Evaluation of the Analgesic Efficacy of a Protocol of Opioid-Free Anesthesia in Healthy Cats Undergoing Ovariectomy

Background/Objectives: Opioids are widely used for perioperative analgesia in small animal practice; however, their administration is associated with dose-dependent adverse effects, regulatory restrictions, and increasing stewardship concerns. Evidence supporting opioid-free anesthesia protocols in cats remains limited. The aim of this study was to evaluate the analgesic efficacy of a dexmedetomidine constant rate infusion as part of an opioid-free anesthetic protocol in cats undergoing ovariectomy, as well as to determine its effect on intraoperative opioid requirements. Methods: This prospective, randomized clinical trial included forty healthy female cats (mean age 1.9 ± 0.7 years; mean body weight 3.5 ± 0.6 kg; body condition score 5 range 4–5/9) undergoing elective ovariectomy. Cats were randomly assigned to receive either a dexmedetomidine constant rate infusion (CRI) at 1 mcg kg−1 h−1 (GR-E) or a control protocol without dexmedetomidine CRI (GR-C). Anesthesia was induced and maintained using standardized protocols in both groups. Intraoperative fentanyl (5 mcg kg−1 IV) was administered as rescue analgesia when two of three physiological parameters (heart rate, respiratory rate, mean arterial pressure) increased by ≥20% compared to the previous recorded value. Cardiovascular and respiratory variables, rescue opioid requirements, and recovery quality were recorded. Results: The requirement for rescue analgesia was significantly lower in GR-E (4/20; 20%) compared to GR-C (13/20; 65%) (p = 0.0097). Cats receiving dexmedetomidine showed greater intraoperative cardiovascular stability during ovarian pedicle manipulation. No clinically relevant adverse effects were observed. Recovery was smooth in all cats, and all resumed feeding within eight hours postoperatively. Conclusions: A low-dose dexmedetomidine CRI effectively reduced intraoperative opioid requirements during feline ovariectomy while maintaining physiological stability and satisfactory recovery. This opioid-free anesthetic protocol represents a safe and clinically applicable alternative in settings where opioid use is restricted or limited.