Post-prandial reflux suppression by a raft-forming alginate (Gaviscon Advance) compared to a simple antacid documented by magnetic resonance imaging and pH-impedance monitoring: mechanistic assessment in healthy volunteers and randomised, controlled, double-blind study in reflux patients

Aliment Pharmacol Ther. 2013 Jun;37(11):1093-102. doi: 10.1111/apt.12318. Epub 2013 Apr 18.


Background: Alginates form a raft above the gastric contents, which may suppress gastro-oesophageal reflux; however, inconsistent effects have been reported in mechanistic and clinical studies.

Aims: To visualise reflux suppression by an alginate-antacid [Gaviscon Advance (GA), Reckitt Benckiser, UK] compared with a nonraft-forming antacid using magnetic resonance imaging (MRI), and to determine the feasibility of pH-impedance monitoring for assessment of reflux suppression by alginates.

Methods: Two studies were performed: (i) GA and antacid (Alucol, Wander Ltd, Switzerland) were visualised in the stomach after ingestion in 12 healthy volunteers over 30 min after a meal by MRI, with reflux events documented by manometry. (ii) A randomised controlled, double-blind cross-over trial of post-prandial reflux suppression documented by pH-impedance in 20 patients randomised to GA or antacid (Milk of Magnesia; Boots, UK) after two meals taken 24 h apart.

Results: MRI visualized a "mass" of GA form at the oesophago-gastric junction (OGJ); simple antacid sank to the distal stomach. The number of post-prandial common cavity reflux events was less with GA than antacid [median 2 (0-5) vs. 5 (1-11); P < 0.035]. Distal reflux events and acid exposure measured by pH-impedance were similar after GA and antacid. There was a trend to reduced proximal reflux events with GA compared with antacid [10.5 (8.9) vs. 13.9 (8.3); P = 0.070].

Conclusions: Gaviscon Advance forms a 'mass' close to the OGJ and significantly suppresses reflux compared with a nonraft-forming antacid. Standard pH-impedance monitoring is suitable for clinical studies of GA in gastro-oesophageal reflux disease patients where proximal reflux is the primary outcome.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Alginates / therapeutic use*
  • Aluminum Hydroxide / therapeutic use*
  • Antacids / therapeutic use*
  • Cross-Over Studies
  • Double-Blind Method
  • Drug Combinations
  • Electric Impedance
  • Esophageal pH Monitoring
  • Female
  • Gastroesophageal Reflux / diagnosis
  • Gastroesophageal Reflux / drug therapy*
  • Humans
  • Hydrogen-Ion Concentration
  • Magnesium Oxide / therapeutic use*
  • Magnetic Resonance Imaging
  • Male
  • Manometry
  • Middle Aged
  • Postprandial Period*
  • Silicic Acid / therapeutic use*
  • Sodium Bicarbonate / therapeutic use*
  • Treatment Outcome


  • Alginates
  • Antacids
  • Drug Combinations
  • Silicic Acid
  • Magnesium Oxide
  • Aluminum Hydroxide
  • alginate, aluminium hydroxide, magnesium trisilicate, sodium bicarbonate drug combination
  • Sodium Bicarbonate