For decades, equine veterinarians have been using antimicrobials intra-articularly but this route of administration is considered off-label and there are no established appropriate dosages for practitioners to reference. Despite research showing antimicrobials do not have a significant effect on post-injection infection rates intra-articular antimicrobial therapy usage appears to be increasing, writes Stacey Oke, DVM, MSc.
Based on published studies, researchers believe there is a lack of rationale for preventative antimicrobial use with IA injections in horses due to the low incidence of infection with joint injections overall.” – Lynn Pezzanite, DVM, PhD, Dipl. ACVS
Source: The Horse, November 7, 2023. Link. Depending on the dosage used, antimicrobials are cytotoxic to joint tissues, but more powerful antibiotics such as amikacin are particularly toxic when compared to other antimicrobials. Veterinarians who inject antimicrobials to treat active infection in horses’ joints can minimize local toxicity by reducing the doses and selecting antimicrobial classes that have lower toxicity.