Does Aspirin Lower Blood Pressure? Not for Everyone

Aspirin does not lower blood pressure on its own. However, its ability to thin out the blood may benefit some people with high blood pressure (hypertension).

High blood pressure is a risk factor for heart disease. For years, a low dose of daily aspirin has been considered a safe and healthy way to prevent it. However, in recent years, there has been more debate about the widespread use of this practice.

This article discusses what you should know about taking aspirin to lower blood pressure, including the risks and alternatives. 

Is There Evidence to Support Taking Aspirin to Lower Blood Pressure?

A lot of people think of aspirin as a way to lower blood pressure and prevent heart attacks and strokes. 

The cardiovascular benefits of aspirin are thought to be related to the medication's ability to thin the blood and make it less sticky—not its ability to affect blood pressure. 

The research looking at the link between aspirin and high blood pressure is limited and controversial. For example, some studies have suggested that aspirin may affect blood pressure in some cases and when it’s taken at certain times of the day.

Here are some key points that researchers have found out:

• In people with pre-hypertension or mild, untreated hypertension, aspirin given before bedtime may reduce blood pressure.
• For pregnant people at high risk for developing preeclampsia, taking a low dose of aspirin at bedtime can lower blood pressure.
• In people with long-standing hypertension who take high blood pressure medications, aspirin does not seem to affect blood pressure. This was true whether it was taken at night or in the morning.
• Aspirin is a nonsteroidal anti-inflammatory drug (NSAID). NSAIDs can actually raise blood pressure in people with hypertension.

Reasons for Taking a Daily Aspirin

Healthcare providers do not recommend that most people take aspirin daily to control their blood pressure. However, there are cases in which your provider might recommend a daily low dose of aspirin.

For example:

• You have had a heart attack or stroke in the past
• You have stable coronary artery disease (CAD) or peripheral artery disease
• You are pregnant and are at high risk for preeclampsia

Guidelines from the American Heart Association (AHA) and American College of Cardiology (ACC) state that daily aspirin use can actually be dangerous. Because aspirin thins your blood, taking it makes you more likely to experience internal bleeding.

Organizations including the AHA, the ACC, and the Food and Drug Administration (FDA) advise that people do not start taking aspirin without talking to their healthcare provider first. 

Aspirin Side Effects and Risks

Aspirin can have some side effects, such as:

• Heartburn
• Nausea
• Stomachache
• Vomiting

For most people, these effects are mild. However, aspirin also poses a serious risk of bleeding in the stomach, small intestines, and the brain. Other potential risks of taking aspirin include:

• Kidney failure
• Liver injury
• Ringing in the ears (tinnitus) or hearing loss (often when taking large daily doses of aspirin)
• Allergy or intolerance to aspirin

If you have severe side effects while taking aspirin (e.g., wheezing, rash, vomiting blood, black stools) or any symptoms are not getting better, tell your provider right away.

If Your Healthcare Provider Recommends Aspirin

If your provider tells you to start taking daily low-dose aspirin, you must take it exactly how they tell you to. Taking the wrong dose or using aspirin the wrong way can increase your risk for side effects or complications.

Before you start taking aspirin, talk to your provider about:

• If and how much alcohol you can drink
• What medications or supplements you should avoid: For example, taking another NSAID like Advil (ibuprofen) along with aspirin increases your risk for bleeding.
• If you are undergoing a surgical procedure, whether (and when) you should stop your aspirin
• Symptoms to watch out for and what to do if they occur (e.g., black or bloody stools)

Lowering Your Blood Pressure Without Aspirin

There are other ways that you can lower your blood pressure without taking aspirin. Your provider will focus your care on lifestyle modifications and/or choosing one or more medications that have been proven effective and safe for treating hypertension.

Lifestyle changes that can help lower blood pressure include:

• Restricting salt in your diet
• Staying hydrated by drinking plenty of water throughout the day
• Losing weight, if you're overweight or obese
• Exercising at least 30 minutes a day, most days of the week
• Finding ways to relax and relieve stress, like meditation or deep breathing
• Limiting alcohol consumption
• Quitting smoking

Medications that your healthcare provider may recommend include:

• Thiazide diuretics
• Calcium channel blockers
• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin receptor blockers (ARBs)
• Beta-blockers

Summary

Aspirin on its own does not lower blood pressure. Aspirin is not the main way to treat high blood pressure, and daily aspirin use as a preventive treatment is controversial. Taking aspirin carries risks, especially for bleeding. You should only take aspirin after talking to your provider.

There are many other ways to lower your blood pressure without aspirin, such as making lifestyle changes and taking medications that are meant to treat high blood pressure.