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Can Rimadyl Kill Dogs? Dosage, Risks, Overdoses.

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This article was updated on August 26th, 2023

With all of the medicines we use as vets, our aim is to use the lowest effective dose only as needed. As with many of the other medications we use, there is the potential for side effects, adverse reactions and even toxicities when Rimadyl is prescribed, so vets and owners alike need to be aware of the potential outcomes.

On the whole, Rimadyl is well tolerated and effective at what it does. It is something I personally prescribe often and most owners find it works well for their pet and is something they would be happy to use again.

What is Rimadyl (Carprofen)? What is Rimadyl used for in dogs?

Rimadyl is an NSAID; a non steroidal anti inflammatory drug. It is incredibly useful and something many of us vets use on a daily basis for our patients. Rimadyl inhibits COX enzymes, specifically those in the COX 2 pathway. This inhibits the release of a number or prostaglandins, thus reducing inflammation.

The majority of dogs tolerate it well and benefit from the pain relief and anti inflammatory effects it provides. It is also an antipyretic, meaning it can bring a fever down.

We will commonly issue Carprofen for those dogs suffering with ongoing joint disease such as arthritis. We also often use it as a pain relief after routine surgery such as neutering or after orthopedic surgery.

How much Rimadyl can I safely give my dog? Can I give my dog Rimadyl every day?

It is important that owners only ever give the dose as prescribed by their vet. There is a specific dosing regime that should be adhered to.

Generally, the dose will be 2.2mg/kg twice daily or 4.4mg/kg once daily. It is given orally as a chewable or caplet or as an injection which would be administered by the vet.

The dose is sometimes halved after 7 days, if we need to continue giving the medicine. If Rimadyl is to be used longterm, this has to be under the supervision of a vet and routine checkups and blood tests are advised.

Can Rimadyl seriously negatively impact the overall health of a dog?

When taken as prescribed, most animals benefit from Rimadyl. However, side effects are possible and are seen in a proportion of patients. The more widely reported serious side effects include gastric uclers, bloody stool, bloody vomit and melena (black, digested blood in the stool).

Uncommonly, those on long term Rimadyl will develop elevated liver enzymes.

Can Rimadyl kill dogs?

Very rarely, when dosed correctly, Rimadyl can cause idiosyncratic hepatocellular toxicosis. The average time it takes for this to present after medicine is started is three weeks.

We treat this by discontinuing the medicine and starting supportive care. The majority of patients recover well from this.

Rimadyl causes acute toxicosis when an overdose is taken. This can be due to an owner misunderstanding instructions, or because a dog gets access to their medicine and eats it all in one go. As the chewable tablets are palatable, it is not unusual for a dog to present to the emergency clinic after eating a whole tub of Rimadyl.

Vomiting, diarrhea, black stool, weakness and seizures can occur within just a few hours of the medicine being eaten. If left untreated or if treatment is delayed, there is the potential for death with significant overdoses.

Common side effects Of Rimadyl

Some of the more common side effects would include a mild stomach upset (so abdominal cramps, flatulence, bloating, vomiting and diarrhoea). Some owners report constipation and some dogs may seem a bit more lethargic than usual.

Disclaimer: This content is not a substitute for veterinary care. Always consult with your vet for health decisions. Learn more.

We may find lab changes on bloodwork, including high liver enzymes, altered blood cell counts and a change in clotting times.

Gastric ulcers, bloody vomit and black stool can also occur but these side effects are less commonly seen.

Why you should consult a vet before administering Rimadyl

Rimadyl is a prescription only medicine that should only be given under the direction of a vet at the right dose for the minimal amount of time needed.

We would not use Rimadyl in certain situations, such as in dogs with known blood clotting disorders or alongside other NSAIDs or steroids.

Are there any alternatives to Rimadyl?

As Rimadyl is a COX 2 inhibitor, there are several other NSAIDs that work in the same way available to us. Meloxicam (Metacam, Loxicom) is possibly one of the best known alternatives but there are several others.

For owners of dogs with daily arthritic pain who do not want to be tied to giving daily medicine, there are alternatives including a monthly tablet called Trocoxil (Mavacoxib) and a monthly injection called Cartrophen (PPS).

How to tell if your dog is in pain 

Importantly signs of pain in a dog can be subtle and are frequently overlooked. A dog will rarely refuse food or walks and won’t generally yelp, moan or complain.

Signs to watch for would include:

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  • A general slowing down
  • Stiffness on rising
  • Reluctance to exercise
  • A mild appetite reduction
  • Panting
  • Restlessness or difficulty settling
  • A limp
  • Reduced muscle mass
  • Hiding away
  • Reluctance to be touched in certain places


Does Rimadyl affect a dogs’ kidneys?

Side effects affecting the kidneys are rare but can occur, which is why most vets recommend routine blood monitoring for those on longterm Rimadyl.

During an overdose of Rimadyl, casts can form in the kidneys causing damage.

How long does it take for Rimadyl to start working with dogs?

Rimadyl reaches peak levels within 1-3 hours of being given. However, it sometimes take a day or two to see changes in your dog.

What’s a lethal dose of Rimadyl?

Rimadyl can cause signs of toxicity from about 22mg/kg, or ten times above the split daily dose. At this dose, dogs generally experience GI side effects. Doses over 40mg/kg can affect kidney health. Neurological signs are reported at doses over 280mg/kg.

Death despite treatment has been reported at 536 mg/kg


  • Dr. Linda Simon, Veterinarian

    Dr Linda Simon (MVB MRCVS) has 10 years of experience as a veterinarian. She is a veterinary surgeon with a special interest in geriatric patient care, dermatology and endocrinology. She is a member of the British Royal College of Veterinary Surgeons. She graduated top of her class from UCD School of Veterinary Medicine in Dublin in 2013. Linda has also worked as a locum vet in a range of clinics, including 24 hour emergency clinics and busy charity clinics.

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