Try our beta test site

Mechanism and Treatment of Sympathetically Maintained Pain

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified February 2015 by The Cleveland Clinic.
Recruitment status was:  Recruiting
Murdoch University
Information provided by (Responsible Party):
Michael Stanton Hicks, The Cleveland Clinic Identifier:
First received: March 12, 2013
Last updated: February 12, 2015
Last verified: February 2015

40 CRPS patients will be recruited over a three-year period (target of 160 patients at all sites). Assessment of exclusion criteria will be undertaken during initial recruitment. Exclusion criteria are: <18 years; a second chronic pain syndrome that would interfere with pain rating; psychiatric comorbidity; pain in both hands or feet; pregnancy or breastfeeding; sympathectomy in the affected limb; use of topical medication; known sensitivity to alpha 1- adrenoceptor agonists or other contraindications. Patients will maintain their regular oral medications throughout the study period.

Assessment of sympathetically maintained pain (SMP) will require an intradermal dose of Phenylephrine to rekindle SMP and mechanical hyperalgesia. Clonidine will be used to control for affects of lgometer iction and may inhibit SMP by inhibiting the release of more norepinephrine from sympathetic nerve terminals. Skin biopsies will be obtained under sterile conditions from a site of mechanical or thermal hyperalgesia using a 3mm diameter skin biopsy punch under local anesthesia. Samples from a mirror image site on the contralateral body side will also be taken.

Condition Intervention
Complex Regional Pain Syndrome (CRPS)
Drug: phenylephrine and clonidine
Other: punch biopsy

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Supportive Care

Resource links provided by NLM:

Further study details as provided by The Cleveland Clinic:

Primary Outcome Measures:
  • expressed pain in patients with sensitivity following nerve trauma [ Time Frame: Day 1 ]
    Determine whether this neural expression is altered in the skin of a subgroup of patients whose pain is associated with increased adrenergic sensitivity after nerve trauma.

  • expression of pain association with chronic inflammation in patients with sympathetically maintained pain [ Time Frame: Day 1 ]
    Determine whether heightened expression of cutaneous 1-adrenoceptors is associated with signs of chronic inflammation in patients with sympathetically maintained pain

  • decrease in pain after topical adrenoceptor blockade. [ Time Frame: 2 weeks after blockade ]
    To determine whether pain decreases in this subgroup after topical 1-adrenoceptor blockade.

Estimated Enrollment: 75
Study Start Date: August 2012
Estimated Study Completion Date: December 2016
Estimated Primary Completion Date: December 2016 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: phenylephrine and clonidine
Subjects will be injected with phenylephrine and clonidine at affected and unaffected sites.
Drug: phenylephrine and clonidine
Subjects will be injected with phenylephrine and clonidine at both affected and unaffected sites.
Other: punch biopsy
Other Name: After local anesthetic, subjects will receive punch biopsy (1/8"diameter and 1/8" deep) from both affected and unaffected sites.


Ages Eligible for Study:   18 Years to 80 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • CRPS patients

Exclusion Criteria:

  • <18 years
  • a second chronic pain syndrome that would interfere with pain rating
  • psychiatric comorbidity
  • pain in both hands or feet
  • pregnancy or breastfeeding
  • sympathectomy in the affected limb
  • use of topical medication
  • known sensitivity to alpha 1- adrenoceptor agonists or other contraindications
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01813149

Contact: Michael Stanton Hicks, MD 216-445-5995
Contact: Gretchen Upton 216-445-6500

United States, Ohio
Cleveland Clinic Recruiting
Cleveland, Ohio, United States, 44195
Principal Investigator: Michael Stanton Hicks, M.D.         
Sponsors and Collaborators
The Cleveland Clinic
Murdoch University
  More Information

Responsible Party: Michael Stanton Hicks, M.D., The Cleveland Clinic Identifier: NCT01813149     History of Changes
Other Study ID Numbers: 12-400
Study First Received: March 12, 2013
Last Updated: February 12, 2015

Keywords provided by The Cleveland Clinic:
Complex Regional Pain Syndrome (CRPS)

Additional relevant MeSH terms:
Complex Regional Pain Syndromes
Reflex Sympathetic Dystrophy
Autonomic Nervous System Diseases
Nervous System Diseases
Peripheral Nervous System Diseases
Neuromuscular Diseases
Cardiotonic Agents
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Vasoconstrictor Agents
Nasal Decongestants
Respiratory System Agents
Adrenergic alpha-1 Receptor Agonists
Adrenergic alpha-Agonists
Adrenergic Agonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Protective Agents
Sensory System Agents
Antihypertensive Agents
Adrenergic alpha-2 Receptor Agonists processed this record on March 24, 2017