Effects of multimodal analgesia with low- Dose buprenorphine and meloxicam on fecal glucocorticoid metabolites after surgery in New Zealand white rabbits (Oryctolagus cuniculus)

Despite the increasing use of rabbits as companion animals and models for biomedical research, rabbits have not been extensively studied to identify an efficacious postsurgical analgesic that does not cause systemic complications. The synergy of NSAID and systemic opioids is well-documented, and their combined use reduces the amount of either drug required for adequate analgesia. We measured fecal corticosterone metabolites (FCM) in rabbits after a minimally invasive vascular cut-down procedure. Rabbits received buprenorphine (0.03 mg/kg SC every 12 h for 3 d), meloxicam (0.2 mg/kg SC every 24 h for 3 d), buprenorphine-meloxicam (0.01 mg/kg-0.1 mg/kg SC every 24 h for 3 d), or a single dose of 0.5% bupivacaine (0.5 mL) infused locally at the incision site. By day 3 after surgery, buprenorphine, meloxicam, and bupivacaine groups showed elevated FCM levels, which continued to rise until day 7 and then gradually returned to baseline by day 28. In the buprenorphine-meloxicam group, FCM was relatively unchanged until day 3, when treatment was discontinued, and then began to rise. Rabbits in the buprenorphine-meloxicam group gained more weight over the 28-d study than did those in the other 3 treatment groups. This study shows that in rabbits low-dose buprenorphine administered with meloxicam effectively mitigates the FCM response that develops after surgery without the adverse effects associated with higher doses.