Efficacy and Safety of Oxymorphone Immediate Release in Post-surgical Acute Pain

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.