Angiotensin II receptor blockers (ARBs) are drugs that treat certain conditions affecting the heart and blood vessels as well as a kidney condition resulting from diabetes. People generally tolerate them well.

While the risk of side effects is low, they can still occur for some people. Some side effects can include experiencing headaches, drowsiness, and dizziness. Doctors do not recommend them for individuals who are pregnant or have high potassium levels or low blood pressure.

This article discusses ARBs, including conditions they treat, how they work, examples, dosages, contraindications, and side effects. It also answers some common questions.

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Research notes that ARBs can treat the following conditions:

Additionally, the medications are a common alternative treatment for people who cannot tolerate angiotensin-converting enzyme (ACE) inhibitors because of the side effect of a long-term, nonproductive cough.

Learn more about ACE inhibitors.

Angiotensin II is a hormone that constricts blood vessels, an effect that narrows the space through which blood can flow and increases blood pressure. It can also stimulate water and salt retention, raising blood pressure further.

These medications block some receptors where angiotensin II binds, an effect that decreases the hormone’s actions. The blocked receptors involve AT1 receptors in the kidneys, heart, and blood vessels. Consequences of blocking the receptors include reduced blood pressure and prevention of damage to the kidneys and heart.

Some examples of angiotensin II receptor blockers and their brand name, include:

  • azilsartan (Edarbi)
  • eprosartan (Teveten)
  • candesartan (Amias)
  • olmesartan (Olmetec)
  • telmisartan (Micardis)
  • valsartan (Diovan)
  • losartan (Cozaar)
  • irbesartan (Aprovel)

The table below lists the dosage recommendations in milligrams (mg) for each drug:

MedicationCondition it treatsInitial doseMaximum dose
high blood pressure20 mg once daily80 mg
high blood pressure600 mg once daily900 mg
high blood pressure16 mg once daily32 mg
heart failure4–8 mg once daily32 mg
high blood pressure20 mg once daily40 mg
high blood pressure40 mg once daily80 mg
reducing cardiovascular-related deaths in certain people80 mg once daily80 mg
high blood pressure80–160 mg once daily320 mg
heart failure20 mg twice daily160 mg twice daily
high blood pressure or stroke prevention or treating diabetic neuropathy or proteinuria (high protein levels in the urine)50 mg once daily100 mg
high blood pressure150 mg once daily300 mg
diabetic nephropathy75 mg once daily300 mg

In some cases, doctors may not recommend ARBs. The contraindications, which are situations where using them is unsuitable, include when a person:

  • has high potassium
  • has low blood pressure
  • is pregnant

Generally, people tend to tolerate the medications well, with a low incidence of side effects. However, side effects occur and can include:

  • drowsiness
  • headache
  • low blood pressure
  • dizziness
  • swelling under the skin
  • low blood sugar
  • high potassium levels

Below are answers to some commonly asked questions on the topic:

Are ARBs safe to take when pregnant?

They are not safe during pregnancy because they may lead to the following severe effects on the fetus:

  • kidney conditions
  • skull or bone deformities
  • incomplete development of lung tissue
  • death

People who become pregnant or believe they have become pregnant when taking these medications need to discontinue them immediately. The only exception involves the necessity of taking them to save the life of the pregnant individual.

Do ARBs interact with other medications?

A person should not take ARBs with ACE inhibitors or dopamine receptor inhibitors because they may increase the risk of:

  • high potassium
  • low blood pressure
  • acute kidney failure

Additionally, they can intensify the potassium-increasing effects of the following:

  • potassium-sparing diuretics, drugs that increase urination without the loss of potassium, such as amiloride (Midamor)
  • potassium supplements
  • nonsteroidal anti-inflammatory drugs, such as ibuprofen (Motrin)

What is the difference between ACE inhibitors and ARBs?

Both suppress the renin-angiotensin system, so they have similar uses. According to a 2023 research article, this system controls the heart, blood vessels, and kidney functions by regulating blood vessel tone and salt and water balance.

However, the two types of medications work in different ways. ARBs prevent angiotensin II from connecting to some of its receptors. In contrast, evidence indicates that ACE inhibitors stop the conversion of the precursor angiotensin I to angiotensin II.

Angiotensin II receptor blockers prevent angiotensin from reaching some of the sites it binds to in the kidneys, heart, and blood vessels. The results of this action lower blood pressure and help prevent damage to the heart and kidneys.

People generally tolerate them well, as the incidence of side effects is generally low.

However, they can worsen some conditions and interact negatively with certain drugs. For this reason, a person can consult their doctor about their health issues and all the medications they take.