German Expert Consensus on Opioid-Induced Constipation (OIC): Recommendations and a Treatment Algorithm for Clinical Practice

<b>Background/Objectives:</b> Opioid-induced constipation (OIC) is a frequent adverse effect of opioid therapy. In contrast to other opioid-related side effects, OIC usually does not improve over time and significantly impairs the quality of life of affected patients. Despite its high prevalence, OIC remains underdiagnosed and undertreated in clinical practice, which has been demonstrated in several European countries. Healthcare data indicates that approximately 2.3 million people in Germany received potentially OIC-inducing opioids in 2023, the majority being patients with chronic non-cancer pain. <b>Methods:</b> An interdisciplinary board of experts in gastroenterology, pain medicine, neurology, oncology, and palliative care developed consensus-based recommendations to improve the diagnosis and management of OIC. Fifteen statements were drafted according to current national German and international guidelines and literature and subsequently discussed. Out of the fifteen statements, twelve statements remained, which achieved consensus with at least 90% agreement. <b>Results:</b> The consensus statements address key aspects of OIC management, including pathophysiology, patient education, diagnosis, prevention, treatment and structured follow-up. Following the statements, a practical treatment algorithm was developed to facilitate clinical implementation. Use of validated tools such as the Bowel Function Index (BFI) for diagnosis and monitoring, early initiation of laxative therapy and timely escalation to mechanism-oriented therapy with peripherally acting μ-opioid receptor antagonists (PAMORAs) in cases of inadequate response have been recommended by the panel. Accordingly, treatment should follow an approach with the following steps: (1) Laxative, (2) switch to PAMORA, (3) rotation of PAMORA, and (4) combination of PAMORA with laxative. In Europe, the PAMORAs methylnaltrexone, naloxegol and naldemedine are approved for the treatment of OIC. <b>Conclusions:</b> This consensus paper provides both evidence-based and practice-oriented recommendations for the systematic management of OIC. By promoting patient education, early recognition, structured evaluation and stepwise treatment escalation, the presented statements and algorithm aim to improve patient outcomes and quality of life under opioid therapy including better adherence to opioid therapy.