Randomized Controlled Trial Multicenter Study
Endogenous opioid function mediates the association between laboratory-evoked pain sensitivity and morphine analgesic responses.
- Stephen Bruehl, John W Burns, Rajnish Gupta, Asokumar Buvanendran, Melissa Chont, Ellen Kinner, Erik Schuster, Steven Passik, and Christopher R France.
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37212, USA. Stephen.Bruehl@vanderbilt.edu
- Pain. 2013 Sep 1;154(9):1856-64.
AbstractPredictors of responsiveness to opioid analgesic medications are not well understood. This study tested whether individual differences in endogenous opioid (EO) function are associated with analgesic responsiveness to morphine. In randomized, counterbalanced order over 3 sessions, 45 chronic low back pain participants and 31 healthy controls received an opioid antagonist (8 mg naloxone), morphine (0.08 mg/kg), or placebo. Participants then engaged in 2 laboratory-evoked pain tasks (ischemic and thermal). Outcomes included pain threshold, pain tolerance, and pain ratings. Indexes of EO function and morphine analgesic responsiveness were derived for each measure as the difference in pain responses between the placebo condition and naloxone or morphine condition, respectively. For all 7 pain measures across the 2 laboratory pain tasks, greater EO function was associated with significantly lower morphine analgesic responsiveness (P<0.001-P=0.02). Morphine reduced pain responses of low EO individuals to levels similar to those of high EO individuals receiving placebo. Higher placebo condition-evoked pain sensitivity was associated with significantly greater morphine analgesic responsiveness for 5 of 7 pain measures (P<0.001-P=0.02). These latter associations were significantly mediated by EO function for 4 of these 5 pain outcomes (all P values<0.05). In the laboratory-evoked pain context, opioid analgesic medications may supplement inadequate EO analgesia, with little incremental benefit in those with preexisting high EO function. Implications for personalized medicine are discussed.Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.
Knowledge, pearl, summary or comment to share?
You can also include formatting, links, images and footnotes in your notes
- Simple formatting can be added to notes, such as
- Superscript can be denoted by
- Numbered or bulleted lists can be created using either numbered lines
1. 2. 3., hyphens
- Links can be included with:
[my link to pubmed](http://pubmed.com)
- Images can be included with:
![alt text](https://bestmedicaljournal.com/study_graph.jpg "Image Title Text")
- For footnotes use
[^1](This is a footnote.)inline.
- Or use an inline reference
[^1]to refer to a longer footnote elseweher in the document
[^1]: This is a long footnote..