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Rimadyl* Caplets (75 mg) (Canada)

This page contains information on Rimadyl* Caplets (75 mg) for veterinary use.
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  • Rimadyl* Caplets (75 mg) Indications
  • Warnings and cautions for Rimadyl* Caplets (75 mg)
  • Direction and dosage information for Rimadyl* Caplets (75 mg)

Rimadyl* Caplets (75 Mg)

This treatment applies to the following species:
Manufacturer: Pfizer

carprofen caplets

Non-steroidal anti-inflammatory drug

For Oral Use In Dogs

DIN: 02239914 (25 mg), 02239915 (75 mg), 02239916 (100 mg)


Rimadyl (carprofen) is a non-steroidal anti-inflammatory drug (NSAID) of the propionic acid class that includes ibuprofen, naproxen, and ketoprofen. The chemical name for Rimadyl, a substituted carbazole, is (±)-6-chloro-α-methylcarbazole-2-acetic acid and its structural formula is:

Carprofen is a white, crystalline compound with an empirical formula of C15H12NO2Cl and a molecular weight of 273.72. It is freely soluble in ethanol, but practically insoluble in water at 25°C.

Clinical Pharmacology

Carprofen is a non-narcotic, non-steroidal anti-inflammatory agent with characteristic analgesic and antipyretic activity approximately equipotent to indomethacin in animal models.1

As with other NSAIDs, the exact mode of action of carprofen has not been established; however, inhibition of prostaglandin synthesis accounts for at least part of its mechanism of action. Carprofen is a moderately potent inhibitor of phospholipase A2 and a reversible inhibitor of cyclo-oxygenase (COX). In in vitro cell culture of canine origin, carprofen displayed 129-fold selectivity for COX-2, the inducible form of the enzyme upregulated in damaged and inflamed tissue, compared with its inhibition of COX-1, the isozyme which is involved in normal gastric function. In rats, carprofen has been shown to be a much weaker blocker of arachidonic acid-induced diarrhea than indomethacin.2 This decreased effect of carprofen on prostaglandin synthesis in the gastrointestinal tract may explain its relatively low ulcerogenic activity compared to other drugs in its class.1

Carprofen has also been shown to inhibit the release of several prostaglandins in two inflammatory cell systems: rat polymorphonuclear leukocytes (PMN) and human rheumatoid synovial cells, indicating inhibition of acute (PMN system) and chronic (synovial cell system) inflammatory reactions.1

Several studies have demonstrated that carprofen has modulatory effects on both humoral and cellular immune responses.3-7 Data also indicate that carprofen inhibits the production of osteoclast-activating factor (OAF), PGE1, and PGE2 by its inhibitory effects on prostaglandin biosynthesis.1

Based upon comparison with data obtained from intravenous administration, carprofen is rapidly and nearly completely absorbed (more than 90% bioavailable) when administered orally.8 Peak blood plasma concentrations are achieved in 1-3 hours after oral administration of 1, 5, and 25 mg/kg to dogs. The mean terminal half-life of carprofen is approximately 8 hours after single oral doses varying from 1-35 mg/kg of body weight. After a 100 mg single intravenous bolus dose, the mean elimination half-life was approximately 11.7 hours in the dog. Rimadyl is more than 99% bound to plasma protein and exhibits a very small volume of distribution.

Carprofen is eliminated in the dog primarily by biotransformation in the liver followed by rapid excretion of the resulting metabolites (the ester glucuronide of carprofen and the ether glucuronides of 2 phenolic metabolites, 7-hydroxy carprofen and 8-hydroxy carprofen) in the feces (70%) and urine (10-20%). Some enterohepatic circulation of the drug is observed.

Rimadyl* Caplets (75 mg) Indications

Rimadyl is indicated for the relief of pain and inflammation in dogs. Rimadyl was shown to be clinically effective for the relief of signs associated with osteoarthritis in dogs.

Rimadyl* Caplets (75 mg) Dosage And Administration

The recommended daily dose for dogs is 4.4 mg carprofen per kg of body weight administered orally once daily, or in divided doses of 2.2 mg/kg twice daily. Caplets are scored and dosage should be calculated in half-caplet increments.


