The purpose of this study is to evaluate the safety profile of tapentadol (CG5503) PR at doses of 100 mg - 250 mg administered twice daily over a maximum one year period to patients with at least a 3-month history of low back pain, or pain caused by knee or hip osteoarthritis.

Tapentadol (CG5503) is a centrally active pain-relieving drug being investigated for the treatment of acute and chronic pain. This study is a randomized (patients are assigned different treatments based on chance in a ratio of 4 patients on tapentadol (CG5503) PR to every 1 patient on oxycodone CR), open-label (both the Investigator and the patient know what medication is allocated), active-controlled, parallel-group, multicenter study. It is designed to investigate the long-term safety (side effects during up to one year of administration) and effectiveness (level of pain control) of tapentadol (CG5503) PR compared to oxycodone CR (an opioid commonly used for relief of moderate to severe pain) taken orally. The doses of both of these medications will be adjusted to give the best therapeutic benefit for the patient. Approximately 1075 patients will be screened. Safety evaluations include monitoring of adverse events, physical examinations, and clinical laboratory tests. Assessments of pain relief include the pain intensity numerical rating scale, and patient global impression of change scale (PGIC). Venous blood samples will be collected for the determination of serum concentrations of tapentadol (CG5503) and oxycodone. Tapentadol (CG5503) PR is also referred to as Tapentadol (CG5503) Extended Release (ER). Starting oral dose is randomly assigned to tapentadol (CG5503) PR 50 mg or oxycodone CR 10 mg twice daily (BID) x 3days; then increase to tapentadol (CG5503)100 mg BID, oxycodone CR 20 mg BID x 4 days; during the maintenance phase upward titration may occur at a minimum of 3 day intervals in increments of tapentadol (CG5503) PR 50 mg BID or oxycodone CR 10 mg BID. The maximum doses are tapentadol (CG5503) PR 250 mg BID or oxycodone CR 50 mg BID

• Osteoarthritis, Hip
• Osteoarthritis, Knee
• Lower Back Pain
• Pain

• Drug: tapentadol (CG5503) PR
• Drug: oxycodone CR

Inclusion Criteria:

• Clinical diagnosis of knee or hip osteoarthritis with history of pain at the reference joint for at least 3 months or clinical diagnosis of low back pain of benign origin for at least 3 months
• Must be dissatisfied with their current analgesic therapy (e.g. Non-steroidal anti-inflammatory drugs NSAIDS, COX-2 inhibitors, opioids, paracetamol/acetaminophen
• Have a pain intensity >4 on Numerical Rating Scale

Exclusion Criteria:

• Life-long history of seizure disorder or epilepsy
• Any of the following within one year: mild/moderate traumatic brain injury, stroke, transient ischemic attack, and brain neoplasm
• Severe traumatic brain injury within 15 years (consisting of more than one of the following: brain contusion (injuries resulting in hemorrhage), intracranial hematoma, unconsciousness or post traumatic amnesia lasting for more than 24 hours) or residual sequelae suggesting transient changes in consciousness
• History of malignancy within past 2 years, with exception of a successfully treated basal cell carcinoma
• Presence of significant pain associated with conditions other than osteoarthritis or low back pain that could confound the assessment or self-evaluation of pain