Sufentanil: clinical use as postoperative analgesic--epidural/intrathecal route

Although morphine and fentanyl remain the predominant epidural opioids, sufentanil offers some unique advantages. Because of its greater lipophilicity and mu-receptor binding capacity, sufentanil has a faster onset of action and longer duration than epidural fentanyl. Compared with morphine, sufentanil has been associated with a lower incidence of side effects, particularly delayed respiratory depression. The effective doses and adverse effects profile of epidural sufentanil are relatively well understood. Ventilatory depression is minimal with both bolus and continuous administration. Rapid vascular uptake after large epidural bolus, however, has been associated with acute-onset respiratory depression and even respiratory arrest. Sufentanil is more ideally suited than morphine to continuous epidural administration. The faster onset in comparison with fentanyl may make sufentanil the ideal agent for patient-controlled epidural analgesia. The synergistic effect of combined sufentanil and low-concentration bupivacaine offers advantages over sufentanil alone. High doses of epidural sufentanil have been uniquely associated with cessation of shivering and hypothermia. As with fentanyl, the intrathecal administration of sufentanil for postoperative analgesia is limited by its short duration of action.