Abstract:Objective: To study the analgesia efficacy of epidural neostigmine. Methods: The study consists of two parts: part 1, the analgesic action of neostigmine in normal humans, part 2, the analgesic action of neostigmine in postoperative pain patients. Results: There was no analgesic effect on upper extremities after epidural administration of 0.5mg or 1.0mg of neostigmine. There was analgesia on lower extremities following 1.0mg but not 0.5mg neostigmine. In post operative pain patients epidural neostigmine 0.5 or 1.0mg induced dose related analgesia as assessed by VAS scores. Conclusion: Epidural neostigmine produced dose rated analgesic effect in human experimental pain model, and in patients with post operative pain. Its aversive side effects (bradycardia, increased GI movement) prevented it from clinical application.