Trial reportPain2013
Endogenous opioid function mediates the association between laboratory-evoked pain sensitivity and morphine analgesic responses.
Trial report in Pain, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to 3 registered trials, which are not on this map. Cited by 26 papers, 2 of them syntheses 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.
Reduced Opioid Analgesic Requirements Via Improved Endogenous Opioid Function
Evaluating Specific and Non-Specific Mechanisms in Two Distinct Complementary/Integrative Interventions for Chronic Pain
Stress and Opioid Misuse Risk: The Role of Endogenous Opioid and Endocannabinoid Mechanisms
Who cites it
26 citing papers in PubMed, 2 syntheses or guidelines pooled it, 40 citations in OpenAlex.
- Pooled it
- Endogenous opioid antagonism in physiological experimental pain models: a systematic review.PloS one · 2015Pooled it
- An Open Trial of Morning Bright Light Treatment Among US Military Veterans with Chronic Low Back Pain: A Pilot Study.Pain medicine (Malden, Mass.) · 2019Trial
- Trial
- Self-reported cumulative medical opioid exposure and subjective responses on first use of opioids predict analgesic and subjective responses to placebo-controlled opioid administration.Regional anesthesia and pain medicine · 2019Trial
- Endogenous Opioid Function and Responses to Morphine: The Moderating Effects of Anger Expressiveness.The journal of pain · 2017Trial
- Trial
- Do Resting Plasma β-Endorphin Levels Predict Responses to Opioid Analgesics?The Clinical journal of pain · 2017Trial
- The Contribution of Differential Opioid Responsiveness to Identification of Opioid Risk in Chronic Pain Patients.The journal of pain · 2015Trial
- Relationship between endogenous opioid function and opioid analgesic adverse effects.Regional anesthesia and pain medicineTrial
- Endogenous opioid inhibition of chronic low-back pain influences degree of back pain relief after morphine administration.Regional anesthesia and pain medicineTrial
- Prospective evaluation of cerebrospinal fluid concentrations of β-Endorphin as a predictor of opioid use after scheduled cesarean delivery.BMC pregnancy and childbirth · 2025Article
- Psychophysics of Pain: A Methodological Introduction.Pain management nursing : official journal of the American Society of Pain Management Nurses · 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
- Endogenous opioid systems alterations in pain and opioid use disorder.Frontiers in systems neuroscience · 2022Review
- Is Resolution of Chronic Pain Associated With Changes in Blood Pressure-related Hypoalgesia?Annals of behavioral medicine : a publication of the Society of Behavioral Medicine · 2018Article
- Ethnic Differences in the Effects of Naloxone on Sustained Evoked Pain: A Preliminary Study.Diversity and equality in health and care · 2017Article
- Expectancy Effects on Conditioned Pain Modulation Are Not Influenced by Naloxone or Morphine.Annals of behavioral medicine : a publication of the Society of Behavioral Medicine · 2016Article
- An Evaluation of Central Sensitization in Patients With Sickle Cell Disease.The journal of pain · 2016Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
9 authors at 3 institutions in 1 country.
Funding
Abstract
Predictors 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.
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.