Ace%252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520inhibitors

# ACE Inhibitors ## Overview Angiotensin-converting enzyme (ACE) inhibitors are a class of drugs that primarily treat hypertension and heart failure by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. ## Primary Indications * Hypertension * Heart failure (systolic dysfunction) * Myocardial infarction (post-MI management) * Diabetic nephropathy * Proteinuric kidney disease ## Adult Dosing Dosing varies significantly by agent. Typical starting doses are low and titrated upwards. * **Hypertension:** * Benazepril: Start 10 mg once daily, titrate up to 40 mg/day. * Captopril: Start 25 mg twice daily, titrate up to 50 mg three times daily. * Enalapril: Start 5 mg once daily, titrate up to 20 mg twice daily. * Lisinopril: Start 10 mg once daily, titrate up to 40 mg/day. * Ramipril: Start 2.5 mg once daily, titrate up to 10 mg/day. * **Heart Failure:** * Captopril: Start 6.25 mg three times daily, titrate up to 50 mg three times daily. * Enalapril: Start 2.5 mg twice daily, titrate up to 10 mg twice daily. * Lisinopril: Start 5 mg once daily, titrate up to 40 mg/day. * Ramipril: Start 1.25 mg once daily, titrate up to 10 mg/day. Maximum doses are agent-specific and should not be exceeded. ## Pediatric Dosing Dosing is based on weight and indication and often requires specialist consultation. * **Hypertension:** * Enalapril: 0.07 mg/kg/day to 0.5 mg/kg/day divided every 12-24 hours. Maximum dose is 40 mg/day. * Lisinopril: 0.07 mg/kg/day once daily. Maximum dose is 40 mg/day. * Captopril: 0.3 mg/kg/dose every 8 hours. Maximum dose is 6 mg/kg/day. ## Dose Adjustments * **Renal Impairment:** Dose reduction is often required, especially in significant renal impairment. Specific guidelines vary by agent and degree of impairment (e.g., CrCl < 30 mL/min). * **Hepatic Impairment:** Use with caution; some agents may require dose reduction. Captopril and enalapril are generally preferred in mild hepatic impairment. ## Contraindications * History of angioedema related to ACE inhibitor therapy. * Concomitant use of aliskiren in patients with diabetes. * Pregnancy (contraindicated due to risk of fetal harm, especially in the second and third trimesters). * Known hypersensitivity to the specific ACE inhibitor. ## Adverse Effects * **Common:** Cough (dry, persistent), hyperkalemia, dizziness, hypotension, fatigue, headache. * **Serious:** Angioedema (facial, lip, tongue, throat, intestinal), acute kidney injury, hyperkalemia, neutropenia/agranulocytosis (rare). ## Key Drug Interactions * **Potassium-sparing diuretics, potassium supplements, spironolactone, eplerenone, aliskiren, ARBs:** Increased risk of hyperkalemia. * **NSAIDs, COX-2 inhibitors:** May reduce antihypertensive effect and increase risk of renal dysfunction. * **Lithium:** Increased lithium levels and risk of toxicity. * **Diuretics (especially loop and thiazide):** Increased risk of hypotension, particularly with first-dose therapy. * **mTOR inhibitors (e.g., sirolimus, everolimus):** Increased risk of angioedema. ## Monitoring * **Baseline:** Serum potassium, serum creatinine, blood pressure. * **During Therapy:** Serum potassium, serum creatinine (especially after dose initiation/titration or in patients with risk factors for renal dysfunction), blood pressure. * **Consider:** Complete blood count (CBC) with differential if neutropenia is suspected. ## Clinical Pearls * Cough is a common side effect, often dose-limiting. If cough is bothersome, consider switching to an ARB. * First-dose hypotension can occur, especially in volume-depleted patients or those on diuretics. Monitor closely after initiation. * Angioedema is a rare but life-threatening reaction. Discontinue immediately if suspected and do not rechallenge. * ACE inhibitors are generally renoprotective in patients with diabetes and proteinuria. * Combination therapy with ARBs is generally avoided due to increased risk of adverse events without significant added benefit. *** *Disclaimer: This information is intended for healthcare professionals and should not replace current prescribing information or professional judgment. Always consult the most up-to-date drug monographs and institutional protocols.*