Can a patient on enalapril (angiotensin-converting enzyme inhibitor) 10mg twice daily (bd) be switched to perindopril (angiotensin-converting enzyme inhibitor) and what would be the equivalent dose?

Switching from Enalapril to Perindopril

Yes, you can switch from enalapril 10mg twice daily to perindopril 8mg once daily, which represents an equivalent therapeutic dose based on established dosing guidelines for heart failure. 1

Dose Conversion Rationale

The patient is currently on enalapril 10mg twice daily (total 20mg/day), which is the target maintenance dose for heart failure with reduced ejection fraction. 1 The equivalent perindopril dose is 8mg once daily, as both represent the maximum recommended doses for heart failure in major cardiology guidelines. 1

Evidence Supporting This Conversion:

• ACC/AHA guidelines list enalapril maximum dose as 10-20mg twice daily and perindopril maximum dose as 8-16mg once daily for heart failure patients. 1
• Both medications are long-acting ACE inhibitors with proven mortality and morbidity benefits in heart failure. 1
• Perindopril has a longer duration of action than enalapril, making it better suited for once-daily dosing. 2

Practical Switching Protocol

Start perindopril at 4mg once daily for the first 2 weeks, then increase to 8mg once daily if tolerated. 3

Step-by-Step Approach:

• Day 1: Stop enalapril and begin perindopril 4mg once daily in the morning. 3
• Week 2: If blood pressure remains stable and no adverse effects occur, increase to perindopril 8mg once daily. 3
• Monitoring: Check blood pressure, renal function (creatinine), and potassium levels within 1-2 weeks after the switch. 4

Critical Safety Considerations

Monitor Closely For:

• Hypotension: Particularly in the first 2 weeks after switching, especially if the patient is on concurrent diuretics. 3
• Hyperkalemia: Risk increases with ACE inhibitors, particularly in patients with renal impairment or those on potassium-sparing diuretics. 1
• Worsening renal function: Check creatinine within 1-2 weeks of the switch. 4, 3

Special Precautions:

• If the patient is on diuretics, consider reducing the diuretic dose temporarily or starting perindopril at 2mg daily to minimize hypotension risk. 3
• In elderly patients (>70 years), start at 2mg daily for week 1, then 4mg daily for week 2, before advancing to 8mg if needed. 3
• If creatinine clearance is 30-60 mL/min, do not exceed 8mg daily; if <30 mL/min, perindopril safety is not established. 3

Common Pitfalls to Avoid

• Do not combine two ACE inhibitors: Never overlap enalapril and perindopril—this significantly increases risk of hypotension, hyperkalemia, and renal dysfunction without added benefit. 1, 4
• Do not start at full dose: The FDA label recommends starting at 4mg and titrating up, not initiating at 8mg directly. 3
• Do not ignore cough: If the patient had ACE inhibitor-induced cough with enalapril, they will likely experience it with perindopril as well, as this is a class effect. 1
• History of angioedema is an absolute contraindication: If the patient ever had angioedema with any ACE inhibitor, do not prescribe perindopril—consider an ARB instead (with extreme caution). 1

Expected Outcomes

• Blood pressure control should be maintained or improved, as perindopril provides more consistent 24-hour coverage than enalapril. 2
• The once-daily dosing typically improves medication adherence compared to twice-daily regimens. 5
• Cardiovascular outcomes (mortality, hospitalization) should remain protected as both drugs have equivalent evidence-based benefits in heart failure. 1