Pharmacological Modulation of Peripheral Nerve Excitability

Not Applicable

Completed

• Conditions: Peripheral Neuropathy
• Interventions: Drug: Topical Mepyramine 2%; Other: Topical Placebo; Drug: Topical lidocaine 5%; Drug: Topical Phenytoin 10%

• Registration Number: NCT06312254
• Lead Sponsor: Aalborg University

Brief Summary

The present project is a human experimental study. The aim is to assess the pharmacologically modulated excitability of peripheral sensory nerves with a human experimental model.

The study measures the excitability of peripheral sensory nerves before and after application of different topical drugs (lidocaine (5%), phenytoin (10%),mepyramine (2%) and placebo).

Detailed Description

Design and method Study design The study is a randomized, double-blinded, placebo-controlled study. To minimize the risk of bias and achieve balance in the allocation of participants and application of creams, block randomization is used. To ensure double blinding, 1-2 colleagues from Center for Neuroplasticity and Pain (CNAP), who is not otherwise involved in the project, will keep the randomization list in a secure room.

Study procedure and experimental test The PTT model will be used to measure the excitability of peripheral sensory afferents. PTT will be measured before and after topical drug application at four distinct areas - two at each side of the volar site of the forearms.

In total four topical creams will be used in the study. One cream containing placebo, one with lidocaine (5%), one with phenytoin (10%) and one with mepyramine (2%).

The study consists of one session lasting 3-4 hrs. The study will include 20 healthy volunteers.

Study Timeline

• Study First Submitted: 2024-02-27
• Study First Submitted QC: 2024-03-13
• Study First Posted: 2024-03-15
• Study Start: 2024-04-09
• Primary Completion: 2024-12-02
• Study Completion: 2024-12-11
• Status Verified: 2025-04
• Last Update Submitted: 2025-04-28
• Last Update Posted: 2025-04-30

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Men and Women age > 18 years
• Understand and speak Danish
• No medication besides contraceptives

Exclusion Criteria

• Pregnancy or lactating women
• Drug addiction (use of cannabis, opioids, or other drugs)
• Use of pain killers, alcohol, or nicotine within the last 24 hours before study start
• Any other medical treatment (e.g., antidepressants, anticonvulsants)
• History of peripheral or chronic pain conditions / neuropathy
• Skin diseases
• Scars and/or tattoos at the volar site of the forearm
• Previous traumatic experience of an electrical accident
• Application of moisturizing lotion of the volar site of the forearms (24 hours before study start)
• Participation in any other research projects/studies 7 days before study start
• Known allergy/intolerance to lidocaine/phenytoin/mepyramine
• Lack of ability to cooperate

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Pharmacological modulation with Mepyramine 2%	Topical Mepyramine 2%	Experimental investigation of pharmacological modulation of peripheral nerve excitability, which is measured with the human perception threshold tracking method. With this method neurophysiological mechanisms of sensory afferents can be investigated
Control	Topical Placebo	Experimental investigation of pharmacological modulation of peripheral nerve excitability, which is measured with the human perception threshold tracking method. With this method neurophysiological mechanisms of sensory afferents can be investigated
Pharmacological modulation with lidocaine 5%	Topical lidocaine 5%	Experimental investigation of pharmacological modulation of peripheral nerve excitability, which is measured with the human perception threshold tracking method. With this method neurophysiological mechanisms of sensory afferents can be investigated
Pharmacological modulation with Phenytoin 10%	Topical Phenytoin 10%	Experimental investigation of pharmacological modulation of peripheral nerve excitability, which is measured with the human perception threshold tracking method. With this method neurophysiological mechanisms of sensory afferents can be investigated

Primary Outcome Measures

Name	Time	Method
Change in PTT-value	1 hour after application of cream	Primary outcome measures are changes in the PTT-value (registered as mA) before and after application with topical pharmaceutical drugs.

Trial Locations

Locations (1)

Center for Neuroplasticity and Pain; 🇩🇰 Aalborg, Denmark