Efficacy and safety of dipyrone versus tramadol in the management of pain after hysterectomy: A randomized, double-blind, multicenter study

Background and Objectives: We assessed the efficacy and safety of dipyrone in comparison with tramadol in the relief of early postoperative pain follo wing abdominal hysterectomy. Methods: A total of 151 women between 18 and 60 years of age undergoing abd ominal hysterectomy during general anesthesia participated in a randomized, double-blind, controlled, multicenter study. Seventy-three patients receiv ed dipyrone and 78 received tramadol. Patients received an intravenous load ing dose of the study drug immediately after operation followed by intraven ous (TV) maintenance infusion and IV on-demand boluses up to a maximum numb er of predetermined doses/day of 8 g dipyrone and 500 mg tramadol. The dura tion of the study was 24 hours. Results: The mean (SD) number of boluses in the dipyrone group was 3.8 (2.4 ) and 3.5 (2.5) in the tramadol group (95% confidence interval, -0.455 to 1 .175), and the percentage of patients requiring rescue IV morphine (dipyron e 26.9%, tramadol 26.8%) was not statistically significant. Other analgesic efficacy parameters, such as pain intensity differences, sum of pain inten sity differences, pain relief assessed by the patient, or patients who requ ired the maximum number of demand doses, were not different between treatme nt groups. A significantly higher percentage of adverse gastrointestinal ef fects was found in patients given tramadol (42.1%) than in patients given d ipyrone (20.2%) (P < .05). Also, a significantly higher number of tramadol- treated patients required ondansetron to control nausea and vomiting at 1 h our (19% v 7%), 2 hours (26% v 11%), and 24 hours (46% v 29%) (P < .05) aft er surgery. Patients and the investigators reported similar tolerability fo r both study arms. Conclusions: Dipyrone and tramadol showed similar efficacy for early pain r elief after abdominal hysterectomy. Nausea and vomiting, possibly caused by the tramadol, occurred more frequently in those patients. In this group, t he need of the antiemetic drug ondansetron was also higher.