Ace%25252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520inhibitors

# ACE Inhibitors ## Overview Angiotensin-converting enzyme (ACE) inhibitors are a class of medications primarily used to treat 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) with reduced ejection fraction * Diabetic nephropathy (proteinuria) ## Adult Dosing Dosing is highly individualized and depends on the specific agent, indication, and patient response. Common starting doses and maximums for frequently used agents include: * **Lisinopril:** Start at 5-10 mg once daily. Titrate up to a maximum of 40 mg once daily. * **Enalapril:** Start at 5 mg once or twice daily. Titrate up to a maximum of 40 mg once daily (divided doses may be needed). * **Ramipril:** Start at 2.5 mg once daily. Titrate up to a maximum of 10 mg once daily. * **Benazepril:** Start at 10 mg once daily. Titrate up to a maximum of 40 mg once daily. * **Captopril:** Start at 25 mg two to three times daily. Titrate up to a maximum of 450 mg once daily (divided doses). *Note: Shorter half-life, often dosed more frequently.* ## Pediatric Dosing Established pediatric dosing varies by agent and indication. Consult specific pediatric guidelines or drug monographs. * **Enalapril:** For hypertension, recommended starting dose is 0.07 mg/kg/day (maximum 5 mg/day) administered once daily or divided into two doses. Doses can be increased every 48 hours to a maximum of 0.57 mg/kg/day (maximum 40 mg/day). * **Lisinopril:** For hypertension, recommended starting dose is 0.07 mg/kg/day (maximum 5 mg/day) administered once daily. Doses can be increased every 48 hours to a maximum of 0.61 mg/kg/day (maximum 40 mg/day). ## Dose Adjustments * **Renal Impairment:** Reduce initial dose and titrate cautiously. Specific adjustments depend on the degree of renal impairment and the individual ACE inhibitor's renal clearance. Generally, initial doses are halved in moderate renal insufficiency (CrCl < 30 mL/min) and further reduced in severe impairment. * **Hepatic Impairment:** Use with caution. Enalapril bioavailability may be increased in hepatic cirrhosis. ## Contraindications * History of angioedema related to previous ACE inhibitor treatment. * Hereditary or idiopathic angioedema. * Concomitant use with aliskiren in patients with diabetes mellitus. * Pregnancy (especially second and third trimesters). ## Adverse Effects * **Common:** Dry cough (most frequent), dizziness, headache, fatigue, hyperkalemia, hypotension. * **Serious:** Angioedema (can be life-threatening, especially involving the airway), acute kidney injury (AKI), hyperkalemia, elevated liver enzymes, neutropenia, rash. ## 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 volume-depleted patients. * **Aliskiren, ARBs:** Increased risk of hyperkalemia and renal dysfunction. Avoid concomitant use, especially in diabetics. * **Lithium:** ACE inhibitors can reduce lithium clearance, increasing lithium toxicity risk. Monitor lithium levels closely. * **Diuretics:** Additive hypotensive effect. Risk of profound hypotension, especially with the first dose of ACE inhibitor. ## Monitoring * **Blood Pressure:** Regularly assess to ensure efficacy and guide titration. * **Renal Function (serum creatinine, BUN):** Baseline and periodically, especially in patients with pre-existing renal disease or risk factors. * **Potassium:** Baseline and periodically, especially in patients with renal impairment, diabetes, or those on potassium-sparing diuretics. * **Angioedema:** Educate patients to report any swelling immediately. ## Clinical Pearls * The characteristic dry cough is thought to be due to increased bradykinin levels and typically resolves within 1-4 weeks of discontinuation. * Angioedema is a medical emergency and requires immediate discontinuation of the ACE inhibitor. * First-dose hypotension can occur, especially in patients who are volume-depleted or on diuretics. Consider a lower starting dose and administer the first dose under medical supervision. * ACE inhibitors are renoprotective in patients with diabetes and proteinuria. * Discontinuation of ACE inhibitors is recommended prior to conception due to teratogenicity. *** *This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and relevant guidelines for specific patient management.*