Aspirin for Dogs and Cats
Vet-reviewed by Dr. Pippa Elliott, BVMS MRCVS ·
What is Aspirin for Dogs and Cats
Overview
Aspirin is a medication that works by blocking cyclooxygenase (COX) enzymes—chemicals responsible for creating inflammation and pain. It also blocks the formation of thromboxane, a chemical that helps platelets form blood clots. Because of this, aspirin has both anti-inflammatory and anti-clotting benefits.
In dogs, aspirin has limited modern use because safer NSAIDs are available. In cats, aspirin must be used with extreme caution because they metabolize it very slowly. While aspirin can help with certain heart-related or clotting disorders, it has a narrow safety margin, making veterinary supervision essential.
Explore more joint and mobility medications in our Mobility section.
What Is Aspirin for Dogs and Cats Used For
| Condition | Notes |
|---|---|
| Inflammatory pain (dogs) | Used for arthritis or pain, but safer alternatives are usually preferred. |
| Fever reduction | Can lower fever but is rarely used for this purpose in modern vet practice. |
| Blood clot prevention | Sometimes used for heart disease or clot-related conditions in dogs. |
| Aortic thromboembolism in cats | Occasionally used for cats with heart disease, but dosing is difficult and risky. |
| Short-term pain relief in cats | Possible use, but only with strict veterinarian guidance due to toxicity risk. |
How Aspirin for Dogs and Cats Works
Aspirin inhibits COX-1 and COX-2 enzymes, reducing the creation of prostaglandins responsible for inflammation and pain. It also irreversibly inhibits thromboxane, decreasing platelet function and lowering the blood’s ability to clot. Because this effect is permanent for the life of the platelet, the drug’s anti-clotting actions persist well beyond the dosing period.
Drug Facts
Aspirin is an NSAID with analgesic, antipyretic, anti-inflammatory, and antithrombotic properties. Despite these uses, it has a high risk of stomach ulcers, kidney strain, and toxicity, especially in cats. Most veterinarians now choose newer drugs instead of aspirin for routine pain or inflammation.
Common Brands
AniPrin, Arthricare, Equi-Prin, Vetrin
Drug Class
NSAID (non-steroidal anti-inflammatory drug)
Substance Classification
Not a controlled medication
Generic Status
Generic widely available
Availability
OTC with vet guidance required
Aspirin for Dogs and Cats Dosage Forms
Aspirin is available in multiple human formulations, including tablets, buffered tablets, and enteric-coated tablets. In veterinary practice, non-enteric coated aspirin is preferred because enteric coatings may stick inside a dog’s stomach and lead to overdose or delayed absorption. Cats require very specific dosing schedules due to their slow metabolism.
Oral Tablets / Capsules (100 tablets)
| Qty/Size | Price as low as | Price per unit |
|---|---|---|
| 81 mg | $5.00 | $0.05 |
| 325 mg | $6.00 | $0.06 |
| 500 mg | $8.00 | $0.08 |
Typical Dosing For Aspirin for Dogs and Cats
Aspirin dosing varies greatly between dogs and cats, and incorrect dosing can cause severe toxicity. Dogs metabolize aspirin faster than cats, while cats have a very slow clearance rate, making overdoses easy even at typical human doses.
Veterinary guidance is mandatory before giving aspirin to any pet.
Oral Dosing
| Group | Typical Dose | Notes |
|---|---|---|
| Dogs (anti-inflammatory dosing) | 10–20 mg/kg every 12 hours | Can help inflammation but carries high GI and kidney risks. Safer NSAIDs are preferred. |
| Dogs (anti-clotting) | 0.5–2 mg/kg once daily | Lower doses have inconsistent platelet inhibition; individual responsiveness varies. |
| Cats (all sizes) | 10–20 mg/kg every 48–72 hours | Extreme caution required due to slow metabolism and high toxicity risk. |
Cats should NEVER receive aspirin without explicit dosing instructions from a veterinarian.
Risks and Warnings for Aspirin for Dogs and Cats
Aspirin has significant risks in both dogs and cats. The most common and serious complication is stomach and intestinal ulceration, which can appear suddenly and progress quickly. In cats, aspirin toxicity is even more severe because the drug remains in their system for a long time.
