Owners of dogs in pain may often question why a drug like Ibuprofen is bad for dogs, when Rimadyl is OK to use. The question makes perfectly sense, considering that both medications are quite similar and belong to the same class of drugs, yet at a closer inspection, they are different in many ways. Skeptics of vet practices may think veterinarians must recommend Rimadyl, over the more readily available and cheaper over-the-counter drug Ibuprofen, for profit purposes, but it turns out there are real risks with giving dogs Ibuprofen.
Ibuprofen is categorized as a nonsteroidal anti-inflammatory drug, which means that it is meant to reduce pain, inflammation and fever without relying on any steroids. This medication is available over the counter under the name of several different trade names such as Advil, Motrin or Midol.
As with other nonsteroidal anti-inflammatory drugs, Ibuprofen works by inhibiting the production of prostaglandins, more specifically the enzyme cyclooxygenase (COX). Prostaglandins are responsible for the redness, swelling and warmth associated with inflammatory conditions. However, prostaglandins also play an important role in protecting the stomach and small intestine from the damaging effects of stomach acid and also play a role in providing good blood flow to the kidneys.
Ibuprofen is a non-selective COX inhibitor, meaning that it inhibits the prostaglandins that trigger the inflammatory response (COX-2) but also the prostaglandins that protect the stomach and promote kidney health (COX-1). This means that this drug has the potential for causing unwanted effects on the gastrointestinal tract and even kidney impairment.
Rimadyl, also known by its generic name carprofen, is also categorized as a nonsteroidal anti-inflammatory drug that reduces pain and inflammation without relying on any steroids. This medication is available by veterinary prescription only and is also known by other brand names such as Novox or Vetprofen.
Just like Ibuprofen, Rimadyl is a non-selective COX-1 and COX-2 inhibitor, and therefore it inhibits both cyclooxygenase 1 (COX-1), the enzyme that promotes normal gastrointestinal and kidney function, and cyclooxygenase-2, COX-2, the enzyme that provides anti-inflammatory activity. And just like Ibuprofen, Rimadyl can cause potential damage to the gastrointestinal tract and even kidney impairment.
So what is the difference between these two drugs? So far they may seem quite similar for the fact that they are both nonsteroidal anti-inflammatory drugs and that they are non-selective, inhibiting both cyclooxygenase 1 (COX-1) , and cyclooxygenase-2, (COX-2), but there is one big factor that makes the use of Ibuprofen particularly unsafe in dogs.
Ibuprofen Dangers to Dogs
The biggest danger of using Ibuprofen is the fact that this drug has a narrow margin of safety when it comes to dogs. What does this mean? It means that the ranges between the minimal therapeutic dose and the minimal toxic dose of this drug are very close to one another.
According to Dr. Sharon Gwaltney-Brant, a board-certified veterinary toxicologist, even if Ibuprofen is given at the therapeutic dosage of 5 mg/kg, this drug can potentially cause stomach ulcers and even perforations with prolonged use. In one case, a dog who was given a dose of 3 mg/kg every other day for six weeks, ended up developing a deadly gastric perforation.
While the most common over-the-counter strength of Ibuprofen for human adults is 200 mg, prescription Ibuprofen strength for human use may contain up to 800 mg, which can be particularly risky for dogs. Dogs who happen to accidentally ingest Ibuprofen by gaining access to pill bottles risk developing hemorrhage and ulceration of the stomach and duodenum with its associate nausea and vomiting, perforations and even renal failure at high dosages. In some case, dogs develop toxic effects because dog owners purposely gave Ibuprofen to their dogs in belief that this drug was safe.
Ibuprofen is one of the most common causes for toxicity in dogs along with chocolate, rat poison and fertilizers. While in humans, Ibuprofen appears to have quite a wide margin of safety, in dogs and cats it does not, and therefore it's a common cause of poisoning, often reported to the ASPCA Animal Poison Control Center, explains Dr. Eric K. Dunayer. If you believe your dog was poisoned by ibuprofen, call your veterinarian or Pet Poison Helpline (855-764-7661) immediately.
"A wide range of NSAID is used to treat human beings with osteoarthrits; however, it is imperative to remember that dogs are especially sensitive to these drugs, and reports of serious, and occasionally fatal, complications are numerous."~Fox SM, Johnston SA
The Bottom Line
Because Ibuprofen has such a narrow margin of safety for dogs, there are no approved dosages that veterinarian can provide dog owners with for this drug. Prescribing Ibuprofen to a dog would therefore be considered unsafe and veterinarians doing so may be even accused of malpractice, explains veterinarian Dr. Brian. Rimadyl and other dog specific nonsteroidal anti-inflammatory drugs such as Deramaxx, Previcox and Metacam, albeit not being completely free of side effects, remain far safer and more effective options that veterinarians feel confident prescribing.
" We can't recommend a drug that is significantly more dangerous when there are effective and safer alternatives cleared for animal use readily available just because a human product is cheaper. "~Dr. Brian DVM
- DVM360: Toxicology Brief, The 10 most common toxicoses in dogs
- DVM360: Toxciology Brief, Ibuprofen toxicosis in dogs, cats, and ferrets
- Smith, K.J.; Taylor D.H.: Letter: Another case of gastric perforation associated with administration of ibuprofen in a dog. JAVMA 202 (5):706; 1993
- Pet Poison Helpine, Ibuprofen