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

# ACE inhibitors

Medicines that block the enzyme making angiotensin II, so vessels relax and the heart and kidneys work under less strain.

Updated 2026-11-01

## What they are

Blockers of angiotensin-converting enzyme (ACE), a cornerstone of treatment for high blood pressure, heart failure with reduced ejection fraction and proteinuric kidney disease. In Latin America they are also part of heart failure care in chronic Chagas cardiomyopathy.

## Mechanism of action

ACE turns angiotensin I into angiotensin II and also breaks down bradykinin. Blocking it lowers angiotensin II, so arterioles dilate, aldosterone falls and the efferent arteriole of the glomerulus relaxes. Bradykinin builds up, which adds vasodilation but also explains the dry cough and angioedema.

Target: Angiotensin-converting enzyme (ACE), a zinc peptidase

## Key points

- Dry cough and angioedema come from bradykinin build-up, not from angiotensin II blockade; angioedema can appear even after years of use.
- Contraindicated in pregnancy: they damage the fetal kidney, mainly in the second and third trimesters.
- Less aldosterone means potassium is retained: watch for hyperkalaemia, especially with kidney disease or potassium-sparing diuretics.
- Creatinine may rise when treatment starts; a sharp rise suggests bilateral renal artery stenosis.
- They reduce proteinuria and slow diabetic kidney disease by relaxing the efferent arteriole.

## Drugs in this class

- [**Enalapril** A blood pressure and heart failure medicine that blocks the enzyme making angiotensin II. Its best-known side effect… Angiotensin-converting enzyme (ACE)](https://durgical.com/en/pharmacology/enalapril/)
- [**Captopril** The first ACE inhibitor, short-acting and with a sulfhydryl group. Used for high blood pressure, heart failure and… Angiotensin-converting enzyme (ACE)](https://durgical.com/en/pharmacology/captopril/)
- [**Lisinopril** A long-acting ACE inhibitor that is active as taken and cleared unchanged by the kidneys. Used for high blood… Angiotensin-converting enzyme (ACE)](https://durgical.com/en/pharmacology/lisinopril/)
- [**Ramipril** A long-acting ACE inhibitor prodrug. Used for high blood pressure, heart failure after infarction and to prevent heart… Angiotensin-converting enzyme (ACE)](https://durgical.com/en/pharmacology/ramipril/)
- [**Perindopril** A long-acting ACE inhibitor prodrug. Used for high blood pressure and, in stable coronary disease, to lower… Angiotensin-converting enzyme (ACE)](https://durgical.com/en/pharmacology/perindopril/)

## Others in the class

- Captopril
- Lisinopril
- Ramipril
- Perindopril

## Test yourself

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

## Why do ACE inhibitors cause dry cough while ARBs rarely do?

ACE also breaks down bradykinin. Blocking it lets bradykinin accumulate in the airway, which triggers cough. ARBs act on the AT1 receptor and leave ACE working, so bradykinin is not raised.

## Which electrolyte disturbance is typical of ACE inhibitors, and why?

Hyperkalaemia: less angiotensin II means less aldosterone, so the kidney excretes less potassium.

## Why can creatinine rise sharply after an ACE inhibitor in bilateral renal artery stenosis?

Glomerular filtration in those kidneys depends on angiotensin II constricting the efferent arteriole. Removing it drops filtration pressure, so filtration falls.

## Why are ACE inhibitors avoided in pregnancy?

Blocking the renin-angiotensin system in the fetus harms kidney development and can cause oligohydramnios and other malformations, mainly in the second and third trimesters.

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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: [Enalapril: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a686022.html) (MedlinePlus (U.S. National Library of Medicine), 2017); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/) (World Health Organization, 2025).

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