Is paracetamol toxic to cats?
Yes, severely. Cats cannot process paracetamol (acetaminophen, Tylenol) at all, and even one tablet can be fatal. It damages red blood cells within a few hours, so the cat cannot carry oxygen, and in larger amounts it also damages the liver. Go to a vet now with the packet, even if your cat looks normal: there is an antidote, and it works best when given early.
General information, not veterinary advice. If your pet may have eaten this, contact a vet now; do not wait for signs.
What to do right now
- Go to a vet or emergency clinic now
- Take the packet or bottle with you, including any combined cold or flu remedy
- Count the missing tablets or estimate how much liquid was taken
- Keep your cat calm and warm on the way
- Do not try to make your cat sick or give any food or medicine at home
Go to an emergency clinic now if
- Your cat swallowed or chewed any amount of paracetamol
- Someone gave your cat paracetamol for pain
- Gums or tongue look brown, muddy, grey or blue
- Fast or laboured breathing
- Swelling of the face or paws
- Weakness, collapse or cold body
Who to call
Your own vet first. If they are closed, the nearest emergency or out-of-hours clinic.
In the United States
Both answer 24 hours a day and may charge a consultation fee.
Signs to watch for
| Sign | Usually starts |
|---|---|
| Brown, muddy or blue-tinged gums | Within a few hours |
| Fast or laboured breathing | Within a few hours |
| Lethargy, weakness, not eating | Within a few hours |
| Vomiting, drooling | Within a few hours |
| Swelling of the face or paws | Hours, variable |
| Low body temperature | Hours, variable |
| Yellow gums or eyes (liver damage) | Later, with larger amounts |
Why can't cats take paracetamol?
Cats lack enough of the liver enzyme that most animals use to clear paracetamol safely. In the Merck Veterinary Manual's words, cats have limited capacity for glucuronidation, the main detox route for this drug. The backup route is quickly overwhelmed, and the toxic by-products then attack red blood cells and the liver.
The first damage is methaemoglobinaemia. Methaemoglobin is a form of haemoglobin that cannot carry oxygen, and it turns the blood and the gums a chocolate-brown or muddy colour. This happens within a few hours in cats, which is why the breathing becomes fast and the cat weak long before liver damage would show.
How much paracetamol is dangerous for a cat?
There is no safe amount. Merck reports that poisoning generally occurs at 40 to 50 mg per kg, but some cats have shown signs at 10 mg per kg. A single 500 mg tablet given to a 4 kg cat is about 125 mg per kg, many times the lower figure, and even a quarter of a tablet is above it. Liquid paracetamol for children and combined cold and flu remedies count too.
Which products contain paracetamol?
Paracetamol is sold as acetaminophen in North America, under brand names such as Tylenol, and as Calpol and similar syrups for children. It is also an ingredient in many combined cold, flu and headache remedies, including powders dissolved in hot drinks. If a packet lists paracetamol or acetaminophen anywhere among the ingredients, treat it as dangerous for your cat.
What will the vet do?
The vet will usually start treatment straight away rather than wait for blood results. If the paracetamol was swallowed very recently, the vet may make your cat vomit with an injection and give activated charcoal. The key treatment is an antidote that helps the body replace what paracetamol uses up; it is given into a vein, together with oxygen, fluids and repeated checks of the blood and liver. Many cats need a few days in hospital. The outlook depends on how much was taken and how quickly treatment started: a Cornell case report describes a cat with severe blood changes that recovered within 24 hours of treatment, while cats with severe liver damage do much worse.
How do I stop it happening again?
Never give a cat any human painkiller, even "just half". Keep paracetamol, ibuprofen and cold remedies in a closed cupboard, and pick up dropped tablets at once. Cats hide pain well, so if you think your cat is sore, Pativo's pain score for cats can help you describe what you see before you call the vet. Other human painkillers carry their own risks: see ibuprofen and similar painkillers in cats and paracetamol in dogs.
Questions owners ask
Can I give my cat paracetamol for pain?
No. There is no safe amount of paracetamol for a cat. If your cat seems to be in pain, call your vet, who can prescribe a painkiller made for cats.
My cat only licked a crushed tablet. Is that serious?
Yes, treat it as serious. Some cats show signs at a small fraction of a tablet, so go to the vet and let them judge the amount.
Is paracetamol also dangerous for dogs?
Yes, though dogs tolerate more than cats before they are harmed. See the guide on paracetamol in dogs.
Sources
- Merck Veterinary Manual: Toxicoses From Human Analgesics in Animals
- International Cat Care: Cats and Poisons
- Cornell University College of Veterinary Medicine: Acetaminophen toxicity in a cat (case report)
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