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

The aim of this study was to evaluate the analgesic effects of adjunctive gabapentin for postoperative pain control in dogs. Twenty dogs (10.5 ± 3.0 years; 3.3 to 34 kg ASA II and III) were randomly distributed into two groups of 10 animals each and received: 10 mg/ kg orally gabapentin solution (Gabapentin) every 12 hours starting 120 min prior to surgery or an equivalent volume of vehicle (Placebo). All animals were premedicated IM with acepromazine (0.03 mg/kg) in combination with morphine (0.5 mg/kg). Twenty minutes later, continuous IV infusion of morphine (0.1 mg/kg/h) was initiated and maintained until the end of the surgical procedure. Anesthesia was induced and maintained with propofol (dose effect, IV) and isoflurane, respectively. Meloxicam (0.2 mg/kg IV) was administered prior to surgery and was maintained at a daily dose of 0.1 mg/kg PO, for 10 days. Postoperative analgesia was assessed by a blinded observer for 72 hours after extubation, using the Dynamic and Interactive Visual Analogue Scale (DIVAS) and/or the Modified Glasgow Measure Composite Pain Scale (GCMPS). Rescue analgesia consisted of morphine (0.5 mg/kg IM), which was given if DIVAS and/or GCPS were greater than 50% and 33% of the maximum score, respectively. Sedation was evaluated by the scoring system. Data were analyzed by ANOVA, Tukey Friedman and Mann-Whitney test, as indicated (p <0.05). There were no significant differences between treatments in relation to body weight, age, surgical time, pain, and sedation scores. The rescue analgesia was more frequent in the bitches of the placebo group (8/10) compared to gabapentin (6/10), with a trend towards difference between groups (p = 0.06). Gabapentin can contribute to control post-mastectomy pain in bitches. Further studies with larger numbers of animals are recommended to confirm this effect.