Comparative Evaluation of the Epidural Dexmedetomidine, Ketamine or Fentanyl in Combination with Bupivacaine in Dogs

Castration is one of the most common procedure. It is a potential source of mild to moderate pain which is enough to induce inflammatory process, necessitate the incorporation of analgesics. This study was designed to evaluate the effect of epidural bupivacaine alone or in association with fentanyl, ketamine or dexmedetomidine on analgesia for the first 24 h post surgical castration. Forty male mongrel dogs were randomly allocated into 4 groups received bupivacaine 0.25% (1.5 mg kg^-1) alone or in combination with fentanyl citrate (2 µg kg^-1) or ketamine hydrochloride (2 mg kg^-1) or dexmedetomidine hydrochloride (1.13 µg kg^-1) into the lumbosacral space. Dogs were scored for sedation using numeric descriptive scale. Analgesia was assessed subjectively through Modified University of Melbourne Pain Scale score and objectively by following up the circulating level of interleukins 6 and 10. The bupivacaine-dexmedetomidine group showed the greatest sedation score, the lowest pain score without neuroendocrine modulation in contrast with bupivacaine or bupivacaine-fentanyl groups. From these result, it is concluded that bupivacaine-dexmedtomidine group provide long term analgesia last for the first 24 h post operative without additional analgesics.