Medication Guide • Reviewed by Dr. Tiffany Delacruz, DVM
Vetmedin for Dogs
Vetmedin is a prescription medication for dogs with congestive heart failure or asymptomatic mitral valve disease. It increases the heart's pumping strength and opens up blood vessels.
What Vetmedin is used for in dogs
- Congestive heart failure from mitral valve disease
- Dilated cardiomyopathy
- Pre-clinical mitral valve disease (early intervention)
How it works
Pimobendan strengthens heart contractions and dilates blood vessels at the same time — reducing the work the heart has to do while improving its output.
Available formulations
1.25 mg chewable
2.5 mg chewable
5 mg chewable
10 mg chewable
Side effects to know
Common side effects
- • Mild GI upset
- • Decreased appetite
These usually resolve on their own. If they persist past the first few doses, ask your vet.
Call your vet immediately if you see
- ⚠ Worsening of heart symptoms
- ⚠ Severe lethargy
- ⚠ Collapse
Drug interactions
- • Concurrent ACE inhibitors (enalapril, benazepril) commonly co-prescribed but monitor closely
When not to use
- • Dogs with hypertrophic cardiomyopathy
- • Aortic stenosis
- • Severe acute liver disease
Monitoring during treatment
Periodic cardiology rechecks (typically every 3-6 months) with chest X-rays or echocardiogram to track disease progression.
Need a Vetmedin refill?
RexVet is the first 501(c)(3) non-profit online vet service in the U.S. Talk to a licensed veterinarian by video, get your dogs's Vetmedin prescription, and have it shipped through RexVetRx — all for $64.99 per visit.
Book a vet visit — $64.99Vetmedin for Dogs
Frequently asked questions
How long can a dog live on Vetmedin?
Many dogs with stage B2 or C heart disease live months to years on Vetmedin. Survival depends on the underlying disease, response to medication, and how early treatment started.
Can my dog skip a Vetmedin dose?
Try not to. Vetmedin's effect is most reliable when given consistently every 12 hours. Missing doses can lead to fluid accumulation. If you miss a dose, give as soon as you remember unless it's close to the next dose.
Can RexVet refill Vetmedin?
Yes, for an established heart disease case with current cardiology records. RexVet can manage chronic refills via video visit through RexVetRx.
Does Vetmedin work for all heart conditions?
No — it's specifically for systolic dysfunction (weak pumping). Dogs with hypertrophic cardiomyopathy (stiff, thick heart) typically should NOT take Vetmedin. Your vet will diagnose the specific type.
What if my dog suddenly worsens on Vetmedin?
Acute worsening of heart failure (severe breathing difficulty, blue gums, collapse) is an emergency. Go to an ER vet immediately — don't wait for a telehealth visit.
Medical review by Dr. Tiffany Delacruz, DVM
Chief Executive Officer & Lead Veterinarian, RexVet. Licensed in Florida, New York, and Virginia.
Last fact-checked: 2026-05-19
Sources
This page is an educational reference and does not replace veterinary advice. Always consult a licensed veterinarian before starting, changing, or stopping medication for your pet.