Human Experimental Models of Pain (HEMP)

This pilot study will test an innovative way to establish how pain medicines provide analgesia in healthy adults. The study uses a group of short, controlled pain tests to look at different types of pain responses in the body. The main goal is to find out if this testing approach can show the pain-relieving effects of 2 medicines, pregabalin and naproxen versus placebo, and show how they provide relief of different types of pain.

The study hypothesis is that this pain testing approach administered as a battery would be able to tell the difference between a medicine that works mainly in the brain and spinal cord (pregabalin) and a medicine that works mainly on inflammation in body tissues (naproxen).

Up to 25 healthy adults will take part. Each participant will receive all 3 study treatments, pregabalin, naproxen, and placebo, administered in random order during separate study periods. The order will be assigned by chance. Neither the participant nor the study team will know which treatment is given at each visit.

The study includes several experimental pain tests. These include:

a heat and capsaicin skin test that causes short-term skin sensitivity,

a UVB light test that causes a temporary sunburn-like sensitivity, and

a cold pressor test, in which a hand is placed in very cold water for a short time.

Participants will also have sensory testing to measure how they feel touch, pressure, pinprick, warmth, heat, and cold. Blood samples will be collected to measure study drug levels. Urine samples, vital signs, and other safety checks will also be done.

Each treatment visit includes testing before and for several hours after taking the study drug. There will be a washout period of at least 48 hours between treatments. Total participation may last up to about 10 weeks.

This study is not expected to provide direct medical benefit to participants. The information learned may help researchers improve early testing of future pain treatments....