Opioid induced bowel disease: a twenty-first century physicians' dilemma. Considering pathophysiology and treatment strategies.

The treatment of cancer-associated pain as well as chronic non-cancer-related pain (CNCP) is an increasingly relevant topic in medicine. However, it has long been recognized that opiates can adversely affect many organ systems, most notably the gastrointestinal system. These are referred to as the spectrum of "opioid-induced bowel dysfunction" (OBD) or what we will refer to as "opioid-induced bowel disease" (OIBD) which include constipation, nausea, vomiting, delayed gastric emptying, and gastro-esophageal reflux disease (GERD), and a newer entity known as narcotic bowel syndrome (NBS). Opioid analgesics are increasingly being used for the treatment of cancer pain, non-cancer-associated pain, and postoperative pain. As we achieve our goals towards pain control, we need to be cognizant of and competent in how to prevent and treat OIBD. The basis is due in part to µ-receptor activation, decreasing the peristaltic contraction and leading to sequelae of OIBD. Treatment beyond lifestyle interventional strategy will employ laxatives and stool softeners. However, studies performed while patients were already using laxativies and stool softeners have elicited the necessity of peripherally acting agents such as methylnaltrexone (MNTX) and alvimopan. Patients responded dramatically to both medications, but these studies were limited to patients that were deemed to have advanced illness. Lubiprostone, while different in its mechanism of action from MNTX and alvimopan, has proven effective and should be considered for use in OIBD. Further investigational research will promulgate more information and allow for better and more efficient treatment options for OIBD.