Morphine-induced ventilatory failure after spinal cord compression.

We describe a patient who required large doses of parenteral morphine for severe pain secondary to epidural spinal cord compression caused by metastatic cancer. The pain improved suddenly after neurological progression to a complete cord compression. Shortly afterwards, the patient developed acute respiratory depression caused by an apparent relative overdose of morphine. Our hypothesis is that the cord compression relieved the pain by interrupting the nociceptive pathway. The dose of morphine was then physiologically excessive once the neurologic damage was completed and the pain had been relieved. We advise caution in patients receiving high doses of opioids in which a change in disease status or a pain-relieving intervention may produce rapid pain relief.