The study compares the analgesic efficacy of OXN PR vs placebo in opioid-naive subjects suffering from severe pain due to Bladder Pain Syndrome.

The study consists of a screening period followed by randomisation of the patients in a 1:1 ratio to OXN PR treatment or placebo treatment in a double blind fashion. The double blind phase will last for 8 weeks.

Inclusion Criteria:

• History of severe pain due to Bladder Pain Syndrome (BPS) for at least 6 months
• Subject's treatment of pain due to BPS is insufficient
• Subjects must not have received opioid containing medication in the last 6 months

Exclusion Criteria:

• Females who are pregnant or lactating
• Subjects with any contraindication/history of hypersensitivity to oxycodone, naloxone, paracetamol, related products or other ingredients
• Subjects with any situation in which opioids are contraindicated like severe respiratory depression with hypoxia and/or hypercapnia, severe chronic obstructive lung disease, cor pulmonale, severe bronchial asthma or paralytic ileus
• Evidence of clinically significant cardiovascular, renal, hepatic, gastrointestinal or psychiatric disease, as determined by medical history, clinical laboratory tests, ECG results, and physical examination that would place the subject at risk upon exposure to the study medication or that may confound the analysis and/or interpretation of the study results
• Abnormal aspartate aminotransferase, alanine aminotransferase, or alkaline phosphatise levels (> 3 times the upper limit of normal), gamma glutamyl transpeptidase > 3 times the upper limit of normal
• Abnormal total bilirubin and/or creatinine level(s)