What is the equivalent dose of lisinopril for a patient with hypertension or heart failure taking losartan (angiotensin II receptor antagonist)?

Losartan to Lisinopril Dose Equivalency

For patients switching from losartan to lisinopril, use the following conversion: losartan 50 mg daily is approximately equivalent to lisinopril 10-20 mg daily, and losartan 100 mg daily is approximately equivalent to lisinopril 20-40 mg daily. 1

Evidence-Based Conversion Table

The American Heart Association, American College of Cardiology, and Heart Failure Society of America provide the following equivalency guidance 1:

Losartan Dose	Lisinopril Equivalent
25-50 mg	2.5-10 mg
50 mg	10-20 mg
100 mg	20-40 mg

Target Dosing for Optimal Outcomes

For heart failure with reduced ejection fraction, target doses are losartan 100-150 mg daily or lisinopril 20-40 mg daily to achieve maximum mortality and morbidity benefits. 2, 1

• The target dose of losartan for heart failure is 100 mg once daily according to ACC guidelines, with some evidence supporting up to 150 mg daily 2
• The target dose of lisinopril for heart failure is 20-40 mg daily 1
• Clinical trials demonstrate that higher doses provide superior cardiovascular outcomes compared to lower doses 2, 3

Clinical Rationale for Conversion

• The HEAAL trial showed losartan 150 mg daily was superior to 50 mg daily, with a 10% relative risk reduction in death or heart failure hospitalization 2, 1
• Lisinopril at dosages of 20-80 mg once daily is effective in lowering blood pressure in all grades of essential hypertension 4
• Both medications require uptitration to target doses to achieve maximum benefit, as underdosing is widespread in clinical practice with less than 25% of patients reaching target doses 2

Practical Conversion Algorithm

When converting from losartan to lisinopril:

1. Identify current losartan dose and indication 1
2. Use the conversion table above to determine equivalent lisinopril starting dose 1
3. Monitor blood pressure in both sitting and standing positions during transition 2
4. Check serum creatinine/eGFR and potassium within 1-2 weeks after conversion 2, 5
5. Titrate to target doses over 2-4 weeks if tolerated 2

Critical Safety Considerations

• Never combine ACE inhibitors (lisinopril) with ARBs (losartan), as this increases risk of hyperkalemia and renal dysfunction without additional benefit 1, 5
• Monitor for symptomatic hypotension, especially in patients with baseline low blood pressure or heart failure 2
• Avoid abrupt withdrawal to prevent rebound hypertension 5
• Both medications carry similar risks of hyperkalemia and require monitoring, particularly in patients with renal impairment or diabetes 2, 5

Special Population Adjustments

• In elderly or frail patients, start at lower doses and titrate more gradually over 2-4 weeks 2
• For hepatic impairment, reduce initial losartan dose to 25 mg daily (lisinopril does not require adjustment) 2
• For renal impairment, both medications require dose adjustment when eGFR <30 mL/min per 1.73 m² 2

Common Pitfalls to Avoid

• Underdosing is the most common error—ensure adequate uptitration to target doses for optimal cardiovascular protection 2
• Starting with doses that are too high in patients with low baseline blood pressure (<80 mm Hg systolic) 2
• Failing to monitor potassium and renal function during the transition period 2, 5
• Converting patients who are already on combination ACE inhibitor/ARB therapy without discontinuing one agent first 1