Enalapril for Dogs With Heart Murmur or Heart Failure
By Dr. Zubair Khalid, DVM, MS, PhD ·
Enalapril for dogs with heart murmur is a common heart medication that veterinarians prescribe to lower blood pressure and ease the heart's workload. It does not cure a murmur or reverse valve damage, but it can slow the strain on the heart and help control fluid buildup in dogs with congestive heart failure. Whether your dog needs it depends on the stage of disease, the size of the heart chambers, and whether fluid has started to accumulate in the lungs or belly.
This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Enalapril is an ACE inhibitor. It relaxes blood vessels so the heart does not have to push as hard [1].
- A murmur alone is not always a reason to start enalapril. Many dogs with a murmur and a normal-sized heart take no heart medication at all [2].
- Enalapril is most clearly used once a dog has congestive heart failure, meaning fluid has built up in the lungs or abdomen [3][4].
- Your veterinarian sets the dose based on your dog's weight, kidney values, blood pressure, and other medications.
- Routine bloodwork and rechecks are expected, because enalapril affects the kidneys and blood pressure [1].
What Enalapril Is and What Veterinarians Use It For
Enalapril is an angiotensin-converting enzyme inhibitor, usually shortened to ACE inhibitor. It is prescribed to both people and animals for high blood pressure, heart disease, and some forms of cardiomyopathy [1]. In dogs, it is one of the standard drugs used in the medical therapy of myxomatous mitral valve disease, the most common acquired heart disease and a leading cause of congestive heart failure in dogs [5].
Heart failure is not a single disease. It is a syndrome in which severe heart dysfunction prevents the cardiovascular system from keeping normal blood pressure, normal cardiac output, and normal venous and capillary pressures at the same time [3]. When pressures back up, fluid leaks into the lungs or abdomen, which is called congestive heart failure [3]. Enalapril works on the hormone system that drives much of that pressure problem.
Veterinarians also use enalapril for some kidney diseases, including chronic renal failure and protein-losing nephropathies, because it can improve blood flow to the kidneys and reduce protein loss in urine [1]. That is a separate use from heart disease, but it explains why your vet may ask about kidney values before and during treatment.
What Does Enalapril Do for a Dog's Heart?
Enalapril blocks an enzyme that produces angiotensin II. Angiotensin II narrows blood vessels and triggers hormone release that raises blood pressure [1]. By blocking it, enalapril widens the arteries and veins, which lowers blood pressure and makes it easier for the heart to do its job [1].
Think of it as reducing the resistance the heart pumps against. In a dog with a leaky mitral valve, blood squirts backward into the left atrium with every beat. The heart compensates by remodeling and enlarging. Enalapril does not seal the valve, but it reduces the pressure load that drives that remodeling and fluid backup.
This is why enalapril is described as a drug that modulates hemodynamics and targets the renin-angiotensin-aldosterone system, the hormone chain that controls blood pressure and fluid balance [5]. It is one part of a treatment plan, not the whole plan. Dogs with congestive heart failure often also receive a diuretic such as furosemide and an inodilator such as pimobendan [4]. Each drug does a different job.
When Does a Dog With a Heart Murmur Need Enalapril?
This is the question owners ask most, and the honest answer is: it depends on the stage.
A heart murmur means blood is flowing in a turbulent way, often because a valve is leaking. Many dogs with a murmur have an enlarged heart or thickened walls but no signs of failure, because the body compensates for those changes [2]. Those dogs are not in heart failure and are not in congestive heart failure [2]. For a dog like this, the decision to start enalapril is not automatic.
Coughing is a common worry. Owners often assume a cough means heart failure. A recent study found that only severe left atrial enlargement, with a left atrial-to-aortic ratio above 2.29, increased the probability of coughing in dogs with myxomatous mitral valve disease. Congestive heart failure itself was not an independent predictor of coughing [6]. In other words, a coughing dog with a mildly enlarged heart may be coughing for another reason, such as airway disease. Your vet needs imaging and an exam to sort that out.
When a dog does reach congestive heart failure, with fluid in the lungs or abdomen, enalapril becomes part of standard therapy [3][4]. This is the setting where the drug's benefit is best established. If your dog has been diagnosed with congestive heart failure, you can read more about what that stage means in Canine Congestive Heart Failure: Staging and Therapeutic Plan.
If your dog has a murmur but no diagnosis yet, What to Expect at Your Dog's Vet Visit for a Heart Murmur walks through the tests your vet will likely recommend.
How Enalapril Is Dosed and Given
Your veterinarian calculates the dose from your dog's body weight, kidney function, blood pressure, and other medications. There is no single dose that fits every dog, and this article will not give one. Do not adjust the dose on your own, and do not give a human enalapril tablet unless your vet has specifically calculated it for your dog.
Enalapril is usually given by mouth, often once or twice daily. It can be given with or without food, but keeping the routine consistent helps. If your dog is picky, ask your vet or pharmacist whether the tablet can be hidden in a small treat or compounded into a liquid.
If you miss a dose, give it when you remember, unless it is almost time for the next one. In that case, skip the missed dose and go back to your normal schedule. Never double up to make up for a missed pill. Call your vet if you are unsure.
Side Effects of Enalapril in Dogs
Most dogs tolerate enalapril well, especially when the dose is started low and adjusted. Still, side effects happen, and some are serious.
| Side effect | How common or serious | What to do |
|---|---|---|
| Low blood pressure (hypotension) | Can occur, more likely in pets with underlying kidney or heart disease [1] | Call your vet. Weakness, wobbliness, or collapse needs urgent care |
| Lethargy and weakness | Reported with excessive amounts [1] | Contact your vet if your dog is unusually tired or will not get up |
| Vomiting and diarrhea | Reported with excessive amounts [1] | Call your vet, especially if it lasts more than a day |
| Increased kidney values | Possible because the drug changes kidney blood flow [1] | Detected on routine bloodwork, which is why rechecks matter |
| Reduced appetite | Uncommon but possible | Mention it at your next visit, or sooner if your dog stops eating |
Some of these signs overlap with the symptoms of heart failure itself, which makes monitoring tricky. That is one reason regular rechecks matter. If your dog seems worse after starting enalapril, do not assume it is the disease progressing. Call your vet and describe what you are seeing.
