Tylenol® (Acetaminophen) Poisoning in Cats

Veronica Higgs, DVM
Published: November 8, 2022
Tylenol® (Acetaminophen) Poisoning in Cats

Tylenol® is the common brand name for the drug acetaminophen. It is a staple in many homes for treatment of pain and fever in humans and comes in hundreds of over-the-counter and prescription formulations. However, Tylenol® (acetaminophen) is fatal to cats and must be safeguarded to prevent ingestion by your feline friends. 

Here’s some useful information on why cats can’t take Tylenol and what to do if you suspect that your cat may have eaten Tylenol or other products containing acetaminophen. 

How Is Tylenol Toxic to Cats?

Acetaminophen can be found in many over-the-counter and prescription human medications. While in some drugs acetaminophen may be the only active ingredient, it can also be in combination products such as “cold and flu,” “allergy,” and “fever-reducing” medications. Additionally, acetaminophen can come as tablets, liquids, topicals (creams, lotions, gels, patches, etc.), and injectables. 

Acetaminophen should NEVER be administered to your cat or left in a place where your cat may be able to ingest it. In the case of a topical medication, special attention must be paid to make sure your cat does not contact the medication itself, the treatment area on the person using it, or any residue that has spread on furniture, clothing, or dispensing apparatuses.  

Due to a decreased ability to effectively metabolize acetaminophen, cats are more susceptible to Tylenol poisoning than most other species, including humans and dogs.

Acetaminophen poisoning in cats occurs in two forms:

  • Damage to red blood cells (RBCs): RBCs are the most common type of blood cell in the body and the main way oxygen is carried to tissues and organs. When the RBCs become damaged by Tylenol®, they lose the ability to carry oxygen (a condition called methemoglobinemia), which results in decreased oxygen flow to the tissues and organs. This can result in organ damage and potential organ failure.  

  • Damage to the liver: Tylenol damages liver cells, which can result in liver failure. This damage is dose-dependent—meaning the higher the dose, the worse the liver damage. 

While both forms of acetaminophen poisoning can occur in cats, cats are more prone to RBC damage, while dogs are more prone to liver damage.

How Much Tylenol Is Toxic in Cats?

Acetaminophen is extremely toxic to cats. Given the relatively small size of cats, ingestion of even one Tylenol can be toxic or even fatal. Ingestion of any amount of acetaminophen (partial or full tablet or liquid dose, any exposure to topicals or creams) should be considered an emergency. If you believe your cat has ingested Tylenol or a product containing acetaminophen, contact an emergency veterinarian immediately.  

Tylenol poisoning in cats occurs when a cat gets into the medication or when the pet parent intentionally administers an over-the-counter human acetaminophen product to their cat in an effort to alleviate pain, without realizing the danger these drugs pose.  

No over-the-counter human pain medications are safe for cats, and you should never give your pet a medication without your veterinarian’s specific instruction to do so. If you think your cat is in pain, please call your veterinarian to discuss the best treatment options

Symptoms of Tylenol Poisoning in Cats

Clinical signs and symptoms associated with Tylenol poisoning will depend on which form (RBC damage or liver damage) is affecting the cat. RBC damage is more common in cats, and clinical signs can develop within a few hours. The most common are:

  • Discolored gums: Healthy cats should have pink gums. However, with Tylenol poisoning, you may notice the gums are a chocolate brown or muddy color (due to the methemoglobinemia) or even a bluish color (cyanotic) from decreased oxygen

  • Lethargy or weakness

  • Decreased appetite (anorexia)

  • Difficulty breathing or rapid breathing

  • Swelling of the face and/or paws

  • Decreased temperature

  • Vomiting

  • Red or brown discoloration of urine

Liver damage is more common in dogs but can also occur in cats. While damage to the liver may start 24-36 hours after ingestion, it may take up to 3-6 days to see clinical signs. Additional clinical signs if your cat has liver damage may include:

  • Discolored gums: In cases of liver damage, it is more common to see a yellow (jaundice) discoloring

  • Increased drinking and urinating

  • Abdominal distension or swelling

  • Bruising

Kidney damage is also possible as a result of decreased oxygen to the tissues, secondary to RBC damage. 

What Should I Do If My Cat Eats Tylenol?

If your cat has ingested acetaminophen, contact your local animal hospital. Your vet may also instruct you to call the Pet Poison Helpline at 855-764-7661 or the ASPCA Animal Poison Control Center at 888-426-4435 for more information regarding the toxicity and treatment options. 

