[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › Angiotensin II receptor blockers (ARBs)

[Pharmacology](https://durgical.com/en/pharmacology/) · Class

# Angiotensin II receptor blockers (ARBs)

Medicines that stop angiotensin II from acting on its AT1 receptor. They lower blood pressure much like ACE inhibitors, but with less cough.

Updated 2026-11-01

## What they are

Blockers of the AT1 receptor for angiotensin II, used for high blood pressure, heart failure and diabetic kidney disease. They are the usual choice when an ACE inhibitor causes cough.

## Mechanism of action

Angiotensin II acts on AT1 receptors to constrict arterioles, release aldosterone, retain sodium and remodel the heart and vessels. ARBs block that receptor directly, so the effect does not depend on how angiotensin II was made. ACE is left alone, so bradykinin does not accumulate.

Target: Angiotensin II type 1 (AT1) receptor

## Key points

- Same benefits and the same main risks as ACE inhibitors (hyperkalaemia, kidney function drop, fetal toxicity), but cough is rare.
- Angioedema is much less frequent than with ACE inhibitors, though it can still occur.
- Combining an ARB with an ACE inhibitor raises the risk of hyperkalaemia and kidney injury without clear benefit.
- Losartan is turned by the liver (CYP2C9 and CYP3A4) into an active metabolite that does much of the work.

## Drugs in this class

- [**Losartan** A blood pressure medicine that blocks the receptor for angiotensin II. It protects the kidneys in diabetes and rarely… Angiotensin II type 1 (AT1) receptor](https://durgical.com/en/pharmacology/losartan/)
- [**Valsartan** An angiotensin II receptor blocker (ARB). Used for high blood pressure, heart failure and after a heart attack… Angiotensin II type 1 (AT1) receptor](https://durgical.com/en/pharmacology/valsartan/)
- [**Candesartan** An ARB given as the prodrug candesartan cilexetil. Used for high blood pressure and for heart failure. Angiotensin II type 1 (AT1) receptor](https://durgical.com/en/pharmacology/candesartan/)
- [**Telmisartan** A long-acting ARB cleared in bile. Used for high blood pressure and to lower cardiovascular risk in people who cannot… Angiotensin II type 1 (AT1) receptor](https://durgical.com/en/pharmacology/telmisartan/)
- [**Irbesartan** An ARB used for high blood pressure and to slow diabetic kidney disease in hypertensive people with type 2 diabetes… Angiotensin II type 1 (AT1) receptor](https://durgical.com/en/pharmacology/irbesartan/)

## Others in the class

- Valsartan
- Candesartan
- Irbesartan
- Telmisartan
- Olmesartan

## Test yourself

Think of the answer, then tap the question to see it.

## What is the main practical reason to switch from an ACE inhibitor to an ARB?

Dry cough from bradykinin build-up. ARBs block the AT1 receptor without inhibiting ACE, so bradykinin is not raised and cough is rare.

## Which risks do ARBs share with ACE inhibitors?

Hyperkalaemia, a fall in kidney function (especially with bilateral renal artery stenosis or dehydration), hypotension and fetal toxicity in pregnancy.

## Why is the dual combination of an ACE inhibitor and an ARB generally avoided?

It blocks the same system twice: more hyperkalaemia, hypotension and kidney injury, with no clear gain in outcomes.

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Losartan: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a695008.html) (MedlinePlus (U.S. National Library of Medicine), 2018); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025).

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/classes/angiotensin-ii-receptor-blockers/