Introduction: Opioid treatment for chronic malignant and nonmalignant pain of moderateto-severe intensity is associated with bowel dysfunction leading to constipation; this often requires opioid dose reduction or interruption. Combination opioid agonist/antagonist therapy can restore normal bowel function. A prolonged-released (PR) fixed-dose combination of oxycodone and naloxone has been developed and efficacy has been demonstrated in phase 3 clinical trials.
Methods: This 2-month, retrospective, singlecenter, observational study assessed the effectiveness and safety of PR oxycodone/naloxone in consecutive nononcological patients with constipation and chronic pain despite analgesic treatment; specific subgroup analyses were performed in opioid-experienced or opioid-naïve patients and in age subgroups. Efficacy was assessed by: intensity of pain; bowel function; effective oxycodone/naloxone dose; Patients' Global Impression of Change (PGIC) scale; rescue paracetamol; and laxative use. Safety evaluations were also performed.
Results: Of 1,051 patients starting on the oxycodone/naloxone combination (32.0% male; mean age 67 ± 13 years, 53.9% opioid naïve), 1,012 completed 2 months of treatment. Overall, PR oxycodone/naloxone was associated with a significant decrease in pain intensity (P < 0.001), a reduced need for rescue paracetamol (P < 0.001), and PGIC score of "very much improved" or "much improved" in 84.0% of patients. Constipation markedly decreased (P < 0.001) despite reduced laxative use (P < 0.001 vs. baseline). The most frequent treatment-emergent adverse events were somnolence (2.0%), dizziness (1.1%), and confusion (1.0%). Clinical differences in endpoints were seen between opioid-naïve and opioid-experienced patients, and among agestratified groups, but efficacy was similar to the overall population.
Conclusions: Fixed combination PR oxycodone/naloxone was effective and well tolerated in moderate-to-severe chronic pain in patients with constipation, providing analgesia and relief from bowel dysfunction. Consistent efficacy across patient subgroups provides guidance for daily management of chronic pain when therapy options are limited due to bowel dysfunction, regardless of age or previous medication. Supplementary material belonging to this paper is available on SpringerLink.