Angiotensin II Receptor Blockers (ARBs)

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Angiotensin II Receptor Blockers (ARBs)


Generic NameBrand Name
irbesartan Avapro

Angiotensin II receptor blockers combined with diuretic

Generic NameBrand Name
irbesartan and hydrochlorothiazideAvalide
losartan and hydrochlorothiazideHyzaar

How It Works

Angiotensin II receptor blockers inhibit a substance that causes blood vessels to narrow (constrict). As a result, blood vessels relax and widen (dilate), making it easier for blood to flow through the vessels, which reduces blood pressure. These medicines also increase the release of water and salt (sodium) to the urine, which in turn lowers blood pressure as well.

Preventing the blood vessels from constricting helps improve blood flow, which reduces the backup of blood in the heart and lungs. It also decreases the pressure that the left ventricle of the heart must pump against.

Angiotensin II receptor blockers also act directly on the hormones that regulate sodium and water balance.

Why It Is Used

Angiotensin II receptor blockers can be used to treat coronary artery disease or heart failure in some people who cannot tolerate ACE inhibitors or who have kidney disease from diabetes (diabetic nephropathy) and in people with type 2 diabetes.

An angiotensin II receptor blocker (ARB) may be used instead of an angiotensin-converting enzyme (ACE) inhibitor if you are not able to tolerate certain side effects of an ACE inhibitor. ACE inhibitors can cause an annoying cough. This cough may be hard for some people to live with. So doctors may prescribe an ARB instead, because ARBs are less likely to cause a cough.

How Well It Works

ARBs can lower the risk of death from heart failure. ARBs also reduce the number of people with heart failure who need to go into the hospital. ARBs have been shown to work as well as ACE inhibitors for heart failure.1

For people with type 2 diabetes, ARBs reduce the amount of protein in the urine and protect the kidneys from diabetic nephropathy.

For advanced heart failure, an ARB may be taken with an ACE inhibitor to help lower the risk of dying or needing to go into the hospital.1 But if you take an ARB with an ACE inhibitor, you have a higher risk for kidney problems and for potassium levels that are too high. For this reason, you will likely need close monitoring.

Side Effects

Low blood pressure is the most common side effect with angiotensin II receptor blockers. Light-headedness and dizziness are the most common signs of low blood pressure. ARBs can also make kidney function worse and raise potassium levels.

ARBs may interact with non-steroidal anti-inflammatory drugs (NSAIDs), antacids, potassium supplements, certain diuretics, and lithium. If you are taking one of these medicines, talk with your doctor before taking any other medicines.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

ARBs may increase potassium levels in the blood and may make kidney function worse in people who have diabetes or reduced kidney function. ACE inhibitors also have the same potential complications.

If you are pregnant or could become pregnant, do not take ARBs.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.



  1. McKelvie R (2010). Heart failure, search date May 2009. Online version of BMJ Clinical Evidence:


By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Theresa O'Young, PharmD - Clinical Pharmacy
Last Revised October 14, 2010

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