The study included 12 clinically healthy, adult male dogs of various breeds, admitted to our clinic for castration. After general anesthesia with sevoflurane, we administered epidural fentanyl (1 mcg/kg) to fentanyl group, while lidocaine group was given Lidocaine (3 mg/kg) through epidural administration. When hemodynamic parameters were stabilized, first measurements were recorded at minutes 0, 15, 30, 60 in both groups, which included Heart Rate (HR), body temperature, systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), sodium (Na+), potassium (K+), glucose (GLC), and hemoglobin (HB) measurements. In addition, serum samples were obtained from arterial blood at the same measurement times, and pH, pO₂, pCO₂, HCO₃, %O₂ Saturation, BE levels were measured. For hematological analysis, WBC, RBC, HCT, THR counts were performed. For serum biochemical analysis, venous blood samples were collected at minutes 0 and 60 and CK, TP, UREA, ALT, AST, ALB, GGT, CRE, CK-MB parameters were assessed using auto-analyzer. Moreover, cortisol levels were measured in the samples collected at minutes 0, 30, and 60.Mean arterial blood pressure values measured at minutes 15, 30 and 60 were found significantly lower in the fentanyl group (p<0.01). In conclusion, we suggest that epidural anesthesia with lidocaine and fentanyl can provide an effective and safe option in high-risk groups (Tab. 5, Fig. 1, Ref. 24).