Narcotic bowel syndrome.

Narcotic bowel syndrome is characterised by worsening abdominal pain in the context of escalating or continuous opioid therapy. Although narcotic bowel syndrome is rarely diagnosed, given the current epidemic of opioid use, it is likely to be under-recognised. The underlying pathophysiological mechanisms of narcotic bowel syndrome are incompletely understood; however, opioid-induced hyperalgesia is likely to be a central facet. The putative mechanisms of hyperalgesia include activation of bimodal opioid regulatory systems, counter-regulatory mechanisms, neuroinflammation, opioid facilitation, and interactions of the N-methyl D-aspartate receptor with opioids at the level of the spinal cord. The cornerstone of management is the development of a therapeutic alliance with the patient, education of the patient as to the mechanisms by which opioids might paradoxically worsen pain, and implementation of an opioid detoxification programme. Opioid detoxification regimens vary between centres, but frequently include tapering or substitution of opioids and concomitant co-administration of antidepressants, anxiolytics, and psychological therapies. Despite these interventions, recidivism rates remain high. Further prospective research is warranted to determine the epidemiology of narcotic bowel syndrome and delineate the most efficacious detoxification programmes.