Benazepril For Cats: Dosage, Safety & Side Effects

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black and white cat being checked by the vets

Benazepril is a blood pressure medication used to treat kitties with heart failure, hypertension (high blood pressure), chronic kidney disease, and conditions of protein loss through the urine.

It may also be known by the brand name Lotensin. In this article, you’ll learn how benazepril works, situations where it is most commonly used, side effects, and some frequently asked questions.

Benazepril For Cats Overview

Medication Type:
Angiotensin-converting enzyme (ACE) inhibitor
Form:
Oral tablet
Prescription Required?:
Yes
FDA Approved?:
No
Brand Names:
Lotensin; Lotrel also contains amlodipine; Lotensin HCT also contains hydrochlorothiazine
Common Names:
Benazepril
Available Dosages:
Tables in 5mg, 10mg, 20mg and 40mg size.

About Benazepril For Cats

Causes of high blood pressure in cats

A number of issues may cause high blood pressure in cats

Benazepril is classified as an angiotensin-converting enzyme (ACE) inhibitor.

ACE inhibitors work by blocking the conversion of the protein hormone angiotensin-I to angiotensin-II. Angiotensin-II causes blood vessels to constrict and also stimulates the production of a hormone called aldosterone. 

Blood vessel constriction and high levels of aldosterone in the body can increase blood pressure. By blocking the conversion to angiotensin-II, ACE inhibitors help to lower blood pressure. 

In pets with congestive heart failure (CHF), dilating the blood vessels also helps to reduce strain on the heart because it doesn’t have to work as hard to push blood through the body.

What Does Benazepril Do For Cats?

Cat high blood pressure can cause sneezing blood

High blood pressure may cause cats to sneeze blood or have nosebleeds.

Benazepril has three main applications for use in cats:

The first is as a second-line blood pressure medication to treat high blood pressure, or hypertension. Many veterinarians will start first with a different medication called amlodipine. However, in cases where amlodipine improves a cat’s hypertension, but the blood pressure still is not normal, a second medication needs to be added. A common choice is often benazepril. Telmisartan, a newer medication gaining popularity for use in cats in recent years, may also be considered.

Benazepril can also be used to address high levels of protein in the urine. This indicates that body protein, which the kidneys typically conserve, is being lost in higher amounts. In many (but not all) cases, high levels of proteinuria can indicate kidney dysfunction. 

Benazepril can help to lower pressure in the tiny capillary blood vessels of the glomerulus, which is the main filtration structure of the kidney. This improves kidney blood flow and can help reduce protein loss.

Benazepril’s third application is to aid in the treatment of congestive heart failure. It is not always the first-line preference in all cases, but may help by reducing blood pressure and workload on the heart. 

Side Effects Of Benazepril For Cats

cat refusing to eat out of a bowl

Benazepril’s safety for pregnant or nursing animals is questionable. It is considered contraindicated in some countries for pregnant or lactating animals.

Benazepril is typically well-tolerated and adverse effects are uncommon when used at proper dosages. Sometimes, vomiting or diarrhea may occur. While the medication can be given with or without food, giving with food may help reduce the occurrence of digestive upset.

With any blood pressure medication, there is always the possibility of low blood pressure occuring, which is called hypotension. This is especially if an extra dose or too high a dose is accidentally given. This is why dosage adjustments should only be made based on recheck blood pressure measurements.

While benazepril can be used to assist cats in congestive heart failure, it does need to be used carefully, especially if there are any blood electrolyte abnormalities, or certain complications of heart disease. These types of contraindications for its use can usually be determined when a cat is under the care of a board-certified veterinary cardiologist. 

Benazepril must be used carefully in cats with existing kidney disease. Part of the role of benazepril to help reduce protein loss in the urine is to slow down the filtration rate in the kidneys. However, slowing down the filtration rate can also increase levels of certain waste products in the bloodstream, like blood urea nitrogen (BUN) and creatinine. An increase of these waste products as found on bloodwork is called azotemia.

Cats with mild to moderate renal insufficiency/kidney failure may be unaffected and the benefits for reducing blood pressure and protein loss may outweigh potential risks. But benazepril is typically used very carefully in pets with moderate levels of azotemia and is considered inappropriate to use in cats with advanced kidney disease/renal failure or acute kidney injury (such as that caused by a kidney infection or a toxin).

Benazepril’s safety for pregnant or nursing animals is questionable. It is considered contraindicated in some countries for pregnant or lactating animals. 

