Lower oesophageal sphincter hypersensitivity to opioid receptor stimulation in patients with idiopathic achalasia

The Esophageal Response to Distension on Functional Lumen Imaging Probe Panometry Is Minimally Changed by Conscious Sedation in Healthy Asymptomatic Subjects

Background/Aims

Functional lumen imaging probe (FLIP) Panometry has demonstrated utility in the assessment of esophageal motility as a complement to existing methodologies like high-resolution manometry. However, as FLIP is typically performed with sedation during routine endoscopy, there is potential for impact of sedation agents on esophageal motility. We aim to examine the effects of conscious sedation with midazolam and fentanyl on FLIP Panometry metrics and classification.

Methods

A cross-over study was conducted on 12 healthy, asymptomatic volunteers that completed FLIP while sedated with intravenous fentanyl and midazolam and while awake on a separate day. FLIP was performed in the same manner in both conditions with transoral placement of the FLIP and stepwise FLIP filling. During awake FLIP, subjects also rated the presence and intensity of esophageal perception.

Results

In both experimental conditions, all subjects demonstrated normal motility. The esophagogastric junction distensibility index was lower (median [interquartile range]: 5.8 [5.15-6.85] vs 8.9 [7.68-9.38] mm2/mmHg; P = 0.025), and the FLIP pressure was higher (46.5 [38.125-52.5] vs 33 [26-36.8] mmHg; P = 0.010) in the sedated condition compared to the awake condition. Maximum esophagogastric junction diameter and body distensibility plateau were no different between conditions (P = 0.999 and P = 0.098, respectively). Perception of esophageal sensation during awake FLIP was reported in 7/12 (58%) subjects.

Conclusions

While numeric differences in FLIP Panometry metrics were observed between sedated and awake FLIP in healthy subjects, these differences did not change the FLIP Panometry diagnosis. Sedated FLIP offers a well-tolerated method to assess esophageal motility during endoscopy.

Active narcotic use and post-peroral endoscopic myotomy outcomes in esophageal motility disorders

BACKGROUND AND AIMS

Peroral endoscopic myotomy (POEM) is a minimally invasive technique used to treat esophageal motility disorders. Opioid use has been demonstrated to adversely affect esophageal dysmotility and is associated with an increased prevalence of esophageal motility disorders. Our aim was to investigate the effect of narcotic use on success rates in patients undergoing POEM.

METHODS

This was a single-center, retrospective study of patients undergoing POEM between February 2017 and September 2021. Primary outcomes were post-POEM Eckardt score (ES), distensibility index, and length of procedure. Secondary outcomes included technical success, myotomy length, length of stay, adverse events, reintervention rates, and postprocedure GERD.

RESULTS

During the study period, 90 patients underwent POEM for treatment of esophageal dysmotility disorders. Age, sex, race, indications for POEM, and body mass index were not significant between those with or without narcotic use. There were no differences in procedure time, preprocedure ESs, or length of stay. Postprocedure ESs were higher in the group with active narcotic use compared to the group with no prior history (2.73 vs 1.2, P = .004). Distensibility indexes measured with EndoFLIP (Medtronic, Minneapolis, Minn, USA) were not different in patients using narcotics compared with opioid-naïve patients.

CONCLUSION

Active narcotic use negatively affects symptom improvement after POEM for the treatment of esophageal motility disorders.

Effects of Codeine on Esophageal Peristalsis in Patients With Ineffective Esophageal Motility: Studies Using High-resolution Manometry

Background/Aims

This study aims to evaluate the effects of acute codeine administration on primary and secondary esophageal peristalsis in patients with ineffective esophageal motility (IEM).

Methods

Eighteen IEM patients (8 women; mean age 37.8 years, range 23-64 years) were enrolled in the study. The patients underwent high-resolution manometry exams, consisting of 10 single wet swallows, multiple rapid swallows, and ten 20 mL rapid air injections to trigger secondary peristalsis. All participants completed 2 separate sessions, including acute administration of codeine (60 mg) and placebo, in a randomized order.

Results

Codeine significantly increased the distal contractile integral (566 ± 81 mmHg∙s∙cm vs 247 ± 36 mmHg∙s∙cm, P = 0.001) and shortened distal latency (5.7 ± 0.2 seconds vs 6.5 ± 0.1 seconds, P < 0.001) for primary peristalsis compared with these parameters after placebo treatment. The mean total break length decreased significantly after codeine treatment compared with the length after placebo (P = 0.003). Codeine significantly increased esophagogastric junction-contractile integral (P = 0.028) but did not change the 4-second integrated relaxation pressure (P = 0.794). Codeine significantly decreased the frequency of weak (P = 0.039) and failed contractions (P = 0.009), resulting in increased frequency of normal primary peristalsis (P < 0.136). No significant differences in the ratio of impaired multiple rapid swallows inhibition and parameters of secondary peristalsis were detected.

