Postoperative analgesic effect of intrathecal neostigmine and its influence on spinal anaesthesia

A clinical trial was conducted to evaluate the postoperative analgesic efficacy and the safety of intrathecal neostigmine in patients undergoing anterior and posterior vaginoplasty under spinal anaesthesia. Thirty-six patients were randomly divided into three groups to receive: normal saline (1 ml), morphine (100 micrograms in 1 ml of saline) or neostigmine (100 micrograms in 1 ml of saline) intrathecally just before a spinal injection of hyperbaric bupivacaine (0.5%, 4 ml). The mean [SD] time to the first analgesic (nonsteroidal anti-inflammatory drug) administration was significantly prolonged by intrathecal neostigmine (10.7 [4.3] h) and morphine (15.3 [3.0] h) compared with saline (4.5 [1.0] h). The three groups also differed in the number of patients requiring subcutaneous morphine to complement the analgesia provided…