Other risks include vomiting, diarrhea, black stools, kidney damage, liver injury, bleeding disorders, fever, acidosis, tremors, seizures, and in severe cases, collapse. Because responses vary widely among pets, especially regarding platelet inhibition, aspirin is often replaced by safer and more predictable medications.
Aspirin for Dogs and Cats Warnings and Precautions
Use aspirin only under veterinary supervision and follow all safety guidelines:
- Do not give aspirin with steroids or other NSAIDs.
- Avoid aspirin in pets with stomach ulcers, kidney disease, or bleeding disorders.
- Non-enteric coated forms are recommended for animals.
- Avoid use before surgery or dental procedures.
- Keep pets from ingesting extra tablets due to risk of overdose.
- Monitor for vomiting, black stools, lethargy, or rapid breathing.
Disclaimer: This information is for educational purposes only and should not replace professional veterinary advice. Always consult your veterinarian before using or combining any medications for your pet.
Frequently Asked Questions (FAQ)
Can I give my dog human aspirin?
Not without veterinary approval. Human aspirin products can be dangerous, especially enteric-coated versions.
Is aspirin safe for cats?
Aspirin carries a high toxicity risk in cats and must only be given with precise veterinary dosing.
Why is aspirin no longer recommended for pain in dogs?
Modern NSAIDs are much safer and far more effective, with fewer risks to the stomach and kidneys.
Can aspirin be used to prevent blood clots?
Yes, in some cardiac or kidney conditions in dogs, but the dose must be extremely low and response varies.
What signs of aspirin overdose should I watch for?
Vomiting, diarrhea, black stools, fever, rapid breathing, tremors, or collapse require immediate veterinary care.
Related Medications & Supplements
Dogs being considered for aspirin therapy may benefit from safer or more effective options for managing pain, inflammation, or joint issues. The following medications and supplements are commonly used as alternatives or adjuncts to aspirin.
- Carprofen: prescription NSAID used for osteoarthritis and post-surgical pain
- Meloxicam: NSAID option for chronic inflammation and joint pain
- Piroxicam: NSAID sometimes used for inflammation and certain cancers
- Tramadol: opioid-like pain reliever for moderate pain
- Gabapentin: nerve pain medication often paired with NSAIDs
- Amantadine: medication that helps reduce chronic pain when combined with other treatments
- Glucosamine: joint supplement that supports cartilage and mobility
References
- Thomason, J. M., Mooney, A. P., Price, J. M. & Whittemore, J. C. (2019) ‘Effects of aspirin and prednisone on platelet function and thromboxane synthesis in healthy dogs’, Frontiers in Veterinary Science, 6, 393. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6872492/
- Penny, R.H.C., et al. (1967) ‘Effects of Aspirin (Acetylsalicylic Acid) on the Haemopoietic System of the Cat’, British Veterinary Journal, 123(4), 154-161. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0007193517400546
- Haines, J. M. et al. (2016) Investigation into the causes of aspirin resistance in healthy dogs’, Journal of Veterinary Pharmacology and Therapeutics, 42(3). Available at: https://www.researchgate.net/publication/328194071_Investigation_into_the_causes_of_aspirin_resistance_in_healthy_dogs
- Cafer, S., et al. (2024) ‘Is acetylsalicylic acid use in cats contraindicated or limited indicated?’, Journal of Toxicological Studies, 2(2), 1486. Available at: https://pdfs.semanticscholar.org/b37e/fe93b8943058a9b66446c2338027cb233141.pdf
- Brooks, W. (2024) ‘Aspirin’, Veterinary Partner. Available at: https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951432
Editor
The Webvet Editorial Team is a collective of seasoned pet-care journalists, veterinary content specialists, and industry editors dedicated to delivering accurate, trustworthy, and compassionate pet health information. With decades of combined experience across veterinary reporting, pet wellness education, and consumer product research, our team works closely with veterinarians and certified pet experts to ensure every article is both evidence-based and easy to understand.
Veterinarian · BVMS MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty Puggle named Poggle, 3 cats and a bearded dragon.
