Lisinopril 20-40 mg Daily is the Equivalent to Fosinopril 40 mg
Based on the 2022 AHA/ACC/HFSA guidelines, lisinopril 20-40 mg once daily is the equivalent dose to fosinopril 40 mg once daily. 1
Dose Equivalence of ACE Inhibitors
The 2022 American Heart Association/American College of Cardiology/Heart Failure Society of America guidelines provide a comprehensive table of ACE inhibitor dosing for heart failure with reduced ejection fraction (HFrEF), which clearly outlines the initial and target doses for various ACE inhibitors:
| ACE Inhibitor | Initial Daily Dose | Target/Maximum Dose |
|---|---|---|
| Fosinopril | 5-10 mg once daily | 40 mg once daily |
| Lisinopril | 2.5-5 mg once daily | 20-40 mg once daily |
Pharmacological Considerations
When converting between ACE inhibitors, several factors should be considered:
Pharmacokinetics: Fosinopril has a dual elimination pathway (both hepatic and renal), which distinguishes it from lisinopril that is primarily eliminated through the kidneys 2. This means:
Duration of action: Both medications provide 24-hour blood pressure control with once-daily dosing, though lisinopril has a linear dose-response curve 2
Onset of action: Lisinopril's antihypertensive effect begins within 2 hours, peaks around 6 hours, and lasts for at least 24 hours 3
Clinical Application
When switching from fosinopril 40 mg to lisinopril:
- Start with appropriate dose: Begin with lisinopril 20 mg daily if renal function is normal
- Monitor closely: Check blood pressure, renal function, and potassium levels within 1-2 weeks of switching
- Titrate if needed: Increase to 40 mg daily if blood pressure control is inadequate and the patient tolerates the medication well
Important Considerations and Precautions
Renal function: Monitor renal function and serum potassium within 1-2 weeks of initiating therapy or changing doses, especially in patients with:
- Pre-existing renal impairment
- Diabetes
- Heart failure
- Advanced age
Common side effects to monitor for:
- Cough (occurs in up to 20% of patients)
- Hypotension (especially when initiating therapy)
- Hyperkalemia
- Angioedema (rare but serious; occurs in <1% of patients, more common in Black patients) 2
Contraindications:
- Previous angioedema with ACE inhibitors (absolute contraindication)
- Pregnancy
- Bilateral renal artery stenosis
Guideline Alignment
The dose equivalence recommendation aligns with multiple guidelines, including the American College of Cardiology/American Heart Association guidelines for heart failure management 1 and hypertension management 1, 2.
Remember that the goal of ACE inhibitor therapy is to achieve target doses shown to be efficacious in randomized controlled trials, as this has been proven to reduce cardiovascular mortality and heart failure hospitalizations 1.