The effect of addition of different doses of ondansetron to lidocaine as a component of intravenous regional anesthesia: a randomized double-blinded controlled study

Abstract

Background The aim of this study was to evaluate and compare the analgesic effect of adding two different doses (4or 8 mg) of ondansetron to lidocaine for intravenous regional anesthesia (IVRA). Patients and methods Ninety-nine patients were randomly assigned into three groups. IVRA was achieved with lidocaine 3 mg/kg 0.5% (C group) ( n = 33), lidocaine 3 mg/kg 0.5% plus 4 mg ondansetron (O1 group) ( n = 33) or lidocaine 3 mg/kg 0.5% plus 8 mg ondansetron (O2 group) ( n = 33). Times of onset and offset of sensory and motor blockade and the time of tourniquet pain were recorded. Postoperative visual analogue scale, time to first dose, and total amount of supplementary analgesia (diclofenac) were recorded. Results Significantly shorter onset times and longer recovery times of sensory and motor block were recorded in groups O1 and O2 compared with group C ( P P Conclusion Addition of ondansetron to lidocaine enhanced the performance of lidocaine when used in IVRA, prolonged postoperative analgesia and reduced intraoperative and postoperative analgesia. However, adding 8 mg ondansetron to lidocaine provided better analgesia than 4 mg.