Clopidogrel
Clopidogrel bisulfate
Also known as: Plavix · Antiplaq · Clodian · Cloflow · Clopact · Clopivas · Clopod · Iscover · Iskimil · Nabratin · Noklot · Pleyar · Troken · SR-259990C · PCR-4099 · clopedogreli · Clopidogrel bisulfate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an anti-platelet agent | 1-3 mg/kg PO once daily; if used with aspirin give lower doses (0.5-1 mg/kg PO once daily) | PO | once daily | — | 🌎 NA |
| Thromboprophylaxis | 1.1-4 mg/kg | PO | q24h | — | 🌍 EU |
- Thromboprophylaxis: A single loading dose of 4-10 mg/kg p.o. may help achieve therapeutic concentrations more rapidly.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| To prevent thrombus formation | 18.75 mg (practically, 1/4 of a 75 mg tablet) PO once daily | PO | once daily | — | 🌎 NA |
| To prevent thrombus formation (combination therapy) | 7 mg (total dose) PO once daily in combination with aspirin 40-81 mg (total dose) every 3 days. | PO | once daily | — | 🌎 NA |
| To prevent thrombus formation | 1-3 mg/kg PO once daily; if used with aspirin give lower doses (0.5-1 mg/kg PO once daily) | PO | once daily | — | 🌎 NA |
| Thromboprophylaxis | 18.75 mg/cat | PO | q24h | — | 🌍 EU |
- To prevent thrombus formation (combination therapy): Clinical trials are needed to determine appropriate dosage and indications.
- Thromboprophylaxis: A single loading dose of 4-10 mg/kg p.o. may help achieve therapeutic concentrations more rapidly. Administer in a gelatin capsule to improve compliance due to bitter taste.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Clopidogrel is a potent oral platelet aggregation inhibitor (thienopyridine class) widely used in veterinary medicine to prevent dangerous blood clots (thromboembolism).
- Feline Medicine: It is frequently used to prevent Feline Aortic Thromboembolism (FATE) in cats with underlying heart disease (e.g., Hypertrophic Cardiomyopathy). It may also improve pelvic limb circulation after an embolic event via vasomodulating effects.
- Canine Medicine: Used to manage hypercoagulable states associated with conditions like Immune-Mediated Hemolytic Anemia (IMHA), Protein-Losing Enteropathy/Nephropathy (PLE/PLN), and hyperadrenocorticism.
Clinical Pearl: Clopidogrel is notoriously bitter. Cats may hypersalivate profusely if they taste the tablet. Placing the dose inside an empty gelatin capsule is highly recommended to ensure compliance.
Mechanism of action
Clopidogrel is a prodrug that requires hepatic biotransformation (via CYP450 enzymes) to its active, highly unstable thiol metabolite.
- The active metabolite → binds selectively and irreversibly to the P2Y12 subtype of ADP-receptors on the platelet surface.
- This blocks ADP binding → prevents activation of the glycoprotein IIb/IIIa complex.
- Without this complex, platelet-fibrinogen binding cannot occur, effectively halting both primary and secondary platelet aggregation.
- It also inhibits the release of other pro-aggregation compounds (serotonin, calcium, thromobospondin).
Because the binding is irreversible, the platelet is inhibited for its entire lifespan (approximately 7-10 days). Normal coagulation only returns as new platelets are synthesized.
Safety & warnings
Contraindications
- Active pathologic bleeding
- Known hypersensitivity to the drug
Adverse effects
- Vomiting
- Anorexia
- Bleeding/hemorrhage
- Diarrhea
- Rashes
- Thrombotic thrombocytopenic purpura (TTP) - rare in humans
Precautions
Bleeding Risk: Use with caution in patients at risk for bleeding from trauma, surgery, or other pathological conditions. Pregnancy/Nursing: FDA Category B in humans. Probably safe in nursing veterinary patients, but weigh potential risks to offspring or use a milk replacer.
Drug interactions
Increased risk for bleeding; however, many patients take both medications intentionally for dual antiplatelet therapy.
Clopidogrel appears safe to use concurrently with heparin.
Increased risk for bleeding; clopidogrel may interfere with NSAID metabolism.
Clopidogrel may interfere with phenytoin metabolism.
May decrease the efficacy of clopidogrel by inhibiting CYP2C19, the enzyme needed to convert clopidogrel to its active metabolite.
Clopidogrel may interfere with torsemide metabolism.
Increased risk for bleeding; clopidogrel may interfere with warfarin metabolism.
High risk of bleeding complications
Monitoring
- Clinical efficacy (prevention of thromboembolic events)
- Adverse effects (vomiting, anorexia)
- Signs of bleeding (petechiae, ecchymosis, melena, epistaxis)
Pharmacokinetics
Half-life
Absorption
In humans, rapidly absorbed with ~50% bioavailability. Food does not alter absorption.
Distribution
Highly bound to plasma proteins in humans. Distributed into milk in rats.
Metabolism
Requires hepatic biotransformation to an active, highly unstable compound. Rapidly hydrolyzed to an inactive carboxylic acid derivative.
Elimination
Excreted via urine and feces.
Overdose
Limited information is available. Reported lethal oral doses for mice and rats were 1500 mg/kg and 2000 mg/kg, respectively.
Clinical Signs: Acute toxic signs may include bleeding or vomiting. Treatment: Platelet transfusions have been suggested if rapid reversal is required.
Available products
Formulations
- Oral tablets
- Compounded oral suspension
Human-labeled
- Clopidogrel Bisulfate Tablets: 75 mg & 300 mg (Plavix)
Regulatory status
POM (Prescription Only Medicine)
POM-V
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets at 25°C (77°F); excursions permitted to 15-30°C (59-86°F). Compounded oral suspensions (5 mg/mL in Ora-Plus/Ora-Sweet) retain >90% potency for 60 days at 5°C and 25°C, but must be protected from light.
Client information
- Purpose: This medication helps prevent life-threatening blood clots.
- Administration: May be given with or without food. If vomiting occurs, give with food.
- Feline Tip: This medication is extremely bitter. Do not crush it or let it dissolve in your cat's mouth, as it will cause severe drooling. Hiding the pill fragment inside an empty gelatin capsule or a pill pocket is highly recommended.
- Bleeding Risk: Because it stops blood from clotting, watch for unusual bruising, bleeding from the gums, nosebleeds, or black, tarry stools. Report any of these signs to your veterinarian immediately.
- Appetite: Report any lack of appetite or persistent vomiting to your veterinarian.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.