ASA for prevention: What you need to know

The advice has changed on who should take it and who shouldn’t. Here are the facts.
A woman in a blue shirt holds white pills in her palm

Do you take ASA every day to prevent heart disease, stroke or vascular disease? Many people in Canada do. ASA is short for acetylsalicylic acid, which is sold under names including Aspirin, Entrophen and Novasen.

Updated Heart & Stroke recommendations published in the Canadian Medical Association Journal in 2020 might change this daily routine.

For people who have not had a stroke or been diagnosed with heart or vascular disease, taking ASA daily for prevention is not recommended, according to the updated guidelines.

For people who have been diagnosed with one of these conditions, you should still take a daily dose of ASA if it has been prescribed by your doctor. This might seem confusing. Toronto-based family physician Dr. Jeff Habert, who helped develop the recommendations, clears things up.

Should I take ASA every day to prevent heart disease, stroke or vascular disease?

If you do not have heart or vascular disease or stroke, then likely no.

In our updated recommendations, we say the daily use of ASA is not recommended for primary prevention – that means preventing a first event such as a heart attack or stroke. If you are healthy and have never had a heart attack or stroke or vascular disease and are taking daily ASA, talk to your healthcare provider before making changes.

If you have been diagnosed with a stroke, heart or vascular disease, the recommendations have not changed. So if your doctor suggested you take ASA every day, keep doing that.

Some people might be at very high risk or have some blockage in their arteries but no symptoms. Ask your doctor if this applies to you and if you should take daily ASA.

Doctor Jeff Habert

These recommendations are only about using ASA for prevention.

Dr. Jeff Habert Family physician

Why did the recommendations change?

Over the last few years, new evidence has been published about the risks and benefits of ASA.

Canadian experts wanted to look at all the evidence and make Canadian recommendations, which we published as part of the Heart & Stroke Canadian Stroke Best Practices Recommendations.

The American Heart Association also changed its recommendations in 2019.

Why is ASA good for some people and not others?

This is about balancing risk. ASA increases your chances of dangerous bleeding because it’s a blood thinner.

Taking ASA every day can increase your chance of bleeding from your stomach, which is what we call an upper GI bleed. This is dangerous, but we can treat it in the hospital. Worse is having a bleed on your brain, which can be fatal.

But if you already have cardiovascular disease, the benefits outweigh the risks of bleeding. One study showed that in people taking ASA after a cardiovascular episode, it prevented further events by 19%. That’s a big number.

If I think I’m having a heart attack, should I take ASA?

These updated recommendations are only about using ASA for prevention.

Heart & Stroke still recommends if someone is experiencing signs of a heart attack, call 9-1-1, lie down and take ASA. ASA can help by stopping the blood clot that is causing the heart attack from getting any bigger. That advice did not change.

If I stop taking ASA to prevent heart disease, what can I do instead?

These updated recommendations are an opportunity for Canadians to look at other ways to prevent heart disease, stroke and vascular disease.

You can stop smoking and focus on eating a healthy diet.

There are medications and lifestyle changes to reduce cholesterol and blood pressure. If you have diabetes, you can talk to your healthcare provider about drugs that can protect you against heart attack and stroke.

We have so much evidence showing that exercise is great for the heart and the brain, and that includes mental wellbeing. Just 150 minutes of exercise a week is good prevention and we don’t have any worries about it, it’s just good for you.

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