Evaluation of the Effectiveness of Lidocaine and Ketamine Injections in Reducing Pain from Propofol Injection in General Anesthesia

Abstract

Background: Propofol is a widely used anaesthetic agent, known for its rapid onset and short duration of action. However, pain at the injection site remains a common side effect that may affect patient comfort and the overall quality of anaesthesia. Lidocaine and ketamine are commonly used adjuncts to reduce injection pain; however, their comparative effectiveness remains unclear. This study aimed to evaluate the efficacy of lidocaine and low-dose ketamine in reducing the pain associated with propofol injection. Methods: This double-blind, randomised controlled trial involved 50 adult patients randomly assigned to either the ketamine group (0.1 mg/kg) or lidocaine group (1 mg/kg). Both agents were administered intravenously before propofol injection (2 mg/kg). Pain intensity was assessed using the Verbal Rating Scale (VRS) at several intervals post-injection. Statistical analysis was performed using the Wilcoxon test for within-group comparisons and Mann-Whitney U test for between-group comparisons. Results: In the ketamine group, 52% of the participants reported no pain, 32% experienced mild pain, 12% experienced moderate pain, and 4% reported severe pain. In contrast, 76% of the lidocaine group reported no pain, 20% reported mild pain, and 4% reported moderate pain with no reports of severe pain. A significant difference was found between the two groups (p = 0.001 for lidocaine vs. p = 0.012 for ketamine), indicating that lidocaine was more effective at reducing injection pain. Conclusion: Lidocaine is more effective than ketamine in reducing the pain caused by propofol injection, providing superior analgesia. This suggests that lidocaine is the preferred option to prevent injection pain during anaesthesia induction.