title: 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.
abstract: 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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Department of Gastroenterology, Guys and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: R
authors.initials: R
authors.lastname: Sweis
authors.forename: E
authors.initials: E
authors.lastname: Kaufman
authors.forename: A
authors.initials: A
authors.lastname: Anggiansah
authors.forename: T
authors.initials: T
authors.lastname: Wong
authors.forename: P
authors.initials: P
authors.lastname: Dettmar
authors.forename: M
authors.initials: M
authors.lastname: Fried
authors.forename: W
authors.initials: W
authors.lastname: Schwizer
authors.forename: R K
authors.initials: RK
authors.lastname: Avvari
authors.forename: A
authors.initials: A
authors.lastname: Pal
authors.forename: M
authors.initials: M
authors.lastname: Fox
mesh_terms: D000328:Adult; D000368:Aged; D000464:Alginates / Q000627:therapeutic use*; D000536:Aluminum Hydroxide / Q000627:therapeutic use*; D000863:Antacids / Q000627:therapeutic use*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004338:Drug Combinations; D017097:Electric Impedance; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000188:drug therapy*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008277:Magnesium Oxide / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D008365:Manometry; D008875:Middle Aged; D019518:Postprandial Period; D012824:Silicic Acid / Q000627:therapeutic use*; D017693:Sodium Bicarbonate / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000464:Alginates; D000863:Antacids; D004338:Drug Combinations; D012824:Silicic Acid; D008277:Magnesium Oxide; D000536:Aluminum Hydroxide; C007829:alginate, aluminium hydroxide, magnesium trisilicate, sodium bicarbonate drug combination; D017693:Sodium Bicarbonate