Comparison of the isoflurane concentration of using dexketoprofen or methadone at premedication during orthopedic surgery in dogs

- Dexketoprofen or methadone at premedication showed similar isoflurane concentration.
- Neither drug induced satisfactory analgesia, it should be provided intraoperatively.
- In general, quality of recovery is smooth when both drugs are used preoperatively.

Thirty-two dogs were used in this prospective, randomized, clinical and double-blinded study. Dexmedetomidine was administered at 1 μg/kg IV, and randomly each dog received dexketoprofen 1 mg/kg IV (group DK) or methadone 0.2 mg/kg IV (group M). Dogs were induced with propofol and maintained with isoflurane in 100% oxygen. During surgery, the isoflurane concentration was changed depending on clinical signs of depth of anesthesia. Fentanyl and propofol could be used as required. Qualities of sedation and recovery were evaluated. A generalized linear mixed model or Mann-Whiney U test was used, and P < 0.05 was considered statistically significant. No significant differences were observed between groups in the qualities of sedation and recovery, isoflurane concentration and in the total amount of fentanyl and propofol used intraoperatively. This study shows that the administration of dexketoprofen at 1 mg/kg IV at premedication required a similar isoflurane concentration to maintain anesthesia as methadone at 0.2 mg/kg IV during orthopedic surgery in dogs. Further analgesia is recommended intraoperatively, because of the need of fentanyl and propofol in same animals in both groups.