Original article
Alimentary tract
An Alginate-Antacid Formulation Localizes to the Acid Pocket to Reduce Acid Reflux in Patients With Gastroesophageal Reflux Disease

https://doi.org/10.1016/j.cgh.2013.04.046Get rights and content

Background & Aims

Alginate rafts (polysaccharide polymers that precipitate into a low-density viscous gel when they contact gastric acid) have been reported to form at the acid pocket, an unbuffered pool of acid that floats on top of ingested food and causes postprandial acid reflux. We studied the location of an alginate formulation in relation to the acid pocket and the corresponding effects on reflux parameters and acid pocket positioning in patients with gastroesophageal reflux disease (GERD).

Methods

We randomly assigned patients with symptomatic GERD and large hiatal hernias to groups who were given either 111In-labeled alginate-antacid (n = 8, Gaviscon Double Action Liquid) or antacid (n = 8, Antagel) after a standard meal. The relative positions of labeled alginate and acid pocket were analyzed for 2 hours by using scintigraphy; reflux episodes were detected by using high-resolution manometry and pH-impedance monitoring.

Results

The alginate-antacid label localized to the acid pocket. The number of acid reflux episodes was significantly reduced in patients receiving alginate-antacid (3.5; range, 0−6.5; P = .03) compared with those receiving antacid (15; range, 5−20), whereas time to acid reflux was significantly increased in patients receiving alginate-antacid (63 minutes; range, 23−92) vs those receiving antacid (14 minutes; range, 9−23; P = .01). The acid pocket was located below the diaphragm in 71% of patients given alginate-antacid vs 21% of those given antacid (P = .08). There was an inverse correlation between a subdiaphragm position of the acid pocket and acid reflux (r = −0.76, P < .001).

Conclusions

In a study of 16 patients with GERD, we observed that the alginate-antacid raft localizes to the postprandial acid pocket and displaces it below the diaphragm to reduce postprandial acid reflux. These findings indicate the importance of the acid pocket in GERD pathogenesis and establish alginate-antacid as an appropriate therapy for postprandial acid reflux. www.trialregister.nl, Number: NTR3602

Section snippets

Subjects

The study was performed in 16 patients with proven GERD, which was defined by the presence of esophagitis observed during upper endoscopy and/or 24-hour pH-metry with an acid (pH <4) exposure time >4.5%, in combination with typical GERD symptoms.14 Hiatal hernia size was measured by high-resolution manometry (HRM), and patients with small or no hiatal hernia (<3 cm) were excluded. Patients with confirmed long segment Barrett's epithelium who were unable to stop the use of proton pump inhibitors

Baseline Reflux Characteristics

To determine whether patients were randomized well, we compared reflux variables obtained during the diagnostic 24-hour pH impedance recording before study inclusion. No significant difference in esophageal acid exposure was observed between antacid-treated and alginate-antacid–treated patients (11% [2.2%–12%] vs 10% [6.7%–20%], P = .78), the number of reflux episodes (96 [64–146] vs 113 [69–201], P = 1.0), or the number of acid reflux episodes (41 [24–65] vs 35 [25–126], P = .73). In addition,

Discussion

Increased acid reflux after meals is a hallmark of GERD, with the amount of acid exposure determining the severity of symptoms and complications. The acid pocket, which is the most immediate source of postprandial refluxate in GERD, represents an important therapeutic target.

Among current therapies, alginates, with their raft-forming mode of action in the proximal stomach, are interesting candidates for direct targeting of the acid pocket. Gaviscon Double Action has been shown previously to

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    • Cited by (0)

    This article has an accompanying continuing medical education activity on page e90. Learning Objectives—At the end of this activity, the successful learner will understand the significance of the acid pocket as an important player in the pathogenesis of gastroesophageal reflux disease and will recognize its potential as a therapeutic target.

    Conflicts of interest These authors disclose the following: A.J.P.M. Smout has acted as an invited speaker for Reckitt Benckiser; E.C.M. Thomas is an employee of Reckitt Benckiser; and G.E. Boeckxstaens is a consultant of Reckitt Benckiser. The remaining authors disclose no conflicts.

    Funding Reckitt Benckiser provided an educational grant to support this study but had no role in the study design, running of the study, or the decision to publish.

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    Copyright © 2013 AGA Institute. Published by Elsevier Ltd. All rights reserved.