Enalapril
Enalapril is an ACE inhibitor used in hypertension and heart failure. It was one of the original ACE inhibitors studied in major heart failure trials.
Class: → ACE Inhibitors
Mechanism of Action
• Inhibits Angiotensin-Converting Enzyme (ACE) • ↓ Angiotensin II • ↓ Aldosterone • ↑ Bradykinin
Net Effects: • ↓ Systemic vascular resistance (afterload) • Mild ↓ preload • ↓ Ventricular remodeling • ↓ Blood pressure
Mechanistically similar to other ACE inhibitors.
Unique Features
• Prodrug → converted in liver to active form (enalaprilat) • Available in IV form (enalaprilat) • Slightly shorter duration than lisinopril
Enalaprilat (IV) is useful in inpatient settings.
Indications
Hypertension
Heart Failure (HFrEF)
• Mortality benefit • Reduced hospitalization • Strong evidence base (SOLVD trial)
Core GDMT therapy.
Post-Myocardial Infarction
• Reduces remodeling • Improves survival
Dosing
Hypertension: • Start: 5 mg once or twice daily • Typical range: 10–40 mg daily (once or divided)
Heart Failure: • Start: 2.5 mg twice daily • Target: 10–20 mg twice daily
Often dosed twice daily.
Pharmacokinetics
• Prodrug → converted to enalaprilat • Hepatic activation • Renally cleared • Half-life ~11 hours
Dose adjustment required in renal impairment.
Adverse Effects
• Dry cough • Hyperkalemia • Hypotension (especially first dose) • Angioedema (rare) • Mild creatinine elevation
Monitoring
Check: • Serum creatinine • Potassium
Recheck labs 1–2 weeks after initiation or dose adjustment.
Small creatinine increase is expected.
Contraindications
• Pregnancy • History of ACE inhibitor–induced angioedema • Bilateral renal artery stenosis
Drug Interactions
Higher hyperkalemia risk with: • Spironolactone • Eplerenone • ARBs • Potassium supplements
Avoid ACE + ARB combination.
Clinical Pearls
✔ Classic ACE inhibitor with strong HF data ✔ Prodrug (converted to enalaprilat) ✔ IV formulation available (enalaprilat) ✔ Often dosed twice daily ✔ Monitor potassium and renal function
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