Comparative evaluation of the antiemetic and propofol-sparing effects of acepromazine and maropitant in female dogs undergoing elective ovariohysterectomy

Nausea and vomiting are frequent adverse effects associated with opioid administration, potentially leading to discomfort, risk of aspiration, and reduced postoperative appetite. This study aimed to compare the efficacy of acepromazine and maropitant in preventing morphine-induced nausea and vomiting, to evaluate their propofol-sparing effects, and to assess postoperative appetite in female dogs undergoing elective ovariohysterectomy (OHE). Twenty-four young, healthy female dogs (mean age 32.7 ± 26 months; mean body weight 6.8 ± 3 kg) were included. The animals received an intravenous injection of maropitant (1 mg/kg; GM), acepromazine (0.02 mg/kg; GA), or saline (GS), 30 minutes before the intramuscular administration of morphine (0.5 mg/kg). The incidence of nausea and vomiting was recorded over 30 minutes following morphine administration. Sedation scores, propofol requirements for anaesthetic induction, and postoperative appetite were also evaluated. Compared to saline, maropitant and acepromazine reduced the incidence of vomiting in 100% and 37.5% of the animals, respectively. None of the treatments prevented nausea. Acepromazine induced greater sedation and reduced the propofol dose required for anaesthetic induction in comparison to maropitant and saline. Postoperative appetite recovery did not differ significantly among groups. Despite the small sample size and the limited observation period, it is concluded that maropitant effectively prevents morphine-induced vomiting without sedative or propofol-sparing effects. Conversely, acepromazine does not prevent emesis but provides deeper sedation and reduces the requirement for propofol. Neither drug demonstrated efficacy in managing nausea or enhancing postoperative appetite in healthy female dogs undergoing elective OHE. Keywords: NK-1