The purpose of this study is to determine if oxymorphone ER is effective and safe in treating chronic pain in opioid-naive patients.

The purpose of this study is to assess the effectiveness and tolerability of oxymorphone ER for the treatment of moderate to severe chronic pain in opioid-naive patients. Patients are gradually titrated from a 5mg dose of oxymorphone ER (taken every 12 hours) until stabilized dose is achieved. The study design is an open-label, nonrandomized 6-month study with a titration/stabilization period of ≤ 1 month followed by a 5-month maintenance period.

Inclusion Criteria:

• Currently receive a stable non-opioid analgesic regimen
• Have an initial pain intensity score of greater than or equal to 40 mm on a 100-mm Visual Analogue Scale (VAS) and a categorical pain rating of moderate or severe on a categorical scale of none, mild, moderate, or severe
• If female, must be practicing abstinence or using a medically acceptable form of contraception
• Understand written and spoken English
• Have been informed of the nature of the study and provided written informed consent.

Exclusion Criteria:

• Positive pregnancy test (females only)

• History of or active asthma or emphysema

• Clinically significant hepatic impairment

• Received any of the following medications within 48 hours prior to dosing:

  • Dextromethorphan-containing medications (over-the-counter [OTC] cough and cold preparations, such as Vicks Formula 44)
  • St. John's Wort >1000 mg/day

• Received monoamine oxidase inhibitor (MAOI) drugs within 2 weeks prior to dosing

• Are not stabilized on the following medications for at least 4 weeks prior to dosing:

  • Tricyclic antidepressant drugs
  • Serotonin reuptake inhibitors
  • Amphetamines used for attention-deficit/hyperactivity disorder (ADHD)

• History of alcohol or substance abuse within the last 3 years

• History of opioid abuse within 6 months prior to study entry

• Have a known oxymorphone sensitivity or allergy

• Have scheduled an elective surgery or procedure during the study that would not permit continuation of study medication, and/ or require another analgesic not currently taken by the patient

• Have received an investigational drug or product or participated in an investigational drug study within a period of 30 days prior to receiving study medication

• Have a known allergy or significant reaction to opioids

• Have been a participant in a previous oxymorphone clinical trial

• Have a history of seizure (Patients with a history of juvenile febrile seizures may be included if there has been no seizure history within the past 10 years).