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Can Dogs Take Aspirin? Dangers of Aspirin in Dogs (Vet Answer)

Written by: Dr. Maria Zayas DVM (Veterinarian)

Last Updated on April 10, 2024 by Dogster Team

Can Dogs Take Aspirin? Dangers of Aspirin in Dogs (Vet Answer)


Dr. Maria Zayas  Photo


Dr. Maria Zayas

DVM (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

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One of the most common questions a veterinarian will get is, “What can I give my dog for pain?” While we have many pain medication options for dogs available via prescription, owners usually mean what over-the-counter pain medications they can find in their cabinet to give their dog in an emergency.

For a long time, the best and safest pain medication available for people or dogs was aspirin, but if you ask a veterinarian this question now, they’ll say there are no safe over-the-counter pain medications for dogs. Why is this?

Aspirin presents a high risk of toxicity for dogs, and there are just so many safer alternative options that it’s rare to recommend aspirin for any purpose.

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What Is Aspirin?

Aspirin, also known as acetylsalicylic acid (say that five times fast), is a pain medication part of the NSAID family (Nonsteroidal Anti-Inflammatory Drug).

NSAIDs are used for the following purposes:
  • Pain control
  • Lowering inflammation
  • Decreasing clotting
  • Fever reducer

Aspirin’s long name is because it’s one of many salicylates, which are chemical compounds found in various products.

Some examples would be:
  • Pepto-Bismol (bismuth subsalicylate)
  • Pain creams (Bengay, Icy Hot)
  • Some foundations and concealers
  • Some topical acne products
  • Wintergreen oil

All these salicylates are NSAIDs but have varying levels of toxicity to dogs.

How Does Aspirin Work?

As an NSAID, aspirin works by blocking an enzyme—cyclooxygenase—from forming a chemical compound called prostaglandins. Prostaglandins do a lot of jobs in the body, such as triggering fevers, causing inflammation and pain, and helping platelets clot at the site of cuts. So, aspirin works to block this, thereby lowering fevers, treating pain and inflammation, and decreasing the body’s ability to clot.

Pills and bottle
Image Credit: JF4, Shutterstock

Why Isn’t Aspirin Safe in Dogs?

There are many different types of prostaglandins in the body, each doing those different jobs. Ideally, aspirin would only inhibit the production of the prostaglandins that cause pain, inflammation, and fevers while not triggering other side effects. When we talk about a medication like aspirin that inhibits everything like this, it’s called a non-selective COX inhibitor.

Aspirin has been replaced by many other NSAIDs or NSAID alternatives that more selectively inhibit the production of the prostaglandins we want to inhibit so that there is a lower risk of unwanted side effects.

The most common problem with aspirin, and what it is specifically worse for than the other NSAIDs, is that it will cause a lack of blood flow to the stomach cells, leading to cell death and the creation of stomach ulcers. Life-threatening bleeding into the GI tract can occur, but lack of blood flow to the kidney can also cause kidney damage, and other organs can also be affected. You can imagine how dangerous it is to pair a risk of bleeding with a risk of not clotting for the side effects of medication.

sad and worried border collie dog lying on a wood floor
Image Credit: Elayne Massaini, Shutterstock

Pregnant female dogs are at an even higher risk of aspirin toxicity as it can lead to high concentrations building up in fetuses leading to death and bleeding for the mother.

A single dose of aspirin or repeated dosing can both be toxic to dogs, so since it’s so dangerous compared to other pain medications and isn’t better at controlling pain than the others, aspirin is not safe to give to dogs.

One of aspirin’s lingering uses was as an anticoagulant or medication that prevents clotting. Even that has been replaced by a more effective, safer medication, leaving little use for aspirin in dogs.

