What is the recommended dosing for Fosinopril (Angiotensin-Converting Enzyme inhibitor) in patients with hypertension or heart failure?

Fosinopril Dosing for Hypertension and Heart Failure

For patients with hypertension, fosinopril should be initiated at 10 mg once daily and titrated to a maintenance dose of 20-40 mg once daily based on blood pressure response. For heart failure patients, start with 10 mg once daily (5 mg in those with severe renal failure) and titrate to a maximum of 40 mg once daily. 1

Dosing for Hypertension

• Initial dose: 10 mg once daily, both as monotherapy and when added to a diuretic 1
• Maintenance dose: 20-40 mg once daily, with some patients requiring up to 80 mg daily for adequate response 1
• If blood pressure control is inadequate at trough (24 hours after dosing), consider dividing the daily dose 1
• If monotherapy is insufficient, a diuretic may be added for enhanced effect 1

Special Considerations for Hypertension

• For patients currently on diuretic therapy, if possible, discontinue the diuretic 2-3 days before starting fosinopril to reduce the risk of symptomatic hypotension 1
• If the diuretic cannot be discontinued, use an initial dose of 10 mg with careful medical supervision for several hours until blood pressure stabilizes 1
• Fosinopril is equally effective in both younger and elderly patients, as well as in black and non-black patients 2

Dosing for Heart Failure

• Initial dose: 10 mg once daily 1
• Preferred initial dose in heart failure patients with moderate to severe renal failure or those vigorously diuresed: 5 mg once daily 1
• Titration: Increase dose over several weeks to a maximum tolerated dose not exceeding 40 mg once daily 1
• Usual effective dosage range: 20-40 mg once daily 1
• After the initial dose, observe the patient for at least two hours for hypotension or orthostasis 1

Efficacy in Heart Failure

• Fosinopril improves exercise duration and heart failure symptoms in NYHA class II-III patients 3
• Fosinopril reduces pulmonary capillary wedge pressure, mean arterial blood pressure, and increases stroke volume index and cardiac index in heart failure patients 4
• Fosinopril at 20 and 40 mg once daily provides sustained beneficial hemodynamic effects and improves left ventricular performance 4

Unique Pharmacological Properties

• Unlike other ACE inhibitors, fosinoprilat (the active metabolite) has a dual route of elimination via both hepatic and renal pathways 5, 2
• In patients with diminished renal function, hepatic clearance of fosinoprilat increases, and vice versa 5
• This compensatory elimination allows for the same starting dosage regardless of renal function 5, 2
• No dosage adjustment is required in patients with renal impairment, including those with end-stage renal failure 1

Monitoring and Follow-up

• After initiating therapy, monitor blood pressure response at peak (2-6 hours) and trough (24 hours) 1
• For heart failure patients, monitor for hypotension or orthostasis after the initial dose 1
• Early hypotension, orthostasis, or azotemia during dose titration should not preclude further careful dose titration 1
• Consider reducing the dose of concomitant diuretics if these adverse effects occur 1

Common Side Effects and Precautions

• Most common adverse events in heart failure patients: dizziness (11.9%), cough (9.7%), and hypotension (4.4%) 3
• Use caution when administering fosinopril with potassium supplements, potassium-containing salt substitutes, or potassium-sparing diuretics as they may increase serum potassium 1
• Fosinopril is generally well tolerated with adverse events similar to other ACE inhibitors 5

Clinical Pearls

• Fosinopril may be particularly useful in patients with impaired kidney or liver function due to its dual elimination pathway 5, 6
• Dose-related improvements in symptoms of dyspnea and reduced need for supplemental diuretic therapy have been observed with 20 mg and 40 mg doses 4
• Response rates of up to 80% have been reported in hypertensive patients treated with fosinopril 10-40 mg daily 2