Enalapril
An ACE inhibitor prodrug, converted to enalaprilat in the body, used for high blood pressure and heart failure.
Drug card
- Class
- ACE inhibitor
- How it works
- Blocking the enzyme that makes angiotensin II, so vessels relax
- Used for
- High blood pressure
- Heart failure, and a weak left ventricle before symptoms
- Known for
- Dry cough
- Angioedema, more often in black patients
- Its name
- -pril means an ACE inhibitor
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does enalapril work?
Enalapril is a prodrug: hydrolysis of its ethyl ester releases enalaprilat, a more potent ACE inhibitor. Enalaprilat itself is poorly absorbed by mouth, which is why the ester form is the one taken orally. Enalaprilat levels peak 3 to 4 hours after a dose.
Like other ACE inhibitors: They block angiotensin-converting enzyme (ACE), so less angiotensin I is turned into angiotensin II. Arterioles relax, aldosterone release falls (potassium rises a little) and renin climbs because angiotensin II no longer holds it back. ACE also breaks down bradykinin; the bradykinin that builds up is thought to cause the dry cough and angioedema.
Uses
What is enalapril used for?
- High blood pressure
- Heart failure, and a weak left ventricle before symptoms
Side effects
Side effects of enalapril
- Dry coughKnown for
- Angioedema, more often in black patientsKnown forSerious
- High potassium (hyperkalemia)Serious
- Dizziness
- Dizziness on standing (orthostatic hypotension)
- Headache
- Low blood pressure and fainting, mainly in heart failure
- Worsening kidney functionSerious
- Harm to the unborn baby (fetal toxicity)Serious
- Liver injury, including hepatitis and liver failure (rare)Serious
- Change or loss of taste
- Rash
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Heart failure, high-dose diuretics, low sodium or salt and water depletion: the first doses can drop blood pressure too far.
- Potassium-sparing diuretics, potassium supplements and potassium salt substitutes raise the risk of hyperkalemia.
- It raises lithium levels and can cause lithium toxicity.
Good to know: Used alone it lowers blood pressure less in black patients, who also get angioedema more often.
Remember it
A way to remember it
CAPTOPRIL
- C
- Cough
- A
- Angioedema
- P
- Potassium up
- T
- Taste change
- O
- hypOtension
- P
- Pregnancy: avoid
- R
- Rash
- I
- Increased renin
- L
- Lower angiotensin II
The letters of captopril, itself an ACE inhibitor, spell out the class's main effects and the pregnancy rule.
A mnemonic widely used in teaching
Its name
-pril means ACE inhibitor
Prodrugs such as enalapril and ramipril are turned into active forms named -prilat (enalaprilat). Don't confuse it with -tril: sacubitril blocks neprilysin, not ACE.
- Every drug name stem
Its class
ACE inhibitors
Other ACE inhibitors with a card:
Easily mixed up with angiotensin receptor blockers and angiotensin receptor-neprilysin inhibitors.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Blood pressure
Enalapril is one of 27 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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