Vetmedin Chew 1.25mg (Pimobendan) – 50 Chewable Tablets for Dogs | Heart Failure & MMVD Treatment

What Is Vetmedin Chew 1.25mg?

Vetmedin Chew 1.25mg is a scored, divisible chewable tablet containing 1.25mg pimobendan per tablet, manufactured by Boehringer Ingelheim Vetmedica. Each box contains 50 tablets (5 blister strips of 10).

Vetmedin 1.25mg is the smallest available strength of Vetmedin Chew — specifically designed for small dogs where precise dosing at low doses is critical. It is recommended by the American College of Veterinary Internal Medicine (ACVIM) as the first-line cardiac drug for dogs with symptomatic congestive heart failure and for Stage B2 preclinical mitral valve disease.

Which Dog Sizes Is the 1.25mg Tablet For?

At the standard target dose of 0.5mg/kg/day divided into two doses, the 1.25mg tablet is most suitable for dogs in the 2.5–10kg range. The tablet is scored on both sides and can be halved (each half = 0.625mg) for very small dogs.

Dose range: 0.2–0.6 mg/kg/day. Target: 0.5 mg/kg/day divided into two equal doses. Always determine bodyweight accurately before starting. Your vet may prescribe a specific dose that differs from this table.

For dogs over 10kg, see Vetmedin Chew 5mg (50 tablets) for easier dosing.

50-Tablet Box Duration

How Pimobendan Works — The Dual Mechanism

Pimobendan is a benzimidazole-pyridazinone derivative that improves failing cardiac function through two simultaneous mechanisms. Understanding this explains why it is so effective and why it works fundamentally differently from older heart drugs like digoxin.

Mechanism 1: Calcium Sensitisation — The Heart Pumps Stronger

In a failing heart, cardiac muscle cells lose their ability to respond effectively to calcium signals. During each heartbeat, calcium floods into the cell to trigger contraction — but the myofilaments become less sensitive, producing weaker contractions.

Pimobendan directly increases the calcium sensitivity of the cardiac myofilaments. The heart muscle can now produce stronger contractions using the same calcium signal — without increasing intracellular calcium levels. This is the critical distinction from digoxin: digoxin forces stronger contractions by raising intracellular calcium, which risks calcium overload and arrhythmias at doses not far above therapeutic. Pimobendan sensitises the myofilaments to existing calcium — stronger pumping without calcium toxicity risk.

Mechanism 2: Phosphodiesterase-III Inhibition — The Vessels Relax

Pimobendan also inhibits phosphodiesterase type III (PDE-III), the enzyme that breaks down cyclic AMP (cAMP) in vascular smooth muscle. Elevated cAMP causes vasodilation:

• Arterial vasodilation (afterload reduction): The resistance the heart pumps against is reduced — the failing heart does less work for each unit of blood ejected
• Venous vasodilation (preload reduction): Less blood backs up into the lungs, reducing pulmonary oedema

The combination of stronger pumping and less vascular resistance is the “inodilator” effect — uniquely suited for the failing heart because it increases output while simultaneously reducing cardiac workload.

What Conditions Does Vetmedin 1.25mg Treat?

1. Symptomatic Congestive Heart Failure (CHF) — ACVIM Stage C and D

Once a dog has developed congestive heart failure from:

• Myxomatous mitral valve disease (MMVD) / valvular insufficiency — the most common cardiac disease in dogs. Cavalier King Charles Spaniels are the most predisposed breed; also common in Dachshunds, Miniature Pinschers, Chihuahuas, Poodles, and other small breeds — exactly the dog sizes that use 1.25mg tablets
• Dilated cardiomyopathy (DCM) — less common in small dogs but possible

2. Preclinical MMVD Stage B2 — Delaying Heart Failure in Asymptomatic Dogs

Dogs with mitral valve disease can have a murmur for months to years before developing heart failure. The ACVIM staging system determines when pimobendan should start:

The Stage B2 recommendation comes from the landmark EPIC trial (see below).

3. Preclinical DCM in Doberman Pinschers

When echocardiography identifies dilated left ventricle measurements in an asymptomatic Doberman, pimobendan is indicated to extend the time to CHF onset. (Note: Dobermans typically require 5mg or 10mg tablets given their bodyweight.)

The EPIC Trial — 15 Months of Extra Time Before Heart Failure

The EPIC trial was a landmark randomised, placebo-controlled study in 363 dogs with Stage B2 MMVD. All dogs had a murmur ≥3/6 and echocardiographic evidence of cardiac enlargement (exactly what defines Stage B2).

