Should you take aspirin to prevent a stroke?

May 19, 2021

Your Healthcare

This article was reviewed by our Baystate Health team to ensure medical accuracy.

Inexpensive and widely available without a prescription, aspirin has long been a go-to for millions of people looking to relieve pain, reduce inflammation, fight fever, and more. But for some people, the risks associated with aspirin far outweigh its benefits. This is especially true when it comes to strokes.

The role of aspirin in treating strokes

According to Dr. Heydi Podadera Flores, a neurology specialist with Baystate Health, “When it comes to treating strokes, aspirin has its role but only for a specific type of stroke.”

She explains, “There are two primary types of strokes: ischemic and hemorrhagic. Ischemic strokes occur when a clot blocks an artery, keeping oxygen from reaching the brain. Hemorrhagic strokes occur when a weakened blood vessel in the brain ruptures. The leaking blood accumulates puts pressure on the surrounding brain tissue.

“While the symptoms of both types of stroke can be very similar, the treatments are not; the key difference being what’s causing the stroke: a blockage or a bleed.”

Often referred to as an anti-platelet, aspirin keeps cells in the blood (a.k.a platelets) from sticking together to form a clot. “That’s extremely important and helpful in the earliest stages of treating an ischemic stroke where re-establishing blood flow to the brain is the first priority,” says Dr. Flores, “However, in the case of hemorrhagic stroke, the initial goal is to stop the bleeding into the brain. And given how aspirin works, aspirin can lead to more bleeding, actually making the stroke worse.”

Assessing patients for treatment

One of the keys to reducing the risk of permanent damage to the brain due to a stroke is determining what kind of stroke is occurring.

“The first thing we do when someone comes in with a suspect stroke is get a picture of their brain,” says Dr. Flores. “If we’re able to see that there’s no bleeding in the brain, we’ll give them aspirin—ideally in the first 24 hours after the event. If we see bleeding,” she notes, “we’ll skip aspirin and look at other interventions such as controlling blood pressure or, in some cases, surgery.”

The role of aspirin AFTER a stroke

Unfortunately, no one is more at risk of a stroke than a person who has already experienced one. In fact, in the United States, about one-fourth of the nearly 800,000 strokes that occur each year are recurrent events.

“In terms of preventing a stroke, the benefits of aspirin are most apparent at this stage,” says Dr. Flores. “Regularly taking aspirin after a stroke can reduce risk of another stroke by 15-20%. There is no evidence to support taking aspirin as a preventative measure against a stroke if one has not been experienced before. It could, actually, be harmful on other fronts as aspirin has side effects—bleeding in the stomach, heart burn, cramps, rash, etc.”

Dr. Flores advises patients to consult with their doctor before taking any medication, including aspirin.

“The risks and benefits vary for each person and their health history,” she says. “If you suspect you or someone else is having a stroke, instead of reaching for aspirin, reach for the phone. Prompt assessment and treatment is the best way to reduce the risk of permanent damage.”