Evaluation of Effectiveness and Tolerability of Tapentadol Hydrochloride in Subjects With Severe Chronic Low Back Pain Taking WHO Step III Analgesics But Showing a Lack of Tolerability

The main objective of the study is to evaluate the effectiveness, tolerability, and safety of tapentadol hydrochloride prolonged release in subjects suffering from severe chronic low back pain (LBP) who are taking WHO Step III analgesics and show lack of tolerability. This is a clinical effectiveness trial designed to establish a link between anticipated clinical outcomes and the clinical practice by means of selected measures of clinical and subject-reported outcome. The trial will compare the effectiveness of previous analgesic treatment (WHO Step III) with that of tapentadol hydrochloride prolonged release treatment during defined periods of evaluation.