Role of the Endogenous Opioid System Underlying Modulation of Experimental Pain
NCT ID: NCT01327326
Last Updated: 2012-07-13
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
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WITHDRAWN
NA
INTERVENTIONAL
2011-12-31
2012-07-31
Brief Summary
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Detailed Description
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DNIC evaluates an individual's capacity to engage endogenous pain inhibition. The paradigm is a spatial inhibition model based on the principle that "pain-inhibits-pain" in which pain in a local area is inhibited by a second pain that can be anywhere else in the body. DNIC is traditionally studied by observing a reduction of pain produced by a focal pain stimulus (contact heat) as a result of a second painful stimulus. Research from our lab and others suggests that pain inhibition is reduced in a number of chronic pain conditions. The investigators preliminary data suggests that pain inhibition during DNIC is modulated in part by endogenous opioids; however, results from other DNIC studies have been mixed. In addition, it is possible that reductions in the ability to engage endogenous inhibitory systems in chronic pain patients are due to a weakening of the endogenous opioid system. While pharmacological studies have been conducted with healthy cohorts, only one study has examined the opioid involvement in chronic pain patients.
Offset analgesia is thought to reflect a form of temporal pain inhibition which is usually defined by three stimulus temperature phases: a baseline phase followed by a manipulation phase in which the temperature is briefly increased and returns to the baseline temperature during an "offset" phase. A reduction in pain ratings is observed approximately 15s after the temperature drop (third phase), which is \~50% lower than ratings at the same time point for "constant" trials that continued 48°C for 40s. No studies have examined offset analgesia in a chronic pain cohort or its sensitivity of opioid blockade.
Conditions
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Keywords
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Study Design
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RANDOMIZED
CROSSOVER
BASIC_SCIENCE
TRIPLE
Study Groups
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TMD patients
Intervention:
* Drug: Naltrexone
* Drug: placebo
Naltrexone
Oral, 50 mg, 1 Time Dose
Placebo
Oral, 1 Time Dose
Healthy controls
Intervention:
* Drug: Naltrexone
* Drug: placebo
Naltrexone
Oral, 50 mg, 1 Time Dose
Placebo
Oral, 1 Time Dose
Interventions
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Naltrexone
Oral, 50 mg, 1 Time Dose
Placebo
Oral, 1 Time Dose
Other Intervention Names
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Eligibility Criteria
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Inclusion Criteria
* Controls: pain-free based on Research Diagnostic Criteria (RDC) exam
* TMD: chronic musculoskeletal pain (face) based on Research Diagnostic Criteria (RDC) exam
Exclusion Criteria
* Inability to reliably rate pain intensity;
* Uncontrolled hypertension (or receiving treatment for hypertension with BP of greater than 140/95);
* Serious systemic (e.g. Diabetes, thyroid problems, etc.);
* Serious cardiovascular/pulmonary disease;
* Neurological problems with significant changes in somatosensory and pain perception at the intended stimulation sites (hand, foot);
* Serious psychiatric problems requiring treatment (schizophrenia, bipolar disorder);
* Other chronic pain conditions (e.g., low back pain, fibromyalgia);
* Any other ongoing acute pain problem (arthritis, injury-related pain); or,
* Irregular menstrual cycles (\>40 days) or menstrual cycle disorders (e.g. PMS, dysmenorrhea).
18 Years
50 Years
ALL
Yes
Sponsors
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American Pain Society
OTHER
University of Florida
OTHER
Responsible Party
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Principal Investigators
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Christopher D King, PhD
Role: PRINCIPAL_INVESTIGATOR
University of Florida
Countries
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Other Identifiers
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APS2011
Identifier Type: -
Identifier Source: org_study_id