ASA for coronary artery disease

Examples

Generic Name	Brand Name
acetylsalicylic acid (ASA)	Aspirin, Asaphen, Bufferin, Entrophen, Novasen, Tri-Buffered ASA [ASA combined with an antacid]

How It Works

When ASA is chewed, it works quickly (within 15 minutes) to prevent the formation of blood clots. This decreases the chance that a blood clot will form and block a narrowed heart artery, leading to a heart attack.

Brand-name ASA is no more effective than generic or store brands.

Why It Is Used

It has been well-documented that ASA reduces the risk of heart attack in people with known coronary artery disease (CAD). It is also now understood that ASA reduces the risk of symptomatic CAD in people at increased 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 ASA therapy.

ASA may also be used in the following situations:

• During and after a heart attack
• For people with stable angina
• For the treatment of unstable angina
• After angioplasty or bypass surgery
• For 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 benefit of ASA is greater than the risks
• For healthy women over age 65, or women over 65 who have one or more risk factors for heart disease, as long as their blood pressure is controlled and the benefit of ASA is greater than the risks

How Well It Works

ASA and coronary artery disease (CAD)

People who are at high risk for coronary artery disease or who have established coronary artery disease benefit the most from ASA therapy.

• For people at increased risk for CAD, studies have shown that ASA therapy reduces the risk of developing symptomatic CAD by 28%.¹
• For people at low risk for CAD, the risks of ASA therapy may outweigh the benefits.¹

People who have established CAD also appear to benefit from ASA therapy. One large study has shown that people aged 65 and older with both heart failure and coronary artery disease had a significantly lower death rate when they took ASA on a regular basis.²

ASA and heart attacks

• ASA reduces the risk of death and heart attack in people with unstable angina.³
• ASA decreases the risk of first heart attack, death from heart attack, and recurrent heart attacks.⁴
• ASA may help reduce the severity of a heart attack when it is chewed and taken immediately after symptoms begin.

Side Effects

Side effects of ASA include:

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

If you have other conditions or risk factors that increase your risk of stroke or bleeding, you may not be a good candidate for ASA therapy. The risk of bleeding is greater for people with uncontrolled high blood pressure who already take antiplatelet medications, anticoagulants (blood thinners), or anti-inflammatory medications.

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

What To Think About

ASA may be combined with heparin and possibly newer antiplatelet drugs such as abciximab (ReoPro), eptifibatide (Integrilin), and clopidogrel (Plavix) before and after angioplasty to treat unstable angina.

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

Any over-the-counter ASA product will work. No single brand works better than another for preventing coronary artery disease or heart attacks.

The best dose of ASA has not been established; however, 75 mg a day seems to be as effective in preventing heart attack as higher doses and has fewer side effects.⁵ One low-dose ASA contains 81 mg; one regular-strength ASA contains about 325 mg. Consult your doctor before using ASA on a regular basis.

Because of its effect on blood clotting, your doctor may want you to stop your ASA at least 5 days before surgery or before a dental procedure that may cause excessive bleeding.

Even though non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen, relieve pain and inflammation much like ASA does, do not substitute NSAIDs for ASA because they will not lower your risk of another heart attack. If you need to take NSAIDs for a long time, talk with your doctor to see if it is safe for you. Some research suggests that long-term use of these medicines may raise your risk for coronary artery disease.

One study found that regular use of NSAIDs seemed to inhibit ASA's ability to prevent a first heart attack. However, intermittent NSAID use did not interfere. (This trial studied male NSAID users only.)⁶ If you will need to take ASA or other NSAIDs for a long time, talk with your doctor about the interaction between ASA and other NSAIDs. Most doctors recommend taking ASA at least 2 hours before other NSAIDs to reduce the chance of an interaction.

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Author:	Douglas Dana Robin Parks, MS	Last Updated: September 21, 2007
Medical Review:	Anne C. Poinier, MD - Internal Medicine Caroline S. Rhoads, MD - Internal Medicine Stephen Fort, MD, MRCP, FRCPC - Interventional Cardiology Robert A. Kloner, MD, PhD - Cardiology Ruth Schneider, MPH, RD - Diet and Nutrition
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