Ketoprofen
2-(3-benzoylphenyl)propanoic acid
Also known as: Ketofen · Anafen · Comforion Vet · ketoprofenum · RP-19583 · Ketoprofeno
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceAnti-inflammatory/analgesic (extra-label)
Verified clinician required
- q12-24h
NA
Governing clinical context (1)
- Ketoprofen injection should be stored below 25°C (77°F), with brief excursions permitted between 0°C and 40°C (32°F-104°F) and used within 4 months of first vial puncture. 13
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Ketoprofen is a potent propionic acid derivative non-steroidal anti-inflammatory drug (NSAID), structurally related to ibuprofen, naproxen, and carprofen. It is utilized in veterinary medicine for its robust analgesic, antipyretic, and anti-inflammatory properties.
Key pharmacological highlights:
- Enantiomeric Profile: Commercial ketoprofen is a racemic mixture. The S(+) enantiomer is primarily responsible for the anti-prostaglandin activity (and associated GI/renal toxicity), while the R(-) enantiomer provides analgesia without significant gastrointestinal effects.
- Species Utility: It is widely used in horses for musculoskeletal pain and is considered by some clinicians as an NSAID of choice for short-term analgesia in cats. It is also utilized in dogs, cattle, swine, and various exotic species.
- Clinical Pearls: While highly effective, ketoprofen is a non-selective COX inhibitor. Therefore, it carries a higher risk of gastrointestinal ulceration and renal toxicity compared to newer COX-2 selective NSAIDs (coxibs), especially in small animals. Its use in dogs and cats is typically restricted to short courses (e.g., 1 to 5 days).
Mechanism of action
Ketoprofen exerts its effects primarily through the inhibition of the cyclooxygenase (COX) enzymes.
- Arachidonic Acid Cascade: Cell membrane phospholipids → Phospholipase A2 → Arachidonic Acid.
- COX Inhibition: Ketoprofen non-selectively blocks COX-1 and COX-2 enzymes. This prevents the conversion of arachidonic acid into prostaglandin precursors (endoperoxides), thereby halting the synthesis of pro-inflammatory and hyperalgesic prostaglandins (e.g., PGE2) and thromboxanes.
- LOX Inhibition (Theoretical): Ketoprofen purportedly has inhibitory activity on lipoxygenase (LOX), which would theoretically block the formation of leukotrienes. However, in vitro studies have not definitively confirmed this dual-inhibition activity at therapeutic doses in veterinary species.
- Central and Peripheral Action: By reducing peripheral prostaglandins, it decreases nociceptor sensitization. It also acts centrally to reduce fever by inhibiting prostaglandin synthesis in the hypothalamus.
Safety & warnings
Contraindications
- Known hypersensitivity to ketoprofen or other NSAIDs
- Active gastrointestinal ulceration or bleeding
- Significant renal or hepatic impairment
- Late pregnancy (due to risk of premature closure of the patent ductus arteriosus)
- Intra-arterial administration
- Dehydrated, hypovolaemic, or hypotensive patients
- Patients with pre-existing gastrointestinal disease
- Patients with blood clotting problems
- Pregnant animals
- Animals < 6 weeks of age
Adverse effects
- Horses: Gastric mucosal damage, GI ulceration, renal crest necrosis, mild hepatitis, injection site inflammation (IM)
- Dogs and Cats: Vomiting, anorexia, gastrointestinal ulceration, renal toxicity
- General: Masking of infection signs (inflammation, hyperpyrexia)
- Gastrointestinal signs (vomiting, diarrhea, anorexia)
- Gastrointestinal ulceration and bleeding
- Renal toxicity (especially in dehydrated/hypotensive patients)
- Hepatic accumulation (in patients with liver disease)
- Potential precipitation of cardiac failure (rare/unknown risk in animals)
Precautions
High Protein Binding: Because ketoprofen is highly protein-bound, patients with hypoproteinemia may have increased levels of free (active) drug, significantly increasing the risk of toxicity.
- GI and Renal Risks: Use only when potential benefits outweigh risks in patients with a history of GI ulceration or compromised renal/hepatic function.
- Masking Infection: May mask clinical signs of infection such as fever and inflammation. Use appropriate anti-infective therapy if a primary infectious process is present.
- Breeding Animals: Use with caution in breeding animals; effects on fertility and fetal health are not fully established. Avoid in late pregnancy.
- Administration Warnings: Avoid subcutaneous (SC) injections in horses. Do not administer intra-arterially in any species.
Drug interactions
Increased risk for nephrotoxicity.
Increased risk for bleeding.
Plasma levels of ketoprofen could decrease; increased likelihood of GI adverse effects (blood loss). Concomitant use is not recommended.
May increase risk for GI ulceration.
Concomitant administration significantly increases the risks for GI adverse effects and ulceration.
May increase risk for nephrotoxicity.
May increase NSAID levels.
Ketoprofen may reduce the saluretic and diuretic effects of furosemide.
Ketoprofen is 99% protein-bound and may displace other drugs, leading to increased serum levels and duration of action.
Serious toxicity has occurred when NSAIDs are used concomitantly; use with extreme caution.
