Objective:  The aim of this study was to assess safety and efficacy of fixed combination oxycodone prolonged release (PR)/naloxone PR in terms of both analgesia and improving opioid‐induced bowel dysfunction (OIBD) and associated symptoms, such as opioid‐induced constipation (OIC), in adults with chronic non‐cancer pain.

Study design:  These were open‐label extension studies in which patients who had previously completed a 12‐week, double‐blind study received oxycodone PR/naloxone PR for up to 52 weeks. The analgesia study assessed pain using the modified Brief Pain Inventory‐Short Form (BPI‐SF). The bowel function study assessed improvements in constipation using the Bowel Function Index (BFI).

Results:  At open‐label baseline in the analgesia study (n = 379), mean score [± standard deviation (SD)] for the BPI‐SF item ‘average pain over the last 24 h’ was 3.9 ± 1.52, and this remained low at 6 months (3.7 ± 1.59) and 12 months (3.8 ± 1.72). Mean scores for BPI‐SF item ‘sleep interference’, and the BPI‐SF ‘pain’ and ‘interference with activities’ subscales also remained low throughout the 52‐week study. In the bowel function study (n = 258), mean BFI score (± SD) decreased from 35.6 ± 27.74 at the start of the extension study to 20.6 ± 24.01 after 12 months of treatment with oxycodone PR/naloxone PR. Pain scores also remained low and stable during this study. Adverse events in both extension phases were consistent with those associated with opioid therapy; no additional safety concerns were observed.

Conclusion:  Results from these two open‐label extension studies demonstrate the long‐term efficacy and tolerability of fixed combination oxycodone PR/naloxone PR in the treatment of chronic pain. Patients experienced clinically relevant improvements in OIBD while receiving effective analgesic therapy.