Intrathecal neostigmine for postoperative analgesia after orthopedic surgery.
OBJECTIVE
To establish a dose-response curve for the analgesic effect of intrathecal neostigmine in patients undergoing below knee surgery with spinal anesthesia. To assess adverse effects, principally nausea and vomiting.


METHODS
Randomized, double-blind, prospective study.


METHODS
Teaching hospital.


METHODS
60 ASA physical status I and II premedicated patients undergoing orthopedic surgery (tibial or ankle reconstruction).


METHODS
Spinal anesthesia was performed at the sitting position, L3-L4 interspace, 4 ml final volume, injected at a rate of 1 ml/10 sec. The control group (CG) received 15 mg hyperbaric bupivacaine 0.5% plus saline. The 25 micrograms neostigmine group (25NG) received 15 mg hyperbaric bupivacaine plus 25 micrograms neostigmine; the 50 micrograms neostigmine group (50NG) received 15 mg hyperbaric bupivacaine plus 50 micrograms neostigmine; and the 100 micrograms neostigmine group (100NG) received 15 mg hyperbaric bupivacaine plus 100 micrograms neostigmine. Patients were placed supine after the spinal punction.


RESULTS
Time to first rescue analgesics, analgesia, and adverse effects at constant intervals were assessed using the 10 cm visual analog scale (VAS). Intrathecal neostigmine produced a dose-independent reduction in the postoperative rescue analgesic consumption (p < 0.0001). The time to first rescue analgesics was similar among groups (p > 0.05), and the overall 24-hour VAS pain scores were lowest for patients who had spinal neostigmine (p < 0.02). The 100NG group had the highest incidence of postoperative nausea and vomiting of all the groups (p < 0.05).


CONCLUSIONS
Intrathecal neostigmine produced a dose-independent analgesia and a dose-dependent incidence of adverse effects with the doses studied.
Lauretti
G R
GR
Department of Surgery, Orthopedics and Traumatology, Hospital das Clinicas, Faculty of Medicine of Ribeirão Preto-University of São Paulo, Brazil.
Mattos
A L
AL
Reis
M P
MP
Prado
W A
WA
D000328:Adult; D000700:Analgesics / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009388:Neostigmine / Q000008:administration & dosage*; D009985:Orthopedics / Q000379:methods*; D011446:Prospective Studies
D000700:Analgesics; D009388:Neostigmine