May cause a significant increase in serum levels and half-life of ketoprofen.
Increased risk of severe gastrointestinal ulceration and renal toxicity. Do not administer concurrently or within 24 hours.
Increased risk of severe gastrointestinal ulceration and bleeding. Do not administer concurrently or within 24 hours.
Increased risk of nephrotoxicity.
Monitoring
- Clinical efficacy (reduction in pain, lameness, or fever)
- Adverse effects (monitor for vomiting, diarrhea, melena, or anorexia)
- Baseline and periodic liver and renal function tests (BUN, Creatinine, ALT, AST) are recommended with long-term therapy
- Clinical signs of gastrointestinal ulceration (vomiting, melena, anorexia)
- Renal parameters (BUN, Creatinine, USG) especially in older or compromised patients
- Hepatic enzymes
- Hydration status and blood pressure
Pharmacokinetics
Half-life
Absorption
Rapidly and nearly completely absorbed after oral administration in rats, dogs, and humans. Presence of food or milk decreases oral absorption. Oral absorption is poor in horses. IV and IM areas under the curve are relatively equivalent in horses.
Distribution
Volume of distribution is low in adult horses, but higher in foals (doses may need to be 1.5X higher in neonates). Enters synovial fluid. Highly bound to plasma proteins (99% in humans, ~93% in horses).
Metabolism
Metabolized to a conjugated metabolite (primarily glucuronidation in dogs and horses). In cats, thioesterification is proposed as a major elimination mechanism.
Elimination
Eliminated via the kidneys both as a conjugated metabolite and unchanged drug.
Overdose
As with any NSAID, overdosage can lead to severe gastrointestinal and renal toxicity.
- Dogs: The LD50 after oral ingestion is reported to be 2000 mg/kg, but exposures as low as 0.44 mg/kg have caused GI ulcers. Common clinical signs of toxic exposure include vomiting.
- Cats: Highly sensitive; have developed renal toxicity at doses as low as 0.7 mg/kg.
- Horses: Generally tolerate higher doses. Doses up to 11 mg/kg IV once daily for 15 days showed no toxicity. However, severe laminitis occurred at 33 mg/kg/day (15X label dose) for 5 days. At 55 mg/kg/day (25X label dose), horses developed anorexia, depression, icterus, abdominal swelling, gastritis, nephritis, and hepatitis.
Treatment:
- Decontamination: Emetics and/or activated charcoal are appropriate for recent oral exposures.
- GI Protection: Use of gastrointestinal protectants (e.g., omeprazole, sucralfate, misoprostol) is strongly warranted if GI effects are expected.
- Renal Protection: Aggressive IV fluid diuresis is warranted to support renal perfusion if renal effects are expected.
Available products
Formulations
- Veterinary Injection: 100 mg/mL, 10 mg/mL
- Veterinary Tablets: 5 mg, 10 mg, 20 mg
- Human Capsules: 50 mg, 75 mg
- Human Extended-Release Capsules: 100 mg, 150 mg, 200 mg
- Injectable: 1% solution
- Oral: 5 mg tablets
- Oral: 20 mg tablets
Veterinary
- Ketoprofen Injection: 100 mg/mL (Ketofen, generic)
- Ketoprofen Injection: 10 mg/mL (Anafen, Ketofen - Canada/UK)
- Ketoprofen Tablets: 5 mg, 10 mg, 20 mg (Anafen, Ketofen - Canada/UK)
- Ketofen 1% injection
- Ketofen 5 mg tablets
- Ketofen 20 mg tablets
Human-labeled
- Ketoprofen Capsules: 50 mg, 75 mg
- Ketoprofen Extended-Release Capsules: 100 mg, 150 mg, 200 mg
- Oruvail
- Orudis
Regulatory status
Withdrawal times: pig meat 4 days · cattle meat 4 days · cattle milk 0 hours · horse meat 28 days
POM-V classification.
POM-V classification.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Oral capsules should be stored at room temperature in tight, light-resistant containers. Veterinary injection should be stored at room temperature.
Client information
Ketoprofen is a medication used to reduce pain, inflammation, and fever in your pet.
Important Safety Guidelines:
- Give with Food: If you are giving ketoprofen by mouth, it is best to give it with a meal to help reduce the chance of stomach upset.
- Watch for Stomach Issues: The most common side effects are vomiting, loss of appetite, and diarrhea. Stop giving the medication and contact your veterinarian immediately if your pet vomits, stops eating, or if you notice dark, tarry stools or blood in their vomit or feces. These can be signs of stomach ulcers.
- Do Not Mix Medications: Never give your pet aspirin, ibuprofen, or any other pain relievers (like Rimadyl, Metacam, or Deramaxx) while they are taking ketoprofen unless specifically instructed by your veterinarian. Mixing these can cause fatal stomach bleeding or kidney failure.
- Follow Instructions Exactly: Do not increase the dose or give it more frequently than prescribed. Cats and dogs are very sensitive to NSAID overdoses.
- Hydration is Key: Ensure your pet always has access to plenty of fresh drinking water to help protect their kidneys.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.