Project 1 Aim 2, Adaptations of the Brain in Chronic Pain With Opioid Exposure

Inclusion Criteria: * History of low back pain for a minimum of 6 months daily (prior to screening), meeting the Quebec Task Force Classification System symptom categories I-III; * Male or female, age equal or greater than 18 years, with no racial/ethnic restrictions; * Must be able to read and speak English and be willing to read and understand instructions as well as questionnaires; * Must be in generally stable health; * Must sign an informed consent document after a complete explanation of the study documenting that they understand the purpose of the study, procedures to be undertaken, possible benefits and potential risks, and are willing to participate; * Must have, on average ≥ 4/10 units of pain intensity over the course of a 1-4 week period prior to the brain scanning visit; * Must be willing to complete daily smartphone/computer eDiary ratings; * Must be on regular opioid therapy or for at least 3 months prior to randomization which will be up to the clinical investigator's decision * Must be on a short acting opioid therapy (anticipated duration of action \< 6 hours) Exclusion Criteria: * Low back pain associated with any systemic signs or symptoms, e.g., fever, chills; * Other comorbid chronic pain or neurological conditions; * Use of therapeutic doses of antidepressant medications at unstable doses (i.e., tricyclic depressants, SSRIs, SNRIs; low doses used for sleep may be allowed); * Significant other unstable medical disease such as diabetes, congestive heart failure, coronary or peripheral vascular disease, chronic obstructive lung disease, or malignancy; * Uncontrolled hypertension; * Renal insufficiency;(correlated creatinine clearance \< 40mL/min or serum creatinine ≥2) * Daily use of high doses of opioids,, as defined as \> 50mg morphine equivalent/day; * Any medical condition that in the investigator's judgment may prevent the individual from completing the study or put the individual at undue risk; * In the judgment of the investigator, unable or unwilling to follow protocol and instructions; * Evidence of poor treatment compliance, in the judgment of the investigator; * Intra-axial implants (e.g. spinal cord stimulators or pumps); * All exclusion criteria for MR safety: any metallic implants, brain or skull abnormalities, tattoos on large body parts, and claustrophobia; * Pregnancy, or inability to use an effective form of contraception in women of child-bearing age; * An established diagnosis of diabetes (type 1 or type 2) * Lactose…