Evaluation of the Effect Induced by Repeated Administration of Topical Local Anaesthetic (EMLA) on Itch

Lidocaine Clinical Trial

Official title:

A Mechanistic Evaluation of the Nociceptive Desensitization Induced by Repeated Administration of Topical Local Anaesthetic Mixture of Lidocaine and Prilocaine (EMLA) in a Model of Histaminergic and Non-histaminergic Itch.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04076865
• Other study ID #: N-20190043
• Status: Completed
• Phase: N/A
• Start date: October 15, 2019
• Est. completion date: January 1, 2021

Study information

• Verified date: January 2021
• Source: Aalborg University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

In this experiment, the investigators would like to study if the repeated application of local cuaneous anaesthetic EMLA cream will reduce itch induced by small needles from the plant mucuna pruriens (also known as cowhage) and histamine (an itch proving substance formed in the body).

Recruitment information / eligibility

• Status: Completed
• Enrollment: 26
• Est. completion date: January 1, 2021
• Est. primary completion date: October 1, 2020
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 60 Years

Eligibility

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)
• Known history of anaphylactic shock, or local allergy (contact dermatitis) to lidocaine, prilocaine or other local anaesthetics of the amide type.

Related Conditions & MeSH terms

• Itch
• Lidocaine

Intervention

Drug:
• EMLA (lidocaine) +Itch (Histamine and cowhage)
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, AstraZeneca A/S, Albertslund, Denmark). Histamine: To deliver histamine, standard allergy skin prick test (SPT) lancets are applied. Cowhage: Cowhage spicules are 1-2 mm in length and have diameter of 1-3 um at their tip, once inserted into the epidermis, the spicules evoke a moderate sensation of itch and to a lesser extent sensations of burning and stinging pain.

Locations

Country	Name	City	State
Denmark	Aalborg University	Aalborg	Nordjylland

Sponsors (1)

Lead Sponsor	Collaborator
Aalborg University

Country where clinical trial is conducted

Denmark, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Superficial blood perfusion	is measured by a Speckle contrast imager (FLPI, Moor Instruments, England).	Change from baseline, up to three days after the first session
Primary	Warm Detection Thresholds and Heat Pain Thresholds	The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device	Change from baseline, up to three days after the first session
Primary	Pain to Supra-threshold Heat Stimuli	The tests for thermal sensation will all be performed using a PATHWAY ATS (Medoc Ltd, Israel) thermal sensory testing device	Change from baseline, up to three days after the first session
Primary	Alloknesis	Alloknesis is measured by using mildly pruritic, non-painful von Frey nylon filaments of a predetermined intensity (generally 5-30 miliNewton of force).	Change from baseline, up to three days after the first session
Primary	Mechanical Pain Thresholds and Sensitivity	This test is performed using a pin-prick set (Aalborg University, Aalborg). The set consists 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	Change from baseline, up to three days after the first session
Primary	Pain rating	The subject will rate the pain for 9 min by using a a visual analog scale (VAS) on a tablet. This scale goes from 0 to 100. 0 indicates 'no pain' and 100 indicates 'worst imaginable pain'.	only on day 3 (third session)
Secondary	Itch rating	The subject will rate the itch for 9 min by using a a visual analog scale (VAS) on a tablet. This scale goes from 0 to 100. 0 indicates 'no itch' and 100 indicated 'worst imaginable itch'.	only on day 3 (third session)