Gregory J Dale,1 Stephanie Phillips,2 Gregory L Falk3 1Westmead Hospital Clinical School, The University of Sydney, 2Sydney Adventist Hospital Clinical School, The University of Sydney, 3Concord Clinical School, The University of Sydney, Sydney, Australia Abstract: This study aimed to determine if intravenous lidocaine infusion reduces postoperative pain intensity following laparoscopic fundoplication surgery and to also validate the safety of intravenous lidocaine at the dose tested. This was an equally randomized, double-blind, placebo-controlled, parallel-group, single center trial. Adult patients undergoing laparoscopic fundoplication were recruited. The intervention group received 1 mg/kg intravenous lidocaine bolus prior to induction of anesthesia, then an intravenous infusion at 2 mg/kg/h for 24 hours. The primary outcome was pain, measured using a numeric rating scale for 30 hours postoperatively. Secondary outcomes were nausea and vomiting, opioid requirements, adverse events, serum lidocaine concentration, and length of hospital stay. The study was terminated after an interim analysis of 24 patients showed evidence of futility. There was no difference in postoperative pain scores (lidocaine versus control, mean ± standard deviation) at rest (2.0 ± 2.7 vs 2.1 ± 2.4, P=0.286) or with movement (2.0 ± 2.6 vs 2.6 ± 2.7, P=0.487). Three adverse events occurred in the lidocaine group (25% of patients). Intravenous lidocaine did not provide clinically significant analgesia to patients undergoing laparoscopic fundoplication. The serum lidocaine concentration of patients who experienced adverse events were within the therapeutic range. This trial cannot confirm the safety of intravenous lidocaine at the dose tested. Keywords: analgesia, local anesthetics, intravenous infusions, pharmacokinetics