What is the recommended dosage and management of Enalapril (Angiotensin-Converting Enzyme inhibitor) for patients with hypertension or heart failure?

Enalapril Dosage and Management for Hypertension and Heart Failure

For patients with hypertension or heart failure, enalapril should be initiated at a low dose of 2.5 mg daily for heart failure or 5 mg daily for hypertension, then titrated to target doses of 10-20 mg twice daily for heart failure and 10-40 mg daily for hypertension, with careful monitoring of blood pressure, renal function, and electrolytes. 1, 2

Dosing for Hypertension

• Initial dose: 5 mg once daily for patients not on diuretics 2
• For patients currently on diuretics: If possible, discontinue diuretic 2-3 days before starting enalapril; if diuretic cannot be discontinued, start with 2.5 mg under medical supervision 2
• Usual maintenance dose range: 10-40 mg per day as a single dose or divided twice daily 2
• Dose adjustments should be made according to blood pressure response; if once-daily dosing becomes less effective toward the end of the dosing interval, consider twice-daily administration 2

Dosing in Renal Impairment (Hypertension)

• Normal renal function (>80 mL/min): 5 mg/day 2
• Mild impairment (≤80 to >30 mL/min): 5 mg/day 2
• Moderate to severe impairment (≤30 mL/min): 2.5 mg/day 2
• Dialysis patients: 2.5 mg on dialysis days 2

Dosing for Heart Failure

• Initial dose: 2.5 mg twice daily 1, 2
• Target dose: 10-20 mg twice daily 1, 2
• Maximum daily dose used in clinical trials: 40 mg in divided doses 2
• Titration: Increase dose gradually over a period of days to weeks as tolerated 2

Dosing in Asymptomatic Left Ventricular Dysfunction

• Initial dose: 2.5 mg twice daily 2
• Target dose: 20 mg daily in divided doses 2

Monitoring and Management

Initial Dose Administration

• After the initial dose, observe patient under medical supervision for at least 2 hours and until blood pressure has stabilized for at least an additional hour 1, 2
• Consider reducing or withholding diuretics 24 hours before starting enalapril to minimize risk of hypotension 1
• It may be advisable to administer the first dose in the evening when supine to minimize potential negative effects on blood pressure 1

Ongoing Monitoring

• Check blood pressure, renal function, and electrolytes 1-2 weeks after each dose increment 1
• Continue monitoring at 3 months and subsequently at regular 6-month intervals 1
• Monitor for hypotension, especially in patients who are volume-depleted 2
• Monitor serum potassium levels, especially when combining with potassium-sparing diuretics 2

Special Considerations

Combination Therapy

• In hypertension: If blood pressure is not controlled with enalapril alone, a diuretic may be added 2
• In heart failure: Enalapril is typically used in combination with diuretics and sometimes digitalis 2
• Avoid concomitant use of potassium supplements, potassium salt substitutes, or potassium-sparing diuretics unless specifically indicated, as they may lead to increases in serum potassium 2

Comparative Efficacy

• Enalapril shows similar efficacy to hydrochlorothiazide and beta-blockers in hypertension 3
• In heart failure, enalapril improves cardiac performance by reducing both preload and afterload 3
• Once-daily dosing of enalapril (40 mg or tolerated dose) has been shown to be effective in heart failure 4

Common Pitfalls and Caveats

• First-dose hypotension: More pronounced with enalapril compared to some other ACE inhibitors (e.g., perindopril); maximum drop in blood pressure typically occurs approximately 4 hours after dose administration 5
• Pharmacokinetics differ between patient populations: Clearance of enalapril and elimination of its active metabolite (MK 422) is slower in heart failure patients compared to hypertensive patients 6
• Contraindications: Bilateral renal artery stenosis and history of angioedema during previous ACE inhibitor therapy 1
• Common side effects: Dizziness, headache, and asthenia 7
• Serious but rare side effects: Hypotension in hypovolemic patients and reduced renal function in certain patients with renovascular hypertension 3

Specific Guidance for Aortic Stenosis Patients

• In patients with symptomatic severe aortic stenosis (without syncope or hypotension and with preserved LV function), gradual titration of enalapril from 2.5 mg twice daily to 10 mg twice daily has been shown to be well tolerated 1