Intraperitoneal administration of lidocaine or tramadol alone or in combination on postoperative pain after ovariohysterectomy in dogs

The present prospective randomized experimental study aimed to assess the intraperitoneal (ip) administration of lidocaine or tramadol, alone or in combination, on postoperative pain management following ovariohysterectomy in dogs. Eighteen healthy female mixed‐breed dogs, aged 1–2 years, weighed 16.7 ± 3.8 kg, were used. Animals were sedated with acepromazine (0.1 mg/kg, intramuscular). Forty minutes later, anaesthesia was induced through intravenous titration with diazepam (0.5 mg/kg) and ketamine (10 mg/kg) and maintained with isoflurane 1.5%. Afterwards, ovariohysterectomy was performed, and prior to the closure of the linea alba, animals received lidocaine containing epinephrine (8.8 mg/kg, ip) in group L, tramadol (4 mg/kg, ip) in group T and lidocaine containing epinephrine (8.8 mg/kg, ip) plus tramadol (4 mg/kg, ip) in the LT group. Cortisol, vital signs and pain scoring systems were evaluated at different time points. Vital signs did not change among the groups. Cortisol level in the LT group significantly decreased compared to the L and T groups one, three and six hours after surgery. Pain scores also did not change among the groups based on Sammarco and Simple descriptive (SDS) scoring method. However, pain scores in the LT group were higher than the two other groups according to the University of Melbourne pain scale (UMPS) and the short form of Glasgow pain scale (CMPS‐SF). According to the obtained results, the combination of lidocaine and tramadol seemed to be able to provide better analgesia compared with their separate administration. Therefore, combined intraperitoneal administration of lidocaine (8.8 mg/kg) and tramadol (4 mg/kg) with a final volume of (0.2 ml/kg) following ovariohysterectomy is recommended.