Prophylaxis and treatment of the side-effects of neuraxial morphine analgesia following cesarean delivery

Purpose of review Neuraxial morphine is commonly used for analgesia after cesarean delivery, but is frequently associated with postoperative nausea and vomiting (PONV) and pruritus. This review describes the recent advances in the management of those side-effects. Recent findings Neuraxial-morphine-induced side-effects are dose related; therefore, the minimum effective dose should be used. Dexamethasone, 5HT(3) receptor antagonists, antihistamines, and anticholinergics reduce the incidence of PONV, whereas metoclopramide 10 mg does not appear to be effective for PONV prophylaxis in this patient population. Combination antiemetic therapy provides improved prophylaxis compared with monotherapy, but has seldom been studied in women undergoing cesarean delivery with neuraxial morphine. Studies of P6 acupressure reported inconsistent results. Polymorphism of the m-opioid receptor may affect the severity of neuraxial-morphine-induced pruritus. Opioid antagonists and mixed agonist/antagonists appear to be the most useful for the management of opioid-induced pruritus. Prophylactic 5HT(3) receptor antagonists and dexamethasone do not seem to be effective for reducing the incidence of pruritus. In contrast, ondansetron, pentazocine, and dimenhydrinate may be useful for treating established pruritus. Summary PONV and pruritus are frequent side-effects of neuraxial morphine. Future studies investigating combination antiemetic therapy, long-acting antiemetics, and strategies to manage pruritus are needed.