Midazolam in Subarachnoid Block: Current Evidence

Abstract

Midazolam, despite of being the commonest benzodiazepine used in anaesthesia and perioperative care, is a relatively newer addition to the list of adjuvant used in subarachnoid block. Midazolam causes spinally mediated analgesia and the segmental analgesia produced by intrathecal midazolam is mediated by the benzodiazepine-GABA receptor complex. Initial animal studies questioned the safety of intrathecal midazolam in terms of possible neurotoxicity. However subsequent clinical studies also failed to show any neurotoxicity of high dose midazolam even on long-term use. Addition of intrathecal midazolam to bupivacaine significantly improves the duration and quality of spinal anaesthesia and provides prolonged perioperative analgesia without any significant side effects. Clinical studies also reported its safety and efficacy in pregnant women, but some studies also reported mild sedation with intrathecal midazolam. It is also reported to decrease the incidence of PONV. Intrathecal midazolam does not have any clinically significant effect on perioperative hemodynamics.