Enalapril

Enalapril: Uses, Dosage and Side Effects

Overview

• An inhibitor of the angiotensin-converting enzyme (ACE).
• It inhibits both the conversion of angiotensin I to angiotensin II and the degradation of bradykinin.
• The overall effect is a decrease in preload and afterload via vasodilation and arteriodilation, decreased sodium and water retention via decreased aldosterone production, and inhibition of angiotensin aldosterone-mediated cardiac and vascular remodelling.
• In the kidney, efferent arteriolar dilation can reduce intraglomerular pressure and, consequently, glomerular filtration. This could reduce proteinuria.

Uses of Enalapril

• Treatment of congestive heart failure caused by mitral regurgitation or dilated cardiomyopathy in dogs.
• Can be used in combination with other drugs to treat heart failure (e.g. pimobendan, spironolactone, digoxin).
•  Can also be used for heart failure in cats.
• Management of proteinuria associated with chronic renal insufficiency, glomerular disorders and protein-losing nephropathies.
• May reduce blood pressure in hypertension.

Dose of Enalapril in Dogs and Cats

Dogs:

• Cardiac disease: 0.5 mg/kg p.o. q24h increasing to 0.5 mg/kg p.o. q12h after 2 weeks in the absence of clinical response.
• Protein-losing nephropathy: 0.25–1 mg/kg p.o. q12–24h.
• Hypertension: 0.5 mg/kg p.o. q12h. Can be up-titrated slowly to effect.
• Doses up to 3 mg/kg have been used.

Cats:

• Cardiac disease, protein-losing nephropathy: 0.25–0.5 mg/kg p.o. q12–24h.

Side Effects of Enalapril in Dogs and Cats

• Potential adverse effects include hypotension, hyperkalaemia and azotaemia.
• Monitor blood pressure, serum creatinine and electrolytes when used in cases of heart failure.
• Dosage should be reduced if there are signs of hypotension (weakness, disorientation).
• Anorexia, vomiting and diarrhoea are rare.
• No adverse effects were seen in normal dogs given 15 mg/kg/day for up to 1 year.
• It is not recommended for breeding, pregnant or lactating bitches, as safety has not been established.

Contraindications of Enalapril in Dogs and Cats

• Do not use in cases of cardiac output failure or hypotension.

Some Notes:

• Concomitant treatment with potassium-sparing diuretics (e.g. spironolactone) or potassium supplements could result in hyperkalaemia.
• However, in practice, spironolactone and ACE inhibitors appear safe to use concurrently.
• There may be an increased risk of nephrotoxicity and decreased clinical efficacy when used with NSAIDs.
• There is a risk of hypotension with concomitant administration of diuretics, vasodilators (e.g. anaesthetic agents, antihypertensive agents) or negative inotropes (e.g. beta-blockers).