Who Should Not Take Enalapril, and What Interacts With It
Dogs with certain conditions may not be good candidates for enalapril, or may need a lower dose and closer monitoring. These include dogs with low blood pressure, dogs with significant kidney disease, and dogs that are dehydrated or have been vomiting. Because enalapril affects kidney blood flow and blood pressure, a dog who is already borderline on either can tip into trouble [1].
Drug interactions matter too. Enalapril is often combined with furosemide and pimobendan in dogs with congestive heart failure, and that combination is a recognized standard therapy [4]. Your vet knows how these drugs interact and will adjust doses accordingly. Do not add any new medication, supplement, or over-the-counter product without asking your vet first.
Tell your veterinarian about everything your dog takes, including joint supplements, flea and tick products, and anything you have left over from a previous prescription. Also mention if your dog has been diagnosed with kidney disease, because enalapril is sometimes used in kidney patients but requires careful monitoring [1].
Enalapril Overdose: When to Call for Help
Too much enalapril can cause low blood pressure, lethargy, weakness, vomiting, and diarrhea. These signs are more likely to develop in pets who already have kidney failure or heart disease [1].
If your dog ate more enalapril than prescribed, or you are not sure how much was swallowed, call your veterinarian or a pet poison control hotline right away. Do not wait for symptoms to appear. Have the pill bottle with you so you can tell them the strength and how many tablets might be missing.
If your dog collapses, has trouble breathing, or cannot stand, treat it as an emergency and go to the nearest veterinary hospital.
Limitations and When to Contact a Veterinarian
Enalapril is one tool in a treatment plan that also includes monitoring, dose adjustment, and sometimes other drugs. It does not reverse valve damage or cure heart disease. Response varies from dog to dog, and individual cases need a veterinarian who can examine your dog and review the test results.
Call your veterinarian the same day if your dog:
- Vomits repeatedly or has diarrhea that lasts more than a day
- Refuses food or seems suddenly weak
- Develops a new cough or a cough that is getting worse
- Breathes faster than usual while resting or sleeping
Go to an emergency clinic now if your dog:
- Collapses or cannot stand
- Breathes with obvious effort, with the belly moving hard, or with the mouth open
- Has gums that look pale, white, or blue
- Has a resting breathing rate that is clearly higher than your vet's target number
Keep a routine visit if your dog is stable but you have questions about dosing, refills, or side effects. Bring your medication list and note any changes you have seen since the last visit.
Frequently Asked Questions
Does a heart murmur always mean my dog needs enalapril?
No. Many dogs with a murmur have a normal-sized heart and no signs of failure, and they do not need heart medication at that stage [2]. Enalapril is most clearly indicated once congestive heart failure develops [3][4]. Your vet will use an exam, imaging, and bloodwork to decide.
How long does enalapril take to work in dogs?
Enalapril starts affecting blood pressure and blood vessel tone within hours, but the benefits you notice, such as easier breathing or less coughing, build over days to weeks as fluid control improves. Your vet will judge response at recheck visits instead of by a single day's change. Do not stop the drug on your own if you do not see a quick difference.
Can I give my dog human enalapril?
Only if your veterinarian has calculated the dose for your dog's weight and health. Human tablets come in strengths that may not match what your dog needs, and cutting them accurately can be hard. Ask your vet or pharmacist about the safest way to give the exact dose.
What should I monitor at home while my dog takes enalapril?
Watch breathing rate at rest, appetite, energy, and whether your dog seems weaker than usual. Your vet may ask you to count resting breaths per minute and write the number down. Bring those notes to every recheck, because they help your vet judge whether the dose is working.
Can enalapril be stopped suddenly?
Do not stop enalapril without talking to your vet first. Stopping heart failure medication suddenly can allow fluid to build up again and make breathing worse. If you are worried about side effects or cost, call your vet. There may be options, including a different dose or a different medication.
Related Articles
- Congestive Heart Failure CHF in Dogs: Mitral Valve Disease Treatment Progression
- What to Expect at Your Dog's Vet Visit for a Heart Murmur
- Dog Reverse Sneezing Heart Murmur
- Dog Heart Disease: How to Tell If Your Dog Is in Congestive Heart Failure
- Canine Congestive Heart Failure: Staging and Therapeutic Plan
- Dilated Cardiomyopathy in Dogs
- Heart Murmur Treatment in Dogs: Medications and Care
- Heart Murmur in Dogs: Symptoms, Grades, and When to Worry
- Enalapril for Dogs: Side Effects and What It Does
References
- What is Enalapril?. Pet Poison Helpline.
- Heart Failure in Dogs - Dog Owners. Merck Veterinary Manual.
- Heart Failure in Dogs and Cats - Circulatory System. Merck Veterinary Manual.
- Changes in hepatic and renal Doppler ultrasonography: Current standard therapy in dogs with congestive heart failure. Open veterinary journal, 2025.
- Evidence-based medical therapy for mitral regurgitation in dogs. Journal of veterinary cardiology : the official journal of the European Society of Veterinary Cardiology, 2026.
- Severe left atrial enlargement, but not congestive heart failure, increases the probability of coughing in dogs with mitral valve disease. Journal of the American Veterinary Medical Association, 2026.