Effect of methylnaltrexone and naloxone on esophageal motor function in man

Impact of opioids on esophageal motility

Opioids are well known to cause adverse effects on the gastrointestinal tract including nausea, vomiting, and constipation. Data regarding how opioids affect the esophagus are more limited. Opioid-induced esophageal dysfunction (OIED) is a clinical syndrome defined by chronic opioid use (≥3 months), esophageal symptoms (mainly dysphagia), and esophageal motility abnormalities diagnosed by manometry including achalasia type III, hypercontractile esophagus, distal esophageal spasm, and esophagogastric junction outflow obstruction. Up until now, the effect of opioids on esophageal motility assessed by the functional lumen imaging probe (FLIP) had not been described. In this issue of NGM, Patel et al. report that FLIP assessment in patients with esophageal symptoms showed that chronic opioid users have a significant increase in repetitive retrograde contractions, but no significant reduction in distensibility at the esophagogastric junction compared to non-users. Additionally, perceptive symptoms were higher, and quality of life metrics were lower in the chronic opioid users. This review article will discuss our current understanding of OIED and provide context for this latest study in chronic opioid users. Further investigation with larger prospective studies is needed to understand the pathophysiology, diagnosis, and management of OIED.

Effects of remifentanil on pharyngeal swallowing and esophageal motility: no impact of different bolus volumes and partial antagonism by methylnaltrexone

Remifentanil impairs swallowing, and disturbed accommodation to bolus volume may be one of the underlying causes. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. So, this study aimed to investigate if remifentanil-induced swallowing dysfunction is dependent on the bolus volume and whether the effect of remifentanil could be counteracted by methylnaltrexone, a peripherally acting opioid antagonist. Nineteen healthy volunteers were included in this double-blinded, randomized, placebo-controlled, crossover study. Study participants received target-controlled remifentanil infusions and placebo infusions in a randomized order. Methylnaltrexone was administered by intravenous injection of doses of 0.3 mg/kg. Recordings of pressure and impedance data were acquired using a combined manometry and impedance solid-state catheter. Data were analyzed from three series of bolus swallows, baseline, during study medication exposure, and 15 min after methylnaltrexone. Remifentanil induced significant effects on multiple pharyngeal and esophageal function parameters. No significant differences in remifentanil-induced swallowing dysfunction related to different bolus volumes were found. Pharyngeal effects of remifentanil were not significantly counteracted by methylnaltrexone, whereas on the distal esophageal level, effects on distension pressures were counteracted. Changes in pharyngeal and esophageal pressure flow variables were consistent with previous results on remifentanil-induced swallowing dysfunction and uniform across all bolus volumes. The effects of remifentanil on the pharyngeal level and on the proximal esophagus appear to be predominantly centrally mediated, whereas the effects of remifentanil on the distal esophagus may be mediated by both central and peripheral mechanisms.NEW & NOTEWORTHY In this randomized controlled trial, we used the "Swallow Gateway" online platform to analyze the effects of remifentanil on pharyngeal and esophageal swallowing. It is not fully understood whether remifentanil-induced swallowing dysfunction is mediated by peripheral or central mechanisms. By using methylnaltrexone, we demonstrated that effects of remifentanil on pharyngeal swallowing were predominantly centrally mediated, whereas its effects on the distal esophagus may be mediated by both central and peripheral mechanisms.

Codeine induces increased resistance at the esophagogastric junction but has no effect on motility and bolus flow in the pharynx and upper esophageal sphincter in healthy volunteers: A randomized, double-blind, placebo-controlled, cross-over trial

BACKGROUND

Chronic opioid use can induce esophageal dysfunction with symptoms resembling achalasia and a manometric pattern of esophagogastric junction-outflow obstruction (EGJ-OO). However, the effect of opioids in acute setting on pharyngeal function and esophageal body contractility has not been investigated.

METHODS

After positioning the high-resolution impedance manometry (HRiM) catheter, codeine (60 mg) or placebo (glucose syrup) was infused intragastrically. Forty-five minutes post-infusion, participants received liquid, semi-solid, and solid boluses to assess esophageal and pharyngeal function. HRiM analysis was performed adhering to the Chicago classification v3.0. (CC v3.0). Pressure flow analysis (PFA) for the esophageal body and the pharynx was performed using the SwallowGateway™ online platform.

KEY RESULTS

Nineteen healthy volunteers (HV) [5 male; age 38.3] were included. After codeine administration, higher integrated relaxation pressure 4 s values resulted in significantly reduced deglutitive EGJ relaxation and distal latency was significantly shorter. Distal contractility was similar in both conditions. Bolus flow resistance at the EGJ and distention pressures increased significantly after codeine infusion. Based on CC v3.0, acute infusion of codeine induced EGJ-OO in six HV (p = 0.0003 vs. placebo). Codeine administration induced no significant alterations in any of the pharyngeal PFA metrics.

CONCLUSIONS & INFERENCES

In HV, acute administration of codeine increased bolus resistance at the EGJ secondary to induced incomplete EGJ relaxation leading to major motility disorders in a subset of subjects including EGJ-OO. However, an acute single dose of codeine did not affect motility or bolus flow in pharynx and UES. ClinicalTrials.gov number, NCT03784105.

Opioid-induce esophageal dysfunction, prevalence and manometric findings

BACKGROUND

Prescription opioids usage is on the rise. There has been an increasing recognition that chronic opioid consumption can result in esophageal motility disorders and this association has been named opioid-induced esophageal dysfunction (OIED).

