Novox (Carprofen) for Cats: Is It Safe?
By Dr. Zubair Khalid, DVM, MS, PhD ·
Novox (carprofen) for cats is not routinely safe. Carprofen is an NSAID approved for dogs in the United States, and it is not FDA-approved for use in cats. Most veterinarians will not prescribe it for a cat, and safer feline-specific options exist.
This article is educational and is not a substitute for veterinary diagnosis or treatment.
Quick Answer
- Carprofen (sold for dogs as Novox, Rimadyl, and generics) is not approved for cats in the U.S. and is not a routine feline pain medication.
- Cats clear NSAIDs much more slowly than dogs, so the margin between a helpful dose and a harmful one is narrow.
- If your cat was given carprofen, do not give another dose. Call your veterinarian or a poison control hotline right away.
- Never give your cat human NSAIDs such as ibuprofen or naproxen. These are dangerous for cats [1].
- Safer feline pain control usually involves cat-approved NSAIDs like meloxicam, or other drug classes your vet selects [1][2].
What Is Novox (Carprofen) and What Do Veterinarians Use It For?
Novox is a brand name for carprofen, a nonsteroidal anti-inflammatory drug (NSAID). NSAIDs reduce pain, inflammation, and fever. In the United States, carprofen is approved for dogs, mainly for osteoarthritis pain and for short-term pain after surgery or injury.
Cats are a different story. There is no FDA-approved carprofen product for cats in this country. That means no manufacturer has established a safe dose, a safe dosing interval, or a full safety profile for feline patients. When a drug is used in a species it is not approved for, that is called extra-label use, and it carries more uncertainty.
Veterinarians do have NSAIDs made specifically for cats. Meloxicam is the best known example, and it is used to treat general pain and inflammation in cats when prescribed and monitored appropriately [1]. Other drug classes, including opioids, also play a large role in feline pain management. In one study of feral cats having spay surgery, adding buprenorphine (an opioid) under the skin at the end of surgery helped keep postoperative pain scores below the level where rescue pain relief was needed [2].
So where does carprofen fit? In most feline practices, it does not. A veterinarian might consider it only in rare, carefully weighed situations, and even then the risk of stomach and kidney problems makes it a hard sell when better-studied cat options exist.
How Does Carprofen Work?
Carprofen blocks enzymes called cyclooxygenase (COX), which the body uses to make prostaglandins. Prostaglandins drive inflammation and pain, but they also protect the stomach lining and help maintain blood flow to the kidneys. Block those protective prostaglandins too much, and you can get stomach ulcers or kidney injury.
This is the core problem for cats. Cats metabolize many drugs differently from dogs, and NSAIDs tend to stay in a cat's system longer. A dose that a dog tolerates can push a cat toward toxicity. The same biology explains why human NSAIDs are unsafe for cats and can be dangerous if consumed [1].
Dosing Basics for Cats
Who decides the dose?
Your veterinarian does, and only your veterinarian. There is no standard carprofen dose for cats that an owner can safely apply at home. If carprofen is used at all in a cat, the dose is calculated from that cat's weight, age, kidney and liver function, hydration, and other medications. Do not borrow a dose from a dog, a friend, or an internet chart.
How is it given?
Carprofen for dogs comes as chewable tablets and caplets. These are flavored and sized for dogs, which makes accurate dosing in a cat difficult and increases the chance of an accidental overdose if a cat chews into a bottle. If a veterinarian ever dispenses carprofen for a cat, follow the label exactly and never adjust it on your own.
What if you miss a dose?
If your cat is on any prescribed NSAID and you miss a dose, do not double up. Call your veterinarian for instructions. Giving two doses close together raises the risk of stomach and kidney injury. If you are unsure whether a dose was given, treat it as given and wait for your vet's guidance.
What about other pain medicines at home?
Do not combine carprofen with steroids or with other NSAIDs unless your vet specifically plans that combination. Cats have developed full-thickness stomach and intestinal ulcers after receiving NSAIDs, corticosteroids, or both, and some of those ulcers perforated and required surgery [3]. That is a serious outcome for a treatable problem.
If you are sorting through what you can and cannot give at home, these guides can help: What Human Medications Are Safe for Cats? A Vet's Guide to OTC Options and Can I Give My Cat Tylenol? Why Acetaminophen Is Deadly for Cats.
Side Effects of Novox (Carprofen) in Cats
Because carprofen is not approved for cats, side effect rates in cats are not well established. The table below reflects what veterinarians watch for with NSAIDs in cats generally.
| Side effect | How common or serious | What to do |
|---|---|---|
| Vomiting, nausea, reduced appetite | Common early sign of stomach irritation | Stop the drug and call your vet the same day |
| Diarrhea or black, tarry stool | Black stool suggests bleeding in the upper gut | Stop the drug and seek veterinary care the same day |
| Lethargy or weakness | Can signal pain, dehydration, or kidney problems | Call your vet the same day |
| Increased drinking and urination | May point to kidney effects | Call your vet the same day |
| Stomach or intestinal ulcer, perforation | Uncommon but life threatening. In one review, 10 cats needed surgery for full-thickness ulcers linked to NSAIDs, steroids, or both, and the duodenum was the most common perforation site [3] | Emergency care now |
| Acute liver injury | Reported in cats exposed to a human topical NSAID, with severely elevated liver enzymes and one death [4] | Emergency care now |
| Kidney injury | A known NSAID risk, especially in dehydrated or older cats | Emergency care now |
Topical NSAIDs are not automatically safer. Two cats in one household developed severe acute liver injury after their caregiver used a human diclofenac cream. One cat improved with supportive care, and the other was euthanized after progressive deterioration [4]. Keep human creams, gels, and patches away from your cat, and wash your hands after applying them.
