Trial reportPain2019
The association between endogenous opioid function and morphine responsiveness: a moderating role for endocannabinoids.
Trial report in Pain, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 2 registered trials, which are not on this map. Cited by 10 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Stress and Opioid Misuse Risk: The Role of Endogenous Opioid and Endocannabinoid Mechanisms
Antagonism of Endogenous Opioids: Use in Interpretation of Injections
Who cites it
10 citing papers in PubMed, 1 synthesis or guideline pooled it, 21 citations in OpenAlex.
- Endogenous mu-opioid modulation of social connection in humans: a systematic review and meta-analysis.Translational psychiatry · 2024Pooled it
- Acute Pain After Total Knee Arthroplasty: 2-Arachidonoylglycerol Tone and Endocannabinoid/Eicosanoid Crosstalk.Anesthesia and analgesia · 2026Article
- Prospective evaluation of cerebrospinal fluid concentrations of β-Endorphin as a predictor of opioid use after scheduled cesarean delivery.BMC pregnancy and childbirth · 2025Article
- The Role of Biomarkers in Acute Pain: A Narrative Review.Pain and therapy · 2025Review
- Predicting Extent of Opioid Use Following Cardiac Surgery: A Pilot Study.Journal of cardiothoracic and vascular anesthesia · 2025Observational
- Interactions Between Endocannabinoid and Endogenous Opioid Systems Prospectively Influence Postoperative Opioid Use in Pregnant Patients Undergoing Cesarean Delivery.The journal of pain · 2024Article
- [Cannabinoids reduce opioid use in older patients with pain : Retrospective three-year analysis of data from a general practice].Schmerz (Berlin, Germany) · 2023Article
- A Theoretical Endogenous Opioid Neurobiological Framework for Co-occurring Pain, Trauma, and Non-suicidal Self-injury.Current pain and headache reports · 2022Review
- Toward Composite Pain Biomarkers of Neuropathic Pain-Focus on Peripheral Neuropathic Pain.Frontiers in pain research (Lausanne, Switzerland) · 2022Review
- AAAPT Diagnostic Criteria for Acute Pain Following Breast Surgery.The journal of painArticle
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
12 authors at 4 institutions in 1 country.
Funding
Abstract
We sought to replicate previous findings that low endogenous opioid (EO) function predicts greater morphine analgesia and extended these findings by examining whether circulating endocannabinoids and related lipids moderate EO-related predictive effects. Individuals with chronic low-back pain (n = 46) provided blood samples for endocannabinoid analyses, then underwent separate identical laboratory sessions under 3 drug conditions: saline placebo, intravenous (i.v.) naloxone (opioid antagonist; 12-mg total), and i.v. morphine (0.09-mg/kg total). During each session, participants rated low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects 4 times in sequence after incremental drug dosing. Mean morphine effects (morphine-placebo difference) and opioid blockade effects (naloxone-placebo difference; to index EO function) for each primary outcome (low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects) were derived by averaging across the 4 incremental doses. The association between EO function and morphine-induced back pain relief was significantly moderated by endocannabinoids [2-arachidonoylglycerol (2-AG) and N-arachidonoylethanolamine (AEA)]. Lower EO function predicted greater morphine analgesia only for those with relatively lower endocannabinoids. Endocannabinoids also significantly moderated EO effects on morphine-related changes in visual analog scale-evoked pain intensity (2-AG), drug liking (AEA and 2-AG), and desire to take again (AEA and 2-AG). In the absence of significant interactions, lower EO function predicted significantly greater morphine analgesia (as in past work) and euphoria. Results indicate that EO effects on analgesic and subjective responses to opioid medications are greatest when endocannabinoid levels are low. These findings may help guide development of mechanism-based predictors for personalized pain medicine algorithms.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.