Comparison of NK-1 Receptor Antagonist (Maropitant) to Morphine as a Pre-Anaesthetic Agent for Canine Ovariohysterectomy

Abstract

ObjectiveTo compare the NK-1 receptor antagonist maropitant to morphine during and after surgery in dogs undergoing ovariohysterectomy (OHE).Methods30 healthy female dogs were randomly divided to receive either a pre-anaesthetic dose of morphine (0.5 mg/kg SQ) or maropitant (1 mg/kg, SQ) prior to OHE. Anaesthesia was induced with propofol and maintained with isoflurane. Expired isoflurane concentration, heart rate (HR), systolic arterial pressure (SAP) and respiratory rate were measured. Post-operative pain scores and appetite were evaluated during the recovery period. Rescue analgesia (morphine 0.1 mg/kg IV) was administered as needed post-operatively based on blinded pain score assessments.ResultsAlthough clinically comparable; during surgical stimulation, the maropitant group had lower HR (108±18 vs 115±24 bpm; p = 0.04), lower SAP (114±23 vs 125±23 mmHg; p = 0.003) and required slightly lower percent of isoflurane anaesthetic (1.35±0.2 vs 1.51±0.4%; p = 0.005), when compared to the morphine group. In the recovery period, the maropitant group had lower pain scores at extubation (1.7±0.7 vs 3.4±2.3; p = 0.0001) and were more likely to eat within 3 hours after extubation (64.7 vs 15.3%). However, post-operative rescue analgesia requirements were similar between groups. All other measured parameters were similar between groups. The overall difference observed between groups was small and all monitored and measured parameters were within the expected range for anesthetized dogs.Clinical SignificanceNo major differences in cardiorespiratory parameters or anaesthetic requirements were observed between maropitant and morphine when used as a pre-anesthetic agent for OHE. Further studies are necessary to fully elucidate the benefits of maropitant as a pre-anaesthetic agent for canine OHE.

Comparison of the Effects of Maropitant, Lidocaine, and Dextroketamine Administered by the Intratesticular Route in Dogs Undergoing Elective Orchiectomy

“…However, its analgesic effect has been reported through other routes, e.g., when it was used intradermally in an experimental model with gerbil [5]. It has also been reported to show satisfactory analgesia for ovariectomy (OH) with a single pre-operative dose of 1 mg/kg that was administered through the SC route in cats and dogs [19,24], and showed analgesic potential similar to morphine [19]. Due to the lack of information on the ideal intratesticular dose, we decided to use the same dose as that used by the previously mentioned authors.…”

“…This decrease could be attributed to the technique of balanced anesthesia, whereby the requirement of an inhalation anesthetic was reduced by an intratesticular block with lidocaine [8,13,20] or dextroketamine [8]. The local analgesic effect of maropitant has been verified by confirmation of NK-1 receptors in the periphery [5,12,30], which confirm its analgesic characteristics by promoting a reduction in CAM in dogs receiving nociceptive stimuli [1,7,19,35].…”

“…Maropitant was developed and approved because of its predominantly central-acting antiemetic effect [29]. However, studies have shown that the antiemetic dose (1 mg/kg) administered by the subcutaneous (SC) route promoted a reduction in the minimum anesthetic concentration (MAC) of inhaled anesthetics in dogs and cats that underwent noxious surgical stimulation [1,7,19,24,35]. Maropitant is a neurokinin-1 (NK-1) receptor antagonist drug that is used in the treatment of visceral [9,15,16,25,31,32] and somatic [5,17,30] pain.…”

The present and future of opioid analgesics in small animal practice

“…The drug has also shown to reduce anesthetic requirements in dogs when administered as a CRI (Boscan et al ., ; Alvillar et al ., ). In dogs undergoing an ovariohysterectomy, SC administration of 1 mg/kg did not reduce inhalant anesthetic requirements but did provide similar analgesia when compared with morphine (Marquez et al ., ). In cats, intravenous administration of 1 mg/kg of maropitant significantly reduces the minimum alveolar concentration of sevoflurane during ovarian ligament stimulation (Niyom et al ., ).…”

Spotlight on the perioperative use of maropitant citrate

“…Marquez et al 39 performed a blinded clinical trial comparing maropitant (1.0 mg/kg) and morphine (0.5 mg/kg) SC in healthy female dogs admitted for elective OHE. Dogs were administered morphine or maropitant 30 minutes prior to induction with propofol followed by inhalant anesthesia.…”