A Mechanistic Evaluation of the Nociceptive Desensitizing Properties of Topical Capsaicin

NCT03587220 | Completed

• 1 other identifier: N-20180034
• Study Type: interventional
• Target: 44
• Locations: 1 country
• Sites: 1

Brief Summary

The aim of this project is to study the role of transient receptor potential (TRP-) channel V1 (TRPV1+) fibers in the development of cutaneous inflammation induced by epidermal Ultraviolet-B damage. Moreover, in this project the investigators want to evaluate if the capsaicin-desensitization action can still be induced in a skin area pretreated with topical, local anesthetic lidocaine.

Conditions

Capsaicin; Ultaviolet B Light Burn; Neuropathic Pain; Lidocaine

Outcome Measures

Primary Outcomes (5)

• Superficial blood perfusion measured by a Speckle contrast imager (FLPI, Moor Instruments, England).

  Changes from baseline to 7 days after intervention

• Measurement of Warm Detection Thresholds and Heat thresholds by using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device.

  Changes from baseline to 7 days after intervention

• Measurement of Pain to Supra-threshold Heat Stimuli by using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device.

  Changes from baseline to 7 days after intervention

• Measurement of Mechanical Pain Thresholds and Sensitivity using a pin-prick set consisting of 8 needles each having a diameter of 0.6 mm and different force applications: 0.8, 1.6, 3.2, 6.4, 12.8, 25.6, 50.1 and 60.0 g.

  Changes from baseline to 7 days after intervention

• Trans-epidermal Water Loss (TEWL) using a 2x2 cm probe to measure the humidity gradient of the skin.

  Changes from baseline to 7 days after intervention

Secondary Outcomes (2)

• assessment of pain rating by using a visual analog scales (VAS)

  Change from baseline to 24 h

• Itch rating by using a visual analog scales (VAS)

  Changes from baseline to 7 days after intervention

Study Arms (2)

Capsaicin+UVB group

EXPERIMENTAL

All subjects will be treated with capsaicin, placebo + UVB, or Capsaicin+UVB.

Drug: Capsaicin Topical; Radiation: Ultraviolet-B (UVB) irradiation

Capsaicin + EMLA group

EXPERIMENTAL

All subjects will be pre-treated with lidocain cream before capsaicin application

Drug: Capsaicin Topical; Other: Histamine 1%; Drug: Lidocaine

Interventions

Capsaicin Topical DRUG

Capsaicin patches (dosage form: patch 8% Qutenza) will be applied on 4x4 cm squared areas on the volar forearm. The patches will be left in place for 24h and 3 hours after which they will be removed.

Capsaicin + EMLA group; Capsaicin+UVB group

Ultraviolet-B (UVB) irradiation RADIATION

Two circular areas (Ø 2 cm) on the forearm are irradiated with 2 x MED (Minimal Erythema Dose) dose of UVB using a calibrated UVB machine (290-320nm wavelength), Saal Mann Multi Tester (Mann Saal, LT SBC 400 Herford, Germany).

Capsaicin+UVB group

Histamine 1% OTHER

To deliver histamine, standard allergy skin prick test (SPT) lancets are applied. The lancets have a 1 mm shouldered tip adapt to introduce a small amount of test substance extremely locally and approximately at the dermo-epidermal junction.

Capsaicin + EMLA group

Lidocaine DRUG

Cutaneous anaesthesia will be topically induced by using EMLA cream 5%, a local anaesthetic cream consisting of equal parts of lidocaine and prilocaine (1g contains 25 mg of lidocaine and 25 mg of prilocaine)

Capsaicin + EMLA group

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy men and women
• years
• Caucasian descent (only in sub-study 1)
• Speak and understand English

You may not qualify if:

• 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
• Moles or tattoos in the area to be treated or tested.
• Exposure of the irradiated area to UV radiation (e.g., sun) 48 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)
• Known history of anaphylactic shock, or local allergy (contact dermatitis) to lidocaine, prilocaine or other local anaesthetics of the amide type.

Sponsors & Collaborators

• Aalborg University: lead

Study Sites (1)

Silvia Lo Vecchio

Aalborg, North Denmark, 9000, Denmark

Location

MeSH Terms

Conditions

Neuralgia

Interventions

Capsaicin; Radiation; Tumor Protein, Translationally-Controlled 1; Lidocaine

Condition Hierarchy (Ancestors)

Peripheral Nervous System Diseases; Neuromuscular Diseases; Nervous System Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Polyunsaturated Alkamides; Amides; Organic Chemicals; Alkenes; Hydrocarbons, Acyclic; Hydrocarbons; Catechols; Phenols; Benzene Derivatives; Hydrocarbons, Aromatic; Hydrocarbons, Cyclic; Solanaceous Alkaloids; Alkaloids; Heterocyclic Compounds; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Fatty Acids; Lipids; Physical Phenomena; Intracellular Signaling Peptides and Proteins; Peptides; Amino Acids, Peptides, and Proteins; Proteins; Neoplasm Proteins; Acetanilides; Anilides; Aniline Compounds; Amines

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Biologist, PhD

Study Record Dates

• First Submitted: June 21, 2018
• First Posted: July 16, 2018
• Study Start: August 1, 2018
• Primary Completion: August 31, 2019
• Study Completion: December 31, 2019
• Last Updated: April 20, 2020

Record last verified: 2020-04

Locations

DK (1)