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Benazepril for cats

Benazepril is generally safe for cats but can have side effects depending on use and allergic reactions
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By | Updated on Feb. 3, 2025 Medically reviewed by Emma Ryan, DVM
Picture of cat. Is benazepril safe for cats?
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Benazepril hydrochloride (brand name: Lotensin) is a safe and effective drug that lowers blood pressure in cats. Veterinarians use benazepril in cats to treat congestive heart failure, kidney disease, and high blood pressure. These are all serious and potentially life-threatening conditions. For kidney problems and heart failure, benazepril’s role in lowering blood pressure significantly slows the progress of these conditions and lengthens the cat’s life. 

What is benazepril used for in cats?

Benazepril lowers blood pressure, so veterinarians use it to treat high blood pressure in cats and dogs. More importantly, benazepril is a first-choice drug for treating congestive heart failure and protein-losing kidney diseases in cats.

Benazepril belongs to a family of medications called angiotensin-converting enzyme (ACE) inhibitors. While there are many ACE inhibitors to choose from, veterinarians primarily use only two: enalapril and benazepril. 

ACE inhibitors block the body’s production of the hormone angiotensin II. It’s one part of a complex interplay of hormones called the renin-angiotensin-aldosterone system (RAAS) that regulates blood pressure, fluid levels, and electrolytes in the body. Angiotensin’s primary effect is to raise blood pressure by tightening blood vessels. When angiotensin production is blocked, blood vessels dilate, and blood pressure goes down.

Congestive heart failure

Heart failure is a common problem in cats. As in people, congestive heart failure in cats is a progressive and ultimately fatal condition. In a cat with heart failure, the heart cannot pump enough blood to the body. It’s caused by other heart diseases, but once it occurs, it has its own feedback loop that makes it gradually worse. Once the heart can’t pump enough blood, the heart compensates by working harder. The extra work makes the heart bigger and stronger, but that decreases the amount of blood that the heart can hold. This is called “cardiac remodeling.” As the interior of the heart gets smaller, the disease gets worse and worse. 

Veterinarians use several drugs to slow the progress of heart failure: 

  • ACE inhibitors like benazepril or enalapril reduce blood pressure, making it easier for the heart to pump blood. The heart pumps more blood to the body and doesn’t work as hard.
  • Diuretics like furosemide make the cat urinate more fluids and electrolytes, reducing the fluid retention caused by heart failure. 
  • The drugs pimobendan and, sometimes, digoxin improve the heart’s performance.

Protein-losing kidney disease (proteinuria)

“Proteinuria” is a seemingly impenetrable medical term, but all it means is “protein in the urine.” It’s a sign that blood pressure in the kidneys is too high and, possibly, that the kidneys are losing the ability to filter waste. That happens when very small filters called glomeruli in the kidneys are damaged. The body compensates for this damage by increasing blood pressure in the other glomeruli. (The kidneys have the ability to partly regulate their own blood pressure.) That increased blood pressure pushes proteins out of the blood and into the urine. While higher blood pressure increases the kidneys’ ability to filter waste, it eventually damages the other glomerular filters throughout the kidney. In other words, proteinuria is a possible sign that a cat is steadily losing its kidney function and could eventually suffer kidney failure.

The goal is to bring down blood pressure in the kidneys specifically. The best drugs for this are ACE inhibitors because they work directly on peripheral arteries like the glomeruli. The ACE inhibitors of choice are enalapril and benazepril. By lowering the blood pressure in the glomeruli, benazepril treatment helps stop the progression of the disease. Started early enough, the treatment may allow the cat to recover some of its compromised kidney function. 

High blood pressure

Hypertension is a common problem in older cats. In most cases, it’s caused by other problems such as chronic kidney disease or overactive thyroid. About 1 in 5 cats have high blood pressure without any identifiable cause, called “primary hypertension.” High blood pressure is rarely a temporary problem in a cat, so drug therapy usually lasts for the rest of the cat’s life.

ACE inhibitors are commonly used for hypertension in cats, but the blood pressure drug amlodipine is often the first-choice treatment. An ACE inhibitor may be a good starter drug if blood pressure is low. Once benazepril is prescribed, the veterinarian will use it as long as it works without causing problems. If it doesn’t work, the veterinarian may need to add or substitute more powerful blood pressure drugs.

Is benazepril safe for cats?

Benazepril is safe to use in cats. Side effects are minimal.

The only contraindication is a history of allergic reactions to benazepril or any other ACE inhibitor such as enalapril or captopril.

Because of potential problems, veterinarians are cautious about the use of benazepril in cats with:

  • Low sodium or sodium depletion
  • Blood disorders
  • Collagen vascular diseases such as lupus
  • Severe heart failure
  • Acute kidney injury with severe azotemia

Tell the veterinarian if the cat is pregnant or nursing kittens. Given to animals in high doses, benazepril increases the risk of low birth weight or the death of the mother. No birth defects have been associated with the use of benazepril in animal studies. Veterinarians do not know if benazepril affects kittens that are breastfeeding.

