What is the recommended dosing strategy when converting a patient from lisinopril (Angiotensin-Converting Enzyme (ACE) inhibitor) to ramipril (ACE inhibitor)?

Converting Lisinopril to Ramipril

When converting from lisinopril to ramipril, stop lisinopril and start ramipril at its recommended initial dose (2.5 mg once daily for most patients), then titrate upward to target doses based on the indication, rather than attempting direct dose equivalency conversion. 1, 2

Why Direct Conversion Ratios Are Not Recommended

• ACE inhibitors within the same class do not have established equipotent dose conversion ratios that have been validated in clinical trials for mortality and morbidity outcomes 1
• Both lisinopril and ramipril are evidence-based ACE inhibitors proven to reduce cardiovascular events in clinical trials, but their dosing was established independently in separate trial populations 1
• The ACC/AHA guidelines emphasize using doses that have been proven effective in clinical trials rather than theoretical equivalencies 1

Recommended Conversion Strategy

Step 1: Discontinue Lisinopril

• Stop the current lisinopril dose on the day you plan to initiate ramipril 2
• No washout period is required between ACE inhibitors 1

Step 2: Initiate Ramipril at Standard Starting Dose

For Hypertension:

• Start ramipril at 2.5 mg once daily (the FDA-recommended initial dose) 2
• Titrate upward based on blood pressure response to usual maintenance range of 2.5-20 mg daily 2

For Heart Failure:

• Start ramipril at 2.5 mg twice daily (5 mg/day total) if the patient has shown signs of heart failure 2
• If hypotension occurs, reduce to 1.25 mg twice daily 2
• Target dose is 5 mg twice daily (10 mg/day total), with increases approximately 3 weeks apart 2

For Post-Myocardial Infarction with Heart Failure:

• Start ramipril at 2.5 mg twice daily 2
• Titrate toward target of 5 mg twice daily over several weeks 2

Step 3: Monitor Closely During Transition

• Check blood pressure within 1-2 weeks after initiating ramipril to assess response 1
• Monitor renal function (creatinine) and serum potassium within 1-2 weeks of starting ramipril 1, 2
• An increase in creatinine up to 50% above baseline is acceptable 1
• Potassium levels should remain below 5.0-6.0 mmol/L 1

Step 4: Titrate to Target Dose

• Increase ramipril dose at intervals of not less than 2 weeks if lower doses are well tolerated 1
• Aim for evidence-based target doses that have been shown to reduce cardiovascular events 1:
  • Hypertension: 2.5-20 mg once daily 2
  • Heart failure: 5 mg twice daily (10 mg/day) 2
• If target doses cannot be achieved due to side effects, use the highest tolerated dose 1

Important Clinical Considerations

Renal Impairment Adjustments

• For patients with creatinine clearance <40 mL/min, start ramipril at 1.25 mg once daily 2
• Maximum dose in severe renal impairment is 5 mg daily for hypertension or 2.5 mg twice daily for heart failure 2

Volume Depletion Precautions

• Reduce or hold diuretics before initiating ramipril if possible, as fluid depletion potentiates hypotensive effects 1, 2
• Observe patient for at least 2 hours after first dose and until blood pressure stabilizes 2
• The appearance of initial hypotension does not preclude careful subsequent titration 2

Common Pitfalls to Avoid

• Do not assume 1:1 dose equivalency between lisinopril and ramipril—this is not evidence-based 1
• Do not delay beta-blocker initiation in heart failure patients while attempting to reach target ACE inhibitor doses 1
• Avoid NSAIDs during ACE inhibitor therapy, as they block favorable effects and enhance adverse effects 1
• Do not abruptly withdraw ACE inhibitor therapy without cause, as this can lead to clinical deterioration 1

Monitoring for Adverse Effects

• Cough is common but rarely requires discontinuation; if intolerable and proven due to ACE inhibition, consider switching to an ARB 1
• Asymptomatic hypotension does not require dose adjustment 1
• Symptomatic hypotension may warrant reducing diuretic dose before lowering ramipril 1
• Angioedema requires permanent discontinuation of all ACE inhibitors 3