OPIOID-INDUCED RIGIDITY AFTER INTRAVENOUS FENTANYL

Background: Large doses of intravenous opioids may cause severe rigidi ty and prevent spontaneous or controlled ventilation. The mechanism of this effect appears to be neuraxis dopamine antagonism. Rigidity afte r analgesic doses of fentanyl has not been reported previously. Case: A pregnant woman receiving haloperidol for multiple psychiatric condit ions presented for evaluation of vaginal bleeding. Intravenous fentany l was administered to facilitate vaginal examination. Severe rigidity of the extremities and truncal region occurred, which prevented sponta neous or assisted ventilation. Conclusion: Opioid administration may r esult in rigidity and respiratory embarrassment. Decreased analgesic r equirements in pregnancy and concomitant butyrophenone administration may predispose to opioid-induced rigidity. (C) 1997 by The American Co llege of Obstetricians and Gynecologists.