1. 2014;17;415-424Effect of a Fixed-Dose Opioid Agonist/Antagonist on Constipation in Patients on Long-term Opioids for Non-Malignant Pain Unable to Tolerate Laxatives
   Observational Study
   Vivek Mehta, MD, Sami Alaward, MD, Sanjay Kuravinakop, MBBS, and Serge Nikolic, FRCA.

BACKGROUND: Chronic pain affects a large number of patients throughout the world and impacts greatly on their quality of life, including the ability of a patient to sleep, go to work, and socialize. Guidance on the use of opioids in chronic pain patients is available from the British Pain Society; however, patients receiving opioid treatment for their pain often suffer from symptoms associated with opioid-induced bowel dysfunction (OIBD), including constipation. The usual treatment of constipation in these patients is laxatives; however, one study has shown that 54% of patients do not receive the desired results from this approach. Oxycodone/naloxone tablets have been shown to provide analgesia to chronic pain patients, while improving the symptoms of OIBD, as the naloxone component blocks the effects of oxycodone at opioid receptors in the gut.

OBJECTIVES: The objective of the present study was to assess improvements in quality of life and bowel function in patients receiving oxycodone/naloxone tablets for their chronic non-malignant pain.

STUDY DESIGN: This was a 12-week observational follow-up study that included 28 outpatients with chronic non-malignant pain attending the Pain Clinic at St. Bartholomew’s Hospital in London. All patients had recently been prescribed oxycodone/naloxone tablets as treatment for their pain.

METHODS: Patients were assessed at baseline, week 1, week 4, and week 12 for functioning and well-being using the Patient Assessment of Constipation Quality of Life questionnaire (PAC-QOL), and for bowel function using the Bowel Function Index (BFI).

RESULTS: Mean PAC-QOL scores, as well as scores for each of the subscales (worries and concerns, physical discomfort, psychosocial discomfort, and satisfaction) significantly improved from baseline to week 12. Mean BFI scores significantly decreased from baseline to all time-points during the study. Subscale analysis of the BFI scores showed that mean scores for ease of defecation and judgment regarding constipation had significantly decreased at week 12; however, mean scores for feeling of incomplete bowel evacuation had not.

LIMITATIONS: The results of the current study should be interpreted in relation to the study design. However, the results are consistent with previous studies that included a comparator group, had a longer duration of treatment, and included larger patient numbers.

CONCLUSIONS: The results of this study indicate that patients receiving oxycodone/naloxone tablets achieved statistically and clinically significant improvements in bowel function as well as quality of life after 12 weeks of treatment.