Narcotic bowel syndrome (NBS) is a subgroup of opioid bowel dysfunction characterized by chronic or frequently recurring abdominal pain that worsens with continued or escalating doses of opioids. While seemingly helpful at first, over time opioids can produce shorter pain-free periods and tachyphylaxis occurs, leading to increasing opioids doses. Ultimately, increasing dosages increase the adverse effects of pain sensation and delayed motility, thereby initiating the development of NBS.
Although pain is the dominant feature, nausea, bloating, intermittent vomiting, abdominal distension, and constipation are common symptoms.

The syndrome can occur in patients with no prior gastrointestinal disorder who receive high dosages of opioids after surgery or for acute painful problems, and among patients with functional GI disorders or other chronic gastrointestinal diseases who are managed by physicians unaware of the hyperalgesic effects of chronic use of opioids.

Basic to the diagnosis of NBS is the recognition that chronic or escalating doses of opioids lead to continued or worsening symptoms rather than benefit. Moreover, the symptoms are nonspecific, and many clinicians are unaware that narcotic medications can actually sensitize patients to the experience of pain. Thus, continued treatment with opioids lead to a vicious cycle of pain, increasing doses and continued or worsening pain. The most perplexing feature of NBS is recognizing and accepting that opioid analgesics can actually cause or aggravate the actual pain that is being treated.

Treatment involves early recognition of the syndrome, an effective physician-patient relationship, gradual withdrawal of the opioids according to a withdrawal protocol, and the institution of medications to reduce removal effects. It can be initiated when the diagnosis is made and there is reasonable evidence that no other diagnosis explains the symptoms. NBS is a positive diagnosis that occurs independent of other pathological conditions, and it may also be the cause of pain in patients with existing inactive abdominal pathology.

See reference for details.

Adapted from Grunkemeier DMS et al. The Narcotic Bowel Syndrome: Clinical features, pathophysiology and management. Clinical Gastroenterol Hepatol 2007; 5 (10):1126-39.