Evaluation of the Analgesic Efficacy and Safety of Preemptive Nefopam Compared with Tramadol in Feline Orthopedic Surgery

Objective:  To compare the clinical efficacy and safety of preemptive nefopam, a non-opioid analgesic, with tramadol, an opioid agonist, for managing post-operative pain in cats undergoing orthopedic surgery. Animals and Procedures:  Twenty-four adult male Himalayan cats were randomly assigned to three groups (n=8). A tibial defect was surgically induced to create a standardized pain model. The Control group received a xylazine-ketamine anesthetic protocol. The Tramadol group received preemptive tramadol (4 mg/kg, IM), and the Nefopam group received preemptive nefopam (2 mg/kg, IM), both administered 10 minutes before anesthesia. Post-operative analgesia was assessed via pain scores, and time to return to normal appetite and gait. Results:  Both preemptive groups demonstrated superior post-operative outcomes compared to the control group. Pain scores were significantly lower in the tramadol and nefopam groups, with complete resolution by day 5 versus day 6 in the control group. Time to return to appetite (171.87±2.97 min for tramadol, 175.62±5.03  min for nefopam) and gait (2.37±0.26 days for tramadol, 2.37±0.18 days for nefopam) was significantly faster than in the control group (247.37±5.62 min for appetite return  and 4.62±0.18 days for normal gait return, respectively).  No significant difference in analgesic efficacy was found between the nefopam and tramadol groups.  Hemodynamically , tramadol induced significant  bradycardia  (117.75±0.75 beat per minutes at time 110min ), whereas nefopam caused a significant increase in systolic blood pressure(149.75±5.06 after 30 min of administration of anesthetic mixture ). Critically, serum  creatinine  levels remained within normal physiological limits in all groups. Conclusions:  Preemptive nefopam was associated with post-operative analgesia similar to tramadol in cats undergoing painful orthopedic surgery. Due to its efficacy and no nephrotoxicity at the dose administered, nefopam could serve as a novel non-opioid painkiller that supports multimodal analgesic protocols in feline clinical practice.