Laboratory studies and clinical field trials have demonstrated that Rimadyl is well tolerated in dogs after oral administration.

In target animal safety studies, Rimadyl was administered to dogs at 1, 3, and 5 times the recommended dose for 42 consecutive days with no significant side effects. Serum albumin for a single female dog receiving 5 times the recommended dose decreased to 2.1 g/dL after 2 weeks of treatment, returned to the pre-treatment value (2.6 g/dL) after 4 weeks of treatment, and was 2.3 g/dL at the final 6-week evaluation. Over the 6 week treatment period, black or bloody stools were observed in 1 dog (1 incident) treated with the recommended dose and in 1 dog (2 incidents) treated with 3 times the recommended dose. Redness of the colonic mucosa was observed in 1 male that received 3 times the recommended dose.

Two of 8 dogs receiving 10 times the recommended dose (22 mg/kg twice daily) for 14 days exhibited hypoalbuminemia. The mean albumin level in the dogs receiving this dose was lower (2.38 g/dL) than each of 2 placebo control groups (2.88 and 2.93 g/dL, respectively). Three incidents of black or bloody stool were observed in 1 dog. Five of 8 dogs exhibited reddened areas of duodenal mucosa on gross pathologic examination. Histologic examination of these areas revealed no evidence of ulceration, but did show minimal congestion of the lamina propria in 2 of the 5 dogs.

In separate safety studies lasting 13 and 52 weeks, respectively, dogs were administered up to 25.1 mg/kg/day (5.7 times the recommended total daily dose) of carprofen. In both studies, the drug was well tolerated clinically by all of the animals. No gross or histologic changes were seen in any of the treated animals. In both studies, dogs receiving the highest doses had average increases in serum L-alanine aminotransferase (ALT) of approximately 20 IU.

In the 52 week study, minor dermatologic changes occurred in dogs in each of the treatment groups but not in the control dogs. The changes were described as slight redness or rash and were diagnosed as non-specific dermatitis. The possibility exists that these mild lesions were treatment related, but no dose relationship was observed.

Clinical field studies were conducted with 549 dogs of different breeds at the recommended dose for 14 days. The drug was clinically well tolerated and the incidence of clinical adverse reactions for Rimadyl -treated animals was no higher than placebo-treated animals (placebo contained inactive ingredients found in Rimadyl). Mean post-treatment serum ALT values were 11 IU greater and 9 IU less than pre-treatment values for dogs receiving Rimadyl and placebo, respectively. Differences were not statistically significant. For animals receiving 4.4 mg/kg once daily, the mean post-treatment serum ALT values were 5 IU greater and 1 IU less than pre-treatment values for dogs receiving Rimadyl and placebo, respectively. Changes in clinical laboratory values (hematology and clinical chemistry) were not considered clinically significant nor reported as adverse reactions. The 2.2 mg/kg twice daily course of therapy was repeated as needed at 2 week intervals in 244 dogs, some for as long as 5 years.


Rimadyl should not be used in dogs exhibiting previous hypersensitivity to carprofen.

Rimadyl* Caplets (75 mg) Cautions

As a class, cyclo-oxygenase inhibitory NSAIDs may be associated with gastrointestinal and renal toxicity. NSAIDs decrease prostaglandin production and inhibit the enzyme cyclo-oxygenase which leads to formation of prostaglandins from arachidonic acid. While NSAIDs inhibit prostaglandins that promote inflammation, they may also inhibit prostaglandins which maintain normal function. These anti-prostaglandin side-effects may result in clinically significant disease in patients with underlying or pre-existing disease more often than in healthy patients. NSAID therapy could therefore reveal the presence of disease that has been previously undiagnosed due to the absence of clinical signs. Patients with underlying renal disease for example, may experience exacerbation or decompensation of their renal disease while on NSAID therapy.9-12

Carprofen is an NSAID and, as with others in that class, side effects may occur with its use. The most frequently reported effects have been gastrointestinal signs. Events involving suspected renal, hematologic, neurologic, dermatologic, and hepatic effects have also been reported. Patients at greatest risk for renal toxicity are those on concomitant diuretic therapy, or those with renal, cardiovascular, and/or hepatic dysfunction. Since many NSAIDs possess the potential to induce gastrointestinal ulceration, concomitant use of Rimadyl with other anti-inflammatory drugs, such as corticosteroids and NSAIDs, should be avoided or very closely monitored. Although the drug class has been associated with renal toxicity and gastrointestinal ulceration, Rimadyl treatment did not produce these effects in well-controlled safety studies of up to ten times the dose in dogs.

