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Is Aspirin Safe for Dogs? 3 Risky Outcomes Pet Owners Should Know

Dr. Paula Simons

Reviewed by: Paula Simons, DVM

Is aspirin safe for dogs? The answer to this question is more complicated than you might think. Technically, aspirin is safe for dogs, but only when prescribed by a veterinarian.

Too many things can go wrong if you attempt to diagnose and treat your dog with aspirin (or any other over-the-counter non-steroidal anti-inflammatory).

For example, your dog may have underlying conditions that you’re not aware of. Kidney disease, liver disease, and blood clotting issues are a few examples.

Determining an accurate dosage is another problem to consider.

A licensed veterinarian can assess whether your dog would benefit from short-term aspirin use and will be able to determine an appropriate dose that won’t lead to aspirin toxicity.

Did you know?

Certain medications, when mixed with aspirin, can lead to serious side-effects, including internal bleeding. This includes natural or herbal supplements.

What can a pet parent do?

We love our dogs and we hate to see them in pain. It makes sense that pet parents sometimes find themselves wondering if there is anything in the medicine cabinet to help.

Dogs are wonderful at hiding their pain, but it doesn’t take long for an observant pet parent to realize something isn’t quite right.

This post helps explain why you should reconsider giving your dog aspirin and what to do instead.

Is Aspirin a Nonsteroidal Anti-Inflammatory Drug?

Yes, aspirin (acetylsalicylic acid or ASA) is a non-steroidal anti-inflammatory drug.

What Can Aspirin Treat?

It’s used to treat fever, pain, and inflammation. Aspirin also works as an anticoagulant to prevent blood clots. Anticoagulants thin the blood, making it a dangerous option for dogs with bleeding disorders like von Willebrand disease.

Even though NSAID’s like aspirin tend to have fewer side-effects than steroids, they can still leave your dog suffering from serious side-effects.

These side-effects, including signs of aspirin toxicity, are detailed later in this post.

brown and white hound dog peaking out from behind a sign that says Is Aspirin Safe for Dogs?

How Does Aspirin Ease Joint Pain in Dogs?

NSAIDs work by blocking two forms of an enzyme called cyclooxygenase (COX). COX-1 protects the stomach lining from digestive acids and helps maintain kidney function. COX-2 is produced when joints are injured or inflamed.

Blocking both forms of this enzyme reduces inflammation, pain, and fever, but can also cause gastrointestinal side effects.

Enzyme Blocking

Aspirin works by inhibiting two forms of enzymes known as cyclooxygenase.

The first type (COX-1) keeps stomach acids from eating away the stomach lining. It also helps to maintain kidney function. Since aspirin blocks this protection for the stomach lining, it can leave a dog with gastrointestinal side-effects.

The second type (COX-2) is only produced when joints are injured or inflamed. When both of these enzymes are blocked, inflammation, pain, and fever are reduced.


The enzymes mentioned above generate prostaglandins (lipids).

Think of them like the chemical messengers that trigger inflammation, pain, and fever. Prostaglandins will show up anywhere there is tissue damage or infection.

The process is a natural function designed to promote the healing process. Unfortunately, it hurts!

This is where aspirin comes in. By blocking COX-2, aspirin helps reduce the number of prostaglandins produced.

Which Over-the-Counter Drugs Contain Aspirin?

The active ingredient in aspirin is acetylsalicylic acid. Acetylsalicylic acid is one compound in a group of chemicals known as salicylates. Although some OTC medications have the word “aspirin” included in the name, some don’t.

You might recognize aspirin by its label. What you might not realize is that aspirin is also found in the following over-the-counter medications:

  • Zorprin
  • Bayer Buffered Aspirin
  • Durlaza
  • Asatab
  • Adprin-B
  • Alka-Seltzer Extra Strength with Aspirin
  • Alka-Seltzer with Aspirin
  • Arthritis Pain Formula
  • Ascriptin
  • Ascriptin Maximum Strength
  • ASA
  • Bayer’s aspirin (most Bayer’s products contain varying degrees of aspirin)
  • Bufferin, including Bufferin extra strength
  • Ecotrin
  • Empirin

It’s important to note that aspirin is one compound in a group of chemicals known as salicylates, and all salicylates can cause toxicity in dogs. The risk depends on the amount of aspirin ingested and the type of salicylate.

a variety of dogs in different sized frames with pinks and blues

The Risks of Administering Aspirin to Your Dog Without Veterinarian Approval

The risks of giving your dog aspirin without veterinarian approval were briefly noted above. The following risks are examined more closely.

