Effect of Combined Morphine and Duloxetine on Chronic Pain

Inclusion Criteria: 1. Subject is 18-70 years old. 2. Subject has chronic neck or back pain for at least 3 months. 3. Subject has a VAS ≥ 5. 4. Has not taken duloxetine in the last 3 months. 5. Has not taken an opioid in the last 3 months, but has taken one in the past without sufficient pain control OR has never taken opioids but has failed at 3 (or more) non-opioid treatments. Exclusion Criteria: 1. Subject has major psychiatric disorders requiring recent hospitalization (within 3 months) such as major depression, bipolar disorder, schizophrenia, anxiety disorder, or psychotic disorder. 2. Subject is using illicit drugs detected by urine toxicology/drug screen. 3. Subject is pregnant or lactating/breast feeding. 4. Subject is allergic to morphine or duloxetine. 5. Subject is on an antidepressant including serotonin-norepinephrine reuptake inhibitors (SNRI), selective serotonin reuptake inhibitor (SSRI), tricyclic antidepressant. 6. Subject has a history of suicidal attempts or current suicidal ideation. 7. Subject takes monoamine oxidase inhibitors, antipsychotics, triptan drugs such as sumatriptan, lithium, linezolid, tramadol (Ultram), St. John's Wort, central nervous system (CNS) stimulants such as amphetamine, methylphenidate, methamphetamine, phentermine, diethylpropion, sibutramine, cocaine, or thioridazine. 8. Subject has uncontrolled narrow-angle glaucoma. 9. Subject has sensory deficits on arms or Raynaud's Syndrome. 10. Subject has a pending litigation related to chronic pain condition. 11. Subject is on methadone or suboxone treatment for addiction.