Angiotensin II receptor blockers (ARBs) are medications that relax blood vessels, allowing blood to flow more freely, which lowers blood pressure. ARBs are used to treat hypertension (high blood pressure), heart failure, and kidney disease. These medications are also prescribed for heart attack and stroke prevention.

What Are Angiotensin II Receptor Blockers (ARBs)?

Angiotensin II receptor blockers (ARBs) decrease blood pressure by relaxing your body’s veins and arteries. Doctors most often prescribe this medication to treat hypertension (high blood pressure).

But ARBs are also important for treating heart failure, chronic kidney disease, and diabetes-related kidney disease.

Poorly controlled hypertension can take a toll on organs like your heart, lungs, kidneys, and brain. High blood pressure increases your risk of heart attack, heart disease, and stroke. If you have hypertension and other risk factors, your doctor may prescribe an ARB to prevent these conditions.

What Conditions Do Angiotensin II Receptor Blockers Treat?

Angiotensin II receptor blockers work by minimizing the effects of the hormone angiotensin. This hormone regulates fluid levels in your body. Too much angiotensin means too much fluid builds up, which causes your blood vessels to tighten and blood pressure to increase. As a result, over time you can develop hypertension.

ARBs not only improve hypertension but also treat conditions that are worsened by constricted blood vessels.

Hypertension

ARBs help veins and arteries relax, which reduces hypertension or high blood pressure. This allows blood to flow more freely and better carry oxygen to your organs.

Heart Attack

ARBs reduce your risk of heart attack, especially if you have hypertension. Doctors can also prescribe ARBs after a heart attack to limit damage to the heart muscle.

Heart Failure

If you have heart failure, your heart has to work extra hard to pump blood to your body. ARBs help your heart work more efficiently by opening veins and arteries.

Stroke

When you have reduced blood flow to the brain, it can cause a stroke. ARBs open blood vessels, allowing blood to flow through easier.

Fatty Liver Disease

Fat buildup and inflammation contribute to nonalcoholic fatty liver disease, a common chronic liver condition. ARBs help reduce liver inflammation.

Kidney Disease

High blood pressure and diabetes are common causes of kidney disease. ARBs treat kidney disease by improving blood pressure and relaxing blood vessels.

How Do Angiotensin II Receptor Blockers Work?

Angiotensin II receptor blockers do exactly what their name implies — they block the receptor that the hormone angiotensin binds to.

Angiotensin I is a naturally occurring hormone produced by the liver. It converts to angiotensin II in your lungs.

Angiotensin II is necessary to keep body functions working. But too much of this protein, because of heart disease or other reasons, can cause issues in how your vascular system functions. Too much angiotensin II can cause blood vessels to narrow blood pressure to rise.

By blocking the receptor, ARBs prevent angiotensin from binding and tightening blood vessels. Blood vessels stay relaxed and open, allowing blood to flow freely through the body.

Are There Any Risks Related to ARBs?

Because of the associated health risks, people with certain health conditions or those taking specific types of medications should not take ARBs.

These conditions include:

Pregnancy: The U.S. Food and Drug Administration (FDA) requires ARBs to have a black box warning because of the increased risk of potential harm to the fetus.
Heart failure with low blood pressure: ARBs are routinely prescribed to treat heart failure symptoms, but they aren’t recommended if you have both heart failure and low blood pressure. These medications can cause your blood pressure being too low or hypotension.
Certain kidney conditions: In some cases people with specific forms of kidney disease should not take ARBs. Specifically people with renal artery stenosis or a narrowing of the arteries that bring blood flow to the kidneys, and very poor kidney function, should not take ARBs.

If you have kidney disease and take an ARB, tell your doctor if you experience an illness that causes vomiting or diarrhea because ARBs can result in acute kidney injury if you are dehydrated.

ARBs should also be avoided if you’re taking the following medications.

Direct renin inhibitors (DRIs): These drugs may increase your risk of low blood pressure and kidney problems including kidney failure and higher levels of potassium.
Other antihypertensive medications: These medications include high blood pressure medications like angiotensin converting enzyme (ACE) inhibitors. Combining these medications with ARBs could cause your blood pressure to drop too low.

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.

Sources

Angiotensin II Receptor Blockers (ARBs). Cleveland Clinic. June 17, 2022.
Angiotensin II Receptor Blockers. Mayo Clinic. August 4, 2023.
Managing High Blood Pressure. Centers for Disease Control and Prevention. May 15, 2024.
Robert HD et al. Angiotensin II Receptor Blockers (ARB). StatPearls. March 27, 2023.
Gin MS et al. Lithium Therapy and Its Interactions. Australian Prescriber. June 2020.
Fine NM. Drugs for Heart Failure. Merck Manual Professional Version. September 2022.
ACE Inhibitors and ARBs. National Kidney Foundation. May 4, 2023.

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Kristina D. Carter, PharmD

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Kristina D. Carter, PharmD, is a clinical pharmacist and freelance health writer who currently works in a managed care setting, performing quality audits on utilization management case reviews for the pharmacy team. She has over 20 years of experience and has worked in several pharmacy practice settings, including at a community pharmacy as well as in ambulatory care, senior care, and pharmacy operations.

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