Epidural morphine for postoperative analgesia: a double-blind study.

Postoperative analgesia and the side effects of epidurally injected morphine were investigated in a double-blind study. Following lumbar epidural anesthesia for orthopedic operations, 174 patients received, in a randomized, double-blind fashion, either 0.1 mg/kg of morphine epidurally, 0.1 mg/kg of morphine intramuscularly, or saline epidurally at the end of surgery. Following epidural morphine, postoperative pain was les frequent, less intense and of shorter duration, use of analgesics and sedative was less frequent; and the postoperative feeling of well-being rated better than after systemic morphine or epidural saline. These effects were more frequent when bupivacaine was used for operative epidural anesthesia than when mepivacaine was used. The results were age independent. Side effects following epidural morphine included pruritus and disturbances of micturition. Nausea, vomiting, fatigue, and headache were of comparable frequency in the three groups.