Patient Selection and Outcomes Using a LowDose Intrathecal Opioid Trialing Method for Chronic Nonmalignant Pain

Abstract

Background: Various methods exist for trialing patients for intrathecal drug delivery. Currently no standards exist regarding “best practices” for trialing techniques. Objectives: The specific aim of the current study is to report results of patients trialed using a low-dose intrathecal morphine technique in the treatment of chronic noncancer pain. Setting: academic pain medicine practice Study Design: Retrospective Review Method: Visual analog pain scores (VAS) were obtained at the initial visit, after a 6 week opioid-free interval prior to trial, at intrathecal doses of 25, 50, 100, 200 and 400 µg of intrathecal morphine during the trial, at one month post-implant, and current VAS. Additionally, intrathecal opioid doses at implant and current state are reported. Results: VAS scores at the initial visit and after 6 weeks of opioid cessation were identical. There was a significant improvement in VAS after the trial, which was sustained over the course of therapy. Additionally, the use of the protocol described in this article suggests that the doseresponse relationship following opioid cessation is in the 50-400 µg/d range for intrathecal morphine and that tolerance may be reversed during the 6 week opioid-free period. Limitations: Small trialing study Conclusions: Opioid taper and a 6 week opioid-free period may 1) improve long-term analgesia versus a combination of oral/ intrathecal drug delivery system therapy 2) it may be possible to maintain analgesia at microgram doses and 3) opioid tolerance may be reversible in 6 weeks. Further it appears that a dose response relationship for effective analgesia may be less than 400 µg of intrathecal morphine. Key Words: Intrathecal opioids, intrathecal drug delivery, oral opioid therapy, chronic noncancer pain