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

Enalapril Dosage and Treatment Plan for Hypertension and Heart Failure

For patients with hypertension or heart failure, enalapril should be initiated at a low dose (2.5-5 mg daily) and titrated gradually to target doses of 10-20 mg twice daily for heart failure or 10-40 mg daily for hypertension. 1, 2

Dosing for Hypertension

Initial Dosing

• For patients not on diuretics: Start with 5 mg once daily 1
• For patients on diuretics:
  • If possible, discontinue diuretic for 2-3 days before starting enalapril
  • If diuretic cannot be discontinued, start with 2.5 mg under medical supervision for at least 2 hours 1

Maintenance and Titration

• Adjust dose according to blood pressure response
• Usual dosage range: 10-40 mg per day (single dose or divided twice daily) 1
• If once-daily dosing shows diminished effect toward end of dosing interval, consider twice-daily administration 1
• If blood pressure not controlled with enalapril alone, add a diuretic

Dosage Adjustment in Renal Impairment

• Normal renal function (>80 mL/min): 5 mg daily
• Mild impairment (≤80 to >30 mL/min): 5 mg daily
• Moderate to severe impairment (≤30 mL/min): 2.5 mg daily 1

Dosing for Heart Failure

Initial Dosing

• Start with 2.5 mg twice daily 1, 2
• Patient should be observed under medical supervision for at least 2 hours after initial dose 1

Maintenance and Titration

• Titrate dose upward over a period of a few days or weeks as tolerated
• Recommended dosing range: 2.5-20 mg twice daily
• Target dose: 10-20 mg twice daily 2, 3
• Maximum daily dose used in clinical trials: 40 mg in divided doses 1
• Consider reducing concurrent diuretic dose to minimize hypotension risk

For Asymptomatic Left Ventricular Dysfunction

• Start with 2.5 mg twice daily
• Titrate as tolerated to target dose of 20 mg daily in divided doses 1

Monitoring and Dose Adjustment

During Initiation

• Monitor blood pressure, renal function, and electrolytes
• Check after each dose increment and at 1-2 weeks 2
• Watch for symptomatic hypotension (dizziness, light-headedness)
• Monitor for hyperkalemia (K+ >5.0 mmol/L)
• Acceptable increase in creatinine: up to 50% or maximum of 3 mg/dL 2

Long-term Monitoring

• Once on stable dose: monitor every 3-6 months
• More frequent monitoring for patients with renal dysfunction or electrolyte disturbances 2

Important Precautions

Contraindications

• History of angioedema
• Bilateral renal artery stenosis
• Pregnancy 2

Drug Interactions

• Avoid potassium-sparing diuretics during initiation 3
• Avoid NSAIDs and COX-2 inhibitors 2
• Concomitant use with potassium supplements may increase serum potassium 1

Special Considerations

• Hypotension risk is higher in volume-depleted patients
• Slower titration and more frequent monitoring needed in elderly and those with renal impairment 4
• Pharmacokinetics differ between heart failure and hypertension patients - clearance is slower in heart failure patients, potentially requiring lower doses or less frequent administration 4
• Once-daily dosing has been shown effective in heart failure 5, though twice-daily dosing is often recommended for optimal 24-hour coverage 1

Treatment Algorithm

1. Assess baseline renal function and electrolytes
2. Determine appropriate starting dose based on indication and renal function
3. Monitor closely after initial dose (2 hours minimum)
4. Double dose at 2-week intervals if tolerated
5. Aim for target doses proven to reduce mortality (10-20 mg twice daily for heart failure; 10-40 mg daily for hypertension)
6. Adjust concurrent medications as needed (especially diuretics)
7. Establish regular monitoring schedule based on clinical stability