POSTOPERATIVE ANALGESIC EFFECT OF INTRATHECAL NEOSTIGMINE AND ITS INFLUENCE ON SPINAL-ANESTHESIA

A clinical trial was conducted to evaluate the postoperative analgesic efficacy and the safety oi intrathecal neostigmine in patients underg oing anterior and posterior vaginoplasty under spinal anaesthesia. Thi rty-six patients were randomly divided into three groups to receive: n ormal saline (1 ml), morphine (100 mu g in 1 ml of saline) or neostigm ine (100 mu g in 1 ml of saline) intrathecally just before a spinal in jection of hyperbaric bupivacaine (0.5%, 4 ml). The mean [SD] time to the first analgesic (nonsteroidal anti-inflammatory drug) administrati on 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 subcut aneous morphine to complement the analgesia provided by the intramuscu lar nonsteroidal anti-inflammatory drugs and the mean [SD] times for t heir administration: eight patients in the saline group (8.0 [3.8] h), one patient in the morphine group (18 h) and two patients in the neos tigmine group (8 and 12.9 h). The morphine and neostigmine groups show ed similar analgesic effectiveness. The characteristics of spinal anae sthesia were not modified by intrathecal morphine or neostigmine. Seve re nausea and vomiting, sweating and distress during surgery were the most obvious adverse effects of intrathecal neostigmine. On the other hand, less hypotension was observed in the neostigmine group. The usef ulness of intrathecal neostigmine as the sole postoperative analgesic may be restricted by the severity of its adverse effects.