Study of the Abuse Liability of Oxycodone HCl/Niacin in Subjects With a History of Opioid Abuse

Inclusion Criteria: * Subject is male or female between 18 and 55 years of age * Subject meets DSM-IV Criteria for the Diagnosis of Opioid Substance Abuse and subject is unlikely to experience an idiosyncratic reaction or respiratory depression after ingesting 40 mg of oxycodone * Body weight is not more than 20% above or below ideal body weight * Subject agrees to abstain from any Rx or OTC drugs (except as authorized by the Investigator) or alcohol * Subject is in generally good health * Subject is reliable, willing, cooperative, able to communicate effectively, and has a minimum of a 6th grade reading level * Subject has an acceptable score on the MMSE for cognitive impairment * For women of child-bearing potential: woman is not pregnant and not nursing, and is practicing an acceptable method of birth control Exclusion Criteria: * Subject has a disease that may endanger the subject or the validity of the data * Subject is currently physically dependent on opiates or alcohol * Subject was exposed to any investigational drug within 30 days prior to the inpatient phase * Subject has a history of hypersensitivity to any drug, or a known allergy to any component of the study drug formulation * Subject has a positive urine drug screen for a non-opiate drug * Subject has a predisposing condition that may place the subject at risk for receiving niacin or oxycodone, or confound the study analyses * Subject ingested niacin at doses higher than SDI within 14 days prior to the inpatient phase * Subject has an abnormal bleeding tendency