Carprofen, marketed under many brand names worldwide, is a nonsteroidal anti-inflammatory drug that veterinarians prescribe as a supportive treatment for various conditions in animals. It provides day-to-day treatment for pain and inflammation from various kinds of joint pain as well as post-operative pain. Carprofen reduces inflammation by inhibition of COX-1 and COX-2; its specificity for COX-2 varies from species to species.
Use in dogs
Adverse effects
Most dogs respond well to carprofen use, but like all NSAIDs, it may cause gastrointestinal, liver and kidney problems in some patients. In 1999, the FDA had more than 6000 anecdotal reports of sudden animal death after usage of Pfizer’s Rimadyl brand of carprofen. As a result, the FDA requested that Pfizer advise consumers in their advertising that death is a possible side effect. Pfizer refused and pulled their advertising; however, they now include death as a possible side effect on the drug label. Plans call for a "Dear Doctor" letter to advise veterinarians, and a safety sheet attached to pill packages. Adverse effects include:
Effects of overdose include gastritis and ulcer formation. In healthy dogs given carprofen, no perioperative adverse effects on the cardiovascular system have been reported at recommended dosages. Perioperative administration of carprofen to cats did not affect postoperative respiratory rate nor heart rate. Carprofen should not be administered concurrently with steroids, as this can cause ulcers in the stomach. Dogs should be taken off carprofen for three full days before ingesting a steroid. Carprofen should not be given at the same time with other types of medications such as other NSAIDs or steroids such as dexamethasone, triamcinolone, cortisone or prednisone. Carprofen must be used with caution within the supervision of a veterinarian in dogs with liver or kidney disease, dehydration, bleeding deficits, or other health problems. It is not recommended for use in dogs with bleeding disorders, as safety has not been established in dogs with these disorders. It has not been established whether carprofen can be safely used in pregnant dogs, dogs used for breeding purposes, or in lactating female dogs. Several laboratory studies and clinical trials have been conducted to establish the safety of using Carprofen. Clinical studies were conducted in nearly 300 dogs, coming from different breeds. The dogs were treated with Rimadyl at the recommended dose for 2 weeks. According to these studies, the drug was clinically well tolerated and the treated dogs did not have a greater incidence of adverse reactions when compared to the control group. A number of factors may contribute to the high incidence of adverse reports received for carprofen by the Center for Veterinary Medicine in the late 1990s. These include:
The type of drug;
Wide use;
Duration of use. While the side effects from carprofen are known to occur within a short period of time after administration, it is believed that long-term use may actually result in a higher risk for adverse reactions;
Senior dog use. Older dogs are generally more prone to side effects caused by carprofen.
Human use
Carprofen was used in humans for almost 10 years, starting in 1988. It was used for the same conditions as in dogs, viz., joint pain and inflammation. Side effects tended to be mild, usually consisting of nausea or gastro-intestinal pain and diarrhea. Carprofen was available only by prescription in 150 to 600 mg doses. Dosage over 250 mg was only for relieving pain after severe trauma, such as post-surgery inflammation. 150 mg doses were commonly used to relieve the pain of arthritis, while 200 mg doses were commonly prescribed in cases of severe arthritis or severe inflammation pain. The drug was taken orally. Pfizer voluntarily removed it from the market for human use on commercial grounds.
Equine use
Carprofen may be administered intravenously to horses. A single dose has been shown to reduce prostaglandin E2 production and inflammatory exudate for up to 15 hours, although there was less effect on eicosanoid production when compared to the effects produced by NSAIDs such as phenylbutazone or flunixin. Prostaglandin E2 and inflammatory exudate are also reduced and leukotriene B4 is inhibited. Carprofen can also be given orally, but intramuscular use may produce muscle damage.
