Ibuprofen

Nonsteroidal Anti-inflammatory Drug (NSAID) Propionic acid derivative

Dosage & Administration Guidelines

Species Route Dose Frequency Duration & Clinical Notes
Dog PO Not recommended. Toxic dose: >5 mg/kg can cause GI signs; >25 mg/kg can cause renal failure; >100 mg/kg can be lethal. Not applicable Duration: Not applicable
Notes: No safe therapeutic dose exists for dogs. Accidental ingestion requires immediate veterinary intervention.
Cat PO Not recommended. Toxic dose: >5 mg/kg can cause severe toxicity due to prolonged half-life. Not applicable Duration: Not applicable
Notes: Cats are extremely sensitive; even a single 50 mg tablet can be fatal.
Horse PO Not recommended. Experimental doses of 5-10 mg/kg have been used but with high risk of adverse effects. Not applicable Duration: Not applicable
Notes: No approved use; safer alternatives exist.

Clinical Indications & Species Uses

Dog (Canine)
  • Not recommended for use in dogs due to high toxicity risk; no approved veterinary indications. Accidental ingestion is a common emergency.
Cat (Feline)
  • Not recommended for use in cats; extremely toxic due to prolonged half-life and high sensitivity. No approved veterinary indications.
Cattle (Bovine)
  • Not approved for use in cattle; not recommended due to lack of efficacy data and potential for toxicity.
Small Ruminants (Sheep / Goat)
  • Not approved; not recommended.
Rabbit & Small Mammals
  • Not recommended; highly toxic to rabbits.
Avian & Poultry
  • Not recommended; no data on safe use.
Exotic & Other Species
  • Not recommended; toxicity risk high.

Pharmacology & Mechanism of Action

Drug Class: Nonsteroidal Anti-inflammatory Drug (NSAID) | Pharmacological Group: Propionic acid derivative

Mechanism of Action: Ibuprofen is a non-selective inhibitor of cyclooxygenase (COX-1 and COX-2) enzymes, which catalyze the conversion of arachidonic acid to prostaglandins and thromboxanes. By inhibiting COX enzymes, ibuprofen reduces the synthesis of prostaglandins, which are key mediators of inflammation, pain, and fever. It also has antiplatelet effects due to inhibition of thromboxane A2 synthesis.

Pharmacodynamics: Ibuprofen exhibits analgesic, anti-inflammatory, and antipyretic effects. In veterinary species, its efficacy is limited by its narrow therapeutic index and high risk of adverse effects, particularly gastrointestinal ulceration and renal toxicity. The drug's effects are dose-dependent, with higher doses providing more anti-inflammatory action but also increasing toxicity risk.

⚡ Pharmacokinetics Summary

Absorption: Ibuprofen is well absorbed after oral administration in most species, with peak plasma concentrations occurring within 1-2 hours in dogs and cats. Food can delay absorption but does not significantly reduce total bioavailability.
Distribution: Ibuprofen is highly protein-bound (90-99%) in plasma. It distributes widely into tissues, with high concentrations in synovial fluid, which is important for its anti-inflammatory effects in joints. It crosses the blood-brain barrier to a limited extent.
Metabolism: Ibuprofen is extensively metabolized in the liver, primarily by oxidation and glucuronidation. The major metabolic pathways involve CYP2C9 and CYP2C19 enzymes in humans; similar pathways are presumed in animals, though species differences exist.
Excretion: Metabolites and a small amount of unchanged drug are excreted primarily in the urine. Biliary excretion also occurs. In dogs, the elimination half-life is approximately 4.6 hours, while in cats it is significantly longer (approximately 35-40 hours) due to slower metabolism.
Half-Life: Dog: 4.6 hours; Cat: 35-40 hours; Horse: 1-2 hours (short); Cattle: 2-3 hours (estimated)
Bioavailability: Oral bioavailability is nearly complete in dogs and cats (approximately 80-100%).
Protein Binding: 90-99% depending on species

Available Formulations & Strengths

Oral Tablet 200 mg, 400 mg, 600 mg, 800 mg (PO)
Oral Suspension 100 mg/5 mL (PO)
Injectable Solution (human use only) 10 mg/mL (IV)

