Please check your internet connection and try again.
# ACE Inhibitors
## Overview
ACE inhibitors (ACEIs) are a class of medications that block the action of angiotensin-converting enzyme, leading to vasodilation and reduced sodium and water retention. This results in decreased blood pressure and reduced cardiac workload.
## Primary Indications
* Hypertension
* Heart failure (systolic dysfunction)
* Myocardial infarction (post-MI management to improve survival)
* Diabetic nephropathy (in patients with proteinuria)
* Chronic kidney disease (in patients with proteinuria)
## Adult Dosing
Dosing varies significantly by specific ACEI and indication. Doses are typically started low and titrated upwards based on patient response and tolerability.
* **Hypertension:** Initial doses for common agents include:
* Lisinopril: 10 mg once daily. Maximum: 40 mg once daily.
* Enalapril: 5 mg once or twice daily. Maximum: 40 mg once or twice daily.
* Ramipril: 2.5 mg once daily. Maximum: 10 mg once daily.
* **Heart Failure:** Initial doses are lower than for hypertension.
* Lisinopril: 5 mg once daily. Maximum: 40 mg once daily.
* Enalapril: 2.5 mg once or twice daily. Maximum: 20 mg twice daily.
* Ramipril: 1.25 mg once daily. Maximum: 10 mg once daily.
* **Post-MI:** Start within 24 hours of MI.
* Captopril: 6.25 mg three times daily. Titrate as tolerated.
* Lisinopril: 5 mg once daily. Titrate as tolerated.
* **Diabetic Nephropathy/CKD:** Dosing is often based on BP response and tolerability, aiming for target BP.
## Pediatric Dosing
ACEIs are used in pediatric patients for hypertension and sometimes heart failure. Dosing varies by age and weight.
* **Hypertension:**
* Enalapril: 0.07 mg/kg/day to 0.5 mg/kg/day divided BID. Maximum: 40 mg/day.
* Lisinopril: 0.07 mg/kg/day to 0.6 mg/kg/day once daily. Maximum: 40 mg/day.
* *Specific pediatric dosing for other ACEIs may be available and should be consulted.*
## Dose Adjustments
* **Renal Impairment:** Dose reduction is often necessary, especially with significant renal dysfunction (eGFR < 30 mL/min/1.73m²). Monitor potassium closely.
* **Hepatic Impairment:** Generally, no dose adjustment is needed, but caution is advised with severe impairment.
* **Volume Depletion:** Initiate at lower doses or temporarily discontinue if significant volume depletion exists.
## Contraindications
* History of angioedema related to previous ACEI treatment.
* Hereditary or idiopathic angioedema.
* Concomitant use with aliskiren in patients with diabetes mellitus or moderate to severe renal impairment.
* Pregnancy (teratogenic).
## Adverse Effects
* **Common:** Cough (dry, persistent), dizziness, headache, fatigue.
* **Serious:**
* Angioedema (face, lips, tongue, throat, extremities) - a medical emergency.
* Hyperkalemia.
* Hypotension (especially with initial doses or in volume-depleted patients).
* Acute kidney injury (particularly in patients with bilateral renal artery stenosis).
* Neutropenia/agranulocytosis (rare).
* Hepatotoxicity (rare).
## Key Drug Interactions
* **Potassium-sparing diuretics (e.g., spironolactone, amiloride), potassium supplements, salt substitutes:** Increased risk of hyperkalemia.
* **NSAIDs (including aspirin):** May reduce antihypertensive effect and increase risk of renal impairment, especially in elderly or volume-depleted patients.
* **Diuretics:** Increased risk of hypotension. May necessitate lower ACEI starting dose.
* **Lithium:** ACEIs can decrease lithium clearance, increasing risk of lithium toxicity.
* **mTOR inhibitors (e.g., everolimus, sirolimus):** Increased risk of angioedema.
* **ARBs and Aliskiren:** Increased risk of hyperkalemia, hypotension, and renal dysfunction. Avoid combination, especially in diabetic patients.
## Monitoring
* **Blood Pressure:** Regularly, especially after initiation or dose changes.
* **Renal Function (Serum Creatinine, eGFR):** Baseline and periodically.
* **Serum Potassium:** Baseline and periodically, especially in patients with renal impairment, diabetes, or those taking potassium supplements/sparing diuretics.
* **Signs/Symptoms of Angioedema:** Educate patients to report immediately.
* **Complete Blood Count (CBC):** If fever or other signs of infection develop.
## Clinical Pearls
* The characteristic dry cough is dose-dependent and often resolves upon discontinuation.
* Start low and titrate slowly, especially in elderly, volume-depleted, or renally impaired patients.
* Monitor for hyperkalemia and renal function decline, particularly with concurrent use of diuretics, potassium supplements, or in patients with pre-existing renal disease.
* Discontinue immediately if angioedema is suspected and manage airway.
* ACEIs are generally preferred over ARBs in heart failure unless angioedema or intolerance occurs.
* Contraindicated in pregnancy due to potential for fetal harm.
***
*This information is intended for healthcare professionals. Always consult the most current prescribing information and relevant clinical guidelines for the specific agent and patient situation.*
