Comparison of the effects of two doses of dexmedetomidine on physiological parameters and sedation in rabbits (Oryctolagus cuniculus)

Abstract

This study aimed to evaluate the effects of dexmedetomidine (DEX) on cardiorespiratory, haemodynamic and glycaemic variables in rabbits, as well as to assess sedation using two different doses. Nineteen rabbits (14.31±12.64 months; 1.98±0.90 kg) were randomly assigned to two groups receiving 40 μg/kg (D40; n=10) or 60 μg/kg (D60; n=9) of DEX via intramuscular injection. Heart rate (HR), respiratory rate (RR), body temperature (T), invasive mean arterial pressure (IMAP), blood glucose (GLU) and cardiac output (CO) were evaluated at baseline (T1) and 15 min after drug administration (T2). Sedation was assessed using a descriptive numerical scale (0–13) adapted for rabbits. Both doses significantly reduced HR, IMAP, CO and RR, and increased GLU at T2 compared to baseline. No significant differences between groups were observed for physiological variables. However, sedation scores were significantly higher in the D60 group, with satisfactory sedation achieved in 89% of animals, compared to 30% in the D40 group. Both doses produced similar physiological effects, while the higher dose resulted in improved sedation quality. The evaluation at a single post-administration time point should be considered a limitation when interpreting these findings.