NCT03587220

A Mechanistic Evaluation of the Nociceptive Desensitizing Properties of Topical Capsaicin

En undersøgelse af Mekanismerne Bag Nociceptiv Desensibilisering forårsaget af Topikal Capsaicin

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 44 (actual)
• Sponsor: Aalborg University · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

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.

Detailed description

In this project the Ultraviolet- B pain model, a model using type B ultraviolet rays to induce a first-degree sunburn, will be used to induce a non-specific inflammation in the skin. This model is well-known to produce both peripheral and central hyperalgesia through sensitization of peripheral and central nociceptors. Capsaicin, the active substance in chili peppers, is currently used to treat peripheral neuropathic pain, and prolonged application of 8% capsaicin patch causes profound desensitization to painful heat stimuli and itch provocations. Therefore, the investigators would like to monitor the development of unspecific UVB-cutaneous inflammation and consequent neurogenic flare in a capsaicin pre-treated area. Moreover the investigators want to test if pre-treating the skin with lidocaine can reduce the pain associated with the capsaicin application without affecting its desensitization action.

Conditions

• Capsaicin
• Ultaviolet B Light Burn
• Neuropathic Pain
• Lidocaine

Interventions

Type	Name	Description
DRUG	Capsaicin Topical	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.
RADIATION	Ultraviolet-B (UVB) irradiation	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).
OTHER	Histamine 1%	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.
DRUG	Lidocaine	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)

Timeline

• Start date: 2018-08-01
• Primary completion: 2019-08-31
• Completion: 2019-12-31
• First posted: 2018-07-16
• Last updated: 2020-04-20

Locations

1 site across 1 country: Denmark