Enalapril: ACE Inhibitor for Hypertension and Heart Failure
Enalapril is a prodrug ACE inhibitor converted to the active form enalaprilat in the liver. It lowers blood pressure by blocking the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone secretion.
Approved for hypertension, symptomatic heart failure, and asymptomatic left ventricular dysfunction. Also used in diabetic nephropathy to reduce proteinuria and slow renal progression.
Mechanism of Action
Enalaprilat inhibits angiotensin-converting enzyme (ACE), reducing angiotensin II formation. This leads to vasodilation, decreased aldosterone secretion (reducing sodium/water retention), and decreased preload and afterload in heart failure.
Indications & Use
Hypertension (first-line, especially with diabetes or CKD), heart failure (all stages, with diuretics), asymptomatic LV dysfunction, and diabetic nephropathy.
Dosage
Hypertension: start 5 mg once daily, target 10–20 mg/day. Heart failure: start 2.5 mg twice daily, target 10 mg twice daily. Reduce initial dose by 50% in renal impairment (GFR <30 mL/min) or with diuretics.
Side Effects
Common: dry cough (10–15%, bradykinin-mediated — class effect). Serious: angioedema (rare but potentially fatal), hyperkalaemia, acute kidney injury (bilateral renal artery stenosis). First-dose hypotension in volume-depleted patients.
Drug Interactions
NSAIDs: reduce antihypertensive effect and increase renal risk. Potassium-sparing diuretics/supplements: hyperkalaemia. Lithium: increased toxicity. ARBs + ACE inhibitors: dual RAAS blockade — avoid combination.
Contraindications
History of ACE inhibitor-induced angioedema, pregnancy (2nd/3rd trimester — fetotoxic), bilateral renal artery stenosis, hypersensitivity. Avoid with aliskiren in diabetes.
Frequently Asked Questions
Why does enalapril cause cough?
The dry cough is caused by accumulation of bradykinin, which ACE normally degrades. It occurs in 10–15% of patients. Switching to an ARB (e.g., losartan) resolves the cough.
Can I take enalapril with NSAIDs?
Avoid if possible. NSAIDs blunt the antihypertensive effect and can cause acute kidney injury when combined with ACE inhibitors, especially in elderly or volume-depleted patients.
Is enalapril safe in pregnancy?
Enalapril is contraindicated in the 2nd and 3rd trimesters (fetotoxic — can cause renal agenesis, oligohydramnios, neonatal hypotension). Discontinue immediately if pregnancy is detected.
References
- ESC Guidelines on Arterial Hypertension 2023
- CONSENSUS Trial (heart failure)
- EMA product information enalapril
Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice.