Effect of Guanfacine on the Reversal of Opioid-induced Hyperalgesia (OIH)

Inclusion Criteria * 18-65 years old * Chronic neck or back pain condition for at least 6 months * VAS score of 4-8, despite opioid therapy * On a stable morphine equivalent dose of at least 60mg/day and ≤ 240mg/day for at least 3 months Exclusion Criteria * Has taken Methadone, Suboxone, Fentanyl, and/or Tramadol in the last six (6) months * Has taken guanfacine (or other alpha-2AR agonists) in the last six (6) months * Changes to current or adding new pain treatment while enrolled in the study (i.e. opiates, epidural steroid injection) will be reviewed by the study physician * Unable to independently provide informed written consent * Sensory deficits at site of QST, such as peripheral neuropathy * Intolerable allergies or has had a severe adverse reaction to study medication (i.e. guanfacine, lactose, vitamin B2 a.k.a. riboflavin) * Takes vitamin B2 \> 1.6mg/day during the study * Pregnant or breastfeeding * Pending litigation related to neck or back pain * Diagnosed with Raynaud's syndrome * Has other chronic pain conditions such as fibromyalgia or joint osteoarthritis that are predominant over back and neck pain with regard to its intensity (VAS) * Has known pre-existing severe cardiovascular disease (i.e. arrhythmia - prolonged QT interval \> 440ms), cerebrovascular disease/accident (i.e., stroke), hepatic or renal impairment, CNS condition, metabolic condition, or history of syncope * Hypotension (SBP \< 90 mmHg and DBP \< 60 mmHg for female or SBP \< 100 mmHg and D…