EFFECTS OF PRETREATMENT WITH KETOPROFEN AND PHENYLBUTAZONE ON EXPERIMENTALLY-INDUCED SYNOVITIS IN HORSES

Objective-To compare the analgesic and anti-inflammatory effects of th e nonsteroidal anti-inflammatory drugs (NSAID), ketoprofen (2.20 and 3 .63 mg/kg of body weight) and phenylbutazone (4.40 mg/kg), in an acute equine synovitis model.Design-4 groups of 6 horses received NSAID or saline solution in a randomized design. Animals-24 clinically normal m ares and geldings. Procedure-Left intercarpal joints were injected wit h sterile carrageenan to induce synovitis al the same time as IV admin istration of NSAID or saline solution. Clinical assessments were made and synovial fluid was withdrawn at 0, 1, 3, 6, 9, 12, 24, and 48 hour s. Results-The eicosanoids, prostaglandin E(2) (PGE(2)) and leukotrien e B-4, increased in synovial fiuid after synovitis induction in all ho rses then returned to near baseline by 48 hours. All NSAID-treated hor ses had decreased PGE(2), compared with saline-treated horses. This ef fect lasted longer in phenylbutazone-treated horses than in ketoprofen -treated horses. There were no treatment effects on leukotriene B-4. I n saline-treated animals, lameness, joint temperature, and synovial fl uid volume, protein concentration, and nucleated cells increased 3 to 12 hours after induction, with marked reduction by 48 hours. Only phen ylbutazone treatment reduced lameness, joint temperature, and synovial fluid volume, Conclusion-Phenylbutazone was more effective than ketop rofen in reducing lameness, joint temperature, synovial fluid volume, and synovial fluid PGE(2). Results do not support lipoxygenase inhibit ion by either NSAID. Clinical Relevance-This reversible model induced synovial fluid alterations similar to those observed in horses with se ptic arthritis, Results indicate that phenylbutazone may be more usefu l than ketoprofen in treating acute joint inflammation.