Intermittent epidural morphine instillation for control of postoperative pain

Opiates such as morphine have a direct spinal effect, acting at special receptor sites in the dorsal horn. When morphine is administered epidurally, it diffuses to the cord substance, producing analgesia of improved quality after a dose of 2 to 4 mg. A protracted analgesia is produced, compared with parenteral narcotics, with a median duration of effect of 12 hours in this series. Significant side effects are uncommon, but pronounced respiratory depression can occur late and careful observation is necessary. The first instance of paraplegia in association with epidural morphine anesthesia has been reported herein.