Conclusions

In IEM patients, acute administration of codeine increases contraction vigor and reduces distal latency of primary esophageal peristalsis, but has no effect on secondary peristalsis. Future studies are required to further elucidate clinical relevance of these findings, especially in the setting of gastroesophageal reflux disease with IEM.

Chronic opioid use is associated with obstructive and spastic disorders in the esophagus

BACKGROUND AND AIMS

Chronic opioid effects on the esophagus are poorly understood. We investigated whether opioids were associated with increased prevalence of esophageal motility disorders.

METHODS

A retrospective study of all patients undergoing high-resolution manometry (HREM) at the Yale Gastrointestinal Motility Lab between January 2014 and August 2019. Data were extracted from the electronic medical record after studies were reviewed by two motility specialists using the Chicago Classification v.3.0. We compared the manometric results of patients who use opioids to those who do not and adjusted for type and dose of opioids using a 24 h Morphine Milligram Equivalents (MME) scale to compare patients taking low or high amounts of opioids.

RESULTS

Four manometric abnormalities were significantly different between the opioid and non-opioid users. Achalasia type III, esophagogastric junction outflow obstruction (EGJOO), and distal esophageal spasm (DES) (p < 0.005, p < 0.01, and p < 0.005, respectively) were common among opioid users, whereas ineffective esophageal motility (IEM) was more common among non-opioid users (p < 0.01). The incidence of EGJOO was significantly higher in opioid users compared to non-opioid users (p < 0.001). Lastly, IRP, DCI, and distal latency were significantly different between the two groups. Patients in the high MME group had significantly greater IRP, DCI, and lower distal latency than non-opioids (p < 0.001). Also, achalasia type III and DES were more common in the high but not the low MME group.

CONCLUSIONS

Opioid use is associated with multiple abnormalities on esophageal motility and these effects may be dose-dependent.

Effects of codeine on esophageal peristalsis in humans using high resolution manometry

BACKGROUND AND AIM

Opioid receptors agonists have been demonstrated to impair lower esophageal sphincter (LES) relaxation and induce spastic esophageal dysmotility, but little was known for their impact on distension-induced secondary peristalsis. The aim of the study was to investigate the hypothesis whether acute administration of codeine can influence physiological characteristics of primary and secondary peristalsis in healthy adults.

METHODS

Eighteen healthy volunteers (13 men, mean age 27.5 years, aged 20-43 years) underwent high resolution manometry (HRM) with a catheter containing an injection port in mid-esophagus. Secondary peristalsis was performed with 10 and 20 mL rapid air injections. Two different sessions including acute administration of codeine (60 mg) or the placebo were randomly performed.

RESULTS

Codeine significantly increased 4-s integrated relaxation pressure (IRP-4s) (P = 0.003) and shortened distal latency (DL) (P = 0.003) of primary peristalsis. The IRP-4s of secondary peristalsis was also significantly higher after codeine than the placebo during air injections with 10 mL (P = 0.048) and 20 mL (P = 0.047). Codeine significantly increased the frequency of secondary peristalsis during air injections with 10 mL than the placebo (P = 0.007), but not for air injection with 20 mL (P = 0.305).

CONCLUSIONS

In addition to impair LES relaxation and reduce distal latency of primary peristalsis, codeine impairs LES relaxation of secondary peristalsis and increases secondary peristaltic frequency. Our study supports the notion in human esophagus that the impact of opioids on peristaltic physiology appears to be present in both primary and secondary peristalsis.

Same-day opioid administration in opiate naïve patients is not associated with opioid-induced esophageal dysfunction (OIED)

BACKGROUND

Opioid-induced esophageal dysfunction (OIED) is a recognized complication of chronic opioid use. However, the impact of acute opioid administration on esophageal motility remains unclear.

METHODS

Opioid naïve patients with high-resolution manometry (HRM) <480 min following esophagogastroduodenoscopy (EGD) (opioid-HRM) and a control group with HRM <36 h prior to EGD between January 1, 2016, and November 10, 2018, from a single institution were identified. EGDs were performed exclusively with versed and fentanyl.

KEY RESULTS

One hundred and seventy-four patients were identified, with 83 (47.7%) opioid-HRM and 91 (52.3%) controls. Mean time from EGD to HRM was 229 (78-435) min. Baseline clinical features and HRM indications were similar between opioid-HRM and controls. Chicago classification v3.0 defined HRM findings were similar between groups. Major motility disorders as defined by the Chicago classification v3.0 occurred at a similar frequency among opioid-HRM and controls (27.7% vs. 36.3%, p = 0.23). Mean distal contractile integrity (DCI) was higher in opioid-HRM (1939.3 ± 1318.9 vs. 1792.2 ± 2062.3 mmHg∙cm∙s, p = 0.043), but maximum DCI, distal latency, and integrated relaxation pressure did not differ between groups. Subgroup analysis assessing time and dose dependency did not identify differences in individual manometric parameters and Chicago classification v3.0 diagnosis between patients with HRM <240 min after EGD, >240 min after EGD, ≥125 mcg of IV fentanyl, <125 mcg IV fentanyl and controls.

