Phenylbutazone concentrations in synovial fluid following administration via intravenous regional limb perfusion in the forelimbs of six adult horses.
Authors: O'Brien Molly, Mochel Jonathan P, Kersh Kevin, Wang Chong, Troy Jarrod
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Phenylbutazone (PBZ) delivered via intravenous regional limb perfusion (IVRLP) represents a potentially safer alternative to systemic NSAID administration in horses, as it could generate high local concentrations within the affected joint whilst minimising the gastrointestinal and renal toxicity associated with oral or parenteral dosing. O'Brien and colleagues evaluated the pharmacokinetic profile and local tolerability of PBZ-IVRLP in six standing horses, measuring synovial fluid concentrations and monitoring for adverse reactions at the site of administration. The technique successfully achieved therapeutic concentrations in synovial fluid whilst maintaining substantially lower systemic levels than would be expected from conventional dosing, suggesting that PBZ delivered via IVRLP could provide effective local analgesia with reduced systemic exposure. No significant local complications were documented during the study period, indicating that the procedure is technically feasible in standing horses. These findings open the possibility of adapting IVRLP protocols—a technique already established in equine practice for antibiotic delivery—to NSAID therapy, potentially offering practitioners a valuable tool for managing localised joint pain whilst circumventing the systemic side effects that currently limit long-term oral NSAID use in horses with chronic lameness.
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Practical Takeaways
- •IVRLP with phenylbutazone offers a promising alternative to systemic NSAIDs for forelimb pain, potentially avoiding gastrointestinal and renal complications associated with oral or IV phenylbutazone
- •This technique may be particularly valuable for horses with contraindications to systemic NSAID use or those requiring prolonged analgesia in specific limbs
- •Further research with larger sample sizes and controlled trials is needed before widespread clinical implementation, but initial safety and pharmacokinetic data are encouraging
Key Findings
- •Phenylbutazone administered via IVRLP achieved high local synovial fluid concentrations while maintaining low systemic levels in all six horses
- •No local complications or adverse reactions were observed during or after IVRLP with phenylbutazone in any of the six horses studied
- •Synovial fluid PBZ concentrations remained therapeutically relevant for extended periods following single IVRLP administration
- •IVRLP administration of phenylbutazone represents a novel technique for localized pain management with potential to reduce systemic NSAID side effects