All dogs should undergo a thorough history and physical examination before initiation of NSAID therapy. Appropriate laboratory tests to establish hematological and serum biochemical baseline data prior to, and periodically during, administration of any NSAID should be considered in some patients. Dogs receiving Rimadyl should be observed for signs of drug intolerance, such as inappetence, vomiting, diarrhea, melena, polyuria/polydipsia, anemia, jaundice, lethargy, ataxia, seizure, or behavioral changes. Susceptibility to drug-associated adverse effects varies with the individual patient. Recognition of possible drug-related clinical signs followed by cessation of drug therapy, and by supportive therapy if appropriate, will improve patient recovery. The side effects of this drug class, in rare situations, may be serious, and if corrective action is not taken may result in hospitalization or even fatal outcomes.

The safe use of Rimadyl in pregnant dogs, dogs used for breeding purposes or in lactating bitches has not been established. Studies to determine the activity of Rimadyl when administered concomitantly with other protein-bound drugs have not been conducted. Drug compatibility should be monitored closely in patients requiring additional therapy. Rimadyl is not recommended for use in dogs with bleeding disorders (e.g., Von Willebrand's Disease), as safety has not been established in dogs with these disorders.

Do Not Use In Cats.

Information For Dog Owners

Rimadyl, like other drugs of its class, is not free from adverse reactions. Owners should be advised of the potential for adverse reactions and be informed of the clinical signs associated with drug intolerance. Adverse reactions may include decreased appetite, vomiting, diarrhea, dark or tarry stools, increased water consumption, increased urination, pale gums due to anemia, yellowing of gums, skin or white of the eye due to jaundice, lethargy, incoordination, seizure, or behavioral changes. Serious adverse reactions associated with this drug class can occur without warning and in rare situations result in death (see Adverse Reactions). Owners should be advised to discontinue Rimadyl therapy and contact their veterinarian immediately if signs of intolerance are observed. The vast majority of patients with drug related adverse reactions have recovered when the signs are recognized, the drug is withdrawn, and veterinary care, if appropriate, is initiated. Owners should be advised of the importance of periodic follow up for all dogs during administration of any NSAID.


Keep out of reach of children.

Adverse Reactions

During investigational studies with twice daily administration of 2.2 mg/kg, no clinically significant adverse reactions were reported. Some clinical signs were observed during field studies (n=297) which were similar for carprofen- and placebo-treated dogs. Incidences of the following were observed in both groups: vomiting (4%), diarrhea (4%), changes in appetite (3%), lethargy (1.4%), behavioral changes (1%), and constipation (0.3%). The product vehicle served as control.

There were no serious adverse events reported during clinical field studies with once daily oral administration of 4.4 mg/kg. The following categories of abnormal health observations were reported. The product vehicle served as control.

Percentage Of Dogs With Abnormal Health Observations Reported In Clinical Field Study (4.4 Mg/kg Once Daily)


Rimadyl (n=129)

Placebo (n=132)







Diarrhea/Soft stool



Behavior change









SAP increase



ALT increase



AST increase



BUN increase









Clinical pathology parameters listed represent reports of increases from pre-treatment values; the use of clinical judgment is necessary to determine clinical relevance.

Post-approval Experience

Although all adverse reactions are not reported, the following adverse reactions are based on voluntary post-approval adverse drug experience reporting to the Center for Veterinary Medicine in the United States. The categories of adverse reactions are listed in decreasing order of frequency by body system.

Gastrointestinal: Vomiting, diarrhea, constipation, inappetence, melena, hematemesis, gastrointestinal ulceration, gastrointestinal bleeding, pancreatitis.

