Intrathecal opioids for the control of pain experienced during labor and in the post-cesarean section period.

Abstract

Since the discovery of opiate receptors in the brain and spinal cord, considerable research has been performed to include intrathecal opioids for the control of pain. No area has used this knowledge more than the practice of obstetrical anesthesia. Intrathecal opioids have been shown to be very effective in controlling the pain experienced in the first stage of labor but have been ineffective in controlling second-stage labor pain. Intrathecal opioids, especially morphine sulfate, provide long-term analgesia but are associated with a high number of side effects. Research studies have attempted to determine the optimal dose of intrathecal opioids to provide the greatest amount of analgesia with the lowest incidence of side effects. Intrathecal morphine sulfate has been shown to be effective in controlling first-stage labor pain but has been shown to be the most efficacious in controlling the pain experienced in the post-cesarean section period. This article reviews the current literature and provides background of information to understand these developments.