Inhibition of Non-histaminergic Pruritus Applied Using 3 Different Pruritogens

Evaluation of the Effect of Repeated Administration of Topical Local Anaesthetic Mixture of Lidocaine and Prilocaine (EMLA) in a Model of Non-histaminergic Itch Induced by Cowhage.

With this experiment, we want to use to investigate whether repeated application of EMLA cream as a tool to modulate non-histaminergic itching, which is produced using small needles from the plant mucuna pruriens (it is known that antihistamine does not attenuate this form of itch) and we want to compare the effect of short (1 hour) and prolonged (3 hours) application of EMLA. The sub-project takes place in 3 sessions over a period of 3 consecutive days (24 hours apart). All sessions will be identical.

Study Overview

• Status: Completed
• Conditions: Itch
• Intervention / Treatment: Drug: Emla 1 hour; Drug: EMLA 3 hours; Other: Vehicle cream for 1 hour; Other: Vehicle cream for 3 hours; Other: Cowhage

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Denmark
  • Aalborg, Denmark, 9220
    • Aalborg University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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 that may affect the results (e.g. neuropathy, muscular pain in the upper extremities, etc.).
• Lack of ability to cooperate
• Current use of medications that may affect the trial such as antihistamine medications or pain killers.
• Skin diseases
• Hypersensitivity to papaya and mango fruit, cashew nuts and rubber latex
• 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)
• Known history of anaphylactic shock, or local allergy (contact dermatitis) to lidocaine, prilocaine or other local anaesthetics of the amide type.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Study group

Drug: Emla 1 hour; At the start of each session, the middle forearms of the subject will each be divided into two squared areas (4x4 cm). On each arm, the two areas will be located 4 cm apart. Then one area will be pre-treated with cutaneous 2.5% lidocaine/2.5% prilocaine cream (EMLA cream) for 1 hour.; Drug: EMLA 3 hours; At the start of each session, the middle forearms of the subject will each be divided into two squared areas (4x4 cm). On each arm, the two areas will be located 4 cm apart. Then one area will be pre-treated with cutaneous 2.5% lidocaine/2.5% prilocaine cream (EMLA cream) for 3 hours.; Other: Vehicle cream for 1 hour; At the start of each session, the middle forearms of the subject will each be divided into two squared areas (4x4 cm). On each arm, the two areas will be located 4 cm apart. Then two area will be pre-treated with a vehicle cream for 1 h.; Other: Vehicle cream for 3 hours; At the start of each session, the middle forearms of the subject will each be divided into two squared areas (4x4 cm). On each arm, the two areas will be located 4 cm apart. Then two area will be pre-treated with a vehicle cream for 3 h.; Other: Cowhage; Cowhage spicules are 1-2 mm in length and have a diameter of 1-3 μm. The spicules are inserted by gently rubbing 30-35 spicules into a 1 cm diameter skin area.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	For 9 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".	For 9 minutes
Superficial blood perfusion measurement	Superficial blood perfusion is measured by a Speckle contrast imager	After 1 hour
Superficial blood perfusion measurement	Superficial blood perfusion is measured by a Speckle contrast imager	After 3 hours
Superficial blood perfusion measurement	Superficial blood perfusion is measured by a Speckle contrast imager	10 min after cowhage application
Measuring Alloknesis	Alloknesis sensation is measured using a standardized sensory brush exerting a force of 200 to 400 mN.	After 1 hour
Measuring Alloknesis	Alloknesis sensation is measured using a standardized sensory brush exerting a force of 200 to 400 mN.	After 3 hours
Measuring Alloknesis	Alloknesis sensation is measured using a standardized sensory brush exerting a force of 200 to 400 mN.	10 min after cowhage application
Measuring Hyperknesis	Hyperknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force).	After 1 hour
Measuring Hyperknesis	Hyperknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force).	After 3 hours
Measuring Hyperknesis	Hyperknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force).	10 min after cowhage application

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Measuring Erythema	The onset of erythema is measured with a spectrometer (ColorMeter, DSM II; Cortex Technology, Hadsund, Denmark).	After 1 hour
Measuring Erythema	The onset of erythema is measured with a spectrometer (ColorMeter, DSM II; Cortex Technology, Hadsund, Denmark).	After 3 hours
Measuring Erythema	The onset of erythema is measured with a spectrometer (ColorMeter, DSM II; Cortex Technology, Hadsund, Denmark).	10 min after cowhage application
Measuring Skin Pigmentation	The onset of skin pigmentation is measured with a spectrometer (ColorMeter, DSM II; Cortex Technology, Hadsund, Denmark).	After 1 hour
Measuring Skin Pigmentation	The onset of skin pigmentation is measured with a spectrometer (ColorMeter, DSM II; Cortex Technology, Hadsund, Denmark).	After 3 hours
Measuring Skin Pigmentation	The onset of skin pigmentation is measured with a spectrometer (ColorMeter, DSM II; Cortex Technology, Hadsund, Denmark).	10 min after cowhage application

Collaborators and Investigators

• Sponsor: Aalborg University
• Investigators: Principal Investigator: Silvia lo Vecchio, Aalborg University

Study record dates

Study Major Dates

• Study Start (Actual): November 15, 2021
• Primary Completion (Actual): August 1, 2022
• Study Completion (Actual): October 1, 2022

Study Registration Dates

• First Submitted: April 21, 2021
• First Submitted That Met QC Criteria: April 21, 2021
• First Posted (Actual): April 26, 2021

Study Record Updates

• Last Update Posted (Actual): January 18, 2023
• Last Update Submitted That Met QC Criteria: January 16, 2023
• Last Verified: January 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Anesthetics, Combined; Lidocaine, Prilocaine Drug Combination
• Other Study ID Numbers: N-20200073 1st sub-project

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No