Evaluation of the analgesic effect of the Fentanyl patch during ovariectomy and the postoperative period in bitch.

For several years now, routine surgical procedures such as ovariectomy are performed as outpatient surgery. Post-operative care turns out to be much more comfortable for the patient than hospitalization, particularly at home in reducing the risk of nosocomial infections. However, this approach rises the problem of the administration of analgesic drugs by the owners at home. The potent opioid fentanyl is market in the form of a patch (DURAGESIC®, Jannsen), which fentanyl is gradually released for approximately 72 hours after application (1). The aim of this study was to evaluate the convenience and the analgesic efficacy of this patch, in comparison to other analgesic protocols usually utilized in ovariectomized bitches. This study involved 20 privately-owned bitches, ovariectomized at the Veterinary Hospital of the Department of Veterinary Medicine (Bari). Only bitches housed without other domestic animals were selected, to allow the owners to perform a strict control in the postoperative period. The animals (healthy and from 2 to 5 years of age) were randomly divided into two 2groups. In both groups after premedication with acepromazine, anesthesia was induced by propofol and maintained with isofluorane. The following parameters were monitored during the procedure in all animals: heart rate, electrocardiogram, EtCO2, pulse oximetry, blood pressure and body temperature. The analgesic protocols in the Fentanyl group and Control group were different. The Fentanyl patches were applied 12 hours before the surgery. Transdermal fentanyl patches were placed on the neck skin, which had been previously shaved and disinfected. The size of individual patch was chosen based on the patient's body weight: <10 kg = 25 mcg/h; 10-20 kg = 50 mcg/h; 20-30 kg = 75 mcg/h, and 30-40 kg = 100 mcg/h (2). The patches were affixed with adhesive tape, and left on site for 72 hours after application (3). In the control group standard analgesic protocol pre-surgically was with methadone and oral administration of analgesic drugs at home was administered (robenacoxib). In the clinic, after the dog awakened from anesthesia, the behavior and level of pain/discomfort were evaluated using the Glasgow Pain Scale. The owners filled out a questionnaire with a numerical scale (from 0 to 10) to assess their dogs behavior and the owners satisfaction, regarding the management of their animals postoperative. All the animals in the study hade an uneventful recovery from anesthesia. The owners of the bitches in Fentanyl group were more satisfied with post-operative management than were the owners of the control group (administration of drugs orally). More pain was reported in the control group, related to bitches refusing oral medication. The bitches in the Fentanyl group tolerated the Fentanyl patch well, without any side effects noted. The data obtained from this study shows that the fentanyl patch is a valid aid for effective analgesia post-ovariectomy in bitches.