Can Gaviscon Cause Diarrhea?
Gaviscon (alginate-based antacid) does not cause diarrhea and is generally well-tolerated with minimal gastrointestinal side effects.
Evidence from Clinical Trials
The available evidence demonstrates that Gaviscon has a favorable safety profile regarding bowel function:
In a randomized, placebo-controlled trial of Gaviscon Advance, diarrhea was not reported as an adverse event when used four times daily for 7 days in patients already taking proton pump inhibitors 1.
The trial specifically monitored for gastrointestinal symptoms and found no significant difference in adverse effects between Gaviscon and placebo groups 1.
Mechanism and Formulation Considerations
Gaviscon's mechanism of action makes diarrhea unlikely:
Gaviscon works by forming a physical raft barrier on top of stomach contents rather than through systemic absorption or alteration of intestinal motility 1.
The alginate formulation does not contain magnesium-based compounds in amounts that would typically cause osmotic diarrhea, unlike magnesium trisilicate or magnesium hydroxide antacids which are well-known causes of osmotic diarrhea 2, 3.
Important Distinctions
Do not confuse Gaviscon with other antacids that DO cause diarrhea:
Magnesium-containing antacids (magnesium trisilicate, magnesium hydroxide) are established causes of osmotic diarrhea and account for a significant proportion of antacid-related diarrhea 2, 3.
If a patient reports diarrhea while taking "antacids," verify the specific product, as many combination antacids contain magnesium salts 3.
Clinical Bottom Line
Gaviscon can be safely recommended for patients concerned about diarrhea as a side effect, as it does not share the osmotic laxative properties of magnesium-based antacids 1.
If diarrhea develops in a patient taking Gaviscon, investigate other medications (particularly antibiotics, NSAIDs, proton pump inhibitors, or other concurrent drugs) as the more likely culprits 3, 4.