Carprofen is a prescription anti-inflammatory painkiller for dogs, FDA-approved to treat osteoarthritis and post-surgical pain. It belongs to the same family of drugs as ibuprofen and naproxen (propionic acid NSAIDs), but it’s formulated specifically for canine use. If your vet recently prescribed it or you’re wondering what those chewable tablets in the bag are for, here’s what you need to know.
How Carprofen Works
When a dog’s joints are inflamed or tissue is damaged after surgery, the body produces chemical signals called prostaglandins that amplify pain and swelling. Carprofen blocks the enzyme responsible for making those prostaglandins, which reduces both inflammation and the pain that comes with it.
What makes carprofen a good fit for dogs specifically is its selectivity. There are two versions of the enzyme it targets. One handles everyday housekeeping in the gut and kidneys. The other drives inflammation. In lab studies using canine cells, carprofen preferentially blocked the inflammation-related enzyme while largely sparing the one that protects the stomach lining and kidneys. That selectivity is why it tends to cause fewer gastrointestinal problems than older anti-inflammatory drugs, though side effects are still possible.
What Carprofen Treats
Carprofen has two primary uses. The first is osteoarthritis, the gradual wearing down of joint cartilage that causes stiffness, limping, and reluctance to jump, climb stairs, or play. Many dogs with arthritis take carprofen daily for months or years to stay comfortable and mobile. The second use is managing pain and swelling after surgery, such as a spay, neuter, or orthopedic procedure. In surgical cases, carprofen is typically a short course lasting a few days to a couple of weeks.
Dosage and How It’s Given
The standard dose is 2.2 mg per kilogram of body weight, given by mouth twice daily, or the full 4.4 mg/kg dose given once a day. Your vet will choose the schedule based on your dog’s condition and how well they respond. Carprofen comes as a flavored chewable tablet that most dogs eat willingly, either from your hand or placed in the mouth. It can be given with or without food, though giving it with a meal may help dogs with sensitive stomachs.
Because the dose is weight-based, your vet will prescribe a specific tablet strength. Never split or adjust the dose on your own, and never give human NSAIDs like ibuprofen or naproxen to your dog as a substitute. Those drugs are toxic to dogs at doses that are safe for people.
Common Side Effects
Most dogs tolerate carprofen well, but the most frequently reported side effects are vomiting, loss of appetite, and lethargy. These are usually mild and may resolve on their own within a day or two. Diarrhea is also reported, though less commonly. If your dog vomits more than once or refuses food for more than a day after starting the medication, contact your vet.
Serious Risks: Liver, Kidneys, and Gut
The side effects worth watching closely for involve three organ systems: the liver, kidneys, and gastrointestinal tract.
Liver Damage
Liver toxicity is the most well-documented serious reaction. In a study of 21 dogs that developed liver problems on carprofen, the most common warning signs were loss of appetite (17 dogs), vomiting (16), lethargy (8), and diarrhea (8). Some dogs also developed jaundice, a yellowing of the gums, whites of the eyes, or skin. Blood work in these dogs showed elevated liver enzymes and bilirubin levels. This reaction is uncommon but can be severe, so recognizing early signs matters.
Kidney Problems
Like all NSAIDs, carprofen can affect the kidneys. In documented cases, kidney issues ranged from mild changes in urine concentration and protein levels to acute kidney failure. Dogs that are already dehydrated, have pre-existing kidney disease, or are on other medications that stress the kidneys are at higher risk.
Gastrointestinal Ulcers
Stomach and intestinal irritation is a known risk with any NSAID. While carprofen’s selectivity makes this less common than with older drugs, it still happens. Signs include vomiting (especially with blood), dark or tarry stools, and bloody stool. In rare cases, ulceration can progress to perforation of the intestinal wall, which is a life-threatening emergency.
Warning Signs to Watch For
While your dog is on carprofen, keep an eye out for these changes:
- Appetite changes: refusing food or eating significantly less than usual
- Vomiting or diarrhea: especially if persistent or containing blood
- Lethargy: noticeably less energy, reluctance to move or engage
- Dark or tarry stools: a sign of bleeding in the digestive tract
- Yellowing of gums or eyes: suggests liver involvement
- Increased thirst or urination: may indicate kidney stress
These signs can appear within the first few weeks of starting carprofen or after months of use. If you notice any of them, stop the medication and contact your vet promptly.
Blood Work and Monitoring
For dogs taking carprofen long-term (as most arthritis dogs do), regular blood work is important. The general recommendation is to check liver enzymes and kidney values two to four weeks after starting the medication, then every three to six months for the duration of treatment. This catches organ changes early, often before your dog shows any visible symptoms. Your vet may also run a baseline blood panel before prescribing carprofen to make sure the liver and kidneys are healthy enough to handle the drug.
Drug Interactions and Cautions
Carprofen should not be combined with other NSAIDs or with corticosteroids like prednisone. Using two anti-inflammatory drugs at the same time dramatically increases the risk of stomach ulcers, kidney damage, and other complications. If your dog is switching from a steroid to carprofen (or vice versa), your vet will typically build in a washout period of several days between the two medications.
Dogs with pre-existing liver disease, kidney disease, or a history of gastrointestinal ulcers are generally poor candidates for carprofen. The same goes for dogs that are dehydrated or in shock, since reduced blood flow to the kidneys makes NSAID-related kidney damage more likely. Puppies under six weeks of age and pregnant or nursing dogs should also avoid it.
What to Expect Day to Day
Most owners notice improvement within the first few days. Dogs with arthritis often become more willing to walk, play, or navigate stairs. The change can be subtle at first, especially in older dogs with advanced joint disease, so it helps to track specific behaviors (willingness to jump on the couch, distance walked, time spent standing) rather than relying on a general impression.
Carprofen manages pain and inflammation but does not reverse arthritis. If you stop giving it, symptoms will return. For dogs on long-term therapy, many vets recommend combining carprofen with weight management, joint supplements, physical therapy, or other strategies to reduce the overall burden on the joints and potentially allow a lower dose over time.