Allodynia, Hyperalgesia
Conditions
Keywords
fenobam, heat, capsaicin, hyperalgesia, allodynia, mood, cognitive function
Brief summary
Our goal is to demonstrate that healthy volunteers treated with fenobam will develop a significantly reduced area of cutaneous hyperalgesia compared to volunteers treated with placebo, after exposure to the heat/capsaicin model of cutaneous sensitization. Additionally we are going to assess changes in mood/affect and cognitive function of subjects following administration of fenobam and after cutaneous sensitization compared to baseline.
Detailed description
All subjects will receive a topical dose of capsaicin cream 0.1%(Capzasin-HP) to the forearm at the start of the study visit. The order of the 2 treatment regimens indicated below will be randomized and blinded to subjects and researchers. Treatment Regimen 1: Fenobam \[1-(3-chlorophenyl)-3-(1-methyl-4-oxo-2-imidazolidinylidine) urea hydrate\]: administration of one 150 mg gelatin capsule. Treatment Regimen 2: Placebo (lactose monohydrate): administration of one 150 mg gelatin capsule.
Interventions
DRUGFenobam
Fenobam 150 mg will be administered and subjects will be monitored for up to 8 hours. During the study day questionnaires will be administered, blood will be drawn a testing site will be marked and pain testing and heat/capsaicin sensitization will be measured.
DRUGPlacebo
A placebo will be administered and subjects will be monitored for up to 8 hours. During the study day questionnaires will be administered, blood will be drawn a testing site will be marked and pain testing and heat/capsaicin sensitization will be measured.
Sponsors
Laura Cavallone
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
1. 18-50 year old 2. Good general health with no remarkable medical conditions (e.g. liver, kidney, heart, or lung failure) 3. BMI between 20-33 4. Willing to comply with study guidelines as outlined in protocol \[including: women of childbearing age must be willing to use a double-barrier method (e.g. oral contraception and condom) for contraception during participation in the study\] 5. Willing to provide informed consent
Exclusion criteria
1. Anatomical malformation of upper extremities 2. Status post recent trauma or chronic lesions on either forearm 3. Medication use (includes vitamin, herbal, dietary and mineral supplements and grapefruit products during or within 14 days prior to study participation; excludes contraceptives) 4. History of allergy or intolerance to capsaicin 5. History of multiple drug allergies 6. History of addiction to drugs or alcohol (prior or present addiction or treatment for addiction) 7. History of chronic pain syndromes 8. Pregnant and nursing females 9. Smokers
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Suppression of the development of cutaneous hyperalgesia and allodynia around the area treated with heat/capsaicin. | During approximately 7 hours of consecutive assessments | size of the area of hyperalgesia and allodynia around the area sensitized by heat/capsaicin as quantified by cutaneous stimulation with foam brush strokes and a von Frey filament requiring 26 g of bending force. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Absence of significant side effects | 7 days | Determined by subjects' monitoring during treatment sessions and follow up at 1 day and 1 week after treatment with drug. |
| Assessment of Heat Pain Detection Thresholds (HPDT) in normal and sensitized skin pre and post treatment with fenobam. | During approximately 7 hours of consecutive assessments | lowest temperature perceived as painful with stimulation starting at 32°C and with a safety cut-off at 52°C. |
| Evaluation of nociception after drug administration as evaluated by prolonged (1 min) thermal stimulation on normal (untreated) skin. | During approximately 7 hours of consecutive assessments | Visual Analog Scale (VAS) rating of pain perception at 1 min 45°C heat stimulation on normal skin. |
| Assessment of significant change in mood/affect | During approximately 6 hours of consecutive assessments | As determined by evaluation of the subjects by combined brief Positive And Negative Affect Scale/Brief State Anxiety Measure (PANAS/BSAM) |
| Assessment of significant change in cognitive function | During approximately 6 hours of consecutive assessments | As determined by evaluation of the Letter and Number Sequencing (LNS) assessment |
Countries
United States
Outcome results
None listed