Who Should Not Take It and What Interacts With It
Cats with any of the following should generally not receive carprofen:
- Kidney disease or a history of kidney problems
- Liver disease
- Stomach or intestinal ulcers, or a history of gastrointestinal bleeding
- Bleeding disorders or low platelet counts
- Dehydration, shock, or low blood pressure
- Known allergy to NSAIDs
- Pregnancy or nursing
Age matters too. Very young kittens and senior cats with reduced organ reserve are higher risk. Your vet weighs these factors before any NSAID is prescribed.
Drug interactions to flag for your veterinarian:
- Corticosteroids such as prednisolone
- Other NSAIDs, including aspirin and meloxicam
- Certain antibiotics and antifungals
- Diuretics and blood pressure medications
- Blood thinners
- Other pain medications, including opioids and tramadol
Combining an NSAID with a steroid or a second NSAID sharply raises the risk of gastrointestinal ulceration [3]. Always tell your vet every product your cat receives, including supplements and flea treatments. Some flea products and household products add their own risks, which are covered in Cat Flea Treatment Safety.
Overdose and When to Call a Veterinarian or Poison Control
An overdose can happen easily. A cat may eat a flavored dog chewable, lick a compounded gel, or receive a second dose by mistake. Signs include vomiting, drooling, wobbliness, dark stool, rapid breathing, and collapse.
If you suspect an overdose or any reaction:
- Call your veterinarian right away.
- Call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Call the Pet Poison Helpline at (855) 764-7661.
Cats can overdose on NSAIDs, and any cat should be evaluated by a veterinarian before receiving medication of this type [1]. Do not wait for symptoms to appear. Early treatment is far easier than treating organ damage.
Limitations and When to Contact a Veterinarian
This article cannot tell you whether your individual cat can safely take carprofen. That decision needs a veterinarian who knows your cat's history, lab work, and current medications.
Contact your veterinarian the same day if your cat:
- Vomits more than once, or vomits blood
- Refuses food or seems painful when you touch the belly
- Has diarrhea, especially black or bloody stool
- Seems weak, wobbly, or unusually quiet
- Drinks and urinates much more than normal
Go to an emergency clinic now if your cat:
- Collapses or cannot stand
- Breathes rapidly or with effort
- Has a swollen, painful, or rigid abdomen
- Has pale gums, a racing heart, or seems to be in shock
- Swallowed a dog NSAID, a human NSAID, or an unknown amount of any pain medication
Schedule a routine visit if your cat has ongoing pain that is not well controlled. Chronic pain deserves a plan, not a leftover pill. Your vet can choose a cat-appropriate NSAID, an opioid, or another approach, and can recheck blood work as needed.
Frequently Asked Questions
Is Novox safe for cats?
No, not in the routine sense. Carprofen is not approved for cats in the United States, and most veterinarians avoid it because cats handle NSAIDs poorly. If a vet ever uses it, that is a rare, carefully monitored decision, not a home treatment you should try.
Can I give my cat my dog's carprofen?
No. Dog carprofen products are dosed and flavored for dogs, and giving them to a cat can cause serious harm. Call your veterinarian or a poison control hotline if your cat ate a dog pill, even if the cat seems fine right now.
What pain reliever can I give my cat instead?
Only what your veterinarian prescribes. Meloxicam is an NSAID made for cats and is used for pain and inflammation under veterinary direction [1]. Opioids such as buprenorphine are also used, and one study found that a single subcutaneous dose improved postoperative comfort in cats after spay surgery [2]. Never reach for a human pain pill on your own.
Are there other feline pain options besides NSAIDs?
Yes. Opioids are a mainstay for moderate to severe feline pain [2]. Researchers have also studied oral combinations such as tramadol with dipyrone for cats recovering from spay surgery, given every 12 hours for 5 days, with pain measured using feline-specific scoring tools [5]. Your vet picks the option that fits your cat's condition, kidney and liver status, and how long treatment is needed.
What if my cat already took carprofen?
Stop giving it and call your veterinarian or a poison control hotline now. Watch for vomiting, drooling, wobbliness, dark stool, or unusual tiredness, and report anything you see. Do not wait for symptoms before you call, because early care gives your cat the best chance.
Related Articles
- Can I Give My Cat Tylenol? Why Acetaminophen Is Deadly for Cats
- Can Cats Have Tylenol?
- Cat Flea Treatment Safety
- Cat Flea Treatment Safe For Cats
- What Human Medications Are Safe for Cats? A Vet's Guide to OTC Options
- Onsior Robenacoxib for Cats: Feline NSAID Safe Dosing Protocol
- Carprofen for Cats: Side Effects and Safety
- Carprofen for Cats: Dosage and Injection Risks
- Over-the-Counter Pain Relief for Cats: What's Safe
References
- Nsaids for Cats. Pet Poison Helpline.
- Evaluation of buprenorphine as optimisation of postoperative analgesia in feral cats undergoing ovariohysterectomy under field conditions. The Journal of small animal practice, 2026.
- Surgical repair of steroidal and non-steroidal anti-inflammatory drug-associated full-thickness gastrointestinal ulcers in 10 cats. Journal of feline medicine and surgery, 2026.
- Potential acute hepatic injury in 2 cats exposed to topical human diclofenac. The Canadian veterinary journal = La revue veterinaire canadienne, 2026.
- Analgesic efficacy of oral tramadol-dipyrone combination in cats undergoing ovariohysterectomy. Frontiers in veterinary science, 2026.