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What is enalapril used for in dogs?

Enalapril treats congestive heart failure, kidney disease, and hypertension in dogs
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By | Nov. 15, 2024 Medically reviewed by Emma Ryan, DVM
A black and white dog holding a stethoscope: What is enalapril used for in dogs?

Key takeaways

  • Enalapril is used to treat congestive heart failure, protein-losing kidney disease, and high blood pressure in dogs.

  • The standard enalapril dosage for dogs is 0.5 mg/kg, taken by mouth every 12–24 hours.

  • Enalapril’s most common side effects in dogs are loss of appetite, vomiting, diarrhea, and tiredness.

  • Do not give enalapril to dogs if they have had an allergic reaction to enalapril or other ACE inhibitors or if they have certain heart conditions.

In this article:

Enalapril is one of the most commonly used prescription medications to treat canine congestive heart failure, kidney disease, or high blood pressure. All are serious, chronic, and progressive conditions. Enalapril treatment improves the dog’s health, slows the progress of these diseases, and lengthens the dog’s life. 

RELATED: Save up to 80% on enalapril

What is enalapril used for in dogs?

Enalapril is a critical treatment for dogs with congestive heart failure or protein-losing kidney diseases (proteinuria), including chronic kidney disease. Enalapril is also a first-choice starting therapy for dogs with high blood pressure. 

Enalapril belongs to a family of drugs called angiotensin-converting enzyme inhibitors (ACE inhibitors). It blocks the production of a hormone called angiotensin II, which tightens blood vessels and increases blood pressure. So, enalapril’s primary effect is to slacken the muscles in blood vessels, widening them and decreasing blood pressure.

Congestive heart failure

When a dog has congestive heart failure (CHF), the heart cannot pump out enough blood to sustain the rest of the body. This can be due to several causes, but the most common in dogs is due to disease of the heart valves. Healthy heart valves should work as one-way valves to direct blood through the heart. When aging or diseased heart valves allow blood to leak, blood pools within the heart and is not pumped efficiently around the body. This blood pooling within the heart can cause the heart muscle to stretch and weaken, worsening the efficacy of the heart’s action as a pump. 

In a dog with heart failure, veterinarians have two goals: to increase the amount of blood pumped by the heart and slow down the disease’s progress. They use three types of drugs to achieve these goals. The first are ACE inhibitors like enalapril to lower blood pressure. This lowers resistance to pumped blood, making it easier for the heart to do its work. The second are diuretics such as furosemide to reduce the volume of the blood and clear the fluid retention caused by heart failure. The third is a drug (pimobendan) that increases the strength of heart contractions to generate greater blood flow. Depending on the condition, a drug that affects heart rhythms and supports blood pressure (digoxin) may be added to the treatment.

Daily doses of ACE inhibitors like enalapril and benazepril are the most commonly used drugs to treat heart failure in dogs and significantly lengthen their lives. ACE inhibitors primarily decrease blood pressure in peripheral arteries. This not only reduces arterial blood pressure—the pressure the heart has to push against to pump blood—but also increases blood pressure in the veins, which increases blood flow into the heart. These effects allow the heart to pump more blood without beating faster.

Proteinuria and kidney disease

Proteinuria may not be a familiar medical term, but it’s well-known to doctors and veterinarians. All it means is that there are more proteins in the urine than there should be. While that doesn’t sound like a big problem, excess protein in the urine can indicate that something is seriously going wrong with the kidneys. Sometimes, it’s a temporary problem like a drug side effect. Sometimes, it means the kidneys are progressively losing their ability to work. 

Think of the kidneys as having little factories called nephrons that filter water, electrolytes, and waste. They’re composed of arteries, veins, and tiny tubes that pass water and waste into the urine. The working parts of the nephrons that filter are called the glomeruli. These are little knots of very tiny, very thin arteries. Their walls are so thin that water and waste get pushed out of the arteries into the “drainage” tubes.

When the dog starts losing these little filtering factories, that’s called nephrotic disease. When the glomeruli start going bad, that’s called glomerular disease. As the kidney loses its filtering system, the body raises the blood pressure in the glomeruli so more plasma can be filtered. This higher blood pressure is what causes proteinuria. 

Increased blood pressure steadily damages the tiny arteries in the glomeruli and destroys what remains of the kidneys’ filtration system. The proteins in the urine also make the condition worse because they cause inflammation, which also damages the glomeruli. This is a progressive disease that may end in kidney failure. 

The goal of treatment is to decrease proteins in the urine and reduce glomerular blood pressure. Because ACE inhibitors primarily affect peripheral blood pressure, enalapril achieves both. It reduces urine proteins, decreases blood pressure, protects kidney function, and increases the dog’s life.

High blood pressure

Veterinarians typically start with the ACE inhibitors benazepril or enalapril to treat high blood pressure in dogs. They’re not powerful blood pressure medications, so they’re not suitable for very high blood pressure. Typically, the veterinarian will wait to see how well the treatment works. The primary goal of treatment is to protect the body’s organs from future damage due to high blood pressure. It’s likely that ACE inhibitors won’t lower blood pressure enough, so the veterinarian will add or switch to another blood pressure medication or diuretic until targets are met.

Is enalapril safe for dogs?

The use of enalapril in dogs is effective and safe. Side effects tend to be minimal and infrequent.

