Firocoxib (Equioxx) Dosage for Pain and Inflammation Management in Horses
The recommended dosage of firocoxib (Equioxx) for pain and inflammation management in horses is 0.1 mg/kg orally once daily for up to 14 days. 1, 2
Pharmacology and Administration Options
Firocoxib is a highly selective COX-2 inhibitor approved for treating musculoskeletal problems and lameness in horses with osteoarthritis. It has two FDA-approved formulations:
- Oral paste formulation: 0.1 mg/kg once daily for up to 14 days 1
- Injectable formulation: 0.09 mg/kg IV once daily for up to 5 days 1
Pharmacokinetic Properties
Firocoxib offers several advantageous pharmacokinetic properties that make it effective for equine pain management:
- High bioavailability: ≥80% oral absorption 1
- Wide distribution: Volume of distribution approximately 2 L/kg 1
- Long half-life: Approximately 30-34 hours, allowing once-daily dosing 3
- Steady state: Reached within 24-48 hours at recommended dosing 1
Loading Dose Option
For more rapid onset of action in acute pain situations:
- A single loading dose of 0.3 mg/kg orally can be administered initially 1, 4
- This approach establishes steady-state drug concentrations within 24 hours 1
- After loading dose, continue with standard 0.1 mg/kg daily maintenance dose 4
Efficacy Considerations
- Firocoxib's IC80 is 103 ng/mL in whole blood with an EC50 of 27 ng/mL 1
- Clinical improvement in lameness and pain is typically observed within 7 days of starting treatment at the recommended dose 4
- With a loading dose strategy, clinical improvement may be observed earlier (1-3 days) 4
Safety Profile
As a COX-2 selective NSAID, firocoxib offers a favorable safety profile compared to traditional NSAIDs:
- COX-1/COX-2 IC50 ratio of 643 in horses, indicating high COX-2 selectivity 1
- Reduced risk of gastrointestinal side effects compared to non-selective NSAIDs
- Metabolized via dealkylation and glucuronidation to inactive metabolites 3
- Primary elimination route is via urinary excretion 3
Practical Considerations
- Formulation options: The equine paste formulation is specifically approved for horses, though studies show the canine tablet formulation has equivalent efficacy when dosed appropriately 5
- Duration: Treatment should not exceed the FDA-approved 14-day treatment period without veterinary supervision 2
- Monitoring: Regular assessment of clinical response and observation for any adverse effects is recommended
Potential Pitfalls and Caveats
- Avoid exceeding recommended dosage or treatment duration to prevent potential adverse effects
- As with all NSAIDs, monitor for signs of gastrointestinal disturbance, although risk is lower with COX-2 selective agents
- Use with caution in horses with known renal, hepatic, or cardiovascular disease
- Drug interactions with other medications should be considered, particularly with other NSAIDs or corticosteroids