Comparison of analgesic efficacy of intrathecal morphine with other opioids in cancer pain management

Abstract

Purpose: We reviewed our experience to see if the widely accepted ratio of oral to intrathecal morphine was appropriate. Methods: Eight patients who underwent intrathecal analgesia between 2009 and 2019 were retrospectively reviewed. The opioid dose before the start of intrathecal analgesia was converted to oral morphine. Results: Intrathecal analgesia was performed with morphine and bupivacaine. The ratio of oral:intrathecal was 10:1, 35:1, 44.6:1, 50:1, 62.5:1, 114.6:1, 125:1, 125:1. It took 2 to 14 days for the intrathecal morphine dose to stabilize. There were no cases that the morphine must reduce after stabilization, and there were cases that the morphine dose needed to be increased further. Conclusion: The ratio of oral to intrathecal morphine has been reported to be 200:1 or 300:1, however, this may not provide sufficient analgesia. Each patient needs to be adjusted individually.