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People use aspirin, also known as acetylsalicylic acid, for all kinds of ailments, so you might be tempted to give it to your dog to ease their fever or pain. After all, aspirin is easy to get over the counter, and it works so well in humans. But does aspirin work for dogs?
It’s not as easy as following an aspirin dosage chart for dogs. Aspirin can have serious side effects in dogs and can even be fatal, so it should never be given without guidance from a veterinarian.
What Is Aspirin Used for in Dogs?
According to Dr. Carly Fox, Senior Veterinarian in the Schwarzman Animal Medical Center’s Emergency & Critical Care Service, aspirin is an NSAID (non-steroidal anti-inflammatory drug) so it can help with pain and inflammation and reduce fever as well as being an antiplatelet medication that prevents blood from clotting. However, she says because the risks outweigh the advantages, “There are truly few benefits to using aspirin in dogs.”
That doesn’t mean your vet will never prescribe aspirin for your dog. But it has a very narrow use in veterinary medicine. Dr. Fox says it was previously used for diseases that put a dog at high risk for blood clots, such as immune-mediated hemolytic anemia, but now there are safer and more effective medications for those conditions such as clopidogrel.
So whether your dog has a fever or you see signs of pain in your dog, like shaking, unexpected aggression, panting excessively, or difficulty moving, don’t just grab your own aspirin and dose your dog. Alternative medications are likely a better choice. Dr. Fox warns, “Do not give your dog aspirin without direct instructions from a veterinarian. At this time, there are much more effective and safer medications, and aspirin use is out of favor in vet med.”
How Aspirin Works in Dogs
Aspirin is an NSAID just like ibuprofen or naproxen, which are medications that are geared to humans and can be extremely harmful to dogs. Aspirin works by inhibiting cyclooxygenase (COX) enzymes. These COX enzymes are responsible for the production of prostaglandin and thromboxane, chemicals that lead to pain and inflammation in the body. Therefore, blocking COX enzymes helps to reduce pain and inflammation.
But there are two types of COX enzymes, and they are expressed differently in the body. COX-1 protects the lining of the gastrointestinal tract, helps platelets clot, and helps with blood flow through the kidneys. COX-2 is expressed when there is inflammation and drives pain.
“Ideally, you want to choose an NSAID that selectively blocks COX-2 and spares COX-1 due to the potential for side effects,” says Dr. Fox. “No NSAID does this perfectly, but the ones we recommend in veterinary medicine are preferential for COX-2.”
How to Administer Aspirin
As injectable or topical forms of aspirin aren’t used in veterinary medicine, if prescribed, the drug will be given orally to your dog. As aspirin isn’t approved for veterinary use by the Food and Drug Administration (FDA), there are no definitive studies on effective dosages. You must follow the advice of your veterinarian.
The aspirin your vet might prescribe to your dog is essentially the same aspirin used for humans. But coated aspirin, helpful for protecting human stomachs, isn’t recommended for dogs. They can’t reliably dissolve the coating which can lead to unpredictable absorption of the drug. Most importantly, Dr. Fox advises never using aspirin together with another NSAID or steroid as this can intensify toxicity.
Side Effects and Aspirin Toxicity
Dr. Fox explains that the only potential benefit of aspirin in dogs is its reduction of the formation of blood clots since this can be seen at lower doses. To achieve anti-inflammatory effects or pain relief you need to use higher doses which come with adverse side effects. NSAID toxicity can lead to gastrointestinal upset, ulceration, and bleeding, as well as acute kidney injury. The signs to watch for include:
- Vomiting
- Diarrhea
- Black or tarry poop (known as melena), which is caused by bleeding in the upper gastrointestinal tract
- Excessive urine production (known as polyuria), which will exhibit as frequent urination or potty-training accidents
- Excessive thirst (known as polydipsia)
- Lack of appetite
- Seizures
Don’t use aspirin in pregnant dogs or those with certain medical conditions such as kidney failure or bleeding disorders. Be sure to talk to your veterinarian about any other medications your dog may be taking in case of drug interactions.
Alternative Medications
When you see signs of pain in your dog, it’s understandable that you’ll want to provide your pet with relief. For arthritis pain, Dr. Fox says there are many safer and more effective therapies available such as a veterinary specific NSAID, like carprofen. Unlike aspirin, these NSAIDs are selective COX-2 inhibitors which means less impact on the gastrointestinal tract and kidneys. There are also non-NSAID pain medications that your vet can prescribe for joint disease such as Librela.
Finally, don’t forget about alternative treatments. For example, nutraceuticals and supplements can provide benefits such as pain relief and lowered inflammation. Glucosamine and the omega 3s in fish oil are both popular joint supplements. CBD oil is another treatment that provides relief for pain, at least anecdotally. And there are drug-free pain relief alternatives like massage, hydrotherapy, and acupuncture for dogs. Dr. Fox says physical therapy exercises can also help with pain by keeping pets lean and their muscle mass high.
This article is intended solely as general guidance, and does not constitute health or other professional advice. Individual situations and applicable laws vary by jurisdiction, and you are encouraged to obtain appropriate advice from qualified professionals in the applicable jurisdictions. We make no representations or warranties concerning any course of action taken by any person following or otherwise using the information offered or provided in this article, including any such information associated with and provided in connection with third-party products, and we will not be liable for any direct, indirect, consequential, special, exemplary or other damages that may result, including but not limited to economic loss, injury, illness or death.