title: Clinical equivalence of IV paracetamol compared to IV dipyrone for postoperative analgesia after surgery for breast cancer.
abstract: OBJECTIVE
  To assess clinical efficacy of IV paracetamol 1 g and IV dipyrone 1 g on a 24-h dosing schedule in this randomised, double-blinded study of 40 ASA I-III (American Society of Anesthesiologists classification of physical status) patients undergoing surgery for breast cancer.
  
  
  METHODS
  General anaesthesia using remifentanil and propofol was performed for surgery. The patients were randomly allocated to two groups, receiving infusions of paracetamol 1 g/100 mL (Para Group) or of dipyrone 1 g/100 mL (Dipy Group) 30 min before arrival in the recovery area and every 6 h up to 24 h postoperatively. All patients had unrestricted access to opioid rescue medication via an IV patient-controlled analgesia (PCA) device.
  
  
  METHODS
  The primary variables for clinical equivalence were the differences between the mean values for pain scores at rest and pain scores on coughing over 30 h postoperatively. The equivalence margin was determined as +/-10 mm on the visual analogue scale (VAS).
  
  
  RESULTS
  Regarding pain scores at rest, the 90% CI of the mean differences between the treatment groups over 30 h postoperatively was found to be within the predefined equivalence margin [+7.5/-6.2], and the CI values for pain scores on coughing [+7.3/-9.0] were similar. The two groups did not differ in cumulative opioid rescue consumption (Dipy-Group 14.8 +/- 17.7 mg vs. Para Group 12.1 +/- 8.8 mg, p = 0.54) nor in piritramide loading dose (Dipy Group 0.95 +/- 2.8 mg vs. Para Group 1.3 +/- 2.8 mg, p = 0.545). Five patients in the Dipy Group experienced hypotension in contrast to none in the Para Group (p = 0.047). There were no significant between-treatment differences for other adverse events, patient satisfaction scores (p = 0.4) or quality of recovery scores (p = 0.3).
  
  
  CONCLUSIONS
  IV paracetamol 1 g is clinically equivalent to IV dipyrone 1 g for postoperative analgesia after surgery for breast cancer.
authors.affiliation: Department of Anaesthesiology, University of Cologne, Cologne, Germany. Sandra.Kampe@uk-koeln.de
authors.forename: Sandra
authors.initials: S
authors.lastname: Kampe
authors.forename: Mathias
authors.initials: M
authors.lastname: Warm
authors.forename: Susanne
authors.initials: S
authors.lastname: Landwehr
authors.forename: Oguzhan
authors.initials: O
authors.lastname: Dagtekin
authors.forename: Sascha
authors.initials: S
authors.lastname: Haussmann
authors.forename: Matthias
authors.initials: M
authors.lastname: Paul
authors.forename: Barbara
authors.initials: B
authors.lastname: Pilgram
authors.forename: Peter
authors.initials: P
authors.lastname: Kiencke
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000328:Adult; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001943:Breast Neoplasms / Q000601:surgery; D004177:Dipyrone / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D008408:Mastectomy; D008875:Middle Aged; D010149:Postoperative Pain / Q000188:drug therapy*; D013810:Therapeutic Equivalency
chemical_list: D018712:Analgesics, Non-Narcotic; D000082:Acetaminophen; D004177:Dipyrone