This study aimed to evaluate the preemptive analgesic effect of amantadine on postoperative pain control in female dogs that underwent ovariohysterectomy. Twenty female dog were randomly assigned to two groups of ten. The control group (CONTROL) received oral placebo capsules, while the amantadine (AMANT) group received 5 mg/kg of oral amantadine one hour before sedation. All the animals were premedicated with 3 mg/kg (IM) meperidine, induced with propofol and maintained with isofluorane. The transanesthetic physiological parameters were recorded, and postoperative pain was evaluated every hour after extubation for six hours with the Dynamic Interactive Visual Analog Scale (DIVAS) and mechanical nociceptive threshold (MNT) and when the necessary analgesic rescue was administered (morphine, 0.2 mg/kg (IM)). During the surgical procedure, there was no significant difference in the variables measured between the two groups. Regarding postoperative pain assessment, there was a significant difference in the DIVAS score (p = 0.004) between the groups, in which AMANT required fewer rescues than did CONTROL (p = 0.03). The MNT was significantly higher ​​in AMANT than in CONTROL (p = 0.03). The results suggested that the preoperative administration of amantadine decreased analgesic requirement in female dogs that underwent elective ovariohysterectomy.

Maropitant, an antagonist of neurokinin-1 (NK-1) receptors, blocks the pharmacological action of substance P on the central and peripheral nervous systems. The objective of this study was to compare the antinociceptive and cardiorespiratory effects of the continuous intraoperative infusion of maropitant with ketamine and lidocaine in female dogs undergoing unilateral radical mastectomy. Twenty-four female dogs were used and were divided randomly into two groups (n = 12). The GLK group received ketamine bolus (1.0 mg/kg), lidocaine bolus (1.5 mg/kg), and continuous infusion of ketamine and lidocaine (10 mcg/kg/min and 50 mcg/kg/min), respectively; the GLKM group received the same anesthetic protocol combined with maropitant bolus (1.5 mg/kg/IV) and continuous infusion of maropitant (100 mcg/kg/h). Continuous infusion was initiated at the start of surgery and was maintained until 1 hour postoperatively. Pain was evaluated in the postoperative period using four scales and a digital analgesimeter. Data were analysed using analysis of variance, Student's t-test, Mann–Whitney test, and Friedman’s test ( P  < 0.05). Kaplan–Meier curves were compared using the log-rank test. The results indicated lower pain scores, better survival curves with a lower number of patients requiring rescue analgesia, and lower peripheral sensitization, in the GLKM group than in the GLK group. It was concluded that the coadministration of maropitant with ketamine and lidocaine had an adjuvant effect with minimal cardiorespiratory effects and effective analgesia, improving pain management and patient comfort.

Background Multimodal analgesia consists of the combination of analgesic drugs at low doses to act in different places along the path of pain. Studies with continuous infusion of analgesic drugs in cats are not common. This study aimed to evaluate the analgesic effect of maropitant, lidocaine and ketamine alone or in combination (intravenous bolus + subsequent continuous intravenous infusion) in the management of acute postoperative pain in cats undergoing ovariohysterectomy. Seventy healthy cats undergoing an ovariohysterectomy received a standard anesthetic protocol consisting of acepromazine and morphine, propofol (anesthesia induction), and isoflurane (anesthesia maintenance). The animals were stratified into seven groups (n = 10 in each group): control (CG), maropitant (MG), lidocaine (LG), ketamine (KG), maropitant + lidocaine (LMG), maropitant + ketamine (KMG), and maropitant + lidocaine + ketamine (LKMG). All drugs were injected first as an intravenous bolus and then by continuous intravenous infusion. During surgery, esophageal temperature, respiratory rate, heart rate, oxygen saturation, expired isoflurane concentration, and partial pressure of carbon dioxide at the end of expiration were evaluated at 7 time points. Postoperative pain was evaluated for 6 h after extubation using the visual analogue scale and the UNESP-Botucatu multidimensional composite pain scale for assessing postoperative pain in cats. Results Adverse effects related to maropitant, lidocaine and ketamine infusion were not observed. Pain scores were lower in the MG, KG and LG groups when compared to the CG group using both scales. Although pain scores were also lower in all combination groups than CG, more animals in these groups required rescue analgesia compared to MG. This indicates that the postoperative analgesic effect of all drugs, either alone or in combination, confers analgesia, although the combinations did not promote greater analgesia. Conclusions Continuous intravenous infusion of maropitant, lidocaine, and ketamine alone induces postoperative analgesic effect in cats undergoing ovariohysterectomy, but combinations of these drugs did not increase the analgesic effect. No adverse effect was observed with any drug or their combination.

Background Amantadine is effective in the treatment of nervous system disorders as it blocks NMDA receptors, showing potential as an analgesic agent by inhibiting central sensitization. The aim was to evaluate the preemptive effect of amantadine on postoperative analgesia in cats undergoing ovariohysterectomy and its influence on the physiological parameters of the treated animals. For this purpose, 20 healthy domestic cats, were divided into two sample groups with 10 animals each and referred for ovariohysterectomy. In the control group (CG) the cats orally received placebo capsules 30 minutes before the standard anesthetic protocol. In the amantadine group (AG) the animals orally received 5mg/kg of amantadine 30 minutes before the standard anesthetic protocol. The presence of adverse effects after administration of the capsule was evaluated. An intraoperative evaluation was performed at different times during the surgical procedure, assessing the following parameters: heart and respiratory rates, oxyhemoglobin saturation, end-tidal carbon dioxide, end-tidal isoflurane concentration, esophageal temperature, and systolic blood pressure. Post-surgical pain was assessed using the Visual Analog Scale and the Multidimensional Scale for the evaluation of post-operative pain in cats of the Universidade Estadual Paulista (UNESP) – Botucatu.Results Amantadine did not influence the evaluated physiological parameters. The group that received amantadine had lower pain scores on both scales when compared to the control group and required fewer analgesic rescues.Conclusions It was concluded that the preemptive, oral administration of amantadine, at a dose of 5mg/kg, was effective in controlling postoperative pain in cats undergoing ovariohysterectomy, without causing adverse effects or alterations in the physiological patterns of the treated animals.