If you accidentally applied acetaminophen cream or ointment to your cat, or they gained access to a tube, your vet may instruct you to bathe your cat in diluted dishwashing liquid (such as Dawn®) right away, before proceeding to the vet’s office, to prevent further absorption of the product.   

Do not induce vomiting at home unless you have been specifically instructed to by a veterinarian. Once at the vet, if your cat ingested Tylenol® or an acetaminophen-containing product within the past 2 hours, your veterinarian may recommend inducing vomiting at the hospital as a means of decontamination. Medications used to induce vomiting in cats are not always reliable and cats can have complications, such as aspiration pneumonia, associated with induced vomiting. Inducing vomiting should always be done with direct veterinary supervision, especially in cats.

Treating Tylenol Poisoning in Cats

Early diagnosis and aggressive treatment are crucial in treating Tylenol (acetaminophen) poisoning in cats. As noted, even just one Tylenol could be fatal. Cats have their best chances of survival if seen quickly by a veterinarian.

Your veterinarian will collect a detailed history of any medications your cat may have ingested. If possible, take the product and product container/packaging of the medication your pet ingested or had access to. If you are unsure how much medication your cat may have ingested, always round up rather than down so that the vet can calculate the worst-case scenario for exposure.

The vet will then perform a thorough physical examination to assess gum color, temperature, and any signs of trouble breathing. Because the toxic metabolite of Tylenol damages the body’s red blood cells (RBCs), causing them to lose the ability to carry oxygen (through methemoglobinemia), a cat’s blood will turn from the normal red to a chocolate brown color. A hallmark sign of Tylenol poisoning in cats is that their blood will be a chocolate brown color. Due to RBC damage, the cat may also have a decreased number of RBCs, or anemia, noted on their complete blood count (CBC). 

A serum blood chemistry to evaluate for liver damage will also be performed. Liver values can be elevated as early as 24-36 hours after ingestion but should be monitored for at least the first 3 days. Urinalysis may also be performed to check for signs of discoloration. 

If your cat ingested Tylenol within the past 2 hours, your veterinarian will likely start by inducing vomiting at the hospital as a means of decontamination. They may also give active charcoal to decrease the absorption of any remaining acetaminophen in the digestive tract. 

There is an antidote available for Tylenol poisoning, called N-acetylcysteine (NAC). It works by improving the metabolism of Tylenol as well as helping to prevent further damage to red blood cells and the liver. However, it does not reverse damage that has already occurred. 

Most cats with Tylenol poisoning will need to be hospitalized and placed on IV fluids for hydration and support. Medications may be administered to protect the liver, such as antioxidants and vitamin C. In severe cases, with significant RBC damage or trouble breathing, cats may even need oxygen therapy and/or blood transfusions.

Recovery from Tylenol Poisoning in Cats

Most cats will remain hospitalized for observation and treatment for 3-5 days. Typically, recheck bloodwork will be performed and may include recheck CBC to assess anemia and to screen red blood cells for damage as well as to recheck liver values. 

The prognosis depends on the amount of acetaminophen ingested and the time it takes to receive care. Cats need to be treated as soon as possible, but have the best prognosis if treated within 14 hours of ingestion.

In cases of full recovery, cats can go on to lead normal, happy lives. However, some cats may have lifelong liver disease that may require long-term management and, in severe cases, Tylenol poisoning can be fatal in cats.  

Preventing Tylenol Poisoning in Cats

Prevention is key! Always keep medications in a safe and secure place away from pets. It is best to store medications in a closed cabinet or drawer, away from your kitty’s reach. If you spill or drop any medication, take special care to make sure every bit of it is picked or wiped up; remember, even one tablet or dose of Tylenol can be deadly for a cat!

Special consideration should also be given to topical human acetaminophen products, as care needs to be taken to avoid leaving medication residues on couches, chairs, bedding, and clothing. It is best to consult your human healthcare provider to discuss if covering the treated area to prevent pet exposure is the best course of action or if there is a specific time frame (often it is at least a few hours and only after thorough washing) between application and handling your cat. 

It is important to remember that no human over-the-counter pain medications are safe for cats. Do not give your cat any human pain medication. If you think your cat is in pain, it is highly recommended to consult with your primary care veterinarian. They will be able to best determine how to proceed and what medications are appropriate for your pet.

References

Peterson, Michael E. Small Animal Toxicology. 3rd ed. Elsevier Saunders; 2001.

Hovda, Lynn, et al. Blackwell’s Five-Minute Veterinary Consult Clinical Companion: Small Animal Toxicology. 2nd ed. John Wiley & Sons; 2016.

Featured Image: iStock/cunfek


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