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Completed

NCT Number: NCT04700007

Evaluation of Peripheral Itch Mechanisms Following Injection of Morphine (Second Sub-Project)

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.

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Key information

Conditions

Itch Pathological Conditions, Signs and Symptoms Pruritus Signs and Symptoms Skin Diseases Skin Manifestations Skin and Connective Tissue Diseases

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Mech-Sense, Medicinsk Gastroenterologisk ambulatorium, Medicineshus, Aalborn Universitethospitalet

Aalborg, North Denmark, 9000, Denmark

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

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

Exclusion criteria

  • Participants with any clinically significant abnormalities that in the opinion of the investigator may increase the risk associated with trial participation or may interfere with the interpretation of the trial results.
  • Pregnancy or lactation
  • Drug addiction defined as any use of cannabis, opioids or other addictive drugs
  • Lack of ability to cooperate
  • Current use of medications that may affect the trial such as antihistamines, antipsychotics and pain killers as well as systemic or topical steroids.
  • Participants with known allergy/discomfort to the opioid morphine and antihistamine.
  • Skin diseases
  • Moles, scars or tattoos in the area to be treated or tested.
  • 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)

Treatment and study plan

Capsaicin

Drug

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.

diphenhydramine

Drug

Diphenhydramin cream 1% (Restamine®) will be applied on a 3x3 cm squared predetermined area on the volar forearm for 24 hours.

Other names: Antihistamine

Morphine Chloride

Drug

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.

Isotonic saline

Drug

injections of isotonic saline (0.05 ml, 0.9%) as vehicle will be performed.

Histamine

Drug

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.

Primary outcomes

  1. Measuring itch intensity by computerized Visual Analog Scale Scoring

    Time frame: For 10 minutes

    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".

  2. Measuring pain intensity by computerized Visual Analog Scale Scoring

    Time frame: For 10 minutes

    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".

  3. Superficial blood perfusion measurement

    Time frame: After 15 minutes

    Superficial blood perfusion is measured by a Speckle contrast imager

Secondary outcomes

  1. While size

    Time frame: After 15 minutes

    While size will be assessed using a ruler

Sponsors and collaborators

Lead sponsor

Aalborg University

Other

Registry information

Official study title

Effect of Intradermal Morphine Application on Histaminergic and Non-histaminergic Itch and Related TRPV1 and Antihistamine Treatments (2nd Sub-project)

Important dates

Study start
2021
Primary completion
2021
Study completion
2021
First posted
Jan 7, 2021
Registry last updated
Jan 27, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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