The primary research objective is to demonstrate that subjects taking OXN PR have improvement in symptoms of constipation as measured by the Bowel Function Index (BFI) compared to subjects taking OxyPR tablets alone with cancer and non-cancer related pain without reducing the effectiveness of pain relief as measured by the Brief Pain Inventory (BPI).

The study OXN3506 is a multicentre, multiple-dose, randomised, double-blind, double-dummy, active-controlled, parallel-group study in male and female subjects with non-malignant or malignant pain requiring opioids to assess analgesic efficacy and symptoms of constipation secondary to opioid treatment. Subjects will be randomised to two treatment groups and will be treated with OXN PR or OxyPR for up to 5 weeks. The study is composed of three phases, a pre-randomisation phase, a double-blind phase and an extension phase.

Inclusion Criteria

• Subjects who are receiving WHO step III opioid analgesic medication for the treatment of non-malignant or malignant pain.
• Documented history of non-malignant or malignant pain that requires around-the-clock opioid therapy

Exclusion Criteria

• Females who are pregnant or lactating.
• Subjects with evidence or significant structural abnormalities of the gastrointestinal tract.
• Subjects with evidence of impaired liver/kidney function upon entry into the study.