Article

Prescription opioid analgesics rapidly change the human brain

Department of Anesthesia, School of Medicine, Stanford University, Palo Alto, CA 94304-1573, USA.
Pain (Impact Factor: 5.84). 04/2011; 152(8):1803-10. DOI: 10.1016/j.pain.2011.03.028
Source: PubMed

ABSTRACT Chronic opioid exposure is known to produce neuroplastic changes in animals; however, it is not known if opioids used over short periods of time and at analgesic dosages can similarly change brain structure in humans. In this longitudinal, magnetic resonance imaging study, 10 individuals with chronic low back pain were administered oral morphine daily for 1 month. High-resolution anatomical images of the brain were acquired immediately before and after the morphine administration period. Regional changes in gray matter volume were assessed on the whole brain using tensor-based morphometry, and those significant regional changes were then independently tested for correlation with morphine dosage. Thirteen regions evidenced significant volumetric change, and degree of change in several of the regions was correlated with morphine dosage. Dosage-correlated volumetric decrease was observed primarily in the right amygdala. Dosage-correlated volumetric increase was seen in the right hypothalamus, left inferior frontal gyrus, right ventral posterior cingulate, and right caudal pons. Follow-up scans that were conducted an average of 4.7 months after cessation of opioids demonstrated many of the morphine-induced changes to be persistent. In a separate study, 9 individuals consuming blinded placebo capsules for 6 weeks evidenced no significant morphologic changes over time. The results add to a growing body of literature showing that opioid exposure causes structural and functional changes in reward- and affect-processing circuitry. Morphologic changes occur rapidly in humans during new exposure to prescription opioid analgesics. Further research is needed to determine the clinical impact of those opioid-induced gray matter changes.

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Available from: Jarred Younger, Jul 27, 2015
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    • "However, given that only 2 TMD subjects reported migraine as an additional complaint, we are confident that our results reflect underlying changes associated with TMD and not migraine. In addition, it is known that opioid use can rapidly change brain anatomy, in particular in the reward circuitry (Younger et al., 2011). Although only 4 of the TMD subjects in this investigation were taking opioids, most were on some form of medications and it is possible that these could have altered brain anatomy. "
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    • "However, it remains unclear whether these findings from neuroimaging (PET or MRI) studies relate to chronic pain or to effects from long-term medication use (including opioids). The issue was partly addressed in a recent longitudinal MR study (Younger et al., 2011). Individuals with chronic low back pain were administered oral morphine daily for 1 month, and compared to those who used placebo. "
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    Neuropharmacology 07/2013; 84(100). DOI:10.1016/j.neuropharm.2013.06.035
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    • "Ce phénomène d'hyperalgésie peut être induit que les morphiniques soient administrés avant l'inflammation chirurgicale (douleur chronique préopératoire) ou après (douleur aiguë postopératoire) [18]. Les études d'imageries fonctionnelles montrent que les changements induits par l'introduction des morphiniques surviennent dans le premier mois du traitement [19]. En conséquence, tout patient sous opioïdes doit être considéré comme à risque de douleur accrue par ce phénomène d'hyperalgésie et, également, à risque de syndrome de sevrage [20]. "
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