Canabidiol reduz resgate analgésico no pós-operatório de cadelas submetidas à ovariohisterectomia

Abstract

The aim of this study was to evaluate the safety and postoperative analgesic effect of cannabidiol oil in female dogs undergoing elective ovariohysterectomy (OH). In a clinical, prospective, randomized, and blinded study, 32 dogs were divided into two groups: GCBD (n = 16), administration of 2 mg/kg cannabidiol oil (0.1 mL/kg) orally; and GControl (n = 16), administration of 0.1 mL/kg saline solution orally. 10 minutes after administration, pre-anesthetic medication was performed with a combination of meperidine (5 mg/kg) and dexmedetomidine (3 mcg/kg) intramuscularly (IM). Intravenous (IV) propofol dose-effect induction was followed by maintenance anesthesia with isoflurane/O2. During surgery, the following parameters were monitored: heart and respiratory rate, systolic blood pressure, esophageal temperature, capnography, and end-tidal isoflurane concentration. Postoperative pain and sedation were assessed at 0.5, 1, 2, 4, 6, 8, and 12 hours after tracheal extubation using the Glasgow Composite Measure Pain Scale – Short Form (CMPS-SF), Dynamic and Interactive Visual Analog Scale (DIVAS), and Short-Form Sedation Scale for Dogs. In dogs with CMPS-SF ≥ 6/24, rescue analgesia was administered with morphine (0.5 mg/kg IM). The occurrence of adverse effects was also evaluated. Data were analyzed using unpaired t-test, Fisher's exact test, ANOVA with Tukey's test, Mann-Whitney tests, and Friedman test (P < 0.05). Pain scores differed between groups only at the 2nd hour after tracheal extubation, with lower scores (CMPS-SF and ID-VAS) observed in the GCBD (P = 0.033-0.036). Postoperative rescue analgesia was required in 43.75% of GCBD animals and 87.5% of GControl animals (P = 0.046). Bradycardia and hypotension were observed in 87.5% and 12.5% of animals, respectively, in both groups, and vomiting occurred in 12.5% and 6.25% of GCBD and GControl animals, respectively. In conclusion, the inclusion of cannabidiol oil in the analgesic protocol reduced pain scores at the 2nd hour after tracheal extubation and postoperative opioid consumption without adverse effects in dogs undergoing elective OH.