Dexamethasone prophylaxis of nausea and vomiting after epidural morphine for post-Cesarean analgesia

Purpose: To determine the minimum effective dose of dexamethasone in preventing nausea and vomiting associated with epidural morphine for post-Cesarean analgesia. Method: One hundred and eighty parturients (n=45 in each of four groups) requiring epidural morphine for post Cesarean analgesia were enrolled in this randomized, double blinded, placebo-controlled study. At the end of surgery, parturients received either dexamethasone, at doses of 10 mg, 5 mg, 2.5 mg, or saline iv. Three milligrams epidural morphine were given to all parturients for postoperative analgesia, The incidence of PONV and side effects were estimated for 24 hr after delivery by blinded, trained nurse anesthetists. Results: Parturients who received dexamethasone, either 10 mg or 5 mg were different from those who received saline alone in the following parameters: the total incidence of nausea and vomiting, incidence of > 4 vomiting episodes, number the of parturients requiring rescue antiemetics, and the total number of parturients with no vomiting and/or no antiemetic medication (P < 0.05 to P < 0.01 ), The differences between dexamethasone 10 mg and 5 mg were not significant. Dexamethasone 2.5 mg was partially effective. Conclusion: Dexamethasone, 5 mg iv, is suggested as the minimum effective dose in preventing nausea and vomiting associated with epidural morphine for post-Cesarean analgesia.