Pimobendan

What is this medication for?

• CHF from DCM or myxomatous mitral valve disease (MMVD)
• Heart failure from DCM (not HCM)

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

• Never use in cats with HCM — positive inotropy is contraindicated in obstructive/hypertrophic disease; only appropriate for feline DCM.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Poor appetite, low energy/tiredness, diarrhea (Common in field trials (30–38%))

Worth a phone call to your veterinarian

• Arrhythmias (atrial fibrillation, VPCs) (Uncommon, causation vs. underlying disease unclear)
• Worsening mitral valve lesions (in one comparative study vs benazepril) (Reported — recommend regular monitoring)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Hypertrophic cardiomyopathy, aortic stenosis, or any condition where increased cardiac output is functionally/anatomically inappropriate
• has or has had: Uncontrolled arrhythmias; not evaluated <6 months age, congenital heart defects, diabetes, breeding/pregnant/lactating

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Verapamil, propranolol (and by extension diltiazem, atenolol)
  • Labeled as safe with

Storage and handling

Room temperature, <25°C, dry place. Compounded formulations do not reliably match label absorption — use only the commercial chewable tablet.

Good to know

• Give ~1 hour before feeding — food affects absorption and label directs empty-stomach dosing.
• Never use in cats with HCM — positive inotropy is contraindicated in obstructive/hypertrophic disease; only appropriate for feline DCM.
• Considered essential first-line therapy (often alongside an ACE inhibitor) for canine DCM and MMVD-associated CHF — improves both survival and quality of life per QUEST study data.