Vetmedin for dogs (pimobendan): uses and side effects

Vetmedin is the best-known brand of pimobendan, a prescription heart medicine for dogs. It helps a weakened heart pump more strongly and relaxes the blood vessels, so the heart has less to push against. Vets prescribe it for congestive heart failure caused by mitral valve disease or dilated cardiomyopathy, and for some dogs whose heart has enlarged but not yet failed. Most dogs who start it take it for the rest of their lives.

Many people land here looking for a dose. This site does not give doses for any medicine. The amount of pimobendan depends on your dog's weight, the stage of the heart disease, kidney function and the other medicines being given, and only the prescribing vet can set or change it. Everything else you are likely to need is below.

What is Vetmedin and what does it do?

Pimobendan does two things at once. It makes the heart muscle contract more effectively, and it widens the blood vessels leading to and from the heart. More blood moves with each beat, and less of it backs up into the lungs or belly.

It does not repair a leaking valve or a stretched heart muscle. It helps a damaged heart cope. Research in dogs with heart failure has linked it to better quality of life and longer survival, which is why it has become a standard part of treatment.

Which heart conditions it is used for

• Mitral valve disease. The most common heart disease in older small dogs. A worn valve leaks, and the heart enlarges to compensate.
• Dilated cardiomyopathy. The heart muscle becomes thin and weak. It is seen mostly in large breeds.
• Congestive heart failure. The stage of either disease at which fluid builds up and the dog coughs, breathes fast or tires easily.
• Before heart failure. In dogs with valve disease whose heart is clearly enlarged on X-rays or ultrasound, research has found that starting pimobendan early can delay heart failure, so vets often prescribe it at that point.

It is not for every dog with a heart murmur. A murmur with a normal-sized heart usually just needs monitoring. It is also avoided in a few conditions where a stronger contraction would do harm, such as a narrowed outflow valve. This is why the vet will want chest X-rays or a heart ultrasound before prescribing.

Heart medication for dogs: where pimobendan fits

The typical patient is an older dog in heart failure on three or four medicines together. Each does a different job, and one is not a substitute for another.

Old dogs with heart disease often have kidney disease too, and diuretics and ACE inhibitors both ask more of the kidneys. That is the reason for the regular blood tests. Do not stop or cut back any of these medicines yourself because the dog seems better. The dog seems better because of them.

How long does Vetmedin take to work?

The drug is absorbed quickly and begins acting on the heart within about an hour of a dose. What you notice at home depends on why it was prescribed.

• A dog in heart failure: easier breathing, less coughing and more interest in food and walks, often within the first few days to a week. The diuretic does much of the early work.
• A dog started before heart failure: usually no visible change. The aim is to put off the day symptoms begin.

If a dog in heart failure is no better after a few days, or is worse at any point, call the vet. Do not wait for the recheck.

Pimobendan side effects for dogs

Most dogs tolerate it well. The side effects that have been reported include:

• Reduced appetite
• Vomiting or diarrhea
• Tiredness or weakness
• Restlessness or wobbliness
• A faster or irregular heartbeat
• Fainting or labored breathing

Many of these are also signs of the heart disease itself getting worse, or of the other medicines, so it is hard to tell them apart at home. Report them and let the vet sort it out. Do not stop pimobendan on your own.

Tell the vet about everything else your dog takes. Some blood pressure and heart-rate medicines can blunt the effect of pimobendan. Arthritis pain is common in these dogs, and any pain relief has to be cleared with the vet because of the kidneys. Never give human painkillers: ibuprofen, naproxen, acetaminophen (paracetamol) and aspirin can seriously harm or kill dogs.

Giving it day to day

Can Vetmedin be given with food?

The long-standing advice, and the label instruction in some countries, is to give it on an empty stomach, around an hour before a meal, because food can reduce how much is absorbed. The US label for the chewable tablets does not require this, and some vets are relaxed about it, particularly if a little food is the only way the tablet goes down. Ask your vet which they want and then do it the same way every day.

Can I crush Vetmedin?

Ask before you do. The chewable tablets are flavored and designed to be eaten like a treat, and they are scored so that a part tablet can be given if that is what the vet prescribed. Capsules and other brands may have different rules. If your dog refuses it, tell the clinic. There are other tablet sizes, a liquid form and other ways to give it, and the vet or pharmacist can say what is suitable for the product you have.

Vetmedin missed dose

Call the clinic and ask what to do, since the answer depends on how late it is and how sick your dog is. Do not give two doses together to catch up. One late dose is rarely a crisis, but a dog in heart failure should not go without for long, so ring the same day if you have run out. Order refills before the last few tablets.

If your dog eats extra tablets

The chewable tablets are made to taste good, so a dog who finds the container may eat everything in it. An overdose can affect heart rate and blood pressure. Call your vet, an emergency clinic or an animal poison control line right away, and keep the container somewhere a dog cannot reach.

Generic pimobendan and other brand names

Pimobendan is sold under several brand names around the world, and approved generic chewable tablets are available in the US and some other countries. A generic approved by the medicines regulator contains the same active ingredient. Compounded versions, made up by a pharmacy, are a different thing and are not checked in the same way. Ask the vet before switching between any of them, and do not buy heart medicine from a source that does not ask for a prescription.

Call the vet today if

• Your dog is breathing fast or with effort while resting or asleep. Many vets ask owners to count sleeping breaths and to call if the number stays above about 30 a minute, or above whatever figure they have given you.
• Gums or tongue look blue, gray or very pale.
• Your dog faints, collapses or cannot settle to lie down.
• The cough is suddenly worse, or your dog brings up foam.
• The belly is swelling.
• Your dog has not eaten for a day or is vomiting up the medicines.
• Your dog has eaten more tablets than prescribed.

Struggling to breathe, blue gums and collapse are emergencies. Go to the nearest open clinic.

Questions to ask the vet

• What stage is my dog's heart disease, and what is this medicine expected to change?
• Do you want it given before food, and what if my dog will only take it with food?
• What should I do about a late or missed dose?
• What resting breathing rate should make me call?
• How often will we recheck blood tests, blood pressure and the heart?
• Is a generic suitable, and what will this cost each month?

Lifelong heart medicine and rechecks add up. Insurance for older pets generally does not cover a condition that is already on the record, so it helps most when it is in place before a heart problem is found. For the wider picture, see the guide to heart disease in senior dogs.

This page is general educational information about pimobendan (Vetmedin), not veterinary advice, and it gives no doses on purpose. Whether your dog should take it, how much, when and with which other heart medicines are decisions for your own veterinarian or a veterinary cardiologist. Never start, stop or change a heart medicine without asking them, and treat breathing difficulty as an emergency.