Inclusion Criteria:

• Male or female patients 18 years of age or older
• Patients undergoing surgery through an abdominal incision of at least 3 cm who are expected to be hospitalized for at least 36 hours and are expected to subsequently require at least 48 hours of oral opioid therapy.
• Washout of at least 45 minutes for parenteral and 4 hours for IM analgesia.
• Initial pain intensity score of at least 50 mm on a 100-mm VAS and a categorical pain rating of moderate or severe on a scale of none, mild, moderate, or severe.
• Written informed consent.

Exclusion Criteria:

• Known allergy or significant reaction to opioids.
• History of chronic opioid use or opioid abuse within 6 months prior to study entry.
• History of alcohol or substance abuse within the last 3 years.
• Have been a participant in a study of an investigational drug or device within 30 days prior to study entry.
• Have been a previous participant in an oxymorphone clinical trial.
• Are currently taking or have taken a monoamine oxidase inhibitor (MAOI) drug within 2 weeks prior to study entry.
• Are currently taking or have taken St. John's Wort >1000 mg/day within 2 days prior to study entry.
• Use of long-acting oral and parenteral analgesics (opioid, non-opioid or non-steroidal anti-inflammatory drug [NSAID]) within 12 hours (at least 24 hours for cyclooxygenase-2 [COX 2] analgesics) prior to receiving study medication.
• 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)
• Have a history of seizure.