Mechanism and Treatment of Sympathetically Maintained Pain
Status:
Terminated
Trial end date:
2016-12-01
Target enrollment:
Participant gender:
Summary
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 algometer fiction 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.
Phase:
N/A
Details
Lead Sponsor:
The Cleveland Clinic
Collaborator:
Murdoch University
Treatments:
Anesthetics Anesthetics, Local Clonidine Oxymetazoline Phenylephrine