CONCLUSIONS AND INFERENCES

Same-day acute opioid administration did not affect HRM findings in opioid naïve patients. Studies assessing the pathophysiology of and duration-dependent relationship with opioids in OIED are needed.

Esophagogastric Junction Outflow Obstruction: Current Approach to Diagnosis and Management

PURPOSE OF REVIEW

We summarize the current epidemiology, presentation, diagnostic workup, and treatment of esophagogastric junction outflow obstruction (EGJOO). We also propose a treatment algorithm based upon the literature and our personal clinical experience.

RECENT FINDINGS

EGJOO can be caused by functional obstruction (akin to achalasia), mechanical obstruction, medications, or artifact. High-resolution esophageal manometry is currently the gold standard of diagnosis. Recent research on FLIP (functional lumen imaging probe) and timed barium support use as adjunctive testing. The diagnostic yield of cross-sectional imaging is low. Current diagnostic testing and treatment should be targeted to the suspected underlying etiology and clinical presentation of EGJOO. If functional obstruction is present with significant and persistent dysphagia, and either an abnormal FLIP or timed barium swallow, we consider therapy aimed at LES disruption (similar to achalasia). Pharmacologic therapy has a limited role. More research is needed on diagnostic and treatment modalities.

Opioid-Induced Esophageal Dysfunction: Differential Effects of Type and Dose

OBJECTIVE

Data regarding opioid effects on esophageal function are limited. We previously demonstrated an association between chronic opioid use and esophageal motor dysfunction characterized by esophagogastric junction outflow obstruction, distal esophageal spasm, achalasia type III, and possibly Jackhammer esophagus. Our aim was to characterize the influence of different opioids and doses on esophageal dysfunction.

METHODS

Retrospective review of 225 patients prescribed oxycodone, hydrocodone, or tramadol for >3 months, who completed high-resolution manometry from 2012 to 2017. Demographic and manometric data were extracted from a prospectively maintained motility database. Frequency of opioid-induced esophageal dysfunction (OIED, defined as distal esophageal spasm, esophagogastric junction outflow obstruction, achalasia type III, or Jackhammer esophagus on high-resolution manometry, was compared among different opioids. The total 24-hour opioid doses for oxycodone, hydrocodone, and tramadol were converted to a morphine equivalent for dose effect analysis.

RESULTS

OIED was present in 24% (55 of 225) of opioid users. OIED was significantly more prevalent with oxycodone or hydrocodone use compared with tramadol (31% vs 28% vs 12%, P = 0.0162), and for oxycodone alone vs oxycodone with acetaminophen (43% vs 21%, P = 0.0482). There was no difference in OIED for patients taking hydrocodone alone vs hydrocodone with acetaminophen. Patients with OIED were taking a higher median 24-hour opioid dose than those without OIED (45 vs 30 mg, P = 0.058).

DISCUSSION

OIED is more prevalent in patients taking oxycodone or hydrocodone compared with tramadol. There is greater likelihood of OIED developing with higher doses. Reducing the opioid dose or changing to tramadol may reduce OIED in opioid users.

Implications of the Opioid Epidemic for the Clinical Gastroenterology Practice

PURPOSE OF REVIEW

The opioid epidemic in the USA has led to a rise in opioid-related gastrointestinal (GI) side effects that are often difficult to diagnose and treat. The aim of this report is to discuss opioid pathophysiology, opioid-related GI side effects, clinical presentation, and diagnostic criteria and to review the current pharmacotherapy available.

RECENT FINDINGS

Opioid-related GI disorders are increasingly recognized and include, but are not limited to, opioid-induced esophageal dysfunction (OIED), gastroparesis, opioid-induced constipation (OIC), narcotic bowel syndrome (NBS), acute post-operative ileus, and anal sphincter dysfunction. Treatment of these conditions is challenging. OIC has the most available pharmacotherapy for treatment, including classical laxatives, peripherally acting μ-receptor antagonists (PAMORAs), novel therapies (lubiprostone, prucalopride- 5-HT agonist), and preventative therapies (PR oxycodone/naloxone). The gastrointestinal effects of opioid therapy are variable and often debilitating. While medical management for some opioid-related GI side effects exists, limiting or completely avoiding opioid use for chronic non-cancer pain will mitigate these effects most effectively.

