Which Epidural Opioid is More Suitable for Postoperative Pain Management?

Abstract

Opioids have always been considered the best option in clinical practice for the treatment of severe postoperative pain. However, the spinal administration of an opioid drug does not always guarantee selective action and segmental analgesia in the spine. This fact is due to partial reuptake to blood systemic circulation reaching brain receptors. Recent evidence from clinical studies indicates that bioavailability in the spinal cord biophase is negatively correlated with liposolubility, which is higher for hydrophilic opioids, than for lipophilic ones. Actually, clinical guidelines recommend using a mixture of local anesthetic plus a strong opioid to improve the global analgesic effect, minimize adverse effects and improve the overall patient´s satisfaction. Moreover, an opioid alone like morphine can be administered to provide a long period of postoperative analgesia for 24h, or even 48 h when an extended release epidural formulation is used. In this narrative review, practical information for correct spinal opioid selection is provided to help the physicians a better choice for postoperative epidural analgesia.