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Signs of Aspirin Toxicity

  • Vomiting, especially with blood
  • Diarrhea
  • Any stool with a black, tarry appearance or blood
  • Lethargy
  • Pale or yellow gums
  • Abdominal pain
  • Rapid breathing
  • Seizures
  • Poor clotting
  • Weakness
  • Hyperthermia
  • Increased drinking and/or urinating
  • Sudden collapse

How Is Aspirin Toxicity Diagnosed in Dogs

The first step in diagnosing aspirin toxicity in dogs is checking for possible exposure to aspirin or similar salicylates, if possible, in any dog showing the above signs. Unfortunately, salicylate drug tests aren’t readily available for bedside testing in dogs, and the time it takes to get results is too long for emergencies.

In a suspected or confirmed aspirin toxicity case, blood work is needed to check in on the dog’s organs, red blood cell count (screens for anemia), and electrolytes. Platelets should not be affected as aspirin doesn’t cause a lack of production of platelets; instead, it stops them from binding together to form clots.

Treatment for Aspirin Toxicity in Dogs

Treatment for aspirin toxicity depends on how soon after ingestion a dog sees a veterinarian.

If a dog ingested aspirin only a couple of hours ago or less, a veterinarian can induce vomiting to bring it back up before it’s completely absorbed.

After inducing vomiting or for cases that were exposed several hours earlier, a veterinarian can give the dog activated charcoal, which will bind to the aspirin in their gut so that it cannot be absorbed into the body, which helps limit the toxic potential of the medication if they get to it in time.

a shih tzu dog being checked by two vets
Image Credit: KongNoi, Shutterstock

Sometimes the aspirin has already been fully digested, and it’s too late to intervene to try and stop or limit the uptake of the drug. Supportive care is all we have left for these cases. In mild cases showing little to no signs, a veterinarian may just screen their bloodwork and give stomach protectants to avoid stomach ulcers along with some hydration support. More severe cases may require hospitalization, including blood transfusions, oxygen therapy, anti-seizure medication, and IV fluids, among other things.

Alternatives to Aspirin in Dogs

Aspirin is specifically meant to treat inflammation-related pain, which in dogs usually means arthritis pain.

Alternative treatments for arthritis include:
  • Joint supplements – glucosamine, fish oil (omega-3 fatty acids), MSM, green-lipped mussel extract, Adequan injections
  • Other NSAIDs – carprofen, meloxicam, etodolac, deracoxib, robenacoxib, firocoxib
  • Alternative pain medications to NSAIDs – grapiprant, gabapentin, amantadine
  • CBD

Aspirin’s other main use in dogs historically has been its anti-clotting effect. It has been mostly replaced by clopidogrel which is a safer anticoagulant with far fewer side effects.

In humans, we would also rely on aspirin to lower fevers. In dogs, we focus on the fact that fevers help the body beat infections and do not intervene against fevers unless they are severe, and in that case, they are treated in alternative ways in the hospital.

Most of what’s on this list are prescription medications, but the joint supplements and CBD are available over the counter and can be used for arthritis pain though not acute episodes of pain, though aspirin wouldn’t have been good for that either.

Aspirin’s Drug Interactions

Aspirin can interact with several other medications, which can cause changes to how that medication works or how much aspirin is absorbed. Some examples of medications that should never be given to a dog that has also had aspirin and can increase their risk of side effects or change how the other medication works are:

  • Other NSAIDs
  • Corticosteroids – i.e., prednisone
  • Lasix (furosemide)
  • Digoxin
  • Spironolactone
  • Phenobarbital
  • Tetracyclines – only an issue for buffered aspirin

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While aspirin works for pain control and as an anticoagulant, we now have many safer and more effective alternatives for controlling pain and inflammation for dogs, in addition to better anti-clotting medication. Aspirin toxicity can occur from as little as a single dose of the medication, and while we used to think it had a relatively wide dosing range, new studies show that the safe dosing range may be significantly smaller than we used to think, making this medication too risky to give.

If your pet needs pain medication, the best thing to do is bring them to a veterinarian as soon as you can so they can treat them safely.

Featured Image Credit: Irin Fierce, Shutterstock

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