Paracetamol versus metamizol in the treatment of postoperative pain after breast surgery: a randomized, controlled trial

Background and objective Intravenously administered paracetamol is an effective analgesic in postoperative pain management. However, there is a lack of data on the effect of intravenous (i.v.) paracetamol on pain following soft tissue surgery. Methods Eighty-seven patients undergoing elective breast surgery with total i.v. anaesthesia (propofol/remifentanil) were randomized to three groups. Group para received 1 g i.v. paracetamol 20 min before and 4, 10 and 16 h after the end of the operation. Group meta and plac received 1 g i.v. metamizol or placebo, respectively, scheduled at the same time points. All patients had access to i.v. morphine on demand to achieve adequate pain relief. Results No significant difference in total morphine consumption between groups was detectable. The proportion of patients who did not receive any morphine in the postoperative period was significantly higher in group para (42%) than in group plac (4%). Ambulation was significantly (P < 0.05) earlier in group para (4.0 +/- 0.2 h)than in groups meta (4.6 +/- 0.2 h) and plac (5.5 +/- 1.0 h). No differences were observed between groups meta and plac. There were no differences between groups with regard to incidence of postoperative nausea and vomiting or changes in vigilance. Conclusion Neither i.v. paracetamol nor i.v. metamizol provided a significant reduction in total postoperative morphine consumption compared with placebo in the management of postoperative pain after elective breast surgery. Administration of paracetamol resulted in a significant reduction in the number of patients needing opioid analgesics to achieve adequate postoperative pain relief. Eur J Anaesthesiol 26:648-653 (C) 2009 European Society of Anaesthesiology.