A Study to Demonstrate Improvement in Symptoms of Constipation in Subjects That Require Around-the-clock Opioid Pain Killer Therapy

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).