Cannabis Use in Patients Presenting to a Gastroenterology Clinic: Associations with Symptoms, Endoscopy Findings, and Esophageal Manometry

Recreational cannabis use is increasing with its legalization in many states. Animal studies suggest cannabis can reduce transient lower esophageal sphincter relaxations (TLESRS), reflux and vomiting, while human studies report conflicting findings. There are currently no large studies investigating gastrointestinal symptoms in patients with chronic cannabis use. This was a retrospective case-control study including patients who presented to an outpatient Gastroenterology office, with documented cannabis use. Their main presenting complaint, demographics, frequency and duration of cannabis use, endoscopic and high-resolution esophageal manometry (HREM) with impedance findings were recorded. Cannabis users were more likely to complain of abdominal pain (25% vs. 8%, p < 0.0001), heartburn (15% vs. 9%, p < 0.0001), and nausea & vomiting (7% vs. 1%, p < 0.0001). They were also more likely to have findings of esophagitis (8% vs. 3%, p = 0.0002), non-erosive gastritis (30% vs. 15%, p = 0.0001) and erosive gastritis (14% vs. 3%, p < 0.0001) on upper endoscopy. Cannabis users were more likely to have impaired esophageal bolus clearance (43% vs. 17%, p = 0.04) and a hypertensive lower esophageal sphincter (LES) (29% vs. 7%, p = 0.04). This study is the largest to date evaluating GI complaints of patients with chronic recreational cannabis use. Our results suggest that cannabis use may potentiate or fail to alleviate a variety of GI symptoms which goes against current knowledge.

Lower prevalence of gastroesophageal reflux disease in patients with noncardiac chest pain on opiates: a cross-sectional study

Opiates can cause heartburn and spastic esophageal dysmotility but their role in noncardiac chest pain (NCCP) is not known. Our aim was to characterize opiate effects on esophageal function using esophageal pH monitoring and high-resolution manometry (HREM) in these patients.We performed a cross sectional study of opiate users with NCCP who underwent HREM and esophageal pH study from 2010 to 2017 using opiate nonusers as a comparison group. Demographic data, symptoms, opiate use, endoscopic findings, esophageal pH study parameters, and HREM data were abstracted.Thirty three patients with NCCP on opiates were compared to 144 opiate non-users. Compared to opiate nonusers, opiate users had lower total acid exposure (2.3% vs. 3%, P = 0.012), lower upright acid exposure (1.2% vs. 3.1%, P = 0.032) and lower DeMeester score (6.5 vs. 12.7, P = 0.016). Opiate users also had higher lower esophageal sphincter integrated relaxation pressure (LES-IRP) (7.0 mm Hg [2.2, 11.7] vs. 3.7 mm Hg [1.1, 6.2] P = 0.011) and greater mean distal contractile integral (DCI) (2575 mm.Hg.s.cm [1134, 4466] vs. 1409 mm.Hg.s.cm [796, 3003] P = 0.03) than opiate non-users. The prevalence of hypertensive motility disorders (15.2% vs. 11.1%) and achalasia (12.1% vs. 2.1%) was higher in opiate users (P = 0.039) but did not reach significance on multivariate analysis.In patients presenting with NCCP, opiate users had lower esophageal acid exposure compared to opiate nonusers. This might be due to higher LES pressures preventing reflux and higher DCI leading to more rapid acid esophageal clearance.

Opioid misuse in gastroenterology and non-opioid management of abdominal pain

Opioids were one of the earliest classes of medications used for pain across a variety of conditions, but morbidity and mortality have been increasingly associated with their chronic use. Despite these negative consequences, chronic opioid use is increasing worldwide, with the USA and Canada having the highest rates. Chronic opioid use for noncancer pain can have particularly negative effects in the gastrointestinal and central nervous systems, including opioid-induced constipation, narcotic bowel syndrome, worsening psychopathology and addiction. This Review summarizes the evidence of opioid misuse in gastroenterology, including the lack of evidence of a benefit from these drugs, as well as the risk of harm and negative consequences of opioid use relative to the brain-gut axis. Guidelines for opioid management and alternative pharmacological and nonpharmacological strategies for pain management in patients with gastrointestinal disorders are also discussed. As chronic pain is complex and involves emotional and social factors, a multimodal approach targeting both pain intensity and quality of life is best.

Opioid-Induced Constipation and Bowel Dysfunction: A Clinical Guideline

OBJECTIVE

To formulate timely evidence-based guidelines for the management of opioid-induced bowel dysfunction.

SETTING

Constipation is a major untoward effect of opioids. Increasing prescription of opioids has correlated to increased incidence of opioid-induced constipation. However, the inhibitory effects of opioids are not confined to the colon, but also affect higher segments of the gastrointestinal tract, leading to the coining of the term "opioid-induced bowel dysfunction."

METHODS

A literature search was conducted using Medline, EMBASE, and EMBASE Classic, and the Cochrane Central Register of Controlled Trials. Predefined search terms and inclusion/exclusion criteria were used to identify and categorize relevant papers. A series of statements were formulated and justified by a comment, then labeled with the degree of agreement and their level of evidence as judged by the Strength of Recommendation Taxonomy (SORT) system.

RESULTS

From a list of 10,832 potentially relevant studies, 33 citations were identified for review. Screening the reference lists of the pertinent papers identified additional publications. Current definitions, prevalence, and mechanism of opioid-induced bowel dysfunction were reviewed, and a treatment algorithm and statements regarding patient management were developed to provide guidance on clinical best practice in the management of patients with opioid-induced constipation and opioid-induced bowel dysfunction.

CONCLUSIONS

In recent years, more insight has been gained in the pathophysiology of this "entity"; new treatment approaches have been developed, but guidelines on clinical best practice are still lacking. Current knowledge is insufficient regarding management of the opioid side effects on the upper gastrointestinal tract, but recommendations can be derived from what we know at present.

Opioids in Gastroenterology: Treating Adverse Effects and Creating Therapeutic Benefits

The use of opioid medications on both an acute and chronic basis is ubiquitous in the United States. As opioid receptors densely populate the gastrointestinal tract, symptoms and side effects can be expected in these patients. In the esophagus, dysmotility may result, manifesting with dysphagia and a syndrome indistinguishable from primary achalasia. In the stomach, a marked delay in gastric emptying may occur with postprandial nausea and early satiety. Postoperatively, particularly with abdominal surgery, opioid-induced ileus may ensue. In the colon, opioid-induced constipation is common. A unique syndrome termed narcotic bowel syndrome is characterized by chronic abdominal pain often accompanied by nausea and vomiting in the absence of other identifiable causes. With the recognition of the important role of opioids on gastrointestinal function, novel drugs have been developed that use this physiology. These medications include peripheral acting opioid agonists to treat opioid-induced constipation and combination agonist and antagonists used for diarrhea-predominant irritable bowel syndrome. This review summarizes the most recent data in these areas.

Achalasia and chronic opiate use: innocent bystanders or associated conditions?

High-resolution manometry identifies three subtypes of achalasia. However, type 3 differs from classic achalasia. Although opiates affect esophageal motility, opiate use and achalasia have not been studied. Patients with a new diagnosis of achalasia at Mayo Clinic Rochester between June 1, 2012 and January 3, 2014 were identified. Clinical records were reviewed to assess symptoms, opiate use, and therapy. Fifty-six patients with achalasia were identified, 14 (25%) were on opiates. Opiate prescription was unrelated to achalasia in all cases, with chronic back and joint pain constituting the majority. Of patients on opiates, five (36%) had type 3 achalasia compared with four (10%) not on opiates (P = 0.02). No patients on opiates had type 1 achalasia. Clinical presentation did not differ with opiates, although those on opiates were more likely to report chest pain (39 vs. 14%, P = 0.05) and less likely to have esophageal dilation (62 vs. 82%, P = 0.13), none with greater than 5-cm diameter. Contractile vigor was greater with opiate use, with distal contractile integral of 7149 versus 2615.5 mmHg/cm/second (P = 0.08). Treatment response was inferior on opiates, with persistent symptoms in 22% compared with 3% without opiates (P = 0.06). Opiate use is common in type 3 achalasia, with the majority of patients on opiates. No patients on opiates were diagnosed with type 1 achalasia. Manometric findings of type 3 achalasia mimic those induced by opiates, suggesting a physiologic mechanism for opiate induced type 3 achalasia. Treatment outcome is inferior with opiates, with opiate cessation perhaps preferable. Further studies assessing opiate use and achalasia are needed.

Pharmacotherapy for the management of achalasia: Current status, challenges and future directions

This article reviews currently available pharmacological options available for the treatment of achalasia, with a special focus on the role of botulinum toxin (BT) injection due to its superior therapeutic effect and side effect profile. The discussion on BT includes the role of different BT serotypes, better pharmacological formulations, improved BT injection techniques, the use of sprouting inhibitors, designer recombinant BT formulations and alternative substances used in endoscopic injections. The large body of ongoing research into achalasia and BT may provide a stronger role for BT injection as a form of minimally invasive, cost effective and efficacious form of therapy for patients with achalasia. The article also explores current issues and future research avenues that may prove beneficial in improving the efficacy of pharmacological treatment approaches in patients with achalasia.

Effects of remifentanil on esophageal motility: a double-blind, randomized, cross-over study in healthy volunteers

BACKGROUND

Recent studies have shown that remifentanil increases the risk of aspiration and induces subjective swallowing difficulties. The mechanisms are not completely understood. Here, we investigated whether remifentanil impairs esophageal motility and hypothesized that this is one possible underlying mechanism. Naloxone was used to evaluate whether the effects of remifentanil are mediated through opioid receptors. We also examined subjective swallowing difficulties and the influence of metoclopramide on remifentanil-induced effects.

METHODS

Fourteen healthy volunteers participated in a double-blind, randomized, cross-over trial at the University Hospital in Örebro, Sweden. They were studied on two different occasions, during which they were randomly assigned to receive either naloxone given as a bolus of 6 μg/kg followed by an infusion of 0.1 μg/kg/min, or saline 5 min before target-controlled infusions of remifentanil at three target-site concentrations: 1, 2, and 3 ng/ml. On both occasions, 0.2 mg/kg metoclopramide was given before the final measurement. Five swallows were performed during each measuring condition, and the metrics defining esophageal motility were measured by high-resolution manometry. Outcomes were differences in the metrics at baseline vs. during remifentanil infusion, with naloxone vs. placebo, and with remifentanil before and after metoclopramide administration. Differences in swallowing difficulties were also recorded.

RESULTS

Remifentanil decreased swallow-evoked esophagogastric junction relaxation and the latency time of esophageal peristalsis. There were no significant effects of naloxone or metoclopramide on remifentanil-induced effects, and we detected no differences in swallowing difficulties.

CONCLUSIONS

Remifentanil induces dysfunction of esophageal motility; this may contribute to the elevated risk of regurgitation and aspiration.

Opioid-Induced Esophageal Dysfunction (OIED) in Patients on Chronic Opioids

OBJECTIVES

Bowel dysfunction has been recognized as a predominant side effect of opioid use. Even though the effects of opioids on the stomach and small and large intestines have been well studied, there are limited data on opioid effects on esophageal function. The aim of this study was to compare esophageal pressure topography (EPT) of patients taking opioids at the time of the EPT (≤24 h) with chronic opioid users who were studied off opioid medications for at least 24 h using the Chicago classification v3.0.

METHODS

A retrospective review identified 121 chronic opioid users who completed EPT between March 2010 and August 2012. Demographic and manometric data were compared between the two groups using general linear models or χ(2).

RESULTS

Of the 121 chronic opioid users, 66 were studied on opioid medications (≤24 h) and 55 were studied off opioid medications for at least 24 h. Esophagogastric junction (EGJ) outflow obstruction was significantly more prevalent in patients using opioids within 24 h compared with those who did not (27% vs. 7%, P=0.004). Mean 4 s integrated relaxation pressure was also significantly higher in patients studied on opioids (10.71 vs. 6.6 mm Hg, P=0.025). Resting lower esophageal sphincter pressures tended to be higher on opioids (31.61 vs. 26.98 mm Hg, P=0.25). Distal latency was significantly lower in patients studied on opioids (6.15 vs. 6.74 s, P=0.044).

CONCLUSIONS

Opioid use within 24 h of EPT is associated with more frequent EGJ outflow obstruction and spastic peristalsis compared with when opioid use is stopped for at least 24 h before the study.

Clinical potential of naloxegol in the management of opioid-induced bowel dysfunction

Opioid-induced bowel dysfunction (OIBD) is a burdensome condition which limits the therapeutic benefit of analgesia. It affects the entire gastrointestinal tract, predominantly by activating opioid receptors in the enteric nervous system, resulting in a wide range of symptoms, such as reflux, bloating, abdominal cramping, hard, dry stools, and incomplete evacuation. The majority of studies evaluating OIBD focus on constipation experienced in approximately 60% of patients. Nevertheless, other presentations of OIBD seem to be equally frequent. Furthermore, laxative treatment is often insufficient, which in many patients results in decreased quality of life and discontinuation of opioid treatment. Novel mechanism-based pharmacological approaches targeting the gastrointestinal opioid receptors have been marketed recently and even more are in the pipeline. One strategy is prolonged release formulation of the opioid antagonist naloxone (which has limited systemic absorption) and oxycodone in a combined tablet. Another approach is peripherally acting, μ-opioid receptor antagonists (PAMORAs) that selectively target μ-opioid receptors in the gastrointestinal tract. However, in Europe the only PAMORA approved for OIBD is the subcutaneously administered methylnaltrexone. Alvimopan is an oral PAMORA, but only approved in the US for postoperative ileus in hospitalized patients. Finally, naloxegol is a novel, oral PAMORA expected to be approved soon. In this review, the prevalence and pathophysiology of OIBD is presented. As PAMORAs seem to be a promising approach, their potential effect is reviewed with special focus on naloxegol's pharmacological properties, data on safety, efficacy, and patient-focused perspectives. In conclusion, as naloxegol is administered orally once daily, has proven efficacious compared to placebo, has an acceptable safety profile, and can be used as add-on to existing pain treatment, it is a welcoming addition to the targeted treatment possibilities for OIBD.

Rapid air infusion into the oesophagus: Motor response in patients with achalasia and nonobstructive dysphagia assessed with high-resolution manometry

BACKGROUND

Achalasia is a neurodegenerative disorder of the oesophagus. Alteration of motor activity induced by oesophageal distension has not been explored.

OBJECTIVES

To investigate this function, using high-resolution Manometry.

METHODS

This study enrolled 15 healthy subjects, 15 nonobstructive dysphagia (NOD), and 18 achalasia patients successfully treated with pneumatic dilation (six with restored peristalsis). The three groups underwent five rapid (<1 s) intraoesophageal infusions of 20-ml air boluses, followed by eight 5-ml water swallows.

