Evaluation of the Analgesic and Sedative Effects of Pethidine (meperidine)with Xylazine in the Horse

A variety of analgesic and sedative agents are available¡ and which one can be used in horses is a highly controversial issue. The purpose of this study was to evaluate the analgesic and sedative effects and effect on vitalsigns and probable side effects of administered pethidine with xylazine in the horse. Ten healthy mix breed horses 2-8 years of age¡ weighing 250-350 kg were randomly divided into two groups. A treatment group received combination of pethidine (2 mg/kg¡ IM) and xylazine (0/2 mg/kg¡ IV). The second control group received a saline placebo (1ml/45 kg bwt¡ IV). Heart rate¡ respiratory rate and rectal temperature were recorded. The records were averaged for the fifteen minutes’ intervals to 6 hours after injection. Analgesia was assessed with pin prick in the tail and perineal region. Data were analyzed statistically by two way of analysis of variance (ANOVA) using repeated measurements and Duncan’s multiple range tests to determine significant differences using P0.05) above baseline in the treatment group at 30 and 60 minutes after injection. Rectal temperature decreased from baseline values in treatment group at 15minutes after injection. The lowest recorded rectal temperature in the treatment group was 35.92 ± 0.3at 15 minutes and returned toward baseline in treatment groups 30 minutes after injection. Respiratory rate in the treatment group significantly decreased following administration at 15 and 30 min compared with the control group. Results of this study showed that parenteral administration of pethidine with xylazine is fast-acting and effective sedation in animals are created while pethidine it is not effective for analgesia and side effects from this combination is acceptable and does not cause any danger to the animal.