The Dangers of Acetaminophen (Tylenol) for Cats

Acetaminophen, most commonly known by the brand Tylenol, poses a dangerous hazard to cats. Cat owners should not to attempt to medicate their pets themselves and be sure to keep medicines, even empty bottles, out of the reach of their cats.


Cat biology is unique; over-the-counter medications aimed at humans can cause illness and death in cats in even small amounts. As little as 10 mg/kg of acetaminophen can cause toxicosis. The reason why cat's bodies cannot handle the drug is because of their low levels of an enzyme called glucuronyl transferase, which is located in the liver. This enzyme usually makes a drug water-soluble and inactive over time, allowing the body to filter out the drug after it has achieved desired results. Cats do not posses enough of this enzyme to properly excrete the drug, meaning the drug will remain in the blood stream for long periods.

Symptoms of Toxicosis

Toxicosis resulting from acetaminophen in cats can result in the following:
  • Methemeoglobinemia: Cells responsible for transporting oxygen throughout the blood stream are overrun by hemoglobins that do not transport oxygen, depriving the cat's body of oxygen. The results of this condition include:
  • Fast heart rate
  • Discolored gums and skin
  • Vomiting
  • Difficulty breathing
  • Depression
  • Swelling in the limbs, neck and face
  • Hypothermia
  • Difficulty walking/keeping balance
  • Coma
  • Hepatic necrosis: The other condition caused by an excess of this drug is death of liver cells. Symptoms are similar to that of methemeoglobinemia:
  • Reduced appetite
  • Diarrhea
  • Depression
  • Vomiting
  • Lethargy
  • Epilepsy
  • Discolored gums
Both conditions can result in death fairly quickly, particularly if not treated within the first 8 hours after ingestion.


Toxicosis from this drug is often fatal, but a vet may attempt treatment if the cat has been brought in within the first 8 hours of ingestion. Treatment may include intravenous medication to combat the poisoning, an oxygen mask and rehydrating the animal. Chances of survival depend on how strong and large the cat is, how much it ingested and how long it has been since the cat ingested the drug.

Found in Numerous Medications

Acetaminophen is present in more than just Tylenol and other pain relievers. It is an ingredient in drugs such as Nyquil, Midol, Pamprin, Panadol, Excedrin, Percogesic, Anacin and BromoSeltzer. Owners should keep all medicines out of reach of cats, preferably locked away in a cabinet, as curious cats may dig through cupboards. Never give cats medicines intended for human consumption unless otherwise directed by a vet.

Empty Bottle May Pose Hazard

In rare cases, cats have come down with toxicosis from playing with empty medicine bottles. If the cat is particularly small or weak, it is possible that even the smallest amount of residue left on the bottle can be inhaled or licked off while the cat is batting the bottle around. Owners should promptly recycle or dispose of empty bottles and never encourage a cat to play with them.

Acetaminophen can be poisonous to cats even in microscopic amounts and there is little chance of recovery. Owners should take precautions to keep medicines out of reach of their cats and should only administer medication to an animal on the instruction of a vet.