That doesn’t mean enalapril is safe for all dogs. Some dogs are never given enalapril, including dogs with:

  • A history of allergic reactions to enalapril or other ACE inhibitors
  • Certain types of heart disease, including aortic stenosis and obstructive hypertrophic cardiomyopathy

Veterinarians are cautious about using enalapril in dogs who have:

  • Low sodium
  • Blood disorders
  • Certain heart disorders
  • Collagen vascular disorders
  • Severe heart failure

Tell the veterinarian if the dog is pregnant or lactating. Enalapril could cause birth defects in unborn puppies.

Side effects of enalapril in dogs

The most common side effects of enalapril in dogs are:

  • Loss of appetite
  • Diarrhea
  • Vomiting
  • Tiredness

These adverse effects are nothing to worry about unless they worsen or persist. If they do, contact the dog’s veterinarian.

More serious but rare side effects include:

  • Low blood pressure (hypotension)
  • Weakness
  • High potassium
  • Kidney dysfunction
  • Hypersensitivity reactions

Contact a veterinarian if you notice any signs of a possible severe side effect, including:

  • Rash
  • Fever
  • Tiredness
  • Weakness
  • Collapse

Interactions of enalapril with other pet meds

Enalapril has several significant drug interactions. Veterinarians may avoid the combination or monitor the dog for side effects. These drugs include:

  • Other drugs that lower blood pressure: The combination raises the risk of blood pressure going too low.
  • Drugs that make the dog pee (diuretics): Diuretics also lower blood pressure, so there’s a risk of dangerously low blood pressure.
  • Drugs that treat high blood sugar (antidiabetic medications): When enalapril is combined with insulin or oral antidiabetics, there is a risk of low blood sugar (hypoglycemia).
  • Drugs and supplements that increase potassium: When combined with enalapril, potassium supplements, potassium-containing drugs, and potassium-sparing diuretics increase the risk of high potassium (hyperkalemia).
  • Non-steroidal anti-inflammatory drugs (NSAIDs): NSAIDs prescribed to dogs, such as carprofen, may block the ability of enalapril to lower blood pressure.

Pet parents who give their dog CBD can typically continue to do so but should ask the veterinarian first.

Enalapril dosage for dogs

The standard enalapril dosage for dogs is 0.5 mg per kilogram of body weight taken by mouth every 12 or 24 hours.

Plumb’s Veterinary Drug Manual lists the following specific dosages:

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

The FDA has approved enalapril for dogs, but pet parents can use veterinary formulations or human versions. Doses can be given as tablets, oral suspension (liquid), or oil-based liquids. 

Can dogs overdose on enalapril?

In veterinary medicine, there is no standardized maximum enalapril dosage for dogs. Consider the prescribed dose to be the maximum dosage.

An enalapril overdose will cause blood pressure to drop. A large enough overdose can cause a dangerous drop in blood pressure. If it’s large enough, the overdose can kill a dog. 

Call a veterinarian or the ASPCA Animal Poison Control Center if a dog has been given too much enalapril or gotten into the medicine. A veterinarian may need to treat the dog or at least monitor it for a few hours.

Can I give my dog enalapril every day?

Pet parents can expect to give their dog enalapril daily for months or years. For serious conditions like chronic kidney disease or heart failure, the dog may never stop taking enalapril. Fortunately, it’s a safe drug for daily use. Side effects aren’t that common and are mild when they happen. Regular visits to the vet can prevent serious problems. 

How to give your dog enalapril

Pet parents can usually expect to give two doses daily, one in the morning and one in the evening. Some vets will prescribe once-daily doses. When giving doses, pet caregivers have a choice between using tablets or liquid versions.

  • Only give a dog enalapril if a veterinarian has prescribed it.
  • Give the doses exactly as prescribed.
  • Don’t miss doses. Enalapril is a long-term daily medication that can help extend the dog’s life.
  • Do not stop giving enalapril to the dog until consulting with the veterinarian. Enalapril does not need to be tapered when discontinued, but heart, kidney, or blood pressure problems will return unless a substitute is in place.
  • Doses can be given with or without food. If the dog experiences digestive system problems, try giving doses with a meal or a snack.
  • If you don’t know how to give a dog tablets, ask a veterinary professional to demonstrate the most effective procedure.
  • Enalapril oral suspension or oil-based liquid may need to be shaken before measuring a dose.
  • Always use the calibrated oral syringe or dropper that comes with the liquid to measure doses.
  • If you forget a dose of enalapril, give it when remembered. If it’s almost time for the next dose, skip the missed dose and give the next dose at the regular time. 
  • Store enalapril tablets at room temperature. For the oil-based liquid or oral suspension, read the storage instructions. 

Enalapril alternatives for dogs

Veterinarians have other alternatives if enalapril doesn’t work. These include:

  • Other ACE inhibitors such as benazepril, lisinopril, ramipril, and captopril
  • Angiotensin receptor blockers (ARBs) such as telmisartan, losartan, or irbesartan for heart failure, proteinuria, kidney disease, or high blood pressure
  • Other high blood pressure medications or diuretics for hypertension

For blood pressure problems, veterinarians usually start with ACE inhibitors like enalapril. They’ll continue treatment if it works and doesn’t cause serious problems. If treatment doesn’t lower blood pressure enough, they may add or switch to another blood pressure drug, such as:

Summary

Enalapril is a blood-pressure-lowering drug commonly used in dogs. It’s safe, effective, and has minimal side effects when used as directed to treat heart failure, kidney problems, and high blood pressure. Because benazepril treats serious conditions, keep all vet appointments so the veterinarian can monitor the dog’s progress.