Gabapentina como adjuvante no controle da dor pós-operatória em cadelas submetidas à mastectomia

Abstract

The aim of this study was to evaluate the analgesic effects of gabapentin as an adjunct in the control of postoperative pain in dogs undergoing mastectomy. In a blinded study, 20 female dogs (10.5±5 kg body weight) were randomly assigned to 2 groups of 10 animals each and received 60 min prior of the surgery, by oral route: 10mg kg-1 of gabapentin (Gabapentin) or placebo (Control). Pre-anesthetic medication was intramuscular (IM) acepromazine (0.03mg kg-1) in combination with morphine (0.3mg kg-1). Anesthesia was induced with intravenously (IV) propofol (dose effect) and maintained with isoflurane. Meloxicam (0.2 mg kg-1, IV) was administered five minutes before the surgical incision. The analgesic intra-operative support was provided by IV continuous rate morphine (0.1mg kg-1h-1). Heart rate, respiratory rate, systolic arterial blood pressure, oxycapnography and end-tidal concentration of isoflurane were evaluated during the surgery. Postoperative analgesia was assessed during the first 72 hours after the tracheal extubation using a Dinamic and Interative Visual Analog Scale (DIVAS) and modified Glasgow Composite Measure Pain Scale (modified-GCMPS). Rescue analgesia with morphine (0.5mg kg-1 IM) was performed if the evaluation score exceeded 50% of DIVAS and/or 33% of GCMPS during the postoperative period. The cardiopulmonary variables, pain and sedation scores did not differ between groups. However, rescue analgesia was 40% less frequently for Gabapentin (6 of 10 dogs needs rescue analgesic, total of 9 rescued doses in the Gabapentin group) than in the Control group (8 of 10 dogs, total of 15 rescued doses in the Control group). It was concluded that the adjuvant gabapentin administration reduce the requirement for rescue opioid in dogs undergoing mastectomy