Intravenous paracetamol does not have significant opioid‐sparing effects when used as part of a multimodal analgesic protocol in dogs undergoing elective orthopaedic surgery

Background:
Data evaluating paracetamol combined with NSAIDs in dogs are scarce. Results of clinical studies in dogs investigating intravenous paracetamol vary.

Methods:
Dogs were randomised to either receive 10 mg/kg paracetamol intravenously after induction of anaesthesia and every 8 hours during hospitalisation (test) or not (control). In both groups, meloxicam or robenacoxib was administered at the licensed dose, interval and route. Intraoperative nociception or postoperative pain, defined by a Glasgow composite measure pain scale—short form score greater than 4 of 20, was treated with 0.1 mg/kg methadone intravenously as needed.

Results:
Data from 14 dogs that received paracetamol and 13 dogs that did not were analysed. There were no statistically significant differences in clinical or demographic data between the two groups. Median (range) rescue methadone requirements were 0.0 (0.0‒0.2) mg/kg and 0.1 (0.0‒0.3) mg/kg for the test and control groups, respectively (p = 0.17), with no difference intraoperatively (p = 0.72) or postoperatively (p = 0.24). Four test and seven control dogs required rescue analgesia perioperatively (p = 0.17).

Limitations:
Low analgesia requirements in both groups may have resulted in a type two statistical error.

Conclusion:
When used as part of a multimodal analgesic protocol, paracetamol did not provide significant opioid-sparing effects in the perioperative period.