Clinical trial NCT03943407: Characterization of the Toll-like Receptor 7-agonist Imiquimod 3.75% As a New Surrogate Model of Itch
Official title: Characterization of the Toll-like Receptor 7-agonist Imiquimod 3.75% As a New Surrogate Model of Itch
Study type: INTERVENTIONAL
Overall status: WITHDRAWN
Phase: NA
Conditions: Itch
Keywords: Imiquimod
Doxepin
Trans-cinnamaldehyde (CA)
L-menthol
Histamine
Cowhage
Lead sponsor: Aalborg University
Sponsor class: OTHER
First posted: 2019-05-09
Enrollment: 0
Sex: ALL
Minimum age (years): 18
Maximum age (years): 60
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: BASIC_SCIENCE

Brief summary: The aim of this research project is to design a new model of human itch by application of Zyclara cream. Further, the aim is to characterize the model and to verify if the mechanism of action of imiquimod follows the histaminergic or non-histaminergic pathway by using the anti-histamine drug doxepin. The last goal is to evaluate the interaction between the activation of TLR7 receptor and the activation of TRPA1 and TRPM8 receptors, which are two of the most important receptors involved in the transduction of noxious stimuli, and to evaluate to which extent these three channel populations functionally overlap.


Eligibility criteria: Inclusion Criteria:

* Healthy men and women
* 18-60 years
* Speak and understand English

Exclusion Criteria:

* Pregnancy or lactation
* Drug addiction defined as any use of cannabis, opioids or other drugs
* Previous or current neurologic, musculoskeletal or mental illnesses
* Lack of ability to cooperate
* Current use of medications that may affect the trial
* Skin diseases
* Consumption of alcohol or painkillers 24 hours before the study days and between these
* Acute or chronic pain
* Participation in other trials within 1 week of study entry (4 weeks in the case of pharmaceutical trials)

Primary outcomes:
measure: Superficial blood perfusion by by a Speckle contrast imager (FLPI, Moor Instruments, England).
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Trans-epidermal Water Loss (TEWL)
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Neurogenic Inflammatory Response and Pigmentation
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Measuring Alloknesis
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Thermal measurements (cold and warm detection thresholds, cold and heat pain thresholds)
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Measurement of Pain to Supra-threshold Heat Stimuli
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Measurement of Mechanical Detection Thresholds, Mechanical Pain Threshold and sensitivity
timeFrame: Change from baseline, to maximum 19 days after intervention
Secondary outcomes:
measure: Measurement of Itch rating by Computerized Visual Analog Scale Scoring
timeFrame: Change from baseline, to maximum 19 days after intervention
measure: Measurement of pain rating by Computerized Visual Analog Scale Scoring
timeFrame: Change from baseline, to maximum 19 days after intervention
Other outcomes:
Locations:
city: Aalborg
country: Denmark
facility: Aalborg University
state: Nordjylland
Study officials:
References: