Toxic to dogs · Medications

Is Aspirin toxic to dogs?

Extreme severity

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

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What to do right now

  1. Call your vet or an animal poison line now, even if your dog seems fine. Early treatment gives the best chance of recovery. In the US: Pet Poison Helpline (855) 764-7661 or ASPCA Animal Poison Control (888) 426-4435.
  2. Don't make your dog vomit at home unless a vet or poison-line expert tells you to. Doing it yourself can put your dog in more danger.
  3. Keep the packaging. Note the product and its strength, how many tablets may be missing, roughly when it happened and your dog's weight. Tell the vet if it was a combination remedy or a skin product such as a muscle rub, which can contain other drugs too.
  4. Tell the vet about any medicine your dog already takes, especially a steroid or another anti-inflammatory. Dogs on these drugs have a higher risk of poisoning.
  5. Don't give Pepto-Bismol for an upset stomach. It contains bismuth subsalicylate, a salicylate that carries the same risk of poisoning.

Go to an emergency vet if

  • Your dog swallowed any amount of aspirin and you can't reach your vet or a poison line. Early treatment gives the best chance of recovery.
  • Your dog vomits blood or passes black, tarry stools. These can be signs of a bleeding stomach ulcer.
  • Your dog breathes fast or pants heavily, or feels hot.
  • Your dog trembles, has a seizure, is very weak or dull, or collapses.
  • Your dog drinks or pees noticeably more or less than usual. This can be a sign of kidney damage.

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

Dogs tolerate aspirin better than cats do, but repeated doses can cause stomach ulcers. In studies reported by the Merck Veterinary Manual, regular aspirin given at 25 mg/kg of body weight every 8 hours caused erosions in the stomach lining in half of the dogs within 2 days. At 35 mg/kg every 8 hours, four of six dogs had stomach ulcers by day 30. Dogs given 100 to 300 mg/kg once a day for 1 to 4 weeks were poisoned. A single large dose of 450 mg/kg can cause stomach and gut upset, a high body temperature, panting, seizures or coma. Dogs that already take a steroid or another anti-inflammatory, and dogs with kidney, liver or bleeding problems, are at higher risk. Your vet works out the dose from the tablet strength, how many tablets are missing and your dog's weight.

When signs appear

Aspirin is absorbed quickly from the stomach and gut: blood levels peak 30 minutes to 3 hours after it is swallowed. Signs can start within 4 to 6 hours and may last 24 hours or longer. Aspirin in creams and ointments can also pass through the skin into the blood. 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 dog vomit, then give activated charcoal to limit absorption. A drip (IV fluids) corrects dehydration and increases urine flow to help clear the drug. In severe cases with acid buildup in the blood, the vet may add sodium bicarbonate while monitoring the blood's acid-base balance. Anti-nausea medicines, acid reducers such as famotidine or omeprazole, sucralfate to coat ulcers, and misoprostol protect the stomach. Kidney function is checked at the start and again at 24, 48 and 72 hours.

Outlook

The outlook depends on the product, how much aspirin your dog swallowed and how much time passed before treatment. Early treatment gives the best chance of recovery. An overdose can cause severe acid-base problems, bleeding, seizures and coma, and can be fatal.

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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