1. Aspirin for Dogs Dosage

Aspirin was never meant for dogs, and it can be difficult to determine a dose that a) is enough to temporarily relieve pain, and b) isn’t so much that it causes toxicity.

Your veterinarian is in the best position to determine the proper dosage for your dog. He/she will assess the risk based on a number of things including:

  • Your dog’s health (whether your dog has underlying health conditions)
  • The severity of the dog’s condition
  • Your dog’s weight

In most cases, the veterinarian will likely prescribe pain medications designed for use in dogs. Some examples of these pain killers include:

  • carprofen
  • meloxicam
  • deracoxib
  • fibrocoxib
  • etodolac

2. Aspirin Toxicity

Aspirin is a trustworthy and secure over-the-counter remedy for pain and fever. Unfortunately, some pet owners mistakenly think that if it’s safe for them, it must be safe for their pet. That’s not always true.

The dosage given to a dog will depend on a variety of things including the dog’s weight, health, age, underlying conditions, and whether the dog is on any other medications or supplements.

Aspirin toxicosis occurs when an animal ingests enough of the medication to cause serious side-effects. The liver is the main organ responsible for breaking down aspirin.

Some of the aspirin byproducts are eliminated later through the kidneys.

Aspirin toxicity can occur if a pet accidentally swallows the medication, or if it has been administered too high a dose.

Signs of Aspirin Toxicity in Dogs

  • Lack of appetite
  • Vomiting – There may be red blood in the vomit.
  • Diarrhea
  • Lethargy
  • Fever
  • Dark, tarry feces (melena). This could indicate blood in the stool.
  • Difficulty walking due to central nervous system dysfunction

If you suspect your dog has ingested aspirin, call your veterinarian ASAP. If you cannot reach your veterinarian, call the pet poison helpline.

Animal Poison Control at (888) 426-4435.

Keep emergency numbers in your contact list for immediate reference.

Some dogs should never be prescribed aspirin.

There are some dogs that a veterinarian will not prescribe aspirin for. These include:

Pregnant Dogs

Pregnant dogs should never be given aspirin.


Puppies should not be given aspirin.

3. Potential Drug Interactions with Aspirin

Aspirin can interfere with the way certain medications work and can cause serious adverse reactions.

Drug interactions could prevent some medications from working properly, increase the risk of serious side-effects, or can cause some medications to become more potent than needed.

The following is a partial list of drugs that should not be taken with aspirin.

ACE Inhibitors

ACE inhibitors are prescribed to treat heart failure, high blood pressure, or proteinuria. Proteinuria means there is elevated protein in the urine.

The following medications are considered ACE inhibitors:

  • Enalapril
  • Benazepril
  • Imidapril
  • Ramipril


Alendronate is used to lower blood calcium concentrations. You may recognize this medicine under its trade name Fosamax. It belongs to a group of medicines called bisphosphonates.

Aminoglycoside Antibiotics

These are commonly used to treat bacterial infections and are effective against E. Coli, Proteus, Pseudomonas, Salmonella, Shigella, Serratia, and Enterobacter.

SSRI Antidepressants

The combination of SSRI (serotonin reuptake inhibitor) antidepressants combined with NSAIDs including aspirin, could increase the risk of gastrointestinal bleeding or hemorrhage.

You may be interested in: 5 No-Fail Steps to Weaning Prozac for Dogs.

Blood Glucose Lowering Agents

These medications are used to help stabilize dogs’ glucose levels.

Calcium Channel Blockers

Calcium channel blockers are used in veterinary medicine to treat various heart conditions in dogs. This includes systemic hypertension, atrial fibrillation, and hypertrophic cardiomyopathy.

Diltiazem HCI is an example of a calcium channel blocker used in dogs. Pet owners may recognize its brand names, including:

  • Cardizem
  • Dilacor XR
  • Tiazac
  • Diltia XT
  • Taztia XT
  • Dilt-XR


One of the most common corticosteroids used in dogs is known as prednisone. Prednisone is used to treat conditions such as pain and itching. It’s a synthetic steroid with anti-inflammatory properties and can be taken orally, topically, or by injection.

