Background and Objectives Postoperative analgesia and antiemetic efficacy after intrathecal neostigmine were investigated in a randomized, double-blind, placebocontrolled trial of 100 patients undergoing abdominal hysterectomy.

Methods The patients were assigned to one of five groups (n = 20), and received intravenous prior to the spinal block the antiemetic test drug (except propofol) and 0.05 mg/kg midazolam. The control group (group C), the neostigmine group (group N), and the propofol group (group P) received saline as the test drug. The droperidol group (group D) received 0.5 mg intravenous droperidol, and the metoclopramide group (group M) 10 mg intravenous metoclopramide. Group P was single-blinded and had an intravenous continuous propofol infusion (2-4 mg/kg/h) turned on 10 minutes after the spinal injection. The intrathecal drugs administered were 20 mg hyperbaric bupivacaine (0.5%) associated with either 100 μg neostigmine or saline (for group C). Nausea, emetic episodes, and the need for rescue medication were recorded for the first 24 hours postoperative and scored by the Visual Analog Scale (VAS).

Results Time-to-first-rescue medication and rescue medications in 24 hours were similar among the groups (P = .2917 and P = .8780, respectively). Intrathecal 100 μg neostigmine was associated with a high incidence of nausea and vomiting perioperative, leading to a high consumption of antiemetics (P < .002). None of the antiemetic test drugs were effective in preventing nausea and vomiting after 100 μg neostigmine.

Conclusions Intrathecal neostigmine (100 μg) was ineffective for post-operative analgesia after abdominal hysterectomy due to side effects of nausea and vomiting.