Fenobam on Heat/Capsaicin Induced Hyperalgesia in Healthy Volunteers

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.

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