Vetmedin Chew 5mg (Pimobendan) – 100 Chewable Tablets for Dogs | Heart Failure & MMVD Treatment

What Is Vetmedin Chew 5mg?

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

Vetmedin is the most widely prescribed cardiac drug in veterinary medicine for dogs with heart disease, and the only drug class with Level I evidence to delay the onset of congestive heart failure in preclinical mitral valve disease. It is recommended as first-line treatment by the American College of Veterinary Internal Medicine (ACVIM) consensus guidelines.

Which Dog Weights Is the 5mg Tablet For?

At the standard target dose of 0.25mg per tablet per dose, given twice daily, the 5mg tablet is most suitable for dogs in the 10–20kg range. The tablet is scored on both sides and can be halved (each half = 2.5mg) for intermediate weights.

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 under 10kg, see Vetmedin Chew 1.25mg (50 tablets).
For dogs over 20kg, a 10mg tablet is typically used.

50-Tablet Box Duration

How Pimobendan Works — The Dual Mechanism

Pimobendan is a benzimidazole-pyridazinone derivative that improves failing cardiac function through two simultaneous, synergistic 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 (myocytes) lose their ability to respond effectively to calcium signals. During each heartbeat, calcium floods into the cell to trigger muscle contraction — but the myofilaments (actin and myosin) become less sensitive to this calcium signal, producing weaker contractions.

Pimobendan directly increases the calcium sensitivity of the cardiac myofilaments. The heart muscle cells can now produce stronger contractions using the same calcium signal — without increasing intracellular calcium levels. This is the critical distinction from digoxin: digoxin works by raising intracellular calcium to force stronger contractions, which risks calcium overload, arrhythmias, and toxicity at doses not far above therapeutic. Pimobendan sensitises the myofilaments to existing calcium — achieving 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 cells. Elevated cAMP causes vascular smooth muscle to relax, dilating both arteries and veins:

• Arterial vasodilation (afterload reduction): The resistance the heart pumps against is reduced. The failing heart does less mechanical work for each unit of blood ejected.
• Venous vasodilation (preload reduction): Less blood backs up into the lungs. Pulmonary oedema and fluid accumulation are reduced.

The combination of a heart that pumps more effectively (inotropy) and vessels that offer less resistance (vasodilation) is called the “inodilator” effect. This synergy makes pimobendan uniquely effective for the failing heart: it increases cardiac output while simultaneously reducing the work the heart must perform to achieve it.

What Conditions Does Vetmedin 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, especially in Cavalier King Charles Spaniels, Dachshunds, Miniature Schnauzers, and other small-to-medium breeds
• Dilated cardiomyopathy (DCM) — particularly in large/giant breeds such as Dobermans, Great Danes, Irish Wolfhounds, and Boxers

Vetmedin is used in combination with furosemide (diuretic) and often an ACE inhibitor. Clinical evidence shows Vetmedin significantly improves quality of life and extends survival in dogs with CHF.

2. Preclinical MMVD (Stage B2) — Before Heart Failure Develops

This is one of the most important indications and one many owners don’t know about. Dogs with mitral valve disease can have a heart murmur for months to years before developing heart failure. The ACVIM consensus categorises these stages:

The Stage B2 recommendation is based directly on the EPIC trial (see below).

3. Preclinical DCM in Doberman Pinschers

Doberman Pinschers are predisposed to DCM, which can progress to sudden cardiac death without warning. When echocardiography identifies increased left ventricular end-systolic and diastolic diameters (even with no clinical signs), pimobendan is indicated to extend the time to CHF onset and prolong survival.

The EPIC Trial — 15 Months of Extra Time

The landmark EPIC (Effect of Pimobendan In dogs with preclinical mitral valve disease) trial was a randomised, placebo-controlled study in 363 dogs with Stage B2 MMVD. All dogs had a murmur ≥3/6 and echocardiographic evidence of cardiac enlargement.

Key results:

• Pimobendan extended the median time to onset of heart failure by approximately 15 months compared to placebo
• Dogs treated with pimobendan showed reduction in heart size during the preclinical phase
• Overall survival was prolonged by approximately 170 days across all dogs regardless of cause of death

This trial directly led to the ACVIM consensus recommendation that all Stage B2 dogs should start pimobendan.

⚠️ Critical: Give 1 Hour Before Food

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

Food reduces the bioavailability of pimobendan. The absolute bioavailability on an empty stomach is 60–63%. Simultaneous food intake reduces this significantly. Unlike Cyclavance (ciclosporin), Vetmedin should consistently be given before the meal, not after.

