A Comparison of the Addiction Liability of Hydrocodone and Sustained Release Morphine

Inclusion Criteria: * Patients with chronic pain for periods greater than 6 months * Patients taking greater than 80 mg morphine equivalents of a short acting opioid (\>8 vicodin or 4 oxycodone/day) * Referral to Pain or Substance Abuse Clinic for self-escalation of opioids Exclusion Criteria: * Inability to understand and comprehend spoken English * Patients with Munchausen's syndrome * Patient has a history of Peripheral Vascular Disease * Patient has a history of Raynaud's Phenomenon * Liver Disease; Child's classification greater than 1 (liver cirrhosis) will be excluded * Renal disease (BUN \>25 or Cr \>1.5) * Congestive Heart Failure; Subjects with New York Heart Association (NYHA)Heart Failure Symptom Classification System Level of Impairment II, III and IV will be excluded * Coronary artery disease; recent MI within the past six months or recent history of angina not controlled with NTG within the past six months * Hypertension; 1)previously normotensive subject; systolic bp \>140 mm Hg and diastolic bp \> 90 mm Hg 2) Hx of active treatment with antihypertensive medications; systolic bp \>150 mm Hg and diastolic bp \> 100 mm Hg * Cerebrovascular disease; recent history within the past year of a transient ischemic attack or recent history within the past year of a cerebrovascular event * Malignancy requiring active treatment * Patient is pregnant (as ascertained by a self-report and a mandatory commercial pregnancy test before any study medication is consumed)