Medically Reviewed by Taylor Froiland, PharmD, RPh
Written by Adam McCown, PharmD
Pimobendan for dogs is used to treat congestive heart failure. It helps animals with serious heart problems live longer lives by aiding the heart to work more efficiently through the widening and opening up of the blood vessels leading to and from their heart. This dilation of the blood vessels decreases blood pressure and makes it easier for your dog’s heart to pump blood throughout their body. Additionally, over time, giving pimobendan to your dog will actually strengthen their heart.
Pimobendan is administered orally to dogs, usually in a chewable form. Although your veterinarian will give you instructions on dosage, frequency, and any tips for making the medication easier to give to your pet, typically pimobendan is given on an empty stomach about one hour before a meal. Usually it is administered twice a day at even intervals.
What We Know about Pimobendan for Dogs
In 2016, a study was undertaken called the Evaluation of Pimobendan In dogs with Cardiomegaly (EPIC). Its goal was to determine the efficacy of pimobendan in treating dogs with heart failure caused by preclinical degenerative mitral valve disease (MVD).
According to the study, EPIC sought to determine whether the administration of pimobendan to dogs with preclinical MVD would delay the onset of clinical signs. It was the largest prospective, blinded, placebo-controlled, randomized study to be conducted in veterinary cardiology to date. It involved 360 dogs recruited by 36 investigators across 11 countries in four continents.
The way the study worked was to recruit client-owned dogs with stage B2 MVD using the below criteria. 180 dogs were randomized to receive pimobendan at approximately 0.5 mg/kg/day, while a further 180 dogs were randomized to receive a visually identical placebo.
- ≥ 6 years of age
- Between 4.1 and 15 kg
- Evidence of preclinical MVD on auscultation (≥ grade 3/6 murmur) and echocardiography
- Evidence of cardiomegaly on radiography and echocardiography
By the time the study had concluded, nearly half of the participating dogs had developed congestive heart failure (CHF). The dogs in the pimobendan group took an average of 41 months to reach CHF, while the dogs in the placebo group took only 25.5 months. This study demonstrated that many of dogs will live longer and have a better quality of life if they are treated with pimobendan before the onset of clinical signs.
Side Effects of Pimobendan for Dogs
Although this study, along with other research, has shown that pimobendan is effective at treating and delaying congestive heart failure, there are potential side effects.
- Upset Stomach and Nausea – About one third of dogs treated with pimobendan experience some type of upset stomach. These symptoms may include vomiting, diarrhea, loss of appetite, and vomiting after eating.
- Lethargy – A common side effect of pimobendan for dogs is a lack of energy. This can present itself as difficulty running or a lack of desire to play. If your dog faints or loses consciousness while on the medication, bring them into the vet right away.
- Cough or Breathing Difficulties – Some dogs may experience coughing symptoms while taking pimobendan. You may also notice that they become out of breath quickly or begin to wheeze after physical activity.
- Apparent Weakness – The last common side effect of pimobendan for dogs is weakness and a lack of coordination. This may cause them to lose their balance and become even more lethargic because of difficulty standing up and moving around.
It’s important to remember that these are just the possible side effects of pimobendan. It’s not a sure thing that your dog will experience all of them or any of them and they should experience fewer effects the longer they are on the medication.
It does mean, however, that you should be sure to discuss your pet’s current and past medical history with your veterinarian. This will reduce the risk of drug interactions and of prescribing the medication to a dog of increased risk for side effects. If any of the above side effects of pimobendan become severe, then contact your vet right away.
You should note that pimobendan and similar drugs for cardiac problems do not cure the underlying issue. They simply improve heart function and allow your dog to live with their disease. This is still a very positive thing—your dog gets to enjoy a longer and better quality life, and you get to have them around for longer than you would otherwise. But it also means that your dog will most likely have to continue taking pimobendan for the duration of their life.
It is not recommended to give this drug to pregnant or nursing dogs, or dogs under 6 months of age. Furthermore, pimobendan has been associated with an increased incidence of abnormal heart rhythm (arrhythmia). However, the progression of congestive heart failure is also associated with an increased incidence of abnormal heart rhythm, so it is not completely known if this is a result of the medication or of the disease itself.
Pimobendan should also be avoided if your pet suffers from hypertrophic cardiomyopath, aortic stenosis, or other types of heart disease in which increasing the amount of blood pumped by the ventricles of the heart could be dangerous for the pet. Again, it is critical that you inform your vet of all your dog’s current and past health problems so they have a full picture and can make the correct medication prescription.
Pimonbendan for Your Dog
The recent research and studies all point towards the fact that dogs who receive this medication can both survive longer and have better quality of life scores than dogs receiving alternate cardiac treatments. For some breeds, the increased time until the onset of clinical signs and the increase in survival time can even be dramatic. If you and your veterinarian think your dog may benefit from trying pimobendan, then give the drug a try today.
At Express Vet Pharmacy, we can formulate the drug however your veterinarian thinks is best and at a lower price than traditional pharmacies. Click here to check out Pimobendan Compounded Oral Liquid.