Acetaminophen Toxicity

Acetaminophen, more commonly known as Tylenol, is a common over the counter medication in humans to treat pain and fevers.  It is often found paired with codeine, hydrocodone, or in multi-symptom cold products.  In dogs, there is a very narrow margin of safety, and in cats, is considered toxic at almost any dose.

The VSH Palm Beach Team is dedicated to your pets health!
Providing Complete Care – Committed To Excellence

Acetaminophen Toxicity

Acetaminophen is broken down into a toxic chemical, called N-acetyl-para-benzoquinoneimine (NAPQI) which can damage red blood cells, causing anemia, and altering the oxygen carrying capabilities of the iron and hemoglobin within the red blood cell.  Due to this, you can see small dogs and cats become quite anemic with a brown discoloration to their gums.  The NAPQI also damages liver and kidney cells, leading to liver and/or kidney failure.  Aside from the brown mucous membranes, one may also see yellow mucous membranes, vomiting, diarrhea, inappetance, lethargy, respiratory distress, and swelling of the face and paws are common clinical signs of toxicity.  Signs can progress to neurologic disease, such as head pressing and imbalance, inability to clot blood, and worsen to coma or death without early treatment.

Alarming Fact About Acetaminophen Toxicity

It would take as little as 1/10th of a 325mg tablet or ½ of an 80mg children’s chewable tablet to cause toxicity in a cat.  Only one 325mg tablet would be toxic to a 10 pound dog.

Ideally, treatment to decontaminate the stomach should be done within two hours of ingestion.  A substantial amount of what has been ingested is likely absorbed within 30-60 minutes of ingestion, however.  Induction of vomiting and administration of activated charcoal are used to attempt decontamination.

Treatments to help treat toxicity often include N-acetylcysteine, S-adenosyl-methionine, Vitamin C, cimetidine (in dogs), intravenous fluid therapy, oxygen therapy, and blood transfusions.  Some or all of these treatments are needed for at least 48 to 72 hours after ingestion.

If your dog or cat has ingested any quantity of Acetaminophen, please have them evaluated by a veterinarian immediately.