Benazepril and Lisinopril Conversion
Benazepril and lisinopril are not equal on a milligram-for-milligram basis; use a 2:1 conversion ratio where 40 mg of benazepril equals 20 mg of lisinopril. 1
Conversion Ratio
The American College of Cardiology establishes a clear 2:1 conversion ratio between these two ACE inhibitors 1. This means:
- 10 mg benazepril = 5 mg lisinopril
- 20 mg benazepril = 10 mg lisinopril
- 40 mg benazepril = 20 mg lisinopril 1
This conversion accounts for differences in relative potencies at equivalent blood pressure lowering effects, even though both medications share the same maximum daily dose of 40 mg 1.
Clinical Approach to Conversion
From Benazepril to Lisinopril
When switching from benazepril to lisinopril, start with a low dose of lisinopril (2.5-5 mg) and titrate gradually, doubling the dose at not less than 2-week intervals, especially in patients on low doses of benazepril (10 mg) 1. This conservative approach minimizes the risk of hypotension during the transition period.
From Lisinopril to Benazepril
When converting from lisinopril 40 mg to benazepril, start with benazepril 40 mg once daily, which represents the maximum allowable dose 1. If blood pressure control remains inadequate on benazepril 40 mg alone, add a thiazide diuretic such as hydrochlorothiazide 12.5-25 mg rather than attempting to exceed the maximum benazepril dose 1.
Monitoring Requirements After Conversion
Check blood pressure, renal function, and potassium levels within 1-2 weeks of initiating therapy, as both medications can affect these parameters 1. Specifically:
- Blood pressure: Ensure adequate control without excessive hypotension, particularly in volume-depleted patients or those on diuretics 1
- Serum creatinine and renal function: Both ACE inhibitors can affect kidney function 1
- Serum potassium: Watch for hyperkalemia, especially in patients with renal dysfunction or those taking potassium supplements or potassium-sparing diuretics 1
Dosing Frequency Advantage
Both medications are dosed once daily, making the conversion straightforward from a dosing frequency perspective 1. This represents a practical advantage over older ACE inhibitors like captopril, which requires multiple daily doses 2.
Target Dosing in Heart Failure
In heart failure patients specifically, aim for target doses of lisinopril (20-35 mg daily) for optimal mortality benefits 1. When converting from benazepril in this population, ensure the lisinopril dose reaches this therapeutic range using the 2:1 conversion ratio as your starting point.