Comparação do efeito analgésico da metadona via intramuscular ou epidural em gatas submetidas a ovariossalpingohisterectomia

Abstract

This study compared the analgesic, sedative and neuroendocrine effects of the epidural (EP) and intramuscular (IM) methadone in cats submitted to ovariohisterectomy. Cats were randomly assigned to three groups of 08 animals each and received EP or IM methadone (0.2mg.kg-1 diluted with saline to 0.2ml.kg-1, G1 and G2, respectively) or a saline placebo (G3). Pre-anaesthetic medication was acepromazine (0.1mg.kg-1 IM). Anaesthesia was induced with thiopental (12mg.kg-1 IV) and maintained with halothane. Serum cortisol concentration, behavioral changes, degree of analgesia and sedation were evaluated. In the epidural methadone group (G1) lower scores of pain were observed when compared with the others groups, but the difference did not significance. Rescue analgesia was administered 3 times to 02 cats in the G1, 9 times to 05 cats in the G2 and 11 times to 06 cats in the G3. It was concluded that the methadone preemptive administration reduced postoperative analgesic requirement. Stress response was modulated by methadone in cats submitted to ovariohisterectomy.