Serious severity

Ibuprofen & Human NSAID Toxicity

Cats lack the liver machinery to process human anti-inflammatories, and a single tablet given with good intentions can cause stomach ulceration and kidney failure.

⚠️ Common symptoms

Vomiting, sometimes with blood or a coffee-ground appearanceBlack, tarry stools indicating digested bloodLoss of appetite and marked lethargyAbdominal pain, with the cat hunched or resenting handlingIncreased or, more ominously, decreased urinationPale gums and weakness from blood lossWobbliness, tremors or seizures at high dosesCollapse

The Most Preventable Poisoning There Is

Almost every case of ibuprofen toxicity in cats arrives with the same story. The cat was limping, or seemed uncomfortable, or had been in a scrap, and it was the weekend, and there was a packet in the kitchen drawer. The dose seems tiny by human standards — a fraction of a tablet for a four-kilogram animal — which is exactly the reasoning that causes the harm, because the calculation that matters is not body weight but the cat's inability to clear the drug at all.

It is worth being concrete: a single 200mg ibuprofen tablet is above the dose at which gastrointestinal damage is expected in an average cat, and comfortably into the range where kidney injury becomes a real prospect. There is no safe household dose to arrive at by dividing.

The Two-Stage Injury

The stomach goes first. Prostaglandins maintain the mucus and bicarbonate layer that stops the stomach digesting itself, and removing them produces erosions and then frank ulcers, which is why vomiting and black stools appear early. The kidney follows. Prostaglandins also regulate the blood vessels that keep filtration going, and a kidney deprived of them — particularly in a cat that is already vomiting and becoming dehydrated — can sustain acute injury within a day or two. This is why fluid therapy is continued well beyond the point at which the cat appears to have recovered.

Not the Same as Paracetamol

Owners often lump the two together, but paracetamol poisoning in cats is a different and even more urgent emergency, causing damage to red blood cells and to the liver, with brown gums, facial swelling and laboured breathing as characteristic signs. It has a specific antidote in acetylcysteine and demands immediate treatment. The practical point is that neither drug is ever appropriate for a cat, and that the vet needs to know precisely which one was given.

What to Do With a Sore Cat Instead

Cats conceal pain thoroughly, so an owner who has noticed it is usually seeing something substantial. The right response is a veterinary appointment rather than the medicine cabinet: meloxicam and robenacoxib are licensed for cats, dosed for feline metabolism and dispensed with clear instructions, and opioid options exist for acute pain. In the meantime, keep the cat warm, quiet and confined, with food, water and a litter tray within easy reach — that is genuinely all that should be attempted at home.

🔍 Causes

Cats are deficient in glucuronyl transferase, the liver enzyme that most mammals use to conjugate and excrete drugs of this type. Ibuprofen, naproxen, aspirin and the rest are therefore cleared far more slowly and reach much higher effective concentrations than the same dose would in a dog or a person. The drugs work by blocking cyclo-oxygenase enzymes, which reduces inflammation but also removes the prostaglandins that maintain the stomach's protective mucus layer and preserve blood flow through the kidney. In a cat, that gives ulceration of the stomach and duodenum at low doses and acute kidney injury as the dose climbs, with neurological signs at higher levels still. Naproxen is more dangerous than ibuprofen, and paracetamol — a different mechanism entirely — is more dangerous than either.

🛡 Prevention

Never give a cat any human painkiller, for any reason, without explicit veterinary instruction. This is the whole of the advice, and it is worth stating bluntly because the great majority of cases are not accidents but well-meant attempts to help a cat that seemed sore or limping. Keep all medication in closed cupboards rather than on bedside tables — cats knock over pill bottles, and loose tablets on the floor get investigated. Be careful with liquid ibuprofen formulations, which are sweetened and considerably more attractive. Dispose of tablets properly and check the floor after handling medication. If your cat is in pain, there are several anti-inflammatories licensed specifically for cats at doses that account for feline metabolism, and a vet can supply them the same day.

💊 Treatment

If the tablet was given within the last hour or two, decontamination at the clinic comes first, followed by activated charcoal — often repeated, since ibuprofen recirculates through the gut. After that, the priority is protecting the two organs at risk. Aggressive intravenous fluid therapy for at least 48 to 72 hours maintains blood flow to the kidneys and is the single most important intervention. Stomach protection is given in parallel: a proton pump inhibitor such as omeprazole, sucralfate to coat existing ulceration, and misoprostol, which specifically counteracts the mechanism by which these drugs damage the stomach lining. Anti-sickness medication, pain relief from a class that is safe in cats, and blood transfusion for significant gastrointestinal haemorrhage may all be needed. Kidney values are rechecked over the following days, because injury can declare itself late.

When to see a vet: Telephone a vet or a poison line immediately if a cat has eaten, or been given, any human anti-inflammatory — at any dose, and whether or not it seems affected. Early treatment prevents damage that later treatment can only manage. Bring the packet so the strength can be read. Go straight in for vomiting blood, black tarry stools, collapse, tremors, seizures, or a cat that has stopped urinating.

⚕️ Medical disclaimer

This information is educational only and is not a substitute for veterinary advice.
Symptoms overlap between conditions — only a vet can diagnose accurately.
Never withhold treatment or self-medicate based on information found online.
When in doubt, call your vet. Early intervention almost always leads to better outcomes.

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