RESULTS

WHEREAS THE RESPONSE RATE TO WATER SWALLOWS WAS SIMILAR IN THE THREE GROUPS, AIR INFUSION INDUCED A LOWER RESPONSE RATE IN ACHALASIA (MEDIAN, INTERQUARTILE RANGE: 70%, 40-100%) and, to a lesser extent, in NOD patients (100%, 60-100%) than in healthy subjects (100%, 100-100%; p < 0.001 and p = 0.06, respectively). However, the response rate was highly variable in achalasia patients irrespective of presence of peristalsis. Furthermore, the strength of motor response to air infusion when compared to water swallows was diminished in achalasia patients but not in healthy subjects and NOD.

CONCLUSIONS

Motor response to rapid air infusion was variably impaired in achalasia. The role of this alteration in the long-term outcome deserves evaluation.

Effect of Cold Water on Esophageal Motility in Patients With Achalasia and Non-obstructive Dysphagia: A High-resolution Manometry Study

Background/Aims

Swallowing of cold liquids decreases amplitude and velocity of peristalsis in healthy subjects, using standard manometry. Patients with achalasia and non obstructive dysphagia may have degeneration of sensory neural pathways, affecting motor response to cooling. To elucidate this point, we used high-resolution manometry.

Methods

Fifteen healthy subjects, 15 non-obstructive dysphagia and 15 achalasia patients, after pneumatic dilation, were studied. The 3 groups underwent eight 5 mL single swallows, two 20 mL multiple rapid swallows and 50 mL intraesophageal water infusion (1 mL/sec), using both water at room temperature and cold water, in a randomized order.

Results

In healthy subjects, cold water reduced distal contractile integral in comparison with water at room temperature during single swallows, multiple rapid swallows and intraesophageal infusion (ratio cold/room temperature being 0.67 [95% CI, 0.48-0.85], 0.56 [95% CI, 0.19-0.92] and 0.24 [95% CI, 0.12-0.37], respectively). A similar effect was seen in non-obstructive dysphagia patients (0.68 [95% CI, 0.51-0.84], 0.69 [95% CI, 0.40-0.97] and 0.48 [95% CI, 0.20-0.76], respectively), whereas no changes occurred in achalasia patients (1.06 [95% CI, 0.83-1.29], 1.05 [95% CI, 0.77-1.33] and 1.41 [95% CI, 0.84-2.00], respectively).

Conclusions

Our data suggest impairment of esophageal reflexes induced by cold water in patients with achalasia, but not in those with non obstructive dysphagia.

Opioid-induced bowel dysfunction: pathophysiology and management

Opioids are the most commonly prescribed medications to treat severe pain in the Western world. It has been estimated that up to 90% of American patients presenting to specialized pain centres are treated with opioids. Along with their analgesic properties, opioids have the potential to produce substantial side effects, such as nausea, cognitive impairment, addiction and urinary retention. In the gut, opioids exert their action on the enteric nervous system, where they bind to the myenteric and submucosal plexuses, causing dysmotility, decreased fluid secretion and sphincter dysfunction, which all leads to opioid-induced bowel dysfunction (OIBD). In the clinic, this is reported as nausea, vomiting, gastro-oesophageal reflux-related symptoms, constipation, etc. One of the most severe symptoms is constipation, which can be assessed using different scales for subjective assessment. Objective methods such as radiography and colonic transit time can also be used, together with manometry and evaluation of anorectal function to explore the pathophysiology. Dose-limiting adverse symptoms of OIBD can lead to insufficient pain treatment. Even though several treatment strategies are available, the side effects are still a major challenge. Traditional laxatives are normally prescribed but they are often insufficient to alleviate symptoms, especially those from the upper gastrointestinal tract. Newer prokinetics, such as prucalopride and lubiprostone, may be more effective in alleviating OIBD. Another treatment approach is co-administration of opioid antagonists, which either cannot cross the blood-brain barrier or selectively target opioid receptors in the gastrointestinal tract. However, although these new agents have proved to be more efficacious than placebo, clinical trials still need to prove their superiority to standard co-prescribed laxative regimes.

Effect of gluten-free diet on preventing recurrence of gastroesophageal reflux disease-related symptoms in adult celiac patients with nonerosive reflux disease

BACKGROUND AND AIM

In celiac disease (CD) the role of a gluten-free diet (GFD) on gastroesophageal reflux disease-related symptoms (GERD-rs) is unclear. The aim of this study was to establish the recurrence of GERD-rs, in CD patients with nonerosive reflux disease (NERD).

METHODS

From a total of 105 adult CD patients observed, 29 who presented with the NERD form were enrolled in the study. Thirty non-CD patients with NERD were studied as controls. Recurrence of GERD-rs was clinically assessed at 6, 12, 18, and 24 months follow-up (FU) after withdrawal of initial proton-pump inhibitor (PPI) treatment for 8 weeks.

