Enalapril

Enalapril is an angiotensin-converting enzyme inhibitor used for cardiovascular and selected renal disorders in veterinary patients. It is administered as a prodrug and converted to active enalaprilat. Its principal roles are adjunctive treatment of congestive heart failure, especially in dogs, and reduction of proteinuria in selected patients with glomerular disease.

Group

ACE inhibitor

Mechanism of Action

Enalaprilat inhibits angiotensin-converting enzyme, reducing formation of angiotensin II and diminishing aldosterone stimulation. This lowers vasoconstrictor and sodium-retaining influences and can reduce cardiac loading conditions. Reduced degradation of bradykinin also contributes to vasodilation. In the kidney, decreased efferent arteriolar tone can lower intraglomerular pressure and reduce protein movement across a damaged glomerular filtration barrier.

Dose Rates

Dog

Use / stage	Dose	Route	Schedule	Instructions
Heart failure or proteinuria	0.5 mg/kg	PO	Every 12–24 h	Do not use in: Pregnancy
Heart failure or proteinuria — Initial	0.25 mg/kg	PO	Every 12 h	Do not use in: Pregnancy; Alternative cautious start in mild disease; reassess before increasing.
Ureterolithiasis adjunct	0.25–0.5 mg/kg	PO	Every 12–24 h	Potential antifibrotic adjunct; the additional source explicitly describes dogs.

Cat

Use / stage	Dose	Route	Schedule	Instructions
Heart failure or proteinuria	0.25–0.5 mg/kg	PO	Every 12–24 h	Do not use in: Pregnancy
Heart failure or proteinuria	1–1.25 mg/animal	PO	Every 24 h	Do not use in: Pregnancy; Alternative fixed-dose regimen.

Ferret

Use / stage	Dose	Route	Schedule	Instructions
Heart failure — Initial	0.5 mg/kg	PO	Every 48 h	May increase to daily if tolerated.
Dilated cardiomyopathy	0.25–0.5 mg/kg	PO	Every 24–48 h

Bird

Use / stage	Dose	Route	Schedule	Instructions
Heart failure	1.25 mg/kg	PO	Every 8–12 h
Heart failure	0.25–0.5 mg/kg	PO	Every 24–48 h	Adjunct to furosemide.

Indications

Adjunctive treatment of congestive heart failure in dogs, alongside other indicated cardiac and diuretic therapy.
Reduction of persistent renal proteinuria in selected dogs and cats with proteinuric nephropathy.
Adjunctive management of systemic hypertension in selected veterinary patients, particularly when proteinuria is also present.
Specialist adjunctive treatment of selected cats with congestive heart failure, with a smaller evidence base than in dogs.

Contraindications

Pregnancy
Use cautiously with dehydration, hypotension or renal dysfunction.

Interactions

Other hypotensive drugs and diuretics can amplify effects.
NSAIDs can impair renal tolerance.

Adverse effects

Azotemia and hypotension

Preparations

Preparation	Form	Strength	Route
Enalapril 1 mg	Tablet	1 mg / tablet	PO
Enalapril 2.5 mg	Tablet	2.5 mg / tablet	PO
Enalapril 5 mg	Tablet	5 mg / tablet	PO
Enalapril 10 mg	Tablet	10 mg / tablet	PO
Enalapril 20 mg	Tablet	20 mg / tablet	PO

Monitoring and Administration

Check renal function, electrolytes and blood pressure 3–7 days after starting and periodically thereafter.

Feline hypertension often requires a more effective primary agent; long-term survival benefit for renal disease is uncertain.