What is the equivalent dose of losartan (angiotensin II receptor antagonist) when switching from lisinopril (angiotensin-converting enzyme inhibitor) 20 mg?

Equivalent Dose of Losartan When Switching from Lisinopril 20 mg

When switching from lisinopril 20 mg to losartan, the equivalent dose is 50 mg once daily, with potential titration to 100-150 mg daily as needed for optimal blood pressure control and cardiovascular outcomes. 1, 2

Dosing Equivalence and Rationale

The 2017 ACC/AHA/HFSA Heart Failure Guidelines provide specific dosing information for both medications:

• Lisinopril: Initial dose 2.5-5 mg once daily, maximum dose 20-40 mg once daily
• Losartan: Initial dose 25-50 mg once daily, maximum dose 50-150 mg once daily 1

Dosing Considerations:

• The mean dose of losartan achieved in clinical trials was 129 mg daily 1
• While lisinopril 20 mg is in the middle-to-high range of its dosing spectrum, an equivalent starting dose of losartan would be 50 mg daily
• For patients with heart failure, losartan should be titrated to target doses or maximally tolerated doses, with a goal of at least 50% of the target dose 2

Titration Strategy

When switching from lisinopril to losartan:

1. Initial conversion: Start with losartan 50 mg once daily when discontinuing lisinopril 20 mg
2. Monitoring: Check blood pressure and renal function within 1-2 weeks after switching
3. Dose adjustment:
   • If blood pressure control is inadequate, increase to losartan 100 mg daily
   • For heart failure patients, consider titrating up to 150 mg daily as this higher dose has shown greater benefit in reducing mortality and heart failure hospitalizations 2, 3

Clinical Considerations

Efficacy Comparison:

• Studies have shown that lisinopril may produce slightly greater blood pressure reduction than equivalent doses of losartan (mean difference 4.7/3.3 mmHg systolic/diastolic) 4
• In approximately one-third of hypertensive patients, the blood pressure response to ACE inhibition fails to predict the response to angiotensin receptor blockade 4

Tolerability Advantages:

• Losartan is generally better tolerated than lisinopril, with fewer adverse events (5.1% vs 10.7%) 5
• Dry cough is significantly less common with losartan (1.0%) compared to ACE inhibitors like lisinopril (7.2%) 5
• Losartan has the unique property of decreasing serum uric acid levels, which may be beneficial in patients with hyperuricemia 6

Important Monitoring Considerations

When switching between these medications:

• Monitor for hypotension, especially in volume-depleted patients
• Check renal function and potassium levels within 1-2 weeks after switching
• Ensure adequate blood pressure control is maintained after the switch
• For heart failure patients, assess for signs of worsening heart failure during the transition

Common Pitfalls to Avoid

1. Underdosing: Starting with too low a dose of losartan (25 mg) when switching from a moderate-high dose of lisinopril may lead to inadequate blood pressure control
2. Inadequate monitoring: Failing to check blood pressure, renal function, and potassium levels after switching
3. Not considering comorbidities: Patients with heart failure may benefit from higher target doses of losartan (up to 150 mg daily) compared to those with hypertension alone
4. Abrupt switching: Consider a brief overlap period in high-risk patients to ensure continuous RAAS blockade

By following these guidelines, you can effectively transition patients from lisinopril 20 mg to an appropriate dose of losartan while maintaining efficacy and potentially improving tolerability.