The effect of maropitant on intraoperative isoflurane requirements and postoperative nausea and vomiting in dogs: a randomized clinical trial
Adam Swallow, Eva Rioja, Tim Elmer & Alex Dugdale
Veterinary Anaesthesia and Analgesia 2017, 44, 785e793
What did the research find?
Maropitant reduced overall intraoperative isoflurane requirements but did not affect the incidence of postoperative nausea and vomiting (PONV).
- The mean end tidal isoflurane percentage was lower in the group receiving maropitant (1.19 ± 0.26%) than in the control group (1.44 ± 0.23%) but was not significantly different between groups at specific noxious events.
- Cardiorespiratory variables and postoperative Glasgow Composite Pain Score (GCPS) were not significantly different between groups.
- Overall, 50% of dogs displayed signs attributable to PONV, with no difference in PONV scores between groups.
- No difference in anaesthetic recovery was noted by owners between groups.
How was it conducted?
24 healthy, client-owned dogs undergoing routine ovariohysterectomy were included in this randomised clinical trial. The dogs were premedicated with acepromazine and methadone IM 45 minutes before anaesthetic induction with IV propofol, dosed to effect. Meloxicam was administered IV.
Dogs were randomly assigned to administration of saline or maropitant (1 mg/kg) SC at the time of premedication. Methadone was repeated 4 hours later. Anaesthesia was maintained with isoflurane in oxygen, dosed to effect by
an observer unaware of group allocation.
The dogs were assessed hourly, using the GCPS, and for ptyalism and signs attributable to PONV by blinded observers. Owners completed a questionnaire at the postoperative recheck.
Why is it important?
Maropitant is an antiemetic drug that acts by antagonizing the neurokinin-1 (NK-1) receptor found in multiple locations throughout the body. Normally, NK-1 is activated by substance P to produce a variety of effects including pain, nausea and vomiting.
Evidence suggests that peripheral NK-1 receptor antagonism could be a possible mechanism of sevoflurane MAC reduction in dogs (Alvillar et al. 2012), and that maropitant could have a potential role in the management of ovarian pain in bitches (Boscan et al. 2011). NK-1 receptors are widely used in humans to improve the post-operative anaesthetic recovery (Lee et al. 2012) as well as to reduce analgesia requirements and PONV in women following gynaecological surgery (Kakuta et al. 2011).
Despite being widely recognized in humans, PONV has been poorly documented in dogs, and to date, there are no published studies evaluating the role of maropitant in reducing inhalational anaesthetic requirements when used alongside methadone and acepromazine premedication in dogs. The authors of this study conclude that maropitant was associated with a significant reduction in the overall intraoperative isoflurane requirements although not at any specific event points.
Link to the full article: https://www.vaajournal.org/art...
Originally published: Thursday, 26th July 2018
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