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 dose-response 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.