NSAIDS and corticosteroids should never be given together. If they are given together, your dog can suffer gastrointestinal problems including:

  • Poor appetite
  • Vomiting
  • Diarrhea
  • Bleeding stomach ulcers

This combination can also create holes within the gastrointestinal tract.

Keep in mind that these side-effects can occur even if your dog is administered corticosteroids or aspirin within days of each other. There should be a minimum 5 day interval between medications.

Carbonic anhydrase inhibitors

These drugs are used to treat glaucoma in cats and dogs. Pet owners may recognize this drug under the names:

  • acetazolamide
  • methazolamide
  • dorzolamide
  • brinzolamide
  • diclofenamide
  • ethoxzolamide
  • zonisamide


Digoxin is used to treat congestive heart failure and a condition in which the upper chambers of the heart (the atria) beat faster than usual. This drug has a small therapeutic range, which means that there isn’t much room between the dose that helps and the dose that could be harmful. 


Furosemide is a diuretic used to treat heart failure, lung fluid retention, and some kidney diseases. It can also be used to help treat high blood pressure and high potassium levels.


Glucosamine is a natural chemical compound in the body that also comes in the form of a supplement. This compound is what keeps the cartilage in joints healthy.

Some evidence suggests that glucosamine supplements may help dogs and people counter the effects of arthritis. Unfortunately, the combination of glucosamine and aspirin may decrease the ability of blood to clot properly.

It may also cause stomach irritation.

Carbonic anhydrase inhibitors

This drug, also known as methazolamide, is used to medically manage primary and secondary glaucoma in cats and dogs. Its primary function is to reduce the amount of fluid in the eye in order to lower eye pressure.

The combination of aspirin (especially in high doses) and methazolamide is not recommended. Side effects of this combination can cause:

  • Appetite loss
  • Rapid Panting/Breathing
  • Fatigue
  • Coma


Heparin is used to prevent blood clots from forming. Anticoagulants like heparin shouldn’t be given in conjunction with aspirin. Heparin may reduce the effects of corticosteroids, insulin, and other drugs.

Combining heparin and aspirin can lead to anticoagulant poisoning. Signs include:

  • Unstable or weak gait
  • Bleeding from the nose
  • Blood in vomit
  • Blood in stools
  • Rectal bleeding
  • Skin bruising
  • Swelling of the belly due to fluid accumulation
  • Difficulty breathing due to blood in the lungs


Phenobarbital is used to treat seizures in animals. It can also be used as a sedative. Phenobarbital can increase the amount of time it takes other medications to leave the body. It can also decrease the effectiveness of many types of medications.

Watch the following video on safe alternatives to aspirin for dogs!

Dog in Pain: 7 Effective Home Remedies

Potential Side Effects of Aspirin in Dogs

Aspirin can be hard on a dog’s gastrointestinal tract. Some potential side-effects could include:

  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Abdominal pain

If a veterinarian were to prescribe aspirin for your dog, it would only be for short-term pain relief. Aspirin isn’t a good choice for managing chronic pain. Long-term risks can lead to organ damage including kidney failure and liver damage.

Is Baby Aspirin or Low-Dose Aspirin Safer for Dogs?

Any type of aspirin, including baby aspirin, should only be prescribed by a veterinarian. Administering aspirin or even acetaminophen (Tylenol) to your dog is risky. The correct aspirin dosage is best left in the hands of a licensed veterinarian.

Is Coated Aspirin Safer Than Uncoated Aspirin for Dogs?

Your dog may be prescribed buffered aspirin by your veterinarian. Buffered aspirin is a combination of aspirin and an antacid which may be easier on your dog’s digestive system.

There is a difference between buffered aspirin and enteric-coated aspirin that you, as pet parents, should be aware of.

Buffered Aspirin

As noted above, buffered aspirin contains aspirin and an antacid.

Enteric Coated Aspirin

Enteric coated aspirin is just regular aspirin with a coating. The coating makes it easier for humans to swallow. Dogs, however, are unable to digest the coating.

Why a Veterinarian Might Recommend Aspirin for Dogs

Aspirin is a good drug for conditions that cause pain due to inflammation and can offer your dog some relief from symptoms.

