A comparative study of the Cardiovascular Effects of Medetomidine and Medetomidine-Acepromazine Premedication in Dogs

Abstract

The aim of this research was to evaluate the cardiovascular and sedative effects of a medetomidine-acepromazine combination compared to medetomidine alone in dogs. Specifically, heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), respiratory rate (RR), quality of sedation and type of recovery were assessed. It was hypothesized that the acepromazine induced vasodilation might attenuate the vasoconstrictive phase of medetomidine, rendering a greater cardiovascular stability. A total of 43 dogs were included: 17 in the medetomidine-acepromazine group (Group 1) and 26 in the medetomidine group (Group 2). Group 1 exhibited a significantly lower (P<0.01) HR (48 bpm ± 10) at 15 minutes after administration compared to group 2 (65 bpm ±22.5), along with a lower RR. The MAP increased in both groups over time, without significant intergroup differences. Quality of sedation scores were also significantly higher (P<0.01) in group 1, which may account for the observed reductions in HR and RR. No differences were observed in the type of recovery between both groups. Contrary to the initial hypothesis, the addition of acepromazine did not mitigate the vasoconstrictive effects of medetomidine. Further research incorporating more extensive diagnostic tools, such as electrocardiography and arterial blood gasses, is recommended to better evaluate the effects on cardiac output and cardiovascular impact of this drug combination.