Role of the Endogenous Opioid System Underlying Modulation of Experimental Pain

This study has been withdrawn prior to enrollment.
Sponsor:
Collaborator:
American Pain Society
Information provided by (Responsible Party):
University of Florida
ClinicalTrials.gov Identifier:
NCT01327326
First received: March 24, 2011
Last updated: July 11, 2012
Last verified: July 2012
  Purpose

The aim of this proposal is to characterize pain inhibition in healthy controls and Temporomandibular Disorder (TMD) patients with two models of endogenous pain modulation (off-set analgesia; conditioned pain modulation), and to investigate the function of the endogenous opioid system in these responses by using pharmacological blockade of the opioid receptor.


Condition Intervention
Temporomandibular Disorder
Facial Pain
Drug: Naltrexone
Drug: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Opioid Modulation of Two Models of Pain Inhibition in Healthy Controls and Patients With Temporomandibular Disorder (TMD)

Resource links provided by NLM:


Further study details as provided by University of Florida:

Primary Outcome Measures:
  • Post-drug efficacy of pain inhibition [ Time Frame: 1 hour after study medication (day 1) ] [ Designated as safety issue: No ]
    A change in the ability to reduce experimental pain sensitivity during two models of pain inhibition will be evaluated before and after medication.


Enrollment: 0
Study Start Date: December 2011
Study Completion Date: July 2012
Primary Completion Date: July 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: TMD patients

Intervention:

  • Drug: Naltrexone
  • Drug: placebo
Drug: Naltrexone
Oral, 50 mg, 1 Time Dose
Other Name: Revia
Drug: Placebo
Oral, 1 Time Dose
Other Name: Placebo/sugar pill
Active Comparator: Healthy controls

Intervention:

  • Drug: Naltrexone
  • Drug: placebo
Drug: Naltrexone
Oral, 50 mg, 1 Time Dose
Other Name: Revia
Drug: Placebo
Oral, 1 Time Dose
Other Name: Placebo/sugar pill

Detailed Description:

Dysfunction in endogenous pain inhibitory systems has been proposed as a factor in the development and maintenance clinical pain disorders particularly in Temporomandibular Disorder (TMD). Dysfunction has been observed with a model known as diffuse noxious inhibitory controls (DNIC), but other models that engage inhibitory systems (offset analgesia) have not been fully evaluated in chronic pain patients.

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.

  Eligibility

Ages Eligible for Study:   18 Years to 50 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • ages 18-50 years old
  • 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 adequately communicate and understand informed consent form;
  • 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).
  Contacts and Locations
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Please refer to this study by its ClinicalTrials.gov identifier: NCT01327326

Sponsors and Collaborators
University of Florida
American Pain Society
Investigators
Principal Investigator: Christopher D King, PhD University of Florida
  More Information

No publications provided

Responsible Party: University of Florida
ClinicalTrials.gov Identifier: NCT01327326     History of Changes
Other Study ID Numbers: APS2011
Study First Received: March 24, 2011
Last Updated: July 11, 2012
Health Authority: United States: Institutional Review Board

Keywords provided by University of Florida:
Pain modulation
Experimental pain
Pain Modulation

Additional relevant MeSH terms:
Facial Pain
Temporomandibular Joint Disorders
Temporomandibular Joint Dysfunction Syndrome
Pain
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Craniomandibular Disorders
Mandibular Diseases
Jaw Diseases
Musculoskeletal Diseases
Joint Diseases
Muscular Diseases
Stomatognathic Diseases
Myofascial Pain Syndromes
Naltrexone
Analgesics, Opioid
Narcotic Antagonists
Physiological Effects of Drugs
Pharmacologic Actions
Sensory System Agents
Peripheral Nervous System Agents
Central Nervous System Agents
Therapeutic Uses
Analgesics
Central Nervous System Depressants

ClinicalTrials.gov processed this record on July 24, 2014