Analgesic efficacy and adverse effects of epidural morphine compared to parenteral opioids after elective caesarean section: A systematic review

Abstract Background: The optimal effective dose of epidural morphine that provides postoperative analgesia after caesarean section with minimal side effects remains debated. Aims: We performed a systematic review to assess the analgesic efficacy and the incidence of adverse effects of epidural morphine after caesarean section compared to systemic analgesia with opioids. Methods: We searched Medline, Embase and Cochrane Collaboration Library databases. Studies were evaluated with the Modified Oxford Scale. Prospective randomized studies comparing analgesic efficacy and/or adverse effects of a single epidural morphine administration versus systemic opioids after elective caesarean section were included. Results: Ten studies ( n = 431) were selected. Epidural morphine increases the time until the first request for a rescue analgesic ( E max, 29.7 h; 95% confidence interval, 25.2–33.9) and decreases pain scores and postoperative morphine request during the first 24 h compared to systemic opioid analgesia. However, epidural morphine increases the incidence of pruritus (relative risk, 2.7; 95% CI, 2.1–3.6) and nausea (relative risk, 2.0; 95% CI, 1.2–3.3). Conclusions: A single bolus of epidural morphine provides better analgesia than parenteral opioids but with an effect limited to the first postoperative day after caesarean section and with an increase in morphine side effects.