An Open-label Extension Study With Flexible Dosing of Extended-release (ER) Tapentadol (CG5503) to Treat Patients With Moderate to Severe Chronic Pain

Inclusion Criteria: * Non-lactating female subjects (Sexually active women must be postmenopausal, surgically sterile, or practicing an effective method of birth control \[e.g., prescription oral contraceptives, contraceptive injections, intrauterine device, double barrier method, contraceptive patch, male partner sterilization\] before entry and throughout the trial. Female patients of childbearing potential must have a negative pregnancy test at screening.) * Completion of the expected double-blind treatment period of the pivotal Tapentadol (CG5503) Phase 3 trials in osteoarthritis (R331333-PAI-3008, KF5503/11) or low back pain (R331333-PAI-3011, KF5503/23), or completion of the 1-year treatment period of the safety CG5503 Phase 3 trial in the non-European sites (R331333-PAI-3007, KF5503/24) * Must be willing to take Tapentadol (CG5503) extended release (ER) and the rescue medication supplied for the duration of the trial Exclusion Criteria: * History of alcohol and/or drug abuse, life-long history of seizure disorder or epilepsy, any of the following within the past year: mild/moderate traumatic brain injury, stroke, transient ischemic attack, or brain neoplasm * Severe traumatic brain injury within the past 15 years * Uncontrolled hypertension (repeated systolic blood pressure \>160 mmHg or diastolic blood pressure \>95 mmHg) * Severely impaired renal function * Moderately or severely impaired hepatic function * Patients taking neuroleptics, monoamine oxidase inhibitor…