An interventional study of Capsaicin and Diphenhydramine in Itch, sponsored by Aalborg University. Completed at 1 site in Denmark. Open to participants aged 18 Years to 60 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-01-27.
Sponsored by Aalborg University · Not applicable, Interventional, and Basic science
The aim of our 2nd sub-project is to clarify if the capsaicin receptor TRPV1 is implicated in the mechanism of morphine-induced mast cell degranulation. Moreover, we also aim to clarify if the mechanism of opioid-induced itch relay on the histaminergic pathway by using the antihistamine (diphenhydramine) to suppress the release of histamine from peripheral mast cells.
Aalborg University is the lead sponsor of 178 studies on the registry; 37 are open to participants now.
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Drug: Capsaicin · Drug: Diphenhydramine · Drug: Morphine Chloride · Drug: Isotonic saline · Drug: Histamine
A capsaicin patch will be applied on a 3x3 cm squared area on the volar forearm. The patch will be left in place for 24h after which it will be removed.
Diphenhydramin cream 1% (Restamine®) will be applied on a 3x3 cm squared predetermined area on the volar forearm for 24 hours.
Also known as: Antihistamine
Morphine solution (0.1mg/ml, Morphine Hydrochloride) 50 μl will be applied intradermally to the center of a predetermined area on the volar forearm by a 1 ml syringe.
injections of isotonic saline (0.05 ml, 0.9%) as vehicle will be performed.
A small drop of histamine dihydrochloride (1%, in saline) will be applied to a previously determined area on the volar forearm followed by a prick through the drop.
Measuring itch intensity by computerized Visual Analog Scale Scoring
We will ask the subjects to rate the sensation of itch on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates "no itch" and 100 indicates "worst itch imaginable".
Time frame: For 10 minutes
Measuring pain intensity by computerized Visual Analog Scale Scoring
We will ask the subjects to rate the sensation of pain on a 100 mm VAS scale ranging from 0 to 100 where 0 indicates "no pain" and 100 indicates "worst pain imaginable".
Time frame: For 10 minutes
Superficial blood perfusion measurement
Superficial blood perfusion is measured by a Speckle contrast imager
Time frame: After 15 minutes
While size
While size will be assessed using a ruler
Time frame: After 15 minutes
This study is completed, as verified in Jan 2022. You cannot join it, but the record below documents what was studied.
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Aalborg University