Aspirin to Prevent a First Heart Attack or Stroke

Also known as aspirin primary prevention.

Aspirin is a proven way to help some people prevent a second heart attack or stroke. When aspirin is used this way it is called aspirin secondary prevention. It appears that aspirin also may help prevent a first heart attack or stroke in some people.

Learn more about what we know about aspirin primary prevention, or the use of aspirin to prevent a first heart attack or stroke.

Who may benefit?

Aspirin primary prevention is not right for everyone. Aspirin primary prevention may be beneficial for adults who:

Are 50 to 69 years old, with the greatest benefit for adults aged 50 to 59;
Have a 10 percent or higher risk of cardiovascular disease in the next 10 years; and
Are able and willing to take low-dose aspirin, about 81 mg per day, for at least 10 years.

Currently, there is not enough evidence to:

Support the use of aspirin primary prevention in patients who are younger than 50 years or older than 70 years.
Know whether aspirin primary prevention benefits or risks differ between men and women or between different races or ethnicities.

Talk to your doctor to find out whether aspirin is right for you to help prevent heart attack, stroke, or other conditions. Do not start aspirin without first talking with your doctor about your risks and benefits. There are conditions, such as atrial fibrillation and deep vein thrombosis, where aspirin alone would not be enough protection. If you have either of these conditions, be sure to talk with your doctor about what prevention method is best for you.

Why does aspirin prevent heart attack and stroke?

Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that is commonly used to relieve pain. But, aspirin also may prevent the formation of blood clots. Aspirin does this by inhibiting platelets from promoting clotting in blood vessels where cholesterol and plaque may be partially blocking blood flow. This clotting can lead to heart attack and stroke. By inhibiting clotting, aspirin helps reduce damage to the heart and brain and helps prevent heart attack and stroke.

What are the risks?

Bleeding is the most common side effect of aspirin. The risk of bleeding is higher in men versus women, and the risk increases in patients who:

Are older
Are using aspirin at a higher dose or for longer periods of time
Are using aspirin at the same time as other medicines that increase the risk of bleeding
Have uncontrolled high blood pressure
Have or previously had ulcers in their gastrointestinal tract
Have other medical conditions such as kidney failure, liver disease, and certain bleeding or blood disorders

Some patients with severe asthma may be sensitive to aspirin. These patients may experience serious respiratory problems when taking aspirin.

Talk to your doctor to find out whether aspirin is right for you. Don’t start taking aspirin without first talking to your doctor.

Why does aspirin cause bleeding as a side effect and is it serious?

Aspirin can cause bleeding in many parts of the body, particularly in the brain or in the gastrointestinal tract including the stomach. This can happen because aspirin can make it easier for the stomach lining to be damaged and bleed. Because aspirin also inhibits clotting, bleeding in the stomach or brain can be fatal if left untreated and it requires immediate medical attention.

What if I’m taking aspirin to prevent another heart attack or stroke?

The information discussed in Who may benefit? only applies to use of aspirin to prevent a first heart attack or stroke. Aspirin is a proven way to prevent a second heart attack or stroke in some people. If you’ve already had a heart attack or stroke and are already taking aspirin to prevent another event, do not stop taking your aspirin without talking to your doctor.

How else can you prevent heart attack and stroke?

Heart-healthy lifestyle changes can help prevent a heart attack and stroke. These changes include:

It is also important to control other medical conditions that increase your risk of heart attack or stroke, such as high blood cholesterol, high blood pressure, diabetes, preeclampsia, and overweight and obesity. You and your doctor should monitor your cholesterol, blood pressure, and blood sugar numbers to know if you are at risk for a first heart attack or stroke or if you are meeting goals to help prevent another event.

Can aspirin prevent other conditions?

Aspirin also may prevent:

Colorectal cancer in some patients. Read Colorectal Cancer Prevention (PDQ®) – Patient Version for more information from the National Cancer Institute.
Preeclampsia when used after the first trimester in pregnant women who are high risk for this pregnancy-related condition. Read An Aspirin a Day for Preeclampsia Prevention for more information from the National Institute of Child Health and Human Development.
Repeat deep vein thrombosis or pulmonary embolism events in patients who discontinue anticoagulants. Aspirin is not preferred over other anticlotting medicines, but aspirin may be beneficial over no therapy to prevent another blood clot that causes deep vein thrombosis or pulmonary embolism.