Evaluation of Effectiveness and Tolerability of Tapentadol Hydrochloride in Subjects With Severe Chronic Low Back Pain Taking Either WHO Step I or Step II Analgesics or no Regular Analgesics

Tapentadol Prolonged Release (PR) Titration and Optimal Dose Period: Starting at 50 mg Tapentadol PR twice daily, adjusted with 50 mg PR steps (upwards or downwards) as necessary to achieve a balance between pain relief and a satisfactory level of tolerability. Participants were not permitted to exceed a dose of 500 mg of Tapentadol per day.

Eligibility assessment period to characterize the baseline over a one week period (week -1). Participants continued their previous treatment prior to allocation to tapentadol, if eligible.

Maintenance Period: In this period participants continued Tapentadol Prolonged Release (PR) on the dose established in the Titration and Optimal Dose Period. Tapentadol IR participants were not permitted to exceed a total daily tapentadol dose of 500 mg.