Hepatic: Inappetence, vomiting, jaundice, acute hepatic toxicity, hepatic enzyme elevation, abnormal liver function test(s), hyperbilirubinemia, bilirubinuria, hypoalbuminemia. Approximately one-fourth of hepatic reports were in Labrador Retrievers.

Neurologic: Ataxia, paresis, paralysis, seizures, vestibular signs, disorientation.

Urinary: Hematuria, polyuria, polydipsia, urinary incontinence, urinary tract infection, azotemia, acute renal failure, tubular abnormalities including acute tubular necrosis, renal tubular acidosis, glucosuria.

Behavioral: Sedation, lethargy, hyperactivity, restlessness, aggressiveness.

Hematologic: Immune-mediated hemolytic anemia, immune-mediated thrombocytopenia, blood loss anemia, epistaxis.

Dermatologic: Pruritis, increased shedding, alopecia, pyotraumatic moist dermatitis (hot spots), necrotizing panniculitis/vasculitis, ventral ecchymosis.

Immunologic or hypersensitivity: Facial swelling, hives, erythema.

In rare situations, death has been associated with some of the adverse reactions listed above.


Store at a temperature between 15° and 30°C.

How Supplied

Rimadyl caplets are scored, and contain 25 mg, 75 mg, or 100 mg of carprofen per caplet. Each caplet size is packaged in bottles containing 60 (25 mg, 75 mg, 100 mg) or 180 (75 mg, 100 mg) caplets.


1. Baruth H, et al in Anti-Inflammatory and Anti-Rheumatic Drugs, Vol. II, Newer Anti-Inflammatory Drugs, Rainsford KD, ed. CRC Press, Boca Raton, pp. 33-47, 1986.

2. Strub KM, Muller RKM: Relation between ulcerogenic activity of various NSAID and their potency as inhibitors of prostaglandin synthesis in vivo. In Arachidonic Acid Metabolism in Inflammation and Thrombosis. Brune K, Baggiolini M, eds. Birkhauser Verlag, Basel, p. 245, 1979.

3. Ceuppens JL, et al: Non-steroidal anti-inflammatory agents inhibit the synthesis of IgM rheumatoid factor in vitro. Lancet 1:528, 1982.

4. Ceuppens JL, et al: Endogenous prostaglandin E2 enhances polyclonal immunoglobulin production by ionically inhibiting T suppressor cell activity. Cell Immunol 70:41, 1982.

5. Schleimer RP, et al: The effects of prostaglandin synthesis inhibition on the immune response. Immunopharmacology 3:205, 1981.

6. Leung KH, et al: Modulation of the development of cell mediated immunity: possible roles of the products of cyclo-oxygenase and lipoxygenase pathways of arachidonic acid metabolism. Int J Immunopharmacology 4:195, 1982.

7. Veit BC: Immunoregulatory activity of culture-induced suppressor macrophages. Cell Immunol 72:14, 1982.

8. Schmitt M, et al: Biopharmaceutical evaluation of carprofen following single intravenous, oral, and rectal doses in dogs. Biopharm Drug Dispos 11(7): 585-94, 1990.

9. Kore AM: Toxicology of nonsteroidal anti-inflammatory drugs. Veterinary Clinics of North America, Small Animal Practice 20, March 1990.

10. Binns SH: Pathogenesis and pathophysiology of isochemic injury in cases of acute renal failure. Compend for Cont Ed 16:1, January 1994.

11. Boothe DM: Prostaglandins: Physiology and clinical implications. Compend for Cont Ed 6:11, November 1984.

12. Rubin SI: Nonsteroidal anti-inflammatory drugs, prostaglandins, and the kidney. JAVMA 188:9, May 1986.

*Rimadyl is a registered trade-mark of Pfizer Products Inc.; Pfizer Canada Inc. licensee.

Pfizer Animal Health, Pfizer Canada Inc., 17 300 Trans-Canada Highway, Kirkland, QC H9J 2M5

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Pfizer Canada Inc.

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Every effort has been made to ensure the accuracy of the Rimadyl* Caplets (75 mg) information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the Rimadyl* Caplets (75 mg) product label or package insert.

Copyright © 2018 North American Compendiums. Updated: 2018-05-30