Anti-inflammatory and analgesic effects of intra-articular injection of triamcinolone acetonide, mepivacaine hydrochloride, or both on lipopolysaccharide-induced lameness in horses.
OBJECTIVE
To assess analgesia, inflammation, potency, and duration of action associated with intra-articular injection of triamcinolone acetonide (TA), mepivacaine hydrochloride, or both in metacarpophalangeal (MCP) joints of horses with experimentally induced acute synovitis.


METHODS
18 horses.


METHODS
Both forelimbs of each horse were injected with lipopolysaccharide (LPS) 3 times. After the first LPS injection, 1 forelimb of each horse was treated with intra-articular injection of mepivacaine (80 mg; n=6), TA (9 mg; 6), or mepivacaine with TA (same doses of each; 6) 12 hours after the initial LPS injection. Contralateral limbs served as control limbs. Joint pain was assessed via lameness score and measurements of vertical force peak and pain-free range of motion of the MCP joint. Periarticular edema was evaluated. Degree of synovial inflammation was determined via synovial fluid analysis for WBC count and total protein concentration. Samples of plasma and synovial fluid were analyzed for TA and mepivacaine concentrations.


RESULTS
Each injection of LPS induced lameness and joint inflammation. Mepivacaine effectively eliminated lameness within 45 minutes after injection, regardless of whether TA was also administered, whereas TA reduced lameness, edema, and concentration of synovial fluid protein after the second LPS injection, regardless of whether mepivacaine was also injected. Treatment with TA also induced higher WBC counts and mepivacaine concentrations in synovial fluid, compared with results for mepivacaine alone.


CONCLUSIONS
Results suggested TA is a potent analgesic and anti-inflammatory medication for acute synovitis in horses and that simultaneous administration of mepivacaine does not alter the potency or duration of action of TA.
Kay
Alastair T
AT
Comparative Orthopedic Research Laboratory, Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA.
Bolt
David M
DM
Ishihara
Akikazu
A
Rajala-Schultz
Paivi J
PJ
Bertone
Alicia L
AL
D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000627:therapeutic use; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D006734:Horse Diseases / Q000139:chemically induced / Q000188:drug therapy*; D006736:Horses; D007270:Injections, Intra-Articular; D007794:Lameness, Animal / Q000188:drug therapy*; D008070:Lipopolysaccharides / Q000009:adverse effects*; D008297:Male; D008619:Mepivacaine / Q000008:administration & dosage / Q000627:therapeutic use*; D014222:Triamcinolone Acetonide / Q000008:administration & dosage / Q000627:therapeutic use*
D000700:Analgesics; D000779:Anesthetics, Local; D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D008619:Mepivacaine; D014222:Triamcinolone Acetonide