Opioids: A Difficult Pill to Swallow

Abstract

The effect of opioids on lower gut motility resulting in bowel dysfunction is well known with a wealth of data surrounding it. However, there is surprisingly little data with regard to clinical effects of opioids on esophageal motility. In this case we present a patient who developed esophageal dysmotility as a result of opioids. A 50 year old female with a history significant for chronic abdominal pain secondary to chronic pancreatitis, presented with acute worsening abdominal pain. A CT abdomen was consistent with acute on chronic pancreatitis. Her home medications included MS Contin for her chronic pain, thus, on admission, she was started on a Hydromorphone PCA pump. Three days later, she reported acute onset of incomplete swallowing with regurgitation. A barium swallow showed prominent tertiary (nonpropulsive) contractions involving the mid and distal esophagus with delayed emptying into the stomach. A subsequent upper endoscopy did not detect any significant reason for her dysphagia. Her dysmotility was thought to be secondary to the acute increase of opioids in the setting of her chronic use. A speech pathology evaluation did not recommend any changes to her diet type. On discharge, she was scheduled for further esophageal motility testing and was also referred to a pain specialist in hopes of weaning her opioid use. There is a large range of manometric abnormalities seen in patients with dysphagia in the setting of opioid use, including impaired lower esophageal relaxation, high amplitude/velocity contractions, and simultaneous waves. Stimulation of peripheral opioid receptors have been shown to alter gastric, small bowel and colon function by affecting motility. In the lower gut, opioids act to block acetylcholine and other excitatory transmitters to inhibit propulsion as well as evoking spasm in smooth muscle by inhibiting nitric oxide. The distribution of these opioid receptors in the esophagus remains unclear. It is speculated that opioids act preferentially on nitric oxide releasing neurons in the esophagus leading to spastic esophageal motility. In one study, increased use of opioids was found to be associated with increased esophageal outflow obstruction, higher relaxation pressure, and manometric patterns similar to type III achalasia. While it is known that opioids can have deleterious effects on any part of gut motility, with the bowel the most often of concern, clinicians must be aware of effect of opioids on esophageal motility as well.