The effect of intravenous preemptive paracetamol on postoperative fentanyl consumption in patients undergoing open nephrectomy: a prospective randomized study.

AIM We investigated the efficacy of intravenous (IV) preemptive paracetamol on postoperative total fentanyl consumption and fentanyl-related side effects in patients undergoing open nephrectomy. MATERIALS AND METHODS A total of 60 patients scheduled for elective open nephrectomy under general anesthesia were included. All patients received Patient-controlled IV analgesia with fentanyl postoperatively. Patients were randomly allocated into three equal groups: The fentanyl group received 100 mL of IV normal saline as a placebo, with the first dose ending 30 min before intubation. In paracetamol group, IV 1 g paracetamol was given to the patients 30 min after extubation with repeated doses every 6 h totally 4 times a day. In preemptive paracetamol group, patients received IV 1 g paracetamol every 6 h, with the first dose ending 30 min before intubation. RESULTS Postoperative cumulative fentanyl consumption for 24 h was significantly higher in the fentanyl group (1009 ± 139.361 μg) than those of paracetamol (752.25 ± 112.665 μg) and preemptive paracetamol groups (761.10 ± 226.625 μg) (P = 0.001 for both). In early postoperative period (0-4 h); whereas total fentanyl consumption showed no statistically significant difference among groups (P = 0.186), the nausea-vomiting scores were significantly higher in the fentanyl group compared with other groups (P = 0.012). CONCLUSION In patients undergoing open nephrectomy, use of preemptive or postoperative paracetamol reduces fentanyl related nausea-vomiting without a decrease in total fentanyl consumption in the early postoperative period. Furthermore, use of preemptive or postoperative paracetamol reduces total fentanyl requirements in the first 24 h postoperatively providing a safe and effective postoperative analgesia.