Mechanistic Study of Duloxetine in Breast Cancer Patients With Chronic Pain

Exclusion Criteria

• •1. Prior use of duloxetine or milnacipran.
• •2. Prior or current use of venlafaxine specifically for treatment of pain (prior or current use for treatment of other indications, such as hot flashes, is permitted, although cases currently taking venlafaxine must discontinue use prior to study treatment initiation)
• •3. Patients must not be taking any contraindicated medications listed on the duloxetine package insert including the following: phenothiazines, propafenone, flecainide, linezolid, or anticoagulation medication (e.g., heparin, warfarin, or direct oral anticoagulants); treatment with monoamine oxidase inhibitor within 14 days prior to registration.
• •4. Thumbnail abnormalities on either hand (such as due to chemotherapy or trauma, or artificial nails) that are likely to alter pain perception during testing
• •5. Peripheral sensory neuropathy at the thumbs bilaterally that interferes with function and/or activities of daily living
• •6. Significant risk of suicide based on the Investigator's judgment
• •7. History or behavior that would, in the Investigator's judgment, prohibit compliance for the duration of the study.
• •8. History of alcohol or other substance abuse or dependence within the year prior to registration
• •9. Known chronic liver disease, end stage renal disease, or creatinine clearance \<30 mL/min as defined by Cockcroft-Gault equation
• •10. Uncontrolled narrow-angle glaucoma.
• •11. Clinically significant coagulation disorder
• •12. History of seizure disorder
• •13. Pregnant or breast-feeding. Urine pregnancy test will be assessed at the baseline visit in women of child-bearing potential with chronic pain.
• •14. Unable to take oral medications or any medical condition that would interfere with the absorption of study medication capsules.
• •15. Currently taking SSRI, serotonin-norepinephrine reuptake inhibitor (SNRI), or TCA regimen (including Wellbutrin) for treatment of major depressive disorder or generalized anxiety disorder (without approval and involvement of the patient's treating psychiatrist to taper cases off these medications prior to study treatment).
• •Controls are patients without chronic pain who otherwise meet the following eligibility criteria (inclusion #1, 2, 8, exclusion #1, 2, 4, 5, worst pain score 0-1, and not currently on medication for pain)