Double-blind Trial of Mannitol Cream to Block the Effect of Capsaicin Cream

Study Overview
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Brief Summary
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Capsaicin is a TRPV1 (transient receptor potential vanilloid 1) agonist, causing pain upon application. The investigators wish to determine whether mannitol blocks the effect of capsaicin application. As both cream bases are identical and mannitol addition is the only difference between the creams, if the mannitol cream is more effective in blocking the effect of capsaicin on the TRPV1 (transient receptor potential vanilloid 1) receptor, the investigators will have established that mannitol down-regulates or blocks the TRPV1 (transient receptor potential vanilloid 1) receptor.

Detailed Description
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Capsaicin cream, which stimulates the TRPV1 (transient receptor potential vanilloid 1) receptor, causing a burning sensation, will be applied to both halves of the upper lip until a burning sensation with 8/10 intensity on an NRS (Visual Analog Scale) scale is experienced or five minutes have elapsed. Following this, the capsaicin cream will be wiped off and 30% mannitol in vehicle cream ( isopropyl palmitate, caprylic capric triglyceride, propylene glycol, ceteareth 20, cetearyl alcohol, glyceryl stearate, polyethylene glycol 100 stearate, dimethicone, octyldodecanol, lecithin, ethylhexyl glycerin and phenoxy ethanol) will be applied to one half of the upper lip, and vehicle cream alone will be applied to the other half. Cream assignment will be randomized and neither the subject nor the person applying the cream will know which half upper lip has which cream. Every minute for 10 minutes, the heat sensation felt in each half upper lip will be measured, using a visual scale from 0 to 10. A repeated measures analysis of variance will compare the NRS (Visual Analog Scale) scores from the 30% mannitol cream, to the NRS (Visual Analog Scale)scores from the vehicle cream. Significance will be accepted if P less than .05.

Official Title
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Double-blind Trial of Mannitol Cream to Block the Effect of Capsaicin Cream

Conditions
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Pain

Intervention / Treatment
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* Drug: 30% Mannitol in vehicle cream
* Drug: vehicle cream


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 19 and 80 years Exclusion Criteria: Diet containing capsaicin (Cayenne pepper, capsicum) (spicy foods), more than once a week. Meal containing capsaicin (spicy foods) within 5 days prior to the experiment. Any lesion, cracking, cold sore or abrasion on the lips Inability to tolerate capsaicin containing spicy foods Wearing lipstick or lip balm on the upper lip Inability to fill out an NRS pain scale Use of painkilling medication, within 24 hours of the study. Allergy to any of the ingredients of the creams, or to mannitol History of contact or allergic dermatitis Pregnant or nursing women

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Mannitol in vehicle cream<br>Once the capsaicin has been removed, .2 mL of 30% mannitol in vehicle cream will be applied to one half of the upper lip and kept there for 10 minutes. | Drug: 30% Mannitol in vehicle cream<br>* applied to one half of the upper lip following removal of capsaicin cream.<br>* Other names: C6H8(OH)6;|
| Placebo Comparator: Vehicle Cream<br>Once the capsaicin has been removed, .2 mL of vehicle cream will be applied to the other half of the upper lip and kept there for 10 minutes. | Drug: vehicle cream<br>* application to the other half of the upper lip following capsaicin cream removal<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| NRS heat score, once per minute | Every minute after capsaicin cream application, subject will indicate NRS (numerical rating scale)heat score. When the score has reached 8/10 or after five minutes, the cream will be removed. The time needed to reach 8/10 heat score and the heat score achieved, or the score at five minutes will be recorded. Following application of the test creams, NRS (Visual Analog Scale) heat scores will be recorded once per minute for each side for 10 minutes. | 15 minutes per subject | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Side effects of capsaicin cream on upper lip | The subject will be observed for redness, swelling, or other side effects following the capsaicin cream application. These side effects will be recorded | One hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Mannitol, TRPV1 receptor, Pain, Burning pain, neuropathy, neuropathic pain