a review of the clinical manifestations, pathophysiology and management of opioid bowel dysfunction and narcotic bowel syndrome

opioids are widely used for the treatment of malignant and non-malignant pains. these medications are accompanied by adverse effects, in particular gastrointestinal symptoms known as opioid bowel dysfunction (obd). the most common symptom of obd is refractory constipation that is usually stable regardless of the use of laxatives. narcotic bowel syndrome (nbs) is a subset of obd described as ambiguous chronic pain aggravated by continual or increased opioid use for pain relief. pathophysiology of these disorders are not definitely disentangled. some challenging hypothesis have been posed leading to specific  management in order to  mitigate  the  adverse effects. this article is a review of the literature on the prevalence, pathophysiology and management of obd and nbs.