Contraindications & Clinical Warnings

Contraindications:
  • Known hypersensitivity to ibuprofen or other NSAIDs
  • Active gastrointestinal ulceration or bleeding
  • Renal insufficiency or failure
  • Hepatic insufficiency
  • Dehydration or hypovolemia
  • Concurrent use of corticosteroids or other NSAIDs
  • Pregnancy (especially late gestation) and lactation
  • Use in cats and dogs is contraindicated due to high toxicity risk
Warnings & Clinical Precautions:
  • Do not use in cats or dogs as a therapeutic agent; accidental ingestion is a medical emergency.
  • Use with extreme caution in animals with pre-existing renal, hepatic, or cardiac disease.
  • Monitor for signs of gastrointestinal bleeding (e.g., melena, hematemesis) and renal toxicity (e.g., increased thirst, decreased urination).
  • Avoid use in dehydrated or hypotensive animals.
  • Do not combine with other NSAIDs or corticosteroids.
  • In food animals, extra-label use is prohibited due to lack of withdrawal times and potential for human food residues.

Adverse Effects & Reactions

Common:

  • Gastrointestinal upset (vomiting, diarrhea, anorexia)
  • Gastric ulceration
  • Renal toxicity (increased BUN/creatinine)

Serious / Severe:

  • Gastrointestinal perforation
  • Acute renal failure
  • Hepatotoxicity
  • Bone marrow suppression
  • Seizures (in cats)

Rare:

  • Hypersensitivity reactions
  • Coagulopathies
  • Metabolic acidosis

Key Drug Interactions

Interacting Drug / Class Clinical Effect & Mechanism Severity
Corticosteroids Increased risk of gastrointestinal ulceration and renal toxicity. High
Other NSAIDs Additive toxicity, especially gastrointestinal and renal. High
ACE inhibitors Reduced renal function and increased risk of renal failure. Moderate
Diuretics Reduced diuretic efficacy and increased risk of renal toxicity. Moderate
Anticoagulants (e.g., warfarin) Increased risk of bleeding. High
Methotrexate Reduced clearance of methotrexate, increasing toxicity. Moderate

Overdose & Toxicity Management

Signs of Toxicity:

  • Vomiting (often with blood)
  • Diarrhea
  • Abdominal pain
  • Lethargy
  • Ataxia
  • Seizures (especially in cats)
  • Coma
  • Renal failure (oliguria/anuria)
  • Metabolic acidosis
  • Respiratory depression

Emergency Treatment Protocol: Immediate veterinary care. Treatment includes decontamination (induction of vomiting if within 2 hours and no contraindications, gastric lavage, activated charcoal), intravenous fluid therapy to maintain renal perfusion, gastrointestinal protectants (e.g., sucralfate, H2 antagonists or proton pump inhibitors), and supportive care. In severe cases, hemodialysis may be considered. Monitor renal and hepatic function, blood gases, and coagulation parameters.

Food Animal Withdrawal Times

Ibuprofen is not approved for use in food animals. Extra-label use is prohibited in the US under AMDUCA due to lack of established withdrawal times and potential for human food residues. If accidental exposure occurs, consult with regulatory authorities for appropriate withdrawal periods.

Storage, Handling & Regulatory Information

Storage Temperature: Store at room temperature (20-25°C, 68-77°F).

Handling & Special Conditions: Keep in a tightly closed container, protect from moisture.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Not approved for veterinary use in any species. Approved for human use only.

Extra-Label (Off-Label) Use: Extra-label use of ibuprofen in animals is prohibited in the US under AMDUCA because it is not approved for veterinary use and lacks established withdrawal times. In the EU, similar restrictions apply. Use in food animals is strictly forbidden.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Ibuprofen is a common human NSAID that is highly toxic to dogs and cats. Even small doses can cause severe gastrointestinal ulceration, acute renal failure, and central nervous system signs. There are no safe or effective veterinary indications for ibuprofen. Veterinarians should never prescribe ibuprofen for animals. In cases of accidental ingestion, prompt decontamination and aggressive supportive care are critical. Safer NSAIDs approved for veterinary use (e.g., carprofen, meloxicam, deracoxib) should be used instead. Client education is essential to prevent accidental poisonings.

References & Literature

  • 📚 Plumb's Veterinary Drug Handbook
  • 📚 Papich Veterinary Pharmacology and Therapeutics
  • 📚 Compendium of Veterinary Products (CVP)