Acetaminophen (Tylenol) Toxicity in Dogs and Cats

Acetaminophen is one of the most commonly used pain relievers, and it can be found in a variety of over-the-counter medications (Tylenol). Toxic levels can be reached when a pet is unintentionally over medicated with acetaminophen, or when a pet has gotten hold of medication and ingested it. Pet owners often do not realize their animals may break into medicine cabinets or chew through medicine bottles. It is important to be able to recognize the symptoms of toxicity, so that you can properly treat your pet if is has accidentally ingested medication.

Symptoms and Types

The effects of acetaminophen poisoning are quite serious, often causing non-repairable liver damage. The most common symptoms that you may notice in pets suffering from acetaminophen toxicity include:

  • Brownish-gray colored gums
  • Labored breathing
  • Swollen face, neck or limbs
  • Hypothermia (reduced body temperature)
  • Vomiting
  • Jaundice (yellowish color to skin, whites of eyes), due to liver damage
  • Coma

Ibuprofen (Advil) Toxicity in Dogs and Cats

Ibuprofen is a non-steroidal anti-inflammatory medication commonly used in humans as a pain reliever and to reduce fever. It is available in many over-the-counter formulations (Advil, Motrin, Midol) as well as in prescription strength medications. Though relatively safe for people, ibuprofen can be toxic for dogs and cats.


Symptoms of ibuprofen poisoning in dogs may include:

  • Vomiting
  • Diarrhea
  • Bloody feces
  • Blood in vomit
  • Nausea
  • Lack of appetite
  • Weight loss
  • Gastric (stomach) ulcers and perforation
  • Increased thirst
  • Increased urination
  • Decreased or lack of urine
  • Seizures
  • Incoordination
  • Coma
  • Death

Aspirin Toxicity in Dogs and Cats

Aspirin, a non-steroidal anti-inflammatory medication, has beneficial effects including anti-platelet, anti-inflammatory, and analgesic properties. However, it can also be toxic in dogs and cats. Once ingested, aspirin forms salicylic acid, which is then distributed throughout the body.

Symptoms and Types

One of the first noticeable signs is loss of appetite. Other signs include vomiting,diarrhea, and intestinal hemorrhage brought on by ulceration in the stomach and small intestines. The central nervous system is affected and the dog may have trouble walking, appear weak and uncoordinated, or even collapse. Loss of consciousness and sudden death can also occur.

If a significant amount of aspirin is ingested, emergency treatment is necessary.

Aleve (Naproxen) Toxicity in Dogs and Cats

Once swallowed naproxen is rapidly absorbed from the stomach and intestines. Depending on the amount of drug ingested, toxic effects can occur within an hour, but some signs can take a few days to appear. The most common side effect is stomach irritation. In mild cases, this may cause vomiting. In severe cases, it can cause the pet to vomit blood; the irritation can also be severe enough to cause stomach ulcers and stomach perforations (punctures in the stomach wall that allow stomach acid to leak into the abdomen). If stomach bleeding is severe, blood transfusions may be necessary to save the patient. Naproxen toxicity can also inhibit blood flow to the kidneys, which can cause kidney failure. Extremely high toxic doses of this drug can also affect the brain, causing altered mental status, seizures and coma. Other clinical signs associated with toxicity can include the following:

  • Vomiting (sometimes with blood)
  • Diarrhea (may be darker in color due to digested blood)
  • Appetite loss
  • Dehydration
  • Abdominal pain
  • Pale gums (secondary to blood loss)

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