bruising and bleeding (hemorrhage) in the brain (rare) or other internal organs of the body.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

Some doctors believe that people who have two or more risk factors for coronary artery disease should take aspirin every day. Others are concerned that long-term daily aspirin use will increase the risk of stomach problems or hemorrhagic stroke when untreated high blood pressure is present.

Expert guidelines recommend 75 mg to 162 mg daily. One low-dose aspirin contains 81 mg. One regular-strength aspirin contains about 325 mg.⁴Consult your doctor before using aspirin on a regular basis.

Because aspirin reduces your blood's ability to clot, your doctor may want you to stop taking aspirin at least 5 days before surgery or before a dental procedure that may cause excessive bleeding.

Do not substitute nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil, for example) or naproxen (such as Aleve), for aspirin. Although NSAIDS relieve pain and inflammation much like aspirin does, they may increase your risk for a heart attack or stroke.

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.⁵ 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 you doctor if you take these medicines every day.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

Citations

1. Krumholz HM, et al. (2001). Aspirin and the treatment of heart failure in the elderly. Archives of Internal Medicine, 161(4): 577–582.

2. Awtry EH, Loscalzo J (2000). Aspirin. Circulation, 101(10): 1206–1218.

3. Danchin N, Durand E (2006). Acute myocardial infarction, search date August 2004. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.

4. American College of Cardiology (ACC) and American Heart Association (AHA) (2004). ACC/AHA Guidelines for the management of patients with ST-elevation myocardial infarction. Executive summary: Report of the ACC/AHA Task Force on Practice Guidelines. Available online: http://www.acc.org/clinical/guidelines/stemi/Guideline1/index.htm.

5. U.S. Food and Drug Administration (2006). Concomitant use of ibuprofen and aspirin: Potential for attenuation of the anti-platelet effect of aspirin. Food and Drug Administration Science Paper. September 8, 2006. Available online: http://www.fda.gov/cder/drug/infopage/ibuprofen/science_paper.htm.