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Veterinary : Cardiology/Hypertension
Enalapril for Cardiomyopathy and CHF
“Enalapril maleate is an angiotensin-converting enzyme (ACE) inhibitor
labeled to treat mild to severe heart failure in dogs.” Research has shown
that enalapril in combination with diuretics - with or without digitalis glycosides
- “produces statistically significant clinical improvement in dogs with
advanced heart failure due to mitral regurgitation or dilated cardiomyopathy” and
has demonstrated “beneficial hemodynamic and clinical effects of adding
enalapril to conventional therapy for dogs with CHF... Dogs treated with
enalapril and conventional CHF therapy survived two times as long as did
those receiving standard therapy alone.”
Enalapril has also “been effective in treating cardiomyopathy and CHF in
cats and ferrets, and its effects on blood pressure in horses and camels have
been studied.” Because enalapril is a prodrug and can not be converted
to its active form enalaprilat in patients with severe liver dysfunction, captopril
or lisinopril might be a better choice in those patients. Renal function should
be checked before starting enalapril therapy and at least every two months thereafter.
The most common side effects are gastrointestinal, but there have been reports
of enalapril-induced cough in dogs and a bird. Hypotension is a major concern
if overdose occurs. NSAIDs, including aspirin, may reduce enalapril’s
effect. The injectable form (enalaprilat) should not be given orally because
it is very poorly absorbed.
“The recommended dose for enalapril in dogs is 0.5 mg/kg orally every 12
to 24 hours. The dose for cats is 0.25 to 0.5 mg/kg orally every 12 to 24
hours.”
Compendium, Dec. 1999
Amlodipine to Treat Feline Systemic Hypertension
Amlodipine, a calcium channel blocker, has an antihypertensive effect in cats
with coexistent systemic hypertension and renal insufficiency. Its use may
improve the prognosis for cats with systemic hypertension by decreasing the
risk of ocular injury or neurologic complications induced by high blood pressure
(BP). In a retrospective study, medical records from 69 cats with systemic
hypertension and hypertensive retinopathy were reviewed. 68.1% of the cats
were referred because of vision loss; retinal detachment, hemorrhage, edema,
and degeneration were common findings. Amlodipine decreased BP in 31 of 32
cats and improved ocular signs in 18 of 26 cats. Primary hypertension in
cats may be more common than currently recognized.
In a study at the Department of Small Animal Clinical Sciences, College of
Veterinary Medicine, University of Florida, amlodipine was shown to be a
safe and effective once-daily antihypertensive agent when administered to
cats at a dosage of 0.18 +/- 0.03 mg/kg daily as monotherapy. Researchers
at the Department of Medical Sciences, University of Wisconsin-Madison, administered
amlodipine at an oral daily dosage of 0.625 mg per cat (range = 0.08 to 0.23
mg/kg body weight). Average indirect systolic blood pressure measurements
in those 12 cases decreased significantly from 198 to 155 mmHg during amlodipine
treatment. Significant changes in body weight and serum creatinine and potassium
concentrations were not detected.
Relationship between ocular lesions
and hypertension
Retinal lesions, caused predominantly by choroidal injury, are common in
cats with hypertension. Hypertension should be considered in older cats
with acute onset of blindness; retinal edema, hemorrhage, or detachment; cardiac
disease; or neurologic abnormalities. Cats with hypertension-induced ocular
disease should be evaluated for renal failure, hyperthyroidism, diabetes
mellitus, and cardiac abnormalities. Blood pressure measurements and funduscopic
evaluations should be performed routinely in cats at risk for hypertension
(preexisting renal disease, hyperthyroidism, and age > 10 years).
Am J Vet Res 2002 Jun;63(6):833-9
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here to access the PubMed abstract of this article.
J Am Vet Med Assoc 2000 Sep 1;217(5):695-702
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here to access the PubMed abstract of this article.
J Vet Intern Med 1998 May-Jun;12(3):157-62
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here to access the PubMed abstract of this article.
J Am Anim Hosp Assoc 1997 May-Jun;33(3):226-34
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here to access the PubMed abstract of this article. |
