Acepromazine does not enhance sedation or reduce propofol requirements when combined with dexmedetomidine in dogs

This study aimed to evaluate the sedative effects of acepromazine and dexmedetomidine in dogs and their influence on propofol requirements for anesthetic induction, electrocardiographic findings, heart rate and arterial blood pressure. Twenty-one healthy mixed-breed dogs were included in the study. Dogs were randomly assigned to one of 3 protocols (n = 7): dexmedetomidine (2 µg/kg IM) (GD); dexmedetomidine (2 µg/kg IM) and acepromazine (0.02 mg/kg IM) (GAD); or acepromazine (0.02 mg/kg IM) followed 15 minutes later by dexmedetomidine (2 µg/kg IM) (GAD15). Sedation scores and cardiorespiratory variables were recorded at baseline (T0), 15 minutes after the first drug administration (T15), and 15 minutes after the second drug administration (T30). Propofol induction dose was recorded. All protocols produced moderate sedation, with no significant differences among groups. Heart rate decreased significantly at T30 compared with T0 in GD but not in GAD or GAD15. SAP decreased significantly at T30 compared with T0 in GAD15. Propofol induction doses (mean ± SD) were 3.8 ± 1.1 mg/kg (GD), 3.6 ± 0.5 mg/kg (GAD), and 3.1 ± 0.5 mg/kg (GAD15), with no significant differences. Retching occurred in 2 dogs (GD and GAD), and none in GAD15. The combination of acepromazine and dexmedetomidine provided mild to moderate sedation but did not reduce propofol requirements compared with dexmedetomidine alone.