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# ACE Inhibitors ## Overview ACE inhibitors (e.g., lisinopril, enalapril, ramipril) are a class of medications that block the action of angiotensin-converting enzyme, leading to vasodilation and reduced aldosterone secretion. This results in decreased blood pressure and reduced cardiac workload. ## Primary Indications * Hypertension * Heart Failure (reduced ejection fraction) * Post-myocardial infarction (to improve survival) * Diabetic nephropathy (to slow progression) * Chronic kidney disease (in certain patients) ## Adult Dosing Dosing is highly individualized and depends on the specific agent, indication, and patient response. Titration is typically guided by blood pressure and clinical response. * **Hypertension:** Usual starting doses vary by agent (e.g., lisinopril 10 mg daily, enalapril 5 mg daily, ramipril 2.5 mg daily). Maximum doses also vary (e.g., lisinopril 40 mg daily, enalapril 40 mg daily, ramipril 10 mg daily). * **Heart Failure:** Usual starting doses vary (e.g., lisinopril 5 mg daily, enalapril 2.5 mg daily, ramipril 2.5 mg daily). Doses are then titrated upwards based on tolerance and clinical benefit, often to higher target doses than for hypertension (e.g., lisinopril up to 40 mg daily, enalapril up to 40 mg daily, ramipril up to 10 mg daily). * **Post-MI:** Typically initiated within 24 hours in stable patients. Dosing varies by agent and indication. ## Pediatric Dosing ACE inhibitors are not typically first-line agents in pediatric hypertension unless specific comorbidities exist. Dosing is weight-based and requires careful titration. * **Hypertension:** Dosing varies by agent and age group. For example, enalapril may be dosed from 0.05 mg/kg/day to 0.4 mg/kg/day divided every 12-24 hours. Specific protocols are often followed. ## Dose Adjustments * **Renal Impairment:** Dose reduction is often necessary, especially in severe renal impairment. Monitor serum creatinine and potassium closely. * **Hepatic Impairment:** Use with caution; dose adjustments may be needed depending on the specific agent (e.g., enalapril dosing may be reduced). ## Contraindications * History of angioedema related to previous ACE inhibitor treatment * Concomitant use with aliskiren in patients with diabetes mellitus or renal impairment * Pregnancy (Category D in 2nd and 3rd trimesters) * Known hypersensitivity to the drug class ## Adverse Effects * **Most Common:** Dry cough (non-productive), dizziness, hyperkalemia, hypotension, fatigue, headache. * **Less Common/Serious:** Angioedema (including life-threatening airway obstruction), acute kidney injury, rash, taste disturbances, neutropenia/agranulocytosis (rare). ## Key Drug Interactions * **Potassium-sparing diuretics, potassium supplements, salt substitutes:** Increased risk of hyperkalemia. * **NSAIDs:** May reduce antihypertensive effect and increase risk of renal dysfunction, especially in volume-depleted patients. * **Diuretics (thiazide and loop):** Increased risk of symptomatic hypotension. * **Lithium:** Increased serum lithium levels and risk of lithium toxicity. * **ARBs and Aliskiren:** Increased risk of hyperkalemia, hypotension, and renal dysfunction. Avoid concomitant use, especially in diabetics. * **mTOR inhibitors (e.g., sirolimus, everolimus):** Increased risk of angioedema. ## Monitoring * **Baseline:** Serum creatinine, electrolytes (especially potassium), blood pressure. * **During Therapy:** * Blood pressure (regularly) * Serum creatinine and potassium (within 1-2 weeks of initiation/dose change, then periodically) * Signs/symptoms of angioedema or hypersensitivity reactions. ## Clinical Pearls * The dry cough is thought to be due to bradykinin accumulation and is generally reversible upon discontinuation. * Angioedema is a medical emergency; patients should be advised to discontinue immediately and seek urgent care if swelling of the face, lips, tongue, or throat occurs. * Initiate at low doses and titrate slowly, especially in patients who are elderly, volume-depleted, or have renal impairment. * In heart failure, ACE inhibitors are a cornerstone of therapy and should be initiated as tolerated to improve morbidity and mortality. * Monitor renal function closely, especially in patients with pre-existing renal disease or those taking concomitant nephrotoxic agents. *** **Disclaimer:** This information is intended for clinical decision support and does not replace comprehensive prescribing information. Always consult the most current product monographs and institutional protocols for complete and up-to-date guidance.