Background: Opioid-induced constipation (OIC) is a common adverse effect of opioid analgesic therapy that significantly affects the patient's quality of life and may lead to poor adherence and treatment failure. Tapentadol, oxycodone/naloxone, and some transcutaneous opioids were associated with less frequent OIC than morphine or oxycodone in controlled clinical trials. However, few studies compare these newer opioids with each other in terms of OIC.
Methods and patients: We performed a cross-sectional observational study that evaluated the degree of OIC and risk factors in patients receiving long-term treatment (>1 year) at a tertiary care pain unit with tapentadol, oxycodone/naloxone, hydromorphone, fentanyl, or buprenorphine. The degree of constipation was evaluated using the Bowel Function Index (BFI).
Results: Out of 180 enrolled patients (median age: 61.5 years, 66.7 percent women, mean treatment duration: 3 years), 57.2 percent suffered from nociceptive pain, 33.9 percent from mixed pain, and 8.9 percent from neuropathic pain. The most commonly prescribed opioids were oxycodone/naloxone (44.4 percent) and tapentadol (37.8 percent). At the time of the study, 73.9 percent of patients had constipation (BFI > 29), and 21.7 percent had severe constipation (BFI > 69). In a multiple linear regression analysis, previous constipation, morphine equivalent dose, treatment with fentanyl and interaction between morphine equivalent dose and hydromorphone were associated with more severe constipation.
Conclusions: Most patients receiving long-term treatment with opioids present symptoms of constipation. The bowel function profile was more favorable for tapentadol and oxycodone, with no differences between them, even though morphine equivalent doses were on average higher in the tapentadol group.