The purpose of this study is to evaluate the effectiveness (level of pain control) and safety of the administration of Extended Release Hydrocodone/Acetaminophen with placebo over a 5-week dosing period in patients with osteoarthritis.

Inclusion Criteria:

• Males or females ages 21 to 75
• Has osteoarthritis of the hip or knee
• Requires therapeutic doses of medications for osteoarthritis
• If female, must be of non-childbearing potential or practicing birth control
• Has sufficient pain to justify the use of round-the-clock opioids

Exclusion Criteria:

• Has received certain types of procedures or received certain medications for osteoarthritis within a specific timeframe
• Has certain medical conditions which may interfere with pain assessments
• Is allergic to or has a serious reaction to hydrocodone, other opioids, or acetaminophen
• Has had certain infections, injuries or illnesses within the last month
• Has had major abdominal surgery, certain diseases that may cause intestinal narrowing, or has a history of constipation, diarrhea or nausea and vomiting
• Is receiving chemotherapy, or has been diagnosed with certain cancers within the past 5 years
• Has a history of major psychiatric disorders or requires treatment with certain drugs for depression
• Cannot discontinue pain medications, even for a short time, prior to the study start