Placebo In Chronic Back Pain (Phase 2)

Visit 1 (week -3): Screening visit (90 min): Participants will be evaluated with inclusion/exclusion criteria and complete the informed consent documents. A medical/pain history will be taken and physical exam will be completed by a physician and participants will be asked to rate their current back pain intensity. Participants will complete a set of 10 questionnaires that will ask about health and medical history, past and current pain levels, personality, and emotions. Participants will be allowed to take breaks and walk around during this time so that participants don't get tired while filling out questionnaires. Finally, participants will have blood drawn for screening purposes including to see if kidneys and liver are functioning as they should (the investigators will take 40 mL or about 8 teaspoons). Participants will be asked to return in 2 weeks for baseline magnetic resonance imaging (MRI) scans. Participants will be asked to discontinue current pain medications 14 days prior to Visit 2 and take only the rescue medication ("rescue" medication that is also known as acetaminophen/Tylenol ®), given for pain during this time (see below) - this is so that the investigators can assess baseline amount of pain. Participants will be informed that they may be randomized in the placebo group and/or the no-treatment group (Visit 3) once one qualifies to continue in the study. Participants must, therefore,a be willing and able to stop taking the medication for pain for up to a maximum of 12 weeks during this study. Participants will be given acetaminophen (500 mg, up to 4 times per day) to take for pain relief (as rescue medication), a dose that can be continued throughout the study. Participants are free to stop participation at any point in the study. Participants randomized into the treatment arm may receive the anti-inflammatory drug naproxen, since it is known to increase the risk of stomach and intestinal side effects, a combined naproxen/esomeprazole drug regimen will be given to participants to provide some protection for these types of side effects. Visit 2 (week -1): Baseline Scan (90 min): Participants will rate their pain intensity, complete questionnaires, and undergo brain scanning (anatomical and functional scans). Participants will receive medication, which can be used if the pain becomes too much to handle (500 mg four times per day maximum). The researcher will ask participants about how often participants used the "rescue" medication and any changes in health they may have experienced since the last visit. Visit 3 (week 0): Start of Treatment Period and Randomization (30-45 min): Participants will rate their pain intensity and complete questionnaires. Participants will be randomized into either a drug (placebo or naproxen and esomeprazole) treatment group or no treatment group; if participants are assigned to a treatment group (active or placebo), neither participants nor the clinical coordinator/assistant will know which group participants are allocated in. Enough medication will be given to participants to last until the next visit. The placebo group will receive two placebo capsules twice daily and the active drug group will receive one naproxen capsule (500mg) and one esomeprazole capsule (20mg) twice daily (morning and night) for the treatment period. The medication (Naproxen or Placebo) needs to be taken with at least one full glass (8 oz) of water and the other medication (Esomeprazole or Placebo) should be taken one hour before a meal. The researcher will provide the study medication; if participants were randomized into the no treatment group, participants will only receive rescue medication. The researcher will ask participants about how often participants used the "rescue" medication and any side effects participants experienced since Visit 2 took place. Additional "rescue" medication will be given. Visit 4 (week 3): Continuing Assessment (30-45 min). The procedures described for Visit 3 will be repeated during this visit. The researcher will ask participants about how often they used the "rescue" medication and any side effects experienced since Visit 3 took place. As well, the researcher will ask how often participants took the study medication (if in a treatment group) and document the total pills ingested. Visit 5 (week 6): End of Treatment/Start of Washout and Final Scan (60-90 min): The procedures described for Visit 2 will be repeated during this visit. The researcher will ask participants about how often and reliably participants took the medication (if in a treatment group), as well as how often they used the "rescue" medication and any side effects experienced since Visit 4 took place. Participants will only receive the "rescue" medication for the upcoming 3 weeks. Visit 6 (week 9): Final Visit/End of Washout (30-45 min): Participants will return to complete questionnaires, but no brain scans will be done. The researcher will ask participants about how often they used the "rescue" medication and any side effects experienced since Visit 5 took place. If participants are in one of the treatment groups, participants will be asked to return all of the study medication and rescue medication at this time, and all treatment will be stopped at this visit.