Efficacy of combined grapiprant and tapentadol for analgesia in cats undergoing elective ovariohysterectomy

ObjectivesThis study aimed to evaluate the effects of combined grapiprant and tapentadol on intraoperative physiological parameters, the occurrence of adverse events and postoperative analgesic efficacy in cats undergoing elective ovariohysterectomy, using two multidimensional pain scales.MethodsA total of 60 mixed-breed female cats were enrolled in a randomized, prospective, blinded study. The animals were evenly distributed into four groups (n = 15 per group). In total, 51 animals completed the study; the control group received placebo (CON; n = 11), while the grapiprant group (GRA; n = 13) received grapiprant (3.8 ± 0.5 mg/kg), the tapentadol group (TAP; n = 14) received tapentadol (5.3 ± 1.2 mg/kg) and the grapiprant-tapentadol group (GT; n = 13) received a combination of grapiprant (4.2 ± 0.5 mg/kg PO) and tapentadol (5 ± 0.6 mg/kg PO) 1 hour before initiation of the standardized anesthesia protocol and surgical procedure. Physiological parameters were monitored during surgery, and postoperative pain was assessed for 6 h after extubation using the Short Form of the UNESP-Botucatu Feline Pain Score (UFESP-SF) and the Feline Grimace Scale (FGS), administered by two blinded evaluators.ResultsNo adverse effects or statistically significant differences in physiological parameters were observed between groups. The assessment of pain scores showed good reliability, with intraclass correlation coefficient values of 0.89 for the FGS and 0.91 for the UFESP-SF, supporting inter-rater agreement for both instruments. At 3 h postoperatively, FGS scores differed significantly between the CON and GT groups (<i>P</i> = 0.0363). Rescue analgesia requirements also varied among groups (<i>P</i> = 0.0110): the GT group required rescue at 3 h compared with 1 h in the CON group (<i>P</i> = 0.0007) and 2 h in the GRA group (<i>P</i> = 0.0058).Conclusions and relevanceThe results of this study showed that the analgesic effect of the grapiprant-tapentadol combination lasted up to 3 h in the postoperative period, which was longer than the 2 h of grapiprant and tapentadol alone, without compromising intraoperative physiological stability.