Tolerance and analgesic efficacy of a new i.v. paracetamol solution in children after inguinal hernia repair

Background: A new intravenous (i.v.) formulation of paracetamol and propacetamol (prodrug of paracetamol) were compared to determine tolerance and relative analgesic efficacy during the first 6 h after inguinal hernia repair performed under general anesthesia combined with ilioinguinal block in children. Methods: A total of 183 ASA I or II in-patients, aged 1-12 years, admitted for unilateral inguinal hernia repair were randomized to receive in a double-blind design either i.v. paracetamol 15 mg.kg(-1) (n = 95) or propacetamol 30 mg.kg(-1) (n = 88) for postoperative pain relief as soon as pain intensity was greater than 30 on a 100 mm visual analog scale. All patients were evaluated for efficacy and tolerance. Efficacy was evaluated between 15 min and 6 h after the start of the 15 min infusion. Results: The most frequently reported adverse event was injection site pain, which was significantly reduced in the new formulation group (i.v. paracetamol 14.7% vs propacetamol 33.0% of children, P = 0.005). No significant difference was obtained between treatments on pain relief (PR), pain intensity difference (PAID) from baseline, and objective pain scale intensity difference (OPSD). Also, treatment effects did not differ significantly for maximum values and weighted sums of PR, PAID (investigator and child rated), OPSD, time to first request for rescue medication, proportion of children requesting rescue medication, and investigators' global treatment satisfaction. Conclusion: A single infusion of i.v. paracetamol 15 mg.kg(-1) produced analgesia similar to a single infusion of propacetamol 30 mg.kg(-1) following inguinal hernia repair in children. Paracetamol i.v. 15 mg.kg(-1) was better tolerated at the injection site than propacetamol.