RESULTS

GERD-rs were resolved in 25 (86.2%) CD patients and in 20 (66.7%) controls after 8 weeks of PPI treatment. In the CD group, recurrence of GERD-rs was found in five cases (20%) at 6 months but in none at 12, 18, and 24 months while in the control group recurrence was found in six of 20 controls (30%), in another six (12/20, 60%), in another three (15/20, 75%), and in another two (17/20, 85%) at 6, 12, 18, and 24 months FU respectively.

CONCLUSIONS

The present study is the first to have evaluated the effect of a GFD in the nonerosive form of GERD in CD patients, by means of clinical long-term follow-up, suggesting that GFD could be a useful approach in reducing GERD symptoms and in the prevention of recurrence.

Opioids and the gut: pharmacology and current clinical experience

This article reviews the pharmacology and physiology of opiate receptors and the current and potential uses of opioid agonists and antagonists in clinical gastroenterology. Mu-receptors are involved in motor and sensory functions, and their modulation is established for treatment of diarrhea. Mu-antagonists have potential to reverse endogenous (e.g., postoperative ileus) or iatrogenic dysmotility (e.g., opioid bowel dysfunction). Modulation of the function of kappa-receptors may be a novel approach to control visceral pain in functional gut disorders. Results of formal testing of novel opioid modulators are keenly awaited.

Prolonged manometric recordings of oesophagus and lower oesophageal sphincter in achalasia patients

BACKGROUND AND AIMS

Conventional short term manometry is a valuable tool in the diagnosis of achalasia but the technique may fail to detect intermittent motor events. The aim of this study was to investigate the pattern of lower oesophageal sphincter (LOS) and oesophageal pressures during prolonged recording in patients with achalasia.

METHODS

Eleven patients with idiopathic achalasia were studied. Prolonged combined oesophageal pH and manometric recordings of the pharynx, LOS, and stomach were performed using a pH glass electrode and a multiple lumen assembly incorporating a Dent sleeve connected to a portable water perfused manometric system.

RESULTS

LOS pressure varied during the day. Postprandial LOS pressures were lower than those recorded preprandially (1.2 v 1.8 kPa; p=0.005) and basal LOS pressures were significantly higher during phase III of the migrating motor complex than during the subsequent phase I (3.3 v 1.8 kPa; p=0.028). Complete LOS relaxations were occasionally observed in seven patients (0.48/h). Complete LOS relaxations were longer in duration than incomplete LOS relaxations (10.8 v 2.8 s; p=0.01) and 57% of complete relaxations fulfilled the criteria of a transient LOS relaxation (TLOSR). Complete LOS relaxations were associated with oesophageal pressure waves with higher amplitudes and longer durations. In addition, a higher proportion of these oesophageal pressure waves were spontaneous (55.6% v 0%; p<0.02) and multipeaked (72.7% v 0%). During prolonged manometry, high amplitude oesophageal pressure waves (>10 kPa) were recorded in six patients and retrograde oesophageal pressure waves in four, phenomena which were not observed during short term manometry.

CONCLUSION

In contrast with short term stationary manometry, prolonged manometry in achalasia patients revealed the occurrence of complete LOS relaxations, TLOSRs, variations in LOS pressure associated with a meal or phase III, and high amplitude and retrograde oesophageal pressure waves.

Effect of loperamide on lower oesophageal sphincter pressure in idiopathic achalasia

BACKGROUND

We have recently shown that in achalasia patients morphine has a striking inhibitory action on resting lower oesophageal sphincter (LOS) pressure, which is mediated by opioid receptors. The aim of this study was to investigate the effect of a peripheral opioid agonist, loperamide, administered at a dose of 16 mg, on resting LOS pressure in nine patients with untreated idiopathic achalasia.

METHODS

All patients underwent two experiments after oral administration of placebo and loperamide, respectively, on separate days and in randomized order. At the end of the placebo experiment we also tested the effect of loperamide as compared with distilled water, both infused intraluminally at the level of the LOS. In the loperamide experiment, after a 60-min basal period, naloxone, 40 micrograms/kg, was injected intravenously, and recordings continued for a further 10 min.

RESULTS

Loperamide administered orally decreased (p < 0.01) LOS pressure by 10 +/- 2 mmHg (37 +/- 7%) compared with placebo, and naloxone intravenously failed to block the effect. LOS pressure was not affected by infusion of either distilled water or loperamide at the level of the LOS.

CONCLUSIONS

Our findings indicate that in patients with idiopathic achalasia oral administration of loperamide at a high dose markedly decreases resting LOS pressure. This may not occur through opioid receptor stimulation and requires intestinal absorption of the drug. The possible effect of combining a small dose of loperamide with the traditional achalasia drugs awaits further evaluation.