The efficiency and safety of patient-controlled epidural analgesia by using tramadol alone and combined with bupivacaine were investigated for postoperative pain treatment after major urological surgeries. For PCEA: in group I (n = 17) a loading dose of 20 mg tramadol with a continuous infusion of 1 mg/ml tramadol at a rate of 8 ml/h was given. In group II (n = 17), patients received an initial loading dose of 20 ml bupivacaine 0.125% and a supplemental continuous infusion of 8 ml/h. In group III (n = 17), a loading dose of 20 mg tramadol with 20 ml bupivacaine 0.125% were given and a supplemental infusion of 1 mg/ml tramadol in 20 ml bupivacaine 0.125% combination was begun with a rate of 8 ml/h. A demand epidural bolus dose of 5 ml with a lockout time of 30 min was also used in all patients. VAS for pain intensity, vital signs, sedation scale and side effects was monitored at 0, 15, 30 min and 1, 2, 3, 4, 8, 12, and 24 h of the postoperative period. Statistical significance was determined using Kruskal-Wallis, Fisher's exact, analysis of variance for repeated measurements and Tukey tests. The hemodynamic values and sedation scales were insignificantly different (p > 0.05). The adequate analgesia was provided in all patients. However VAS values were significantly lower in group III than in groups I and II at every measurement (p < 0.05). The incidence of side effects in all three groups was low (p > 0.05). In conclusion, we suggested that a combination of tramadol with bupivacaine can provide the most effective and safe postoperative analgesia with minimal risk for side effects. Copyright (C) 2003 S. Karger AG, Basel.