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# ACE Inhibitors
## Overview
Angiotensin-Converting Enzyme (ACE) inhibitors are a class of medications primarily used for treating hypertension and heart failure. They work by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, leading to vasodilation and reduced blood pressure.
## Primary Indications
* Hypertension
* Heart failure (systolic dysfunction)
* Post-myocardial infarction (MI)
* Diabetic nephropathy
* Proteinuric chronic kidney disease
## Adult Dosing
Dosing varies significantly by specific agent and indication. Titration is common.
* **Hypertension:** Initial doses are typically low and titrated up. For example, lisinopril 5-10 mg orally once daily, titrating to a maximum of 40 mg once daily. Ramipril starts at 2.5 mg orally once daily, titrating to a maximum of 10 mg once daily.
* **Heart Failure:** Often initiated at a lower dose than for hypertension and titrated more slowly. For example, enalapril 2.5 mg orally twice daily, titrating to a target dose of 10-20 mg orally twice daily (maximum 40 mg daily).
* **Post-MI:** For example, captopril 6.25 mg orally three times daily, titrating to a maximum of 50 mg three times daily.
## Pediatric Dosing
Dosing is less standardized and often based on weight. Consult specific pediatric guidelines.
* **Hypertension:** Enalapril 0.07-0.1 mg/kg/dose orally once daily, maximum 0.61 mg/kg/day or 20 mg/day.
## Dose Adjustments
* **Renal Impairment:** Dose reduction is typically required based on creatinine clearance. Consult specific agent guidelines.
* **Hepatic Impairment:** Generally no dose adjustment needed, but caution is advised.
## Contraindications
* History of angioedema related to prior ACE inhibitor treatment.
* Hereditary or idiopathic angioedema.
* Concomitant use with aliskiren in patients with diabetes.
* Pregnancy (especially second and third trimesters).
## Adverse Effects
* Dry cough (most common)
* Dizziness, fatigue
* Hypotension
* Hyperkalemia
* Acute kidney injury (especially in patients with bilateral renal artery stenosis)
* Angioedema (rare but serious, can be life-threatening)
* Rash
## Key Drug Interactions
* **Potassium-sparing diuretics, potassium supplements, aliskiren, angiotensin II receptor blockers (ARBs), heparin:** Increased risk of hyperkalemia.
* **NSAIDs:** May reduce antihypertensive effect and increase risk of renal dysfunction.
* **Lithium:** Increased serum lithium levels and risk of toxicity.
* **Diuretics:** Additive hypotensive effect, increased risk of hypovolemia and hypotension.
## Monitoring
* Blood pressure
* Serum potassium
* Renal function (serum creatinine, BUN)
* Signs and symptoms of angioedema
## Clinical Pearls
* Cough is a class effect and usually resolves upon discontinuation.
* Initiate at low doses and titrate slowly, especially in elderly patients, those with heart failure, or renal impairment.
* Monitor for hyperkalemia, particularly in patients with renal insufficiency or those taking potassium supplements.
* Discontinue immediately if angioedema occurs.
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*This information is intended for healthcare professionals. Please verify current prescribing information and local protocols before use.*
