Pain Thresholds Under High-dose Topical Capsaicin

Phase 4

Completed

• Conditions: Pain
• Interventions: Drug: Topical High dose Capsaicin; Drug: Topical Placebo

• Registration Number: NCT02570841
• Lead Sponsor: Medical University of Vienna

Brief Summary

Aim of the study is to determine heat pain thresholds (HPT in °C) and cold pain thresholds (CPT in °C) during topical capsaicin 8% application, and mechanical pain thresholds (MPT in g) immediately after to find out the exact skin temperature by which capsaicin initiates the application pain (heat pain threshold, HPT in °C) but also the temperature by which capsaicin does not yet trigger a cold pain (cold pain threshold, CPT in °C). Moreover the investigators want to find out the mechanical pain threshold in g from topical capsaicin and to verify a prolonged effect of capsaicin on the pain thresholds.

Detailed Description

Capsaicin is the main pungent ingredient in chili peppers. Topical capsaicin 8% is used for the treatment of peripheral neuropathic pain. Application of capsaicin 8% provokes distinct pain by activating the transient receptor potential vanilloid 1 (TRPV1) receptor. Cooling the skin results in a reliable prevention of the application pain. However, the necessary cooling temperature and if cooling itself produces application pain, is unknown.

Materials and Methods: 10 female and 10 male healthy volunteers will be enrolled in a randomised, double blind, placebo controlled, cross-over study. The left or right forearm of each subject is going to be treated with a capsaicin 8% patch (QUTENZA, Astellas Pharma, Tokyo, Japan) of 9 cm² or a placebo patch (Demo patch, Astellas Pharma, Tokyo, Japan) of the same size for 60 min. Then the other forearm (which has not been tested before) will be treated with the remaining patch. During capsaicin and placebo exposure HPT in °C and CPT in °C are going to be obtained by the thermode of a thermal sensory analyser, TSA-II (Medoc Ltd., Ramat Yishai, Israel). Temperature increase/decrease of the thermode will be stopped, as soon as the subject presses a switch because of a beginning pain sensation. Immediately after exposure a pin prick test will be performed 5 times in a row by pressing a Mini-Spike (B. Braun Melsungen AG, Melsungen, Germany) slowly against the skin of the application areal to determine the pressure necessary to provoke a sharp pain (Mechanical pain threshold in g). 2 weeks later HPT, CPT, and MPT will be determined again in the areas of capsaicin and placebo exhibition.

Study Timeline

• Study Start: 2015-02
• Primary Completion: 2015-05
• Study Completion: 2015-09
• Study First Submitted: 2015-09-08
• Status Verified: 2015-10
• Study First Submitted QC: 2015-10-05
• Last Update Submitted: 2015-10-05
• Study First Posted: 2015-10-07
• Last Update Posted: 2015-10-07

Recruitment & Eligibility

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

Inclusion Criteria

• healthy volunteers 18 ore more years old

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Exclusion Criteria

• dermatologic or neurologic injuries on both thighs, (possible) pregnancy

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Capsaicin	Topical High dose Capsaicin	Treatment with Topical High dose Capsaicin
Placebo	Topical Placebo	Treatment with Topical Placebo

Primary Outcome Measures

Name	Time	Method
Heat pain threshold (HPT) in degrees Celsius (°C)	60 minutes during topical highdose Capsaicin/Placebo exposure	During capsaicin and placebo exposure HPT in degrees Celsius (°C) is determined by a thermal sensory analyser TSA-II (Medoc Ltd.)

Secondary Outcome Measures

Name	Time	Method
Cold pain threshold (CPT) in degrees Celsius (°C)	60 minutes during topical highdose Capsaicin/Placebo exposure	During capsaicin and placebo exposure CPT in degrees Celsius (°C) is determined by a thermal sensory analyser TSA-II (Medoc Ltd.)
Mechanical pain threshold (MPT) in grams (g)	Immediately after topical highdose Capsaicin/Placebo exposure	After capsaicin and placebo exposure MPT in grams (g) is determined by pressing a Mini-Spike (B. Braun Melsungen AG, Melsungen, Germany) slowly against the skin of the application areal to determine the pressure necessary to provoke a sharp pain
HPT in degrees Celsius (°C)	2 weeks after exposure	HPT in degrees Celsius (°C) will be determined again in the areas of capsaicin and placebo Exhibition
MPT in grams (g)	2 weeks after exposure	MPT in grams (g) will be determined again in the areas of capsaicin and placebo Exhibition
CPT in degrees Celsius (°C)	2 weeks after exposure	CPT in degrees Celsius (°C) will be determined again in the areas of capsaicin and placebo Exhibition

Trial Locations

Locations (1)

Department of Anesthesia, Critical Care and Pain Medicine; 🇦🇹 Vienna, Austria