Effect of Intramuscular and Intravenous Lidocaine on Propofol Induction Dose

Objective: Our purpose was to study whether or not intravenous (IV) administration of lidocaine reduces propofol dose requirement as intramuscular (IM) lidocaine in a placebo-controlled manner. Subjects and Methods: Seventy-five adult patients with American Society of Anesthesiologists physical status I and II, aged 20-60 years who were scheduled for surgery under general anaesthesia were included in the study. The patients were randomly allocated to 3 groups: IM: intramuscular administration; IV: intravenous administration and C: control. There were 25 patients in each group. The patients in group IM received lidocaine 1.5 mg . kg(-1) administered into the deltoid muscle 10 min before anaesthesia induction. In group IV, the patients received IV lidocaine 1.5 mg . kg(-1), 2 min before anaesthesia induction. Group C patients served as control group who received only propofol injection. Hypnosis after propofol administration was measured with response to verbal commands. Results: There were no statistical differences between group IM (100.8 +/- 26.1 mg) and group IV (110.8 +/- 30.1 mg) regarding the induction dose of propofol (p > 0.05). In group C, the required propofol dose (151.2 +/- 27.4 mg) for anaesthesia induction was significantly higher than in the other groups (p < 0.001). No