Key results:

• Pimobendan extended the median time to onset of heart failure by approximately 15 months vs placebo
• Dogs on pimobendan showed reduction in heart size during the preclinical phase
• Overall survival prolonged by approximately 170 days

This means for your small Cavalier or Dachshund in Stage B2 — starting Vetmedin at this preclinical stage gives them, on average, an extra 15 months before heart failure develops. This is the most compelling argument for early diagnosis and treatment.

⚠️ Critical: Give 1 Hour Before Food

Give Vetmedin approximately 1 hour before feeding. This is the most important practical instruction.

Food significantly reduces pimobendan bioavailability. The absolute bioavailability on an empty stomach is 60–63%. Giving with or just after food can substantially reduce how much drug is absorbed.

Practical approach:

• Morning dose: Give when the dog wakes, before the morning meal
• Evening dose: Set an alarm — give the tablet 1 hour before the evening meal
• The palatable beef-flavoured chewable is accepted by most dogs directly; if the dog refuses, a very small food treat carrier is acceptable as a compromise

Contraindications

• Hypertrophic cardiomyopathy (HCM) — absolutely contraindicated. HCM involves outflow obstruction and diastolic dysfunction; increasing cardiac output with pimobendan worsens obstruction. HCM is the most common feline cardiac disease, which is why Vetmedin is not appropriate for most cats.
• Aortic stenosis or other fixed output obstructions
• Severe hepatic impairment — pimobendan is primarily liver-metabolised
• Not tested in preclinical Doberman DCM with significant arrhythmias (atrial fibrillation, sustained ventricular tachycardia)

Drug Interactions

Side Effects

• Increased heart rate (positive chronotropy) — rare; dose-dependent; reduce dose if excessive
• Vomiting — rare; dose-dependent
• Diarrhoea, anorexia, lethargy — rare and usually transient
• Increased mitral valve regurgitation — rare; has been observed during chronic treatment; warrants cardiac monitoring
• Petechiae / subcutaneous haemorrhages — very rare; resolves on withdrawal
• Monitor blood glucose in diabetic dogs

Storage

• Store below 25°C
• After halving a tablet, use within 3 days; return the half to the blister pocket in the cardboard box
• Flavoured tablets — store out of reach of animals (accidental self-administration is possible)
• Keep out of reach of children. In children, accidental ingestion may cause tachycardia, hypotension, flushing, and headache — seek immediate medical advice.

Vetmedin 1.25mg for Cats?

Vetmedin is not licensed for cats. The most common feline cardiac disease is hypertrophic cardiomyopathy (HCM) — for which pimobendan is contraindicated. Off-label use in cats should only be considered by a veterinary cardiologist in specific cases (such as DCM or unclassified cardiomyopathy where HCM has been definitively ruled out). Do not give Vetmedin to a cat without specialist veterinary guidance.

Frequently Asked Questions

My Cavalier King Charles Spaniel has a heart murmur. Does she need Vetmedin?

It depends on the stage. CKCS are the most commonly affected breed. With a Grade 3/6 or higher murmur and radiographic or echocardiographic evidence of cardiac enlargement (Stage B2), ACVIM consensus guidelines recommend starting pimobendan. With a lower-grade murmur and normal heart size (Stage B1), pimobendan is not yet indicated — regular cardiac monitoring every 6–12 months is recommended to catch the transition to B2.

Is the 1.25mg tablet different from the 5mg in any way other than strength?

No. Both are the same Vetmedin Chew formulation: brownish, oval, flavoured, scored chewable tablets. The only difference is the amount of pimobendan per tablet. The mechanism, indication, dosing frequency, and clinical performance are identical.

Can I give 1.25mg tablets to reach the same dose as 5mg tablets?

Yes — four 1.25mg tablets = 5mg. However, for dogs that need 5mg doses twice daily, the 5mg tablet is significantly more economical and more practical to administer. The 1.25mg tablet exists specifically for small dogs where a 5mg tablet would require difficult quartering.

My dog vomits after taking Vetmedin. What should I do?

Vomiting is a rare but recognised side effect of pimobendan, usually dose-dependent. Try giving the tablet 30–60 minutes after a very small amount of food (a few pieces of kibble or a small treat) rather than strictly fasted — some dogs tolerate this better. If vomiting persists, contact your vet; a dose reduction may resolve the issue.

Related products: Vetmedin Chew 5mg (50 tablets) — for dogs 10–20kg | Cardalis M (Benazepril 5mg + Spironolactone 40mg) — common Vetmedin co-medication | Fortekor Plus 1.25mg (Benazepril + Pimobendan combined tablet)