Carprofen

(carprofen)

Brand

RIMADYL, NOVOX

Availability

Caplets: 25 mg, 75 mg, 100 mg
Chewable: 25 mg, 75 mg, 100 mg
Injectable: 50 mg/mL

Pharmacology

Carprofen is a member of the class of drugs known as NSAIDs (nonsteroidal anti-inflammatory drugs). This is the same class as other more common over-the-counter remedies such as ibuprofen (e.g., Advil), naproxen (e.g., Aleve), ketoprofen (Orudis), and Aspirin.

Carprofen, like other newer NSAIDs, exhibit analgesic, anti-inflammatory, and antipyretic activity through its inhibition of the enzyme called COX-2 (cyclo-oxygenase 2).

The drug is metabolized in the liver and primarily eliminated in feces with a small percentage being eliminated in the urine. There is some enterohepatic recycling of the drug.

Carprofen has not been tested in pregnant or nursing females and is therefore not recommended for use in those animals that are.

Indications

Carprofen is used in the treatment of pain for either short term or long term use. It can also be used as an alternative to opioid based post-op pain. The advantage is less respiratory and cardiovascular side effects than the opioids, and it is longer acting (Golder, n.d.).

Drug Interactions or Contraindications

Drugs that are of the class of NSAIDs are not recommended to be used concurrently with each other as their side effects may be increased.
NSAIDs are not recommended to be used in conjunction with corticosteroid hormones (e.g., prednisone, dexamethasone, etc.). It is the recommendation of Pfizer that a 5–7 day rest period be given when changing from one NSAID to carprofen or from carprofen to another NSAID. If switching to Aspirin allow a rest period of 10-14 days due to Aspirin’s strong platelet inactivating ability. Also, if switching from carprofen to prednisone allow a one week rest period.
Monitor liver function if having to use carprofen with phenobarbital.
Carprofen may reduce the effectiveness of ACE inhibitors such as enalapril or captopril.
Do not use carprofen if bleeding disorders are present (e.g., Von Willebrand’s disorder).
Do not use carprofen in the presence of renal or hepatic insufficiency.
Carprofen may increase serum levels and duration of actions if used with the following:
- Phenytoin
- Anti-inflammatories
- Salicylates
- Sulfonamides
- Digoxin (cardoxin)

Carprofen may reduce the effect of the following:
- Furosemide

Adverse Reactions

Avoid use where pre-existing liver or kidney disease is present.

CNS: depression, lethargy, loss of coordination, seizures

GI: loss of appetite, diarrhea, occult fecal bleeding, increased thirst

GU: increased urination

Metabolic: dehydration

Hematologic: platelet deactivation – (platelets are the cells that control the ability of the blood to clot)

Hepatic: elevated liver enzymes (may indicate hepatopathy)

Dosage Recommendations

*Note: dosages should be adjusted to the lowest effective dose by veterinarian, when needed, to treat chronic conditions.

1.5 mg/kg, PO, q12hr ²⁶^, ³⁴

or

2 mg/kg to 5 mg/kg, total daily dose, PO, SQ, IM, IV. (May be given in a single dose or two divided doses). ⁴¹^, ⁴²^, ⁴⁴

or

2 mg/kg to 5 mg/kg, PO, SQ, q12hr to q24hr. ³⁴^, ³⁵

or

5 mg/kg, SQ, q24hr ²²^, ²⁶^, ³⁴

5 mg/kg to 10 mg/kg, PO, (Rats/can be combined with buprenorphine (0.5 mg/kg) ¹^, ²⁶^, ³⁴ ⁴¹

Considerations

*Note: nonsteroidal anti-inflammatory medicines may mask clinical signs of infection. When deciding to use NSAIDs or steroids in rats long term, it may become necessary to add a broad-spectrum antibiotic as part of the treatment regimen.
Prevent dehydration by providing juicy types of fruit in addition to fresh water.
Carprofen is available as a chewable tablet.
Caplets, and tablets may be stored at room temperature.

References

Dog Arthritis and Rimadyl (Carprofen) Information From Pfizer. (n.d.). Retrieved December 20, 2008, from http://www.rimadyl.com/.
Golder, F. (n.d.). Rat Analgesics. Retrieved December 20, 2008, from https://campusvet.wsu.edu/infofac/ratanalgesicsuse.htm.