Carprofen

Carprofen is a propionic-acid nonsteroidal anti-inflammatory drug with analgesic, anti-inflammatory and antipyretic activity. It is used predominantly in dogs for osteoarthritis and pain associated with surgery or musculoskeletal disease. Veterinary injectable formulations also have species-specific applications, including adjunctive relief of inflammatory clinical signs in cattle with respiratory disease or mastitis.

Group

Nonsteroidal anti-inflammatory drug

Mechanism of Action

Carprofen reduces prostaglandin production by inhibiting cyclooxygenase activity in the arachidonic-acid pathway. Reduced prostaglandin signaling limits inflammatory vasodilation, edema and sensitization of peripheral pain pathways, producing analgesic and anti-inflammatory effects. It also reduces prostaglandin-mediated fever. Relative inhibition of COX-1 and COX-2 depends on species, tissue and concentration, with preferential COX-2 inhibition demonstrated in dogs.

Dose Rates

Dogs

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2.2 mg/kg	PO, SC	Every 12 h
Pain and inflammation	4.4 mg/kg	PO, SC	Every 24 h
Perioperative analgesia	4 mg/kg	PO, IM, SC	Once	Alternative surgical-pain regimen; use a product suitable for the selected route.
Pain and inflammation	2.2 mg/kg	PO	Every 12–24 h

Cats

Use / stage	Dose	Route	Schedule	Instructions
Perioperative analgesia	Reference only	PO		4 mg/kg once by injection. The dosage passage does not specify an injection route; no route is inferred.
Long-term analgesia	0.5 mg/kg	PO	Every 24 h	Pharmacokinetic extrapolation only; long-term feline safety is not established.
Perioperative analgesia	1–4 mg/kg	SC	Once	Pre- or postoperative single-dose alternative; 1–2 mg/kg has been described with similar efficacy and greater safety. Do not extrapolate to repeated canine dosing.
Short-course analgesia	2 mg/kg	PO	Every 12 h	Up to 2 days; Historical feline oral regimen, limited to two days. This is not evidence for long-term safety.
Lower-dose short-course analgesia	Reference only	PO		Less than 1 mg/kg orally once daily for 2–3 treatments; the open-ended less-than limit is not encoded as an invented numeric range.

Horses

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	0.7 mg/kg	IV	Every 24 h
Pain and inflammation	0.7 mg/kg	PO		Oral granules are described; the oral interval is not explicitly stated in that alternative.
Acute pain and inflammation	0.7 mg/kg	IV	Once

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Inflammation	1.4 mg/kg	SC, IV
Escherichia coli mastitis-associated inflammation	0.7 mg/kg	IV		Dose described in the clinical-use discussion.

Rabbits

Use / stage	Dose	Route	Schedule	Instructions
Chronic joint pain	2.2 mg/kg	PO	Every 12 h

Rats

Use / stage	Dose	Route	Schedule	Instructions
Analgesia	5 mg/kg	SC
Analgesia	5–10 mg/kg	PO

Chinchillas

Use / stage	Dose	Route	Schedule	Instructions
Analgesia	4 mg/kg	SC	Every 24 h

Birds

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2 mg/kg	PO	Every 8–24 h

Chickens

Use / stage	Dose	Route	Schedule	Instructions
Lameness-associated pain	1 mg/kg	SC

Reptiles

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	1–4 mg/kg	IV, IM, SC, PO	Every 24–72 h	Broad historical reptile recommendation; individual species evidence and hydration must guide use.

Indications

Relief of pain and inflammation associated with osteoarthritis in dogs.
Control of postoperative pain in dogs after orthopedic or soft-tissue surgery.
Symptomatic relief of painful musculoskeletal inflammation in dogs.
Adjunctive reduction of fever and inflammatory clinical signs in cattle with acute infectious respiratory disease or acute mastitis, alongside treatment of the infection.
Perioperative analgesia in cats with a feline-authorized formulation and indication.

Contraindications

Gastrointestinal ulcer predisposition or previous serious NSAID reaction.
Do not apply canine regimens to cats.
Long-term feline safety has not been established.
Bleeding disorders such as von Willebrand disease; assess dehydration, hepatic or renal disease and geriatric risk.

Interactions

Corticosteroids and other ulcerogenic drugs increase gastrointestinal injury.
May reduce effects of ACE inhibitors and diuretics.
Avoid concurrent aspirin because gastrointestinal blood loss can increase.
Digoxin exposure may increase; methotrexate toxicity may be enhanced by NSAIDs.
Probenecid can increase exposure; hepatic enzyme inducers and other highly protein-bound drugs warrant medication review.

Adverse effects

Vomiting, anorexia and diarrhea
Gastrointestinal bleeding, ulceration or perforation
Rare idiosyncratic hepatic injury
Reduced measured total T4

Toxicity

Stop treatment for suspected hepatic or gastrointestinal toxicity. Canine doses repeated in cats can be toxic.

Preparations

Preparation	Form	Strength	Route
Carprofen 25 mg tablet	Tablet	25 mg / tablet	PO
Carprofen 75 mg tablet	Tablet	75 mg / tablet	PO
Carprofen 100 mg tablet	Tablet	100 mg / tablet	PO
Carprofen 50 mg/mL injection	Injection	50 mg / mL	SC

Monitoring and Administration

Check hepatic enzymes about 7–14 days after starting and reassess if appetite, stool or activity changes.

A compounded oral suspension made using methylcellulose, syrup and a suitable vehicle has reported stability for 28 days refrigerated or at room temperature.

Cattle have prolonged elimination; withdrawal decisions are formulation- and jurisdiction-specific.

Baseline assessment for prolonged therapy includes examination, CBC, chemistry and urinalysis. Recheck liver enzymes at approximately 1, 2 and 4 weeks, then at 3–6-month intervals if stable.

For the described canine injectable product, refrigerate unopened at 2–8°C; after first use it may be held at up to 25°C for 28 days. Do not apply tablet room-temperature storage to injection.

Two compounded vehicles have different stability: the previously described methylcellulose formulation had 28-day data; 100 mg tablet in Ora-Plus/Ora-Sweet to final 20 mL gives 5 mg/mL with 21-day potency at 5°C or 25°C, protected from light.