Clopidogrel (bisulfate)

What is this medication for?

• Prevention of cardiogenic arterial thromboembolism (ATE) in heart disease; improves pelvic-limb circulation post-embolism (serotonin-release inhibition)
• Hypercoagulable states; thromboembolism prevention (e.g., heartworm-associated embolism, IMHA adjunct)

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.

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

• Vomiting, loss of appetite (Main veterinary effect — give with food)

Worth a phone call to your veterinarian

• Bleeding (major bleeding ~2% human pre-clinical rate) (Dose-related; higher with aspirin combo)
• Rare: TTP (<2 weeks onset), rash, diarrhea (Human reports)

⚠️ 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: Active pathologic bleeding; hypersensitivity
• has or has had: Stop ~1 week pre-surgery if possible; limited clinical experience in cats overall

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Aspirin
  • NSAIDs, warfarin
  • Proton pump inhibitors (omeprazole)
  • Heparins
  • Phenytoin, torsemide

Storage and handling

Room temperature. 75 mg human tablets; quartering is the practical feline approach.

Good to know

• Clopidogrel > aspirin for feline ATE prevention (superior platelet inhibition; different mechanism — ADP receptor vs COX-1). The related ticlopidine must NOT be used in cats (adverse reactions).
• Irreversible platelet binding → effect outlasts the drug: plan peri-operative discontinuation ~5–7 days ahead.
• In cats it also inhibits platelet serotonin release — rationale for use after a cardiogenic embolic event to improve collateral circulation.
• ¼ tablet daily of the human 75 mg product is the practical feline regimen; clinical efficacy trials remain limited (dosing largely extrapolated).