Practical approach:

• Morning dose: Give the tablet when the dog wakes up, before the morning meal
• Evening dose: Give the tablet approximately 1 hour before the evening meal
• The chewable beef-flavoured tablet is palatable enough for most dogs to take directly; it can also be hidden in a very small amount of food if needed, though ideally on an empty stomach

Contraindications

• Hypertrophic cardiomyopathy (HCM) — pimobendan increases cardiac output; in HCM (where the problem is stiffness and outflow obstruction, not weak pumping), this worsens the condition. HCM is common in cats, which is a key reason Vetmedin is generally not appropriate for cats with primary HCM.
• Aortic stenosis or other fixed obstructions — increased cardiac output cannot improve flow past a fixed obstruction and may worsen haemodynamics
• Severe hepatic impairment — pimobendan is primarily metabolised by the liver; severe liver disease significantly alters drug handling
• Atrial fibrillation or sustained ventricular tachycardia in preclinical Dobermans — the preclinical DCM indication has not been studied in Dobermans with significant arrhythmias

Drug Interactions

Side Effects

• Positively chronotropic effect (increased heart rate) — rare; dose-dependent; reduce dose if excessive tachycardia
• Vomiting — rare; dose-dependent; reduce dose if persistent
• Diarrhoea, anorexia, lethargy — rare and transient
• Increased mitral valve regurgitation — rare; observed in some dogs during chronic treatment; cardiac monitoring recommended
• Petechiae / subcutaneous haemorrhages — very rare; relationship with pimobendan not clearly established; resolves on withdrawal
• Blood glucose changes — monitor in diabetic dogs

Storage

• Do not store above 25°C
• Once the blister is opened and a tablet has been halved, use the remaining half within 3 days; return the half-tablet to the blister pocket and replace in the box
• The tablets are flavoured — store out of reach of animals to prevent accidental ingestion
• Keep out of reach of children. Accidental ingestion in a child can cause tachycardia, orthostatic hypotension, flushing, and headache — seek immediate medical advice.

Vetmedin for Cats — Important Note

The keyword “vetmedin for cats” is widely searched. Vetmedin is not licensed for cats and is generally not appropriate for cats. The most common feline cardiac disease is hypertrophic cardiomyopathy (HCM) — a condition where pimobendan is contraindicated because it increases cardiac output in a heart that is already struggling with outflow obstruction and diastolic dysfunction. Using pimobendan in HCM can worsen obstruction and hasten decompensation.

Pimobendan may be used off-label in cats with dilated cardiomyopathy or unclassified cardiomyopathy under specialist guidance, but this is a very narrow indication. Always consult a veterinary cardiologist before using pimobendan in a cat.

Frequently Asked Questions

Is pimobendan the same as Vetmedin?

Yes. Pimobendan is the active ingredient; Vetmedin is the brand name from Boehringer Ingelheim Vetmedica. Generic pimobendan products are available in some countries and contain the same active substance. The Vetmedin Chew formulation is a palatable chewable tablet specifically formulated for dogs.

When does my dog need to start Vetmedin?

Your cardiologist or vet will determine this based on echocardiographic and clinical findings. According to ACVIM consensus: Stage B1 (murmur, normal heart size) — not yet. Stage B2 (murmur ≥3/6 with cardiac enlargement) — start pimobendan now. Stage C (symptomatic CHF) — essential, usually combined with furosemide.

My dog accidentally ate extra Vetmedin tablets. What should I do?

Contact your veterinarian or emergency clinic immediately. Vetmedin overdose can cause tachycardia (increased heart rate), vomiting, ataxia, hypotension, and heart murmurs. The treatment is symptomatic; there is no specific antidote. Do not induce vomiting without veterinary guidance.

Can Vetmedin be stopped abruptly?

In dogs with symptomatic CHF, Vetmedin should not be stopped abruptly — the heart has become dependent on its inotropic and vasodilatory support. Stopping suddenly risks acute decompensation. If Vetmedin needs to be discontinued for any reason, discuss a transition plan with your vet. In preclinical B2 dogs, the risk of abrupt stopping is lower but should still be discussed with your vet.

How long will one box last?

50 tablets: a 20kg dog using one 5mg tablet twice daily uses 2 tablets per day — the box lasts 25 days. A 10kg dog using half a tablet twice daily uses 1 tablet per day — the box lasts 50 days.

Related products: Vetmedin Chew 1.25mg (50 tablets) — for dogs under ~10kg | Cardalis (Benazepril + Spironolactone) — common Vetmedin co-medication | Fortekor Plus (Benazepril + Pimobendan) — combined heart failure tablet