AIMS

Analyze the prevalence of chronic opioid consumption in patients referred for esophageal motility testing in a European center and to describe the clinical characteristics and the association of opioid consumption in esophageal motility disorders. METHODS Retrospective descriptive study in patients who had HRM performed in a single center. The clinical history in the electronic medical reports was reviewed. RESULTS The prevalence of opioid prescription in patients referred to our institution was 10.1% and 4.8% patients were on active chronic opioid use. We found a 32% prevalence of OIED. Comparing chronic active opioid user (CAOU) patients with OIED and CAOU patients without OIED, there was a higher prevalence of male sex (43.8% vs 8.8% p value=0.007). Converting the different opioids medication to morphine milligram equivalent daily dose (MMED), CAOU patients with OIED had a higher MMED than CAOU patients without OIED (125.2±31.3 vs 33.4±5.7 MME p=0.041). Dysphagia was the most common indication for performing an HRM in 60.0% in CAOU patients. Furthermore, dysphagia was more frequent in CAOU patients with OIED (87.5% vs 47.0% p= 0.019). CONCLUSIONS Patients on chronic opioids with OIED complained mostly dysphagia. We found an association of male sex and a higher dose of opioids in CAOU patients with esophageal motility disorders.

Esophageal Dysphagia in the Elderly

PURPOSE OF REVIEW

With a globally aging population, dysphagia is a growing health concern among elderly. Increasing reflux disease has contributed to an increased prevalence of dysphagia from peptic strictures and esophageal cancer. Dysphagia can lead to malnutrition and aspiration pneumonia, causing considerable morbidity and mortality. This review article focuses on recent advances in the approach and management of esophageal dysphagia.

RECENT FINDINGS

Endoscopic functional luminal imaging probe is a novel test that complements upper endoscopy, esophagram, and esophageal manometry for evaluation of esophageal dysphagia. Opioid induced esophageal dysfunction (OIED) is an emerging clinical entity that can mimic achalasia. Strictures refractory to dilation can be treated with intralesional steroid injections, electrosurgical incision, or esophageal stents. Peroral endoscopic myotomy (POEM) is gaining in popularity for treatment of achalasia and other spastic disorders of esophagus. Treatment of esophageal dysphagia may include proton pump inhibitors, endoscopic dilation, or surgery and requires a personalized approach based on risks and benefits. POEM is a valuable therapy for achalasia, but further studies are needed to evaluate its use, and other alternatives, for treatment of OIED and spastic esophageal disorders.

Opioid-Induced Foregut Dysfunction

The impact of opioid use on the lower gastrointestinal tract is well described, but recent opioid crisis has caused increased awareness of the detrimental effects of these drugs on esophageal and gastroduodenal motility. Opioid use has been associated with increased incidence of spastic esophageal motility disorders and gastroduodenal dysfunction. Opioid receptors are present with high abundance in the myenteric and submucosal plexus of the enteric nervous system. Activation of these receptors leads to suppressed excitability of the inhibitory musculomotor neurons and unchecked tonic contraction of the autogenic musculature (such as the lower esophageal sphincter and the pylorus).

Reduction in pain: Is it worth the gain? The effect of opioids on the GI tract

The use of opioid medications for acute and chronic pain has increased significantly in the past 20 years in the United States. Given the high density of opioid receptors in the gastrointestinal tract, side effects are common in these patients including constipation, dysphagia, bloating, nausea, and vomiting. These side effects, which are experienced by most patients who take opioids, can lead to significant impairment in quality of life. Unlike other side effects from opioids, gastrointestinal side effects do not diminish with continued use, often leading patients to reduce or discontinue their opioid treatment to relieve these side effects. Therefore, physicians must be aware and anticipate potential side effects in patients receiving opioids to ensure appropriate pain management.

Severity of ineffective esophageal motility is associated with utilization of skeletal muscle relaxant medications

BACKGROUND

Ineffective esophageal motility (IEM) is the most common finding on high-resolution esophageal manometry (HREM). The underlying mechanisms for IEM remain to be fully elucidated. The aim of this study was to determine if utilization of skeletal muscle relaxants is associated with IEM, and with more severe subtypes of the disorder.

METHODS

Patients with diagnosis of IEM were gender and age matched to patients with normal HREM. Demographic information, symptoms, endoscopic findings, medication usage and medical comorbidities were recorded. Patients with a diagnosis of IEM were divided into subgroups based on mean distal contractile integral (DCI) and percentage of ineffective swallows, and assessed for clinically significant differences among patients with varying severity of underlying IEM.

KEY RESULTS

A total of 118 patients were included in each group. There were no significant clinical differences between the group of patients with IEM and the group of patients with normal manometry. Within the group of IEM patients, those with mean DCI < 250 mm Hg/s/cm were more likely to be prescribed skeletal muscle relaxants (27.8% vs 11.0%, P = .044), and those using skeletal muscle relaxants had a larger mean percentage of ineffective swallows (81.1% vs 71.5%, P = .029). There were no significant differences across mean DCI subgroups in usage of any other medication, or in any of the demographic variables or disease comorbidities examined in this study.

CONCLUSIONS & INFERENCES

Use of skeletal muscle relaxants is associated with more severe IEM, which may suggest a causal association between this class of medications and weaker esophageal peristalsis.