Carprofen is not safe for cats and is not approved for feline use in the United States. The FDA-approved labeling for carprofen tablets states explicitly that cats should not be given this medication. While carprofen is widely prescribed for dogs with osteoarthritis and post-surgical pain, cats metabolize it differently, and even moderate doses can cause serious organ damage.
Why Carprofen Is Dangerous for Cats
The core problem is how a cat’s body processes carprofen compared to a dog’s. In dogs, carprofen selectively targets the enzyme involved in inflammation (COX-2) while largely sparing the enzyme that protects the stomach lining and kidneys (COX-1). In cats, this selectivity works differently. A standard dose causes prolonged, near-total suppression of the inflammatory enzyme for roughly 42 hours, which sounds beneficial but leaves the protective enzyme equally vulnerable. This means the drug’s side effects hit cats harder and last longer than they do in dogs.
Cats are also slower to break down and eliminate many drugs from their bodies, a well-known quirk of feline liver metabolism. This makes them more susceptible to toxic buildup even from doses that seem small.
Signs of Carprofen Toxicity in Cats
According to ASPCA poison control data, gastrointestinal ulceration can occur in cats exposed to as little as 4 mg/kg of carprofen. At doses above 8 mg/kg, acute kidney failure becomes a risk. For context, a typical 10-pound cat would only need to ingest a fraction of a standard dog tablet to reach these thresholds.
The most common signs of toxicity include:
- Gastrointestinal damage: vomiting, diarrhea, bloody stool, stomach ulcers, and in severe cases, perforation of the stomach or intestinal wall
- Kidney failure: decreased urination, lethargy, loss of appetite, and dehydration
- Neurological signs: at high doses, carprofen has been associated with seizures and comas in cats
These aren’t rare reactions that happen only in sensitive individuals. The ASPCA lists NSAIDs, including carprofen specifically, among the ten most common toxicoses in cats. Many cases involve a cat accidentally eating a dog’s medication left within reach.
What to Do if Your Cat Ingests Carprofen
If your cat swallows carprofen, whether from a dropped pill, an open bottle, or a well-meaning but incorrect dose, contact your veterinarian or an animal poison control center immediately. Time matters because the faster the drug is addressed, the better the chance of preventing kidney damage or GI ulceration. Do not wait to see if symptoms develop first, and do not attempt to induce vomiting at home unless specifically instructed to by a veterinarian.
Have the medication packaging available when you call so you can report the exact strength of the tablet and estimate how much your cat consumed.
Is Carprofen Ever Used in Cats Anywhere?
In some countries outside the United States, including parts of the European Union, carprofen is registered for short-term use in cats under strict veterinary supervision. This typically involves carefully controlled doses for a limited number of days, not the ongoing use common in dogs with chronic arthritis. The Merck Veterinary Manual notes that feline blood assays show carprofen is more than 5.5-fold selective for the inflammatory enzyme in cats, which suggests some degree of safety at very precise doses, but the margin for error is slim.
In the U.S., however, carprofen carries no feline approval, and the official labeling warns against giving it to cats at all. Any use would be considered off-label, carrying legal and medical responsibility for the prescribing veterinarian.
Safer Pain Relief Options for Cats
Cats have far fewer approved pain medications than dogs, which is part of why owners sometimes end up searching about dog drugs. But there are options specifically evaluated for feline safety.
Robenacoxib (brand name Onsior) is FDA-approved for controlling postoperative pain and inflammation in cats at least four months old and weighing at least 5.5 pounds. It can be given for up to three days following orthopedic surgery or spay/neuter procedures. A generic version was also approved by the FDA, making it more accessible. Robenacoxib was designed to be highly selective for the inflammatory enzyme, which gives it a better safety profile in cats than older NSAIDs like carprofen.
For chronic pain conditions like osteoarthritis, the landscape has expanded in recent years. A newer class of injectable treatments that target nerve growth factor signaling (rather than working as traditional NSAIDs) has been approved specifically for long-term feline arthritis pain. Your veterinarian can evaluate which option fits your cat’s condition, age, and kidney function, since many cats needing arthritis treatment are older and may already have some degree of kidney disease that rules out certain drugs entirely.
The bottom line: never give your cat a medication prescribed for your dog, even if it seems like a small dose. The drugs that are safe across species are the exception, not the rule, and carprofen is firmly on the wrong side of that line for cats.