Comparison of the postoperative analgesic effects of cimicoxib, buprenorphine and their combination in healthy dogs undergoing ovariohysterectomy

Objective To determine the noninferior postoperative analgesic efficacy of cimicoxib compared to buprenorphine following elective ovariohysterectomy in healthy bitches. Study design Prospective, randomized, blinded, controlled clinical trial. Animals A total of 63 healthy dogs. Methods To provide perioperative analgesia, cimicoxib 2 mg kg(-1) (orally), buprenorphine 0.02 mg kg(-1) (two doses, intramuscularly), or both drugs combined, were administered. Dogs were sedated with acepromazine and anaesthetized with propofol and isoflurane. Pain was assessed with the short form of the Glasgow Composite Pain Scale (GCPS), a pain numerical rating scale (NRS) and mechanical nociceptive thresholds (MNT), preoperatively and at 1, 2, 4, 6, 20 and 23 hours after extubation. Sedation was also scored at the same time points. A noninferiority approach was employed to determine the efficacy of cimicoxib compared to buprenorphine. Treatment groups were compared with parametric [analysis of variance (ANOVA), t test] and nonparametric test as appropriate (Kruskale-Wallis, chi-square). Results The GCPS, pain NRS and MNT tests demonstrated noninferiority of cimicoxib compared to buprenorphine (rejection of inferiority: p < 0.001, all). Furthermore, cimicoxib provided better analgesia compared to buprenorphine alone according to the GCPS (p < 0.01) and NRS (p < 0.05), but not the MNT. Conversely, an increase in the analgesic effect when cimicoxib was combined with buprenorphine was only observed with the MNT (p < 0.01). There were no differences in rescue analgesia requirements both intra-and postoperatively between treatments. Gastrointestinal side effects were increased in dogs administered cimicoxib, whereas dogs treated with buprenorphine had higher sedation scores 1-hour postoperatively and required lower doses of propofol for the induction of anaesthesia. Conclusions and clinical relevance Cimicoxib has noninferior postoperative analgesic efficacy compared to buprenorphine, and both drugs have comparable analgesic effects for the control of postoperative pain in bitches undergoing ovariohysterectomy.