A comparison of the haemodynamic effects of epidurally administered medetomidine and xylazine in dogs

Alpha2 agonists have a significant role in epidural anaesthetic techniques. However, there are few reports regarding epidural administration of these drugs especially in small animals (Greene et al. 1995; Keegan et al. 1995; Vesal et al. 1996). This study compared the haemodynamic effects of xylazine and medetomidine after epidural injection in dogs. Six dogs (four females and two males) weighing 27.5 ± 3.39 kg, aged 5.6 ± 1.42 years were studied on two separate occasions one month apart. Dogs were sedated with 0.5 mg kg−1 diazepam IM and 0.1 mg kg−1 acepromazine IM. After 20 minutes, a lumbosacral epidural injection of 0.25 mg kg−1 xylazine was administered (group X). One month later, following the same sedation, 15 µg kg−1 medetomidine was administered epidurally (group M). Haemodynamic variables (ECG and indirect blood pressure (Doppler)), respiratory rate and rectal temperature were recorded before (baseline) and then every 5 minutes after the epidural injection, up to 60 minutes. Differences between groups were compared by a paired t‐test. Within group changes were compared to basal values by anova. A p‐value of