Side effects of benazepril in cats

The most common side effects of benazepril in companion animals are:

  • Lack of appetite
  • Vomiting 
  • Diarrhea

These adverse effects are typically mild and might be improved by giving doses with food. If they worsen or persist, talk to the veterinarian.

The most serious side effects of benazepril in cats are:

  • Low blood pressure
  • Elevated potassium levels
  • Kidney problems
  • Hypersensitivity reactions

Interactions of benazepril with other pet meds

Benazepril has several significant drug interactions. 

The most significant interactions involve other drugs that lower blood pressure, including diuretics. Combining benazepril with these drugs increases the risk of the cat experiencing dangerously low blood pressure. Veterinarians often combine these drugs with benazepril, so caregivers should know the distinguishing signs of low blood pressure in their pets.

Other drugs that may cause problems when combined with benazepril include:

  • Insulin 
  • Potassium supplements or potassium-sparing diuretics
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)

Except for those supplements or vitamins that contain potassium, caregivers can safely continue to give supplements, vitamins, and herbal remedies, including CBD. However, talk to the veterinarian first just to be sure. 

Benazepril dosage for cats

The standard benazepril dosage for cats is 0.25–0.5 mg per kilogram of body weight taken by mouth every 12 or 24 hours. 

Plumb’s Veterinary Drug Manual lists the following dosages:

  • For adjunctive treatment of heart failure: 0.25–0.5 mg/kg given by mouth once or twice a day
  • For proteinuria: 0.25–1 mg/kg given by mouth once or twice a day
  • For hypertension: 0.25–1 mg/kg given by mouth once or twice a day

Benazepril is not approved by the Food and Drug Administration (FDA) for use in animals. Veterinarians frequently prescribe benazepril to cats, however, and when they do, they use the same tablets used in humans. Benazepril tablets for people start at 5 mg. Compounding pharmacies can also supply benazepril as a capsule or oil-based suspension for easier dosing.

Can cats overdose on benazepril?

Cats can overdose on benazepril, but it’s unlikely. There is no specified maximum dosage, so caregivers should regard the prescribed dose as the upper limit. Do not increase the dose for any reason until talking to the veterinarian.

Low blood pressure is the most common result of a benazepril overdose. Signs of a benazepril overdose in a cat include low energy, fast heart rate, weakness, changes in urination, increased salivation, vomiting, and diarrhea.

If an overdose is suspected, call the ASPCA Animal Poison Control Center or a veterinarian.

Can I give my cat benazepril every day?

Benazepril is safe for cats to take for months or years. Some cats may need it every day for the rest of their lives. 

The cat may experience some side effects such as vomiting or appetite loss, but these problems should be minor and temporary. If they become a problem, the veterinarian will probably switch to another drug. 

Some adverse effects, such as increased potassium levels, are bigger problems for the cat. To prevent these side effects, the caregiver should have the cat regularly checked by the veterinarian. 

How to give your cat benazepril

It’s rarely easy to give a cat a pill, but benazepril tablets are relatively small. The veterinarian may be able to supply liquid benazepril to make dosing easier. Keep the following considerations in mind:

  • Follow all the veterinarian’s instructions. 
  • Do not change the dose unless instructed to do so.
  • Do not miss doses or stop the medication unless instructed to do so. 
  • Doses are given once or twice daily.
  • Benazepril doses can be given with or without food. If the cat experiences gastrointestinal problems, try giving future doses with a meal or snack.
  • If you don’t know how to give cats a pill, ask a veterinary professional to demonstrate the proper procedure. 
  • Shake the benazepril liquid before measuring a dose. 
  • Measure benazepril liquid doses with the calibrated oral syringe or dropper that comes with the medicine. 
  • Administer a missed dose as soon as remembered. If it’s almost time for the next dose, skip the missed dose and give the next dose as scheduled.
  • Store benazepril tablets at room temperature. Special storage instructions for liquid benazepril may be included with the medicine or printed on the label.

Benazepril alternatives for cats

Benazepril is often a first-choice drug that treats serious health conditions in cats. If it causes intolerable adverse effects or doesn’t work, veterinarians typically substitute another ACE inhibitor such as enalapril, lisinopril, ramipril, or captopril. 

If no other ACE inhibitor can be used, veterinarians will try using other blood pressure-lowering drugs such as:

Some caregivers may prefer alternative or complementary treatments. Unfortunately, natural or alternative remedies are not considered effective for heart failure or kidney disease. For high blood pressure, the most effective alternative to medications is a healthy diet, healthy weight, and exercise. 

Summary

For cats, benazepril is both a safe and life-saving drug that treats serious conditions such as heart failure, kidney disease, and high blood pressure. It’s vitally important to make sure the cat gets doses faithfully. Side effects are usually minor and transient. They shouldn’t be bad enough to require treatment to stop. Serious side effects can be prevented through regular veterinary visits.