A concise review of opioid-induced esophageal dysfunction: is this a new clinical entity?

Opioids have become the most widely prescribed analgesics in Western countries. Opioid-induced bowel dysfunction is a widely known adverse effect, with constipation the most common manifestation. Most of the opioid-related effects occur in the stomach, small intestine, and colon and have been widely studied. However, the effects related to esophageal motility are less known. Recently published retrospective studies have suggested that long-term use of opioids can cause esophageal motility dysfunction, reflecting symptoms similar to motility disorders, such as achalasia and functional esophagogastric junction outflow obstruction. The most common manometric findings, as reported in the literature, for patients with opioid-induced dysphagia undergoing long-term therapy with these drugs are impaired lower esophageal sphincter relaxation, high amplitude/velocity, and simultaneous esophageal waves, higher integrated relaxation pressure, lower distal latency, and the esophageal contractility can be normal, hypercontractile, or premature. Based on these studies, a new clinical entity known as opioid-induced esophageal dysfunction has been postulated. For these patients, the diagnostic method of choice is high-resolution manometry, although other causes should be ruled out through endoscopy or Computed Tomography (CT). The best therapeutic option for these patients is withdrawal of the opioid; however, this is not always possible, and other options need to be investigated, such as pneumatic dilation and botulinum toxin injection, considering the risks versus the benefits.