Magnesium Trisilicate
| Evidence Level: L5 | Predicted Indications: 1 |
Table of Contents
Magnesium Trisilicate: Gastroduodenitis
One-Sentence Summary
Magnesium trisilicate is a non-systemic antacid, originally used for peptic ulcer disease, gastro-oesophageal reflux disease, oesophagitis and dyspepsia. The supporting evidence is 0 clinical trials and 2 publications (mostly historical) for the top prediction.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Gastroduodenitis |
| TxGNN Prediction Score | 0.9972 |
| Evidence Level | L5 |
| Australia Market Status | Listed on the PBS Schedule (1 of 1 items) – TGA (ARTG) registration status is not included in this data |
| Number of PBS Items | 1 (valid: 1) |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Based on known pharmacology, magnesium trisilicate neutralises gastric acid and forms a silica gel that may coat the ulcer surface.
The other top predictions follow the same pattern. Several lower-ranked predictions are not mechanistically plausible:
- In impaired transit, antacids may also carry a risk of concretions.
- Duodenogastric reflux and hiatus hernia: at best, symptomatic relief only.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrolment | Key Findings |
|---|---|---|---|---|
| NCT03883074 | Not applicable | Completed | 21 | Double-blind, placebo-controlled crossover study of an oral hyaluronic acid, chondroitin sulphate and magnesium trisilicate formulation on mucosal integrity and reflux exposure in GERD patients not taking a PPI. The contribution of magnesium trisilicate cannot be isolated. |
| NCT04202692 | Not applicable | Completed | 40 | Post-market, double-blind, placebo-controlled crossover study of the same type of formulation (GERDOff Plus) added to PPI treatment in GERD patients not fully satisfied with their PPI. Offers limited support for magnesium trisilicate itself. |
No ANZCTR trial identifiers were found in the data compiled for this report.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 4909818 | 1970 | Double-blind trial (combination product) | Gut | 28 patients with active duodenal ulcer; Duogastrone controlled symptoms and appeared to hasten healing versus a magnesium trisilicate placebo over 12 weeks. Magnesium trisilicate served as the comparator. |
| 14248445 | 1965 | Double-blind trial (combination) | Br Med J | Bismuth aluminate and magnesium trisilicate in peptic ulceration with simultaneous gastric analysis. |
| 6328685 | 1984 | Comparative clinical study | S Afr Med J | 88 patients; 4-week ulcer healing with ranitidine versus an aluminium hydroxide and magnesium trisilicate antacid (Gelusil). Duodenal ulcer healing was 74% with ranitidine and 63% with the antacid. |
| 6368445 | 1983 | Controlled clinical trial | Int J Tissue React | De-Nol (16 patients) versus an antacid mixture containing magnesium trisilicate (24 patients) in gastric ulcer over 4 weeks. |
| 15425465 | 1950 | Case series | Am J Dig Dis | Aluminium hydroxide and magnesium trisilicate plus mucin in 125 patients with peptic ulcer. |
| 20271751 | 1947 | Observational study | Arch Surg | Gastroscopic and clinical study of the same combination in peptic ulcer. |
| 20321118 | 1938 | Historical clinical report | Can Med Assoc J | Magnesium trisilicate in the treatment of peptic ulcer. |
| 6547921 | 1984 | Physiological study | Fortschr Med | Local effects of sucralfate, aluminium hydroxide and magnesium trisilicate on transmural potential difference in gastric ulcer (6 patients per group). |
| 4301560 | 1968 | Clinical study (combination) | Wien Med Wochenschr | Antacid effect of a magnesium trisilicate and hyoscyamine combination (Neoplex B). |
| 9789728 | 1998 | Review | Drugs Aging | Mechanisms of drug-induced diarrhoea in the elderly (a safety signal). |
Several other retrieved papers were off-topic and are not listed (phenytoin bioavailability, oral contraceptive availability, Nigerian hypertension drug utilisation). A paper on silica-containing urinary stones is relevant only as a safety signal. Almost all studies used magnesium trisilicate in combination with other agents, so its individual effect cannot be isolated.
Australia Market Information
| ARTG Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 309G (one entry; valid, single-ingredient) | Not available | Not available | Not available |
Safety Considerations
The knowledge graph lists the following conditions as contraindications (these are graph associations, not label text):
- Kidney disease and hypophosphataemia
- Congestive heart failure
- Diarrhoeal disease (including chronic) and constipation disorder
- Intestinal impaction
- Pyoureter
- Haemorrhoid
Supporting literature also flags silica-containing urinary stones and drug-induced diarrhoea in the elderly as possible safety signals. Antacids may reduce the absorption of other drugs (for example, phenytoin and oral contraceptives were studied). No interaction records were found in the data compiled for this report.
Please refer to the TGA-approved Product Information (PI) for warnings, contraindications and interactions.
Conclusion and Next Steps
Decision: Hold
Rationale: The top predictions overlap with the existing indications, so there is no genuine repurposing signal. The evidence is old, mostly on combination products, and has been superseded by modern acid suppression (PPIs). Label safety data and mechanism of action data are also missing.
To proceed, the following is needed:
- The TGA Product Information (PI) and approved indication text for the Australian entry (ARTG 309G)
- Mechanism of action data
- Clarification of whether any predicted indication differs meaningfully from the existing labelled indications
- Modern controlled evidence for magnesium trisilicate alone, compared with current standard care
- A review of the safety issues flagged in the knowledge graph (renal impairment, heart failure, bowel disorders, impaired transit)
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.