Benazepril can interact with several other medications, another reason to consult with your vet is to see if this medication can be used in conjunction with other drugs your kitty might be taking.

Lastly, benazepril can sometimes sound similar to the antihistamine Benadryl and the spelling may also appear similar on some handwritten prescriptions. Always double-check a prescription you pick up at the pharmacy to make sure it is the correct medication.

Benazepril For Cats Dosage

Cat seizure injection

Benazepril dosages should also only be adjusted based on recheck testing, including blood pressure measurements and checking urine protein levels.

The dosage for benazepril for cats, as well as the frequency of dosing, can differ depending on the intended use. This is also a medication that needs to be used carefully, especially with certain medical conditions. For this reason, it is best to have your veterinarian determine if benazepril is okay to start and what dosage to start with. 

Benazepril dosages should also only be adjusted based on recheck testing, including blood pressure measurements and checking urine protein levels. It’s not advisable to adjust benazepril dosages on your own, without recheck testing with your vet.

Conclusion

What is high blood pressure in cats

Your cat’s blood pressure is influenced by multiple factors, including the heart and blood vessels, along with a complex regulatory system across the entire body.

Benazepril can be a very useful medication for addressing some conditions of high blood pressure, urine protein loss, and heart disease in cats.

However, it should be used very carefully as it is not an appropriate medication for these conditions in all situations. If you think your cat might benefit from benazepril, make sure to have a conversation with your vet.

Frequently Asked Questions

What is Benazepril Used for in Cats?

Benazepril is an angiotensin-converting enzyme (ACE) inhibitor used as a blood pressure medication for hypertension. It also has applications to help reduce protein loss through the kidneys and urine and can be of use as an adjunctive medication for cats with heart disease and congestive heart failure.

What are the Side Effects of Benazepril in Cats?

Benazepril is generally very well tolerated by most cats. Signs of digestive upset may be seen and if so, it is best to give this medication with food.

It must be used carefully in cases of advanced kidney disease and heart failure and so should always be prescribed under a veterinarian’s supervision.

Does Benazepril Increase Appetite in Cats?

This has been described, but largely only for cats with chronic kidney disease. This may occur secondary to its effects on reducing protein loss and blood pressure. Benazepril is not typically used as an appetite stimulant in the general sense and in fact could cause concerning effects in pets with normal blood pressure. 

If your kitty is having trouble eating, it is important first to understand what the underlying cause is. There are a couple of other appetite stimulants, like mirtazapine and capromorelin, that veterinarians employ far more often. 

Is Benazepril Hard on the Kidneys?

The short answer is, it depends. In cats with chronic kidney disease, benazepril has shown to lower blood pressure, including the capillary blood vessel pressure in the filtration system of the kidneys called the glomerulus. At the same time, it increases blood flow through the kidneys and preserves the filtration rate. So it does actually have some benefits for kidney function, which is why it is used.

However, in cats with azotemia, where toxic waste products like BUN and creatinine are elevated on labwork, there is a risk that these levels may increase with benazepril use. Benazepril is typically considered inappropriate to use for cats with acute kidney injury, as from a kidney infection or a toxin, and should likely also not be used in cats with advanced kidney disease.

When azotemia starts to develop on a cat’s bloodwork, we know that about 65% of kidney function has at that point already been lost. However, there might be indicators of earlier kidney insufficiency before bloodwork abnormalities develop, including a dilute urine concentration or protein loss through the urine, that can be monitored for on annual or semi-annual lab work. Benazepril may be most beneficial and safest to use in these cases to address protein loss or hypertension, before azotemia develops. 

In the context of how it is metabolized and excreted, benazepril is not very hard on the kidneys at all. It is mostly metabolized and cleared from the body by the liver, with only a smaller percentage by the kidneys. Enalapril by contrast, which is in the same family as benazepril, is excreted almost entirely by the kidneys.

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About Dr. Chris Vanderhoof, DVM, MPH

Dr. Chris Vanderhoof is a 2013 graduate of the Virginia-Maryland College of Veterinary Medicine (VMCVM) at Virginia Tech, where he also earned a Masters in Public Health. He completed a rotating internship with Red Bank Veterinary Hospital in New Jersey and now works as a general practitioner in the Washington D.C. area. Dr. Vanderhoof is also a copywriter specializing in the animal health field and founder of Paramount Animal Health Writing Solutions, which can be found at www.animalhealthcopywriter.com. Dr. Vanderhoof lives in the Northern Virginia area with his family, including 3 cats.

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