Aspirin Poisoning in Dogs

What is aspirin?aspirin_toxicity

Aspirin (brand names: Bayer, Bufferin, Ecotrin, and others) is a commonly used over the counter nonsteroidal anti-inflammatory drug (NSAID) and is used to treat fever, pain, inflammation (swelling), and clotting disorders in humans. It is also commonly found in combination with other medications.


What is aspirin poisoning?

Aspirin poisoning occurs when a dog ingests a toxic dose of aspirin, either through misuse or accidentally. Poisoning over time can occur if a dog is dosed too frequently at an inappropriate dose. Certain conditions such as clotting disorders, underlying kidney disease, low blood proteins, and the use of other steroids (e.g., prednisone) or NSAIDs can predispose a pet to aspirin poisoning.


What causes aspirin poisoning?

Aspirin and other NSAIDs treat inflammation by blocking certain enzyme processes (chemical processes in the body) in the body. Unfortunately, in addition to blocking enzymes that cause inflammation, aspirin also blocks enzymes that are used to control normal gastrointestinal and kidney function, as well as blood clotting.

"Dogs require four times as long to remove aspirin from their body when compared to humans."

When aspirin is ingested, it is easily absorbed and widely spread to most tissues. Elimination of the drug differs among species; dogs require four times as long to remove aspirin from their body when compared to humans. Longer removal times means it is easier for poisoning to occur.


What are the clinical signs of aspirin poisoning?

Clinical signs depend on how much aspirin was eaten. The most common side effect of aspirin is gastrointestinal irritation, which can lead to signs such as a decreased appetite, vomiting, diarrhea, and abdominal pain.

"Clinical signs depend on how much aspirin was eaten."

At higher doses (more than 50 mg/kg every 12 hours), bloody stools and perforating gastric ulcers (a hole in the stomach that leaks into the abdomen) can occur. This can cause signs such as pale mucous membranes, weak pulses, dehydration, and anemia (low number of red blood cells). At the highest doses (greater than 450 mg/kg), seizures, coma, abnormal breathing, kidney disease, and liver disease can occur. 


How is aspirin poisoning diagnosed?

Aspirin poisoning diagnosis is usually based on a history of aspirin ingestion. Other clinical signs can aid in the diagnosis of aspirin poisoning and identify the associated complications needing treatment. Blood work is necessary to evaluate the kidneys, liver, electrolytes (important chemicals that allow body’s cells to work properly), and blood counts. Radiographs (X-rays) of the chest can identify lung disorders secondary to aspirin poisoning. Bleeding tests should also be considered to evaluate the pet’s ability to clot.


How is aspirin poisoning treated?

Treatment for aspirin poisoning depends on how quickly the dog is seen by the veterinarian. If the aspirin was recently ingested, then your veterinarian will induce vomiting. If your dog is seen within two hours of ingestion, your veterinarian will also administer activated charcoal. If more than two hours has passed since ingestion, or for chronic aspirin toxicity, management of clinical signs, metabolic abnormalities, and liver disease is the treatment of choice.

"Treatment for aspirin poisoning depends on how quickly the dog is seen by the veterinarian."

Aggressive intravenous fluids will be administered, as well as stomach protectants and antacids. Anti-vomiting medications can also be helpful in some cases. Liver enzyme and kidney values will be monitored via blood work, and severe elevations will be managed. In cases of respiratory complications, oxygen supplementation will be given. For perforated ulcers, surgery may be necessary.


What care will my dog require after treatment?

If kidney disease is present, fluid administration should continue until clinical signs or lab values improve. Gastrointestinal protectants should be administered for at least 2 weeks, and a bland and easy to digest diet will be recommended until signs have resolved.

Laboratory tests to monitor liver values may be recommended until the tests are normal. If the patient makes a full recovery, no long-term treatments are necessary. In cases of chronic liver or kidney damage, however, long-term management will be required.

Pet Poison Helpline, an animal poison control center based out of Minneapolis, MN is available 24/7 for pet owners and veterinary professionals that require assistance treating a potentially poisoned pet. The staff provides treatment advice for poisoning cases of all species, including dogs, cats, birds, small mammals, large animals and exotic species. As the most cost-effective option for animal poison control care, Pet Poison Helpline’s fee of $65 per incident includes follow-up consultations for the duration of the poison case. Pet Poison Helpline is available in North America by calling 800-213-6680. Additional information can be found online at


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