Melatonin Versus Ketorolac as an Adjuvant in Lidocaine Intravenous Regional Anesthesia

Background and Objectives: Melatonin and Ketorolac delay and minimize intraoperative tourniquet pain when used as premedication to lidocaine-based intravenous regional anesthesia (IVRA). It is unclear if Melatonin is more efficacious compared with Ketorolac. This study compared intra-operative tourniquet pain, postoperative analgesia, and side effects of using Melatonin vs. Ketorolac during outpatient hand surgery. Methods: A total of 78 patients scheduled for hand and forearm surgery were randomly assigned to one of three groups; the control group (Patients received 3mg/kg Lidocaine made with 40ml normal saline), Melatonin group (Patients received 3mg/kg Lidocaine made with 40ml normal saline plus oral Melatonin 0.15mg/kg one hour preoperatively) and Ketorolac group (Patients received 3mg/kg Lidocaine made with 40ml normal saline with an adjuvant Ketorolac 20mg). Ten minutes after proximal tourniquet inflation, the distal tourniquet was inflated, and the proximal tourniquet deflated. Tourniquet pain was measured every 1 0mins. Need for intra-operative opioids were recorded, PACU pain scores, postoperative analgesic consumption, patients and surgeon satisfaction were compared. Patients were contacted 24hrs after surgery and reported their analgesic consumption, satisfaction scores. Results: Hemodynamic stability was recorded among patients of the three groups. Intra-operative pain score was significantly lower while the time of first request of analgesia was significantly longer in the Melatonin and Ketorolac groups than the control group. 24h postoperative analgesic consumption was higher in the Melatonin and the control group than Ketorolac group. Patient and Surgeon satisfaction were significantly higher with Melatonin and Ketorolac than in the control group. Conclusion: Both Melatonin and Ketorolac are effective adjuvant to Lidocaine during intravenous regional anesthesia with hemodynamic stability. However Ketorolac is characterized by being more effective in terms of postoperative analgesia as denoted by time of first request of analgesia and total dose of analgesia given.