Medically Reviewed by Taylor Froiland, PharmD, RPh
Written by Adam McCown, PharmD
Aspirin for dogs is given for much the same reason that we all take aspirin. Namely, to relieve pain and inflammation. We’ve talked many times in past articles about how we aren’t all that different from our four legged friends. But is it safe to ever share human over the counter medicines with our pets? After all, nearly every household has a bottle of aspirin or ibuprofen, and many people consume these types of medications regularly for headaches, swelling, or other mild types of pain.
So if you notice that they are in pain, should you use aspirin for dogs? Well, it’s complicated. First of all, although dogs and humans are very similar in many ways, different drugs can affect different species differently. If you notice that your dog is not acting like themselves, is experiencing swelling, or just appears like they are in pain, it’s best to contact your veterinarian or bring your dog in to see them. Aspirin for dogs can result in some serious side effects that can be different from those in humans.
With that said, vets do prescribe aspirin to dogs in certain circumstances. In most cases, aspirin is given to dogs to treat osteoarthritis or musculoskeletal inflammation, as well as pain caused by other types of inflammation.
How Does Aspirin Work in Dogs?
Aspirin is a type of drug that is similar to carprofen, ibuprofen, and naproxen. All of these are in a class called NSAIDs or non-steroidal anti-inflammatory drugs. They help reduce inflammation and its associated pain, swelling, fever, and discomfort by targeting enzymes that produce the prostaglandins, which is the substance that induces all of those effects. This process is the same in dogs as is it is in humans.
However, unlike humans, vets will also prescribe aspirin to dogs for conditions of chronic pain. In these cases, dogs may be directed to receive aspirin on a daily basis. Another example is aspirin being used by vets to treat hypertrophic cardiomyopathy or other diseases associated with excessive blood clots. This is due to the fact that all NSAIDs act as blood thinners in both dogs and humans.
The fact that dogs may be prescribed aspirin for different applications than humans underscores the reason why you should contact your vet before medicating your dog on your own. This is made even more important because there are serious side effects of aspirin for dogs.
Is Dog Aspirin Safe
Like we mentioned, it can be tempting to just pop some pills out of the cabinet and give them to your dog if you notice they are in pain. The reason that that is problematic, for starters, is that dogs are all very different from one another. There are different breeds, different sizes, different ages, different medical histories, and different current medical conditions—and all these factors change the dosages and concentrations that are appropriate for a given patient.
So is aspirin safe for dogs? The answer is that it can be. But if given incorrectly, then possible side effects of aspirin include:
- Vomiting and diarrhea
- Gastrointestinal bleeding or ulcers (hole in the stomach lining)
- Ineffective pain relief that's not worth the risk (baby aspirin)
- Loss of appetite
- Kidney or liver problems
- Bleeding disorders
If you give too much aspirin to dogs it can result in mild to severe bleeding in their stomachs. This, in turn, can lead to symptoms like black or bloody stool, vomiting blood, and weight loss. If you notice any of the above side effects then you should stop giving aspirin to your dog and contact your vet right away. Furthermore, if they experience severe hemorrhaging, severe vomiting, or seizures, then that could mean your dog is overdosing on aspirin and you should seek emergency medical attention right away.
Aspirin Dosage for Dogs
Obviously, with all these serious side effects, aspirin is not something to give to your dog lightly. It is not a drug you want to mess around with. This makes it extremely important to follow your vet’s instructions carefully if they prescribe aspirin to your dog. Because aspirin for dogs is not approved for animal use by the FDA, there aren’t many studies that have determined a uniform dosage. Despite this, pet medical professionals usually recommend about 10-40mg per kilogram.
You should also confirm with your vet the specific type of aspirin to purchase for your pet. For example, enteric-coated aspirin tablets are designed to protect human stomachs from potential irritation, however, this type of aspirin is not recommended for dogs because about half the time the coating isn’t digested and the aspirin is excreted whole in the dog’s stool.
Conclusion: Aspirin for Dogs
Aspirin for dogs is generally considered safe and tolerable for dogs when prescribed, directed, and monitored by a veterinarian. However, different dogs (of different breeds, sizes, ages, and medical histories) have varying tolerances for the drug. Some animals may be allergic or hypersensitive, and the medication should be avoided if such sensitivities are known.
For this reason, always disclose to your veterinarian any and all medications that your dog is currently consuming, as well any past medical conditions. Drugs that have been known to interact negatively with aspirin in dogs include Phenobarbital, corticosteroids, furosemide and other NSAIDs.
If your vet determines that aspirin is the proper treatment for your dog, then only use as directed and be sure to always pay close attention to dosage.