Toxic to cats · Medications

Is Aspirin toxic to cats?

Extreme severity

Yes, Aspirin is extremely toxic to cats. Even a small amount can be life-threatening, so treat any exposure as an emergency and contact a vet immediately.

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Is aspirin toxic to dogs and cats?

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What to do right now

  1. Call your vet or an animal poison line now, even if your cat seems fine and even if it swallowed only a small amount. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435.
  2. Don't try to make your cat vomit at home.
  3. Keep the packaging. Note the product and its strength, how many tablets may be missing, roughly when it happened and your cat's weight. If you gave your cat aspirin yourself, tell the vet how much and how often.
  4. Tell the vet if your cat already takes a steroid or another anti-inflammatory. Cats on these drugs have a higher risk of poisoning.
  5. Don't give Pepto-Bismol or any other remedy for an upset stomach. Pepto-Bismol contains bismuth subsalicylate, a salicylate that carries the same risk of poisoning.

Go to an emergency vet if

  • Your cat swallowed any amount of aspirin and you can't reach your vet or a poison line. Cats are much more sensitive than dogs, so don't wait for signs.
  • Your cat vomits or has diarrhea with blood in it, or passes black, tarry stools.
  • Your cat breathes fast or heavily, or feels hot.
  • Your cat is very weak or dull, trembles, has a seizure or collapses.
  • Your cat stops eating, or drinks or pees more or less than usual.

Symptoms to watch for

  • Vomiting
  • Diarrhea
  • Vomiting of blood
  • Black-tarry stool
  • Stomach ulcers
  • Hyperthermia
  • Respiratory changes
  • Bone marrow suppression
  • Kidney failure
  • Collapse
  • Extreme weakness
  • Tremors
  • Seizures
  • Cerebral edema
  • Change in thirst or urination
  • Death

How much is dangerous

Cats are much more sensitive to aspirin than dogs. They are short of an enzyme the liver uses to clear it (glucuronyl transferase), so the drug stays in their body far longer. The Merck Veterinary Manual puts the half-life of salicylate, the form aspirin takes in the blood, at close to 40 hours in cats, against about 7.5 hours in dogs. The half-life is the time the body takes to clear half of the drug. Merck reports that even the low doses vets have given cats long term to manage blood clots caused mild side effects, and it gives no toxic dose in mg/kg for cats. Don't use the dog figures to judge your cat's risk: treat any amount your cat swallows as an emergency.

When signs appear

Signs can start within 4 to 6 hours and may last several days. Cats clear aspirin very slowly, so don't wait for signs before calling your vet.

Why it's dangerous

Aspirin is a salicylate that can cause severe gastrointestinal ulceration, kidney failure, and central nervous system depression when ingested in toxic amounts. Cats are particularly sensitive due to their inability to metabolize the drug efficiently.

Toxic compound: acetylsalicylic acid

How vets treat it

There is no antidote. The vet may make your cat vomit and give activated charcoal to limit absorption. A drip (IV fluids) corrects dehydration and helps clear the drug, and in severe cases the vet may add sodium bicarbonate while monitoring the blood's acid-base balance. Treatment can also include anti-nausea medicine and stomach protectants, with blood tests to check the kidneys and liver. Your cat may need to stay in hospital.

Outlook

Cats are much more sensitive to aspirin poisoning than dogs, and signs may last several days. The outlook depends on the product, the amount swallowed and how quickly treatment starts. Early treatment gives the best chance of recovery.

Where pets are exposed

  • Aspirin (acetylsalicylic acid, or ASA) is sold under brand names such as Bayer, Bufferin and Ecotrin. It is an NSAID (non-steroidal anti-inflammatory drug) and belongs to a group of chemicals called salicylates.
  • Regular, chewable and extended-release tablets, including low-dose "baby" aspirin (81 mg). Aspirin also comes in creams, ointments and suppositories.
  • Combination remedies for pain, headache, colds and flu, such as Excedrin, Alka-Seltzer and Goody's Powder. These can also contain acetaminophen, caffeine, antihistamines, decongestants or opioids.
  • Other products that contain a salicylate: Pepto-Bismol (bismuth subsalicylate), oil of wintergreen (methyl salicylate), muscle rubs and liniments such as Bengay and Icy Hot, acne, wart and callus treatments, some shampoos, make-up and sunscreens. Some of these salicylates are more potent than aspirin.
  • A dose given by an owner for pain or an upset stomach before asking a vet. This happens with both dogs and cats.

Prevention

  • Never give aspirin, Pepto-Bismol or any other salicylate to a dog or cat without your vet's advice. The same goes for any human pain reliever.
  • Ask your vet about pain relief made for pets. Vets can prescribe anti-inflammatories made for dogs.
  • Store all medicines out of pets' reach, along with muscle rubs, wart and acne treatments and oil of wintergreen.
  • Never give aspirin on top of an anti-inflammatory or steroid your pet already takes.

Good to know

Cats are much more sensitive than dogs. Sources include Pepto-Bismol, topical acne/wart medications, liniments like BenGay or Icy Hot, and oil of wintergreen.

Common questions

Can I give my dog aspirin for pain?

Only if your vet prescribes it and sets the dose. Never give it on your own. Vets do sometimes use aspirin in pets, but the Merck Veterinary Manual says that even at the doses used for treatment, plain aspirin can damage the stomach lining and cause ulcers in dogs. Ask your vet for a pain medicine made for dogs instead.

Is baby aspirin safe for dogs?

Not without your vet. "Baby" aspirin is low-dose aspirin, 81 mg per tablet in the US, and it carries the same risks as regular aspirin: repeated doses can cause stomach ulcers in dogs. The Merck Veterinary Manual also says enteric-coated aspirin made for people is not recommended in dogs, because it can stay in the stomach and be absorbed unpredictably. Only give aspirin with your vet's prescription and dose, never on your own. If your dog ate some, call your vet or a pet poison line now.

How much aspirin is toxic to a dog?

It depends on the dose and how often it is given. In studies reported by the Merck Veterinary Manual, regular aspirin at 25 mg/kg every 8 hours caused erosions in the stomach lining in half of the dogs within 2 days, and 100 to 300 mg/kg a day for 1 to 4 weeks poisoned dogs. A single dose of 450 mg/kg can cause seizures or coma. Your vet works out the risk from the tablet strength and your dog's weight, so call with the packaging to hand.

Can I give my cat aspirin?

No, not unless your vet prescribes it. Cats are much more sensitive to aspirin than dogs: the Merck Veterinary Manual gives salicylate a half-life close to 40 hours in cats, against about 7.5 hours in dogs, so it stays in a cat's body far longer. Vets sometimes use aspirin in cats with heart disease to prevent blood clots, but newer, safer drugs are now preferred. If your cat swallowed any aspirin, call your vet now.

Is Pepto-Bismol safe for dogs and cats?

Don't give it without your vet's advice. Pepto-Bismol contains bismuth subsalicylate, a salicylate like aspirin, and it can poison pets in the same way. Cats are much more sensitive than dogs. If your pet swallowed Pepto-Bismol or you gave a dose, call your vet or a pet poison line now.

Sources

This page is informational and is not veterinary advice. If your pet has been exposed to something risky, contact your vet or an animal poison control line right away.

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