Enalapril !
A blood pressure and heart failure medicine that blocks the enzyme making angiotensin II. Its best-known side effect is a dry cough.
Updated 2026-11-01
The figure shows enalaprilat, the active form of enalapril, bound to the zinc active site of the C-terminal domain of human ACE (the testis form, tACE).
Mechanism of action
Enalapril is a prodrug: after absorption it is hydrolysed to enalaprilat, which binds the zinc in the active site of ACE. With less angiotensin II, arterioles dilate, aldosterone falls and less sodium and water are retained. ACE also degrades bradykinin, so bradykinin accumulates, adding vasodilation and causing cough and angioedema.
- After absorption, enalapril is hydrolysed to enalaprilat
- Enalaprilat binds the zinc in the ACE active site
- Less angiotensin II and aldosterone; bradykinin builds up
- Arterioles dilate and blood pressure falls
Pharmacokinetics
- Absorption
- Absorbed by mouth; food does not change it much
- Metabolism
- Prodrug: hydrolysed after absorption to enalaprilat, the active form
- Elimination
- Mainly by the kidneys, so it accumulates in kidney failure
- Half-life
- Effective half-life of enalaprilat about 11 hours, longer in kidney failure
Indications
- High blood pressure Arterial hypertension →
- Heart failure with reduced ejection fraction Heart failure →
- Chronic kidney disease with proteinuria, especially diabetic Chronic kidney disease →
Adverse effects
Common
- Dry, persistent cough
- Dizziness and low blood pressure, especially with the first doses
- Hyperkalaemia
- Rise in creatinine
Contraindications
- Pregnancy
- History of angioedema, with or without an ACE inhibitor
- Use with sacubitril/valsartan or within 36 hours of it
- Use with aliskiren in people with diabetes
Key interactions
- Potassium-sparing diuretics, potassium supplements or potassium salt substitutes
- Higher risk of hyperkalaemia
- NSAIDs (for example ibuprofen)
- Weaker blood pressure effect and higher risk of kidney injury
- Lithium
- Higher lithium levels and toxicity
- Sacubitril/valsartan
- Much higher risk of angioedema
What is monitored
- Blood pressure
- Potassium
- Creatinine and kidney function, especially when starting
Test yourself
Think of the answer, then tap the question to see it.
Enalapril is a prodrug. What is its active form?
Enalaprilat, formed by hydrolysis after absorption. Enalaprilat is the molecule that binds the zinc in the ACE active site.
A patient on enalapril has swelling of the tongue and lips. What is the mechanism?
Angioedema from bradykinin build-up, because ACE also breaks bradykinin down. It is a potentially life-threatening reaction and the drug class is not used again.
Which combination with enalapril most raises the risk of hyperkalaemia?
Potassium-sparing diuretics (spironolactone, amiloride), potassium supplements or potassium salt substitutes, especially with kidney disease.
Why is enalapril contraindicated in pregnancy?
Blocking the renin-angiotensin system damages fetal kidney development, with oligohydramnios and malformations, mainly in the second and third trimesters.
Related drugs
Related conditions
← Back to the class: ACE inhibitors
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 (MedlinePlus (U.S. National Library of Medicine), 2017); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025); DailyMed - ENALAPRIL MALEATE- enalapril maleate tablet (DailyMed (U.S. National Library of Medicine), 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.