Difference between revisions of "Carprofen"

Latest revision as of 11:14, 20 September 2010

Carprofen (marketed as Rimadyl, manufactured by Pfizer Animal Health ^[1]) is a non-steroidal anti-inflammatory drug that is used by veterinarians as a supportive treatment for the relief of arthritic symptoms in geriatric dogs. It can be used both short term, for joint pain or post-operative inflammation, or for day-to-day relief from the pain and inflammation associated with osteoarthritis, hip dysplasia, and other forms of joint deterioration .

Carprofen reduces inflammation by inhibiting the production of COX-2 and other sources of inflammatory prostaglandins. This is targeted protection, in that it does not interfere with the activity of COX-1.

Administration

Carprofen is available in the USA in 25, 75 and 100 mg tablets (given either with food or straight into the animal's mouth), and in injectable form.^[2] In the UK, it is available in 20, 50 and 100 mg tablets. The usual dosage is 2 mg per pound daily.^[3] In Australia, Carprofen is marketed as Norocarp or Tergive Injection. Norocarp is available in 20 mg and 50 mg tablets or Norophen in injectable liquid at 5.0% w/v, for cattle and canines.^[4] Carprofen is also marketed in many Latin-American (and some asian and african countries) as Carprodyl in 25 mg and 100 mg tablets for canines.^[5]

Carprofen is sometimes divided between morning and evening doses. It is administered two hours before surgery when being used to relieve post-operative pain.

Health issues

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Although some dogs respond well to carprofen, it is capable of causing liver and kidney problems in some animals, and in the early days of introduction there were significant anecdotal reports of sudden animal deaths arising from its use.

This medication has been found to be deadly for some dogs, as witnessed by the FDA receiving more than 6,000 bad reaction reports about the drug manufactured by Pfizer. As a result, the FDA requested that Pfizer advise consumers in their advertising that death was a possible side effect.^[6] Pfizer refused and pulled their advertising, however they have included "death" as a possible side effect on the drug label. Plans call for a "Dear Doctor" letter to be issued to veterinarians and a safety sheet will be attached to pill packages.

Pfizer acknowledges a problem with some dog owners, especially the consumer group which mounted a campaign dubbed BARKS, for Be Aware of Rimadyl's Known Side-effects (including loss of appetite, wobbling, vomiting, seizures and severe liver malfunction). The drug company is reported to be contacting pet owners who have told their stories on the Internet, and is offering to pay medical and diagnostic expenses for some dogs who may have been harmed by carprofen.^{[citation needed]}

General symptoms to watch for include:

• Loss of appetite
• Vomiting
• Diarrhea
• Increase in thirst
• Increase in urination
• Fatigue and/or Lethargy
• Loss of coordination
• Seizures

Other symptoms which can indicate a problem, and which are worth raising with a vet include excessive drinking or urination, blood or dark tar-like material in urine or stools, jaundice (yellowing of eyes), unusual lethargy and so on.

Other side effects of Rimadyl include:

• Black, tarry stools or flecks of blood in the vomit
• Drowsiness
• Staggering, stumbling, weakness or partial paralysis, full paralysis, dizziness, loss of balance. ^[7]
• Change in urination habits (frequency, color, or smell)
• Change in skin (redness, scabs, or scratching)
• Change in behavior (such as decreased or increased activity level, seizure or aggression). ^[8]

Excess use of Rimadyl can lead to gastritis and ulcer formation. ^[9] It is also believed that in some breeds of dogs it may induce kidney and liver damage.

Carprofen should not be administered to animals that are also being given steroids (one of the primary risks of this combination being that it can cause ulcers in the stomach). In dogs, it is recommended that the dog be taken off carprofen for three full days before ingesting a steroid (such as prednisolone).

According to the official Rimadyl website, the drug should not be given at the same time with other types of medications such as other NSAIDs (aspirin, etodolac, deracoxib, meloxicam, tepoxalin) or steroids such as dexamethasone, triamcinolone, cortisone or prednisone. However, dog owners whose pets have been administered Rimadyl and have experienced side effects are highly recommended to contact a veterinarian as soon as they appear and to stop the therapy.

Also, Rimadyl must be used with caution and within the closely monitoring of a veterinarian in dogs with liver or kidney disease, dehydration, bleeding deficits, or other health problems. Rimadyl is not recommended for use in dogs with bleeding disorders (such as Von Willebrand's disease), as safety has not been established in dogs with these disorders. ^[10] Also, it has been not yet established if Rimadyl 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 Rimadyl. Clinical studies were conducted in nearly 300 dogs, coming from different breeds. These dogs have been treated with Rimadyl at the recommended dose for 2 weeks. According to these studies, the drug was clinically well tolerated and dogs treated with Rimadyl did not have a greater incidence of adverse reactions when compared to the placebo-treated animals.

There is a number of factors that might however contribute to the high incidence of adverse drug experience reports received for Rimadyl 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 Rimadyl 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 usage

Carprofen is no longer marketed for human usage, after being withdrawn on commercial grounds.^[11]

Rimadyl was removed from the market for use in humans once less expensive options were developed. This medicine was prescribed to treat the same conditions for which it is used with dogs, viz., joint pain and inflammation. The drug was accepted well by the human body and the side effects tended to be mild, usually consisting of nausea or gastro-intestinal pain and diarrhea.

This drug was used in humans for almost 10 years, starting in 1988 until it was voluntarily pulled from the market by Pfizer when Advil began successfully competing.

There are differences between NSAIDs such as ibuprofen or Advil and carprofen, the active substance in Rimadyl. The ibuprofen inhibits both COX-1 and COX-2 forms of cyclooxygenase in the human body, while carprofen blocks only COX-2.

For human use, Rimadyl was available only by prescription in 150 to 600 mg doses. Dosage over 250 mg was intended 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.

The current version of Rimadyl is prohibited for use by humans.

References

External links

• Rimadyl warning
• Pfizer product website PDS
• Senior dogs and Rimadyl

de:Carprofen sv:Karprofen

1. ↑ Pfizer Animal Health-Rimadyl
2. ↑ http://www.srdogs.com/Pages/rimadyl.html
3. ↑ Norbrook Pharmaceuticals Worldwide Products ~Norocarp Tablets
4. ↑ Norbrook Pharmaceuticals Wordwide - Australia
5. ↑ Agrovet Market Animal Health - Peru
6. ↑ "Update On Rimadyl, FDA's Center for Veterinary Medicine, December 1, 1999". 
7. ↑ "A Review of Signs of a Potentially Life-threatening Reaction to Rimadyl". Retrieved 2010/05/20.  Check date values in: |access-date= (help)
8. ↑ "Dog Owner Information About Rimadyl® (carprofen)". Retrieved 2010/05/20.  Check date values in: |access-date= (help)
9. ↑ "Generic Dog Rimadyl Online". Retrieved 2010/05/20.  Check date values in: |access-date= (help)
10. ↑ "Rimadyl ® (Carprofen)". Retrieved 2010/05/20.  Check date values in: |access-date= (help)
11. ↑ [1]