The most common reason vets prescribe aspirin to a dog is for inflammatory-related health issues like osteoarthritis or musculoskeletal inflammation.

Some uses of aspirin for dogs could include:

Pain Relief

Used for pain relief in dogs. Pain may be due to dental disease, arthritis, leg injuries, etc.


Aspirin can decrease inflammation and fever in dogs.

Blood Thinner

Aspirin is a blood-thinning agent that can prevent the formation of blood clots. This can decrease the risk of stroke in dogs.

Natural Alternatives to Aspirin for Dogs

Your veterinarian may prescribe carprofen if your dog has osteoarthritis or another inflammatory condition. In addition, there may be non-medical alternatives to aspirin that are beneficial in reducing pain.


Although there is no definitive scientific data on the topic, there is anecdotal evidence that CBD may help reduce pain in dogs with arthritis.

A Cornell University College of Veterinary Medicine study determined that CBD administered at a rate of 4.4 mg per pound, twice daily for one month, showed significant improvement in pain relief.

Talk to a licensed veterinarian before administering CBD to your dog.

Joint Supplements for Pain Relief in Dogs

The two main forms of joint supplements recommended by veterinarians include glucosamine and chondroitin. Your veterinarian will be able to offer advice on the best quality supplements for your dog.

Physical Therapy

Physical therapy can be beneficial for dogs recovering from CCL surgery, hip dysplasia, elbow dysplasia, and other painful conditions.

Pulsed Electromagnetic Field Technology

PEMF therapy is useful in dogs with chronic conditions including orthopedic problems, acute wounds, or other painful conditions. This type of therapy works by sending magnetic energy into the body.

The energy waves work with the body’s natural magnetic field to improve healing. Specifically, PEMF has been used to treat:

  • Arthritis pain
  • Spinal cord injuries
  • Neurological conditions
  • Inflammation
  • Stiffness
  • Bone injuries

Healthy Lifestyle and Weight Management

Help your dog maintain a healthy weight to avoid adding strain on the joints. There are excellent weight management dog food formulations available.

Talk to your veterinarian about the best weight management plan for your dog, especially if your dog has underlying conditions like pancreatitis, diabetes, or allergies.

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Conclusion – Important Takeaways

Never give your dog over-the-counter medications meant for human use unless recommended by a veterinarian. Aspirin can cause severe problems with the digestive system. Too much aspirin can lead to toxicity and not enough aspirin can hurt your dog’s stomach but not do much to help the pain.

Aspirin is dangerous in dogs with bleeding ulcers or bleeding disorders like Von Willebrand disease. If you are unable to get your dog to a veterinarian right away, the best thing to do in the short term is to encourage your dog to rest.

Contact an emergency veterinary clinic if your dog has suffered a severe injury.

Works Cited

Burke, Anna. American Kennel Club: Aspirin for Dogs: Uses, Dosage, and Side Effects., Accessed 7 Aug. 2022.

Veterinarians.Org: Can I Give My Dog Aspirin? A Guide to Aspirin for Dogs Dosage and More!, 6 Sept. 2018,

Pet Releaf: What You Need to Know about Aspirin for Dogs | Pet Releaf., 16 Sept. 2021,

onlinects. “ASPIRIN TOXICOSIS – Canine | Glencoe Animal Hospital.” ASPIRIN TOXICOSIS – Canine | Glencoe Animal Hospital, 25 Aug. 2018,

“Enalapril | VCA Animal Hospital.” Vca, Accessed 2 Sept. 2022.

onlinects. “DIGOXIN LEVEL TEST – Canine | Glencoe Animal Hospital.” DIGOXIN LEVEL TEST – Canine | Glencoe Animal Hospital, 25 Aug. 2018,

“Furosemide | VCA Animal Hospital.” Vca, Accessed 5 Sept. 2022.

“Dangerous Pet Medication Mixes to Avoid | PetMD.” Dangerous Pet Medication Mixes to Avoid | PetMD, Accessed 5 Sept. 2022.

@goodrx. “Drug Interactions Defined: 5 Examples of How Common Medications Interact – GoodRx.” GoodRx, Accessed 5 Sept. 2022.

Drake, Amber L., and Read More. “Aspirin Dosage for Dogs | LoveToKnow.” LoveToKnow, Accessed 5 Sept. 2022.

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