Thiamine

Evidence Level: L5

Predicted Indications: 3

Thiamine

Pharmacist Assessment Report

Thiamine: From an Oral Vitamin B1 Tablet to Resistance to Thyroid Hormone Due to a Mutation in Thyroid Hormone Receptor Beta

One-Sentence Summary

Thiamine (vitamin B1) is marketed in Australia as an oral 100 mg tablet, but the data compiled for this report contain no approved indication text for it. The TxGNN model predicts it may be useful for resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta, but there are 0 clinical trials and 0 publications supporting this prediction, so it rests on the model score alone.

Quick Overview

Item	Content
Original Indication	Not stated in the licence record (approved indication text is blank)
Predicted New Indication	Resistance to thyroid hormone due to a mutation in thyroid hormone receptor beta
TxGNN Prediction Score	0.9943
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?

Currently, detailed mechanism of action data is not available for this drug. Thiamine is a cofactor for enzymes involved in carbohydrate and energy metabolism. However, no established pathway connects it to thyroid hormone receptor beta signalling.

Resistance to thyroid hormone due to a THR-beta mutation is a single-gene disorder caused by a defect in the receptor itself. A vitamin cofactor would not be expected to correct this defect. The high TxGNN score is a model-based prediction only and cannot be cross-checked against the drug’s mechanism, because that mechanism data is missing. No mechanistic link is supported by the data compiled for this report.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

Currently no related literature available.

Australia Market Information

Licence Number	Product Name	Dosage Form	Approved Indication
1070H	Betavit	Oral tablet containing thiamine hydrochloride 100 mg	Not stated in the licence record

Safety Considerations

Please refer to the TGA-approved Product Information (PI) for safety information. No warnings, contraindications or drug interaction records were available in the data compiled for this report.

Other Predictions Noted

Two other predictions for thiamine were also generated:

Primary hereditary glaucoma (score 0.9940): no trials or literature, so L5, Hold.
Open-angle glaucoma (score 0.9936): no trials, but six publications were retrieved. Only one, a 1979 case-control study (PMID 485004, 38 patients and 12 controls), examined thiamine. It found lower blood thiamine in people with chronic open-angle glaucoma. It did not test thiamine as a treatment. The other papers were dietary surveys, such as niacin intake, or basic and biomarker studies without a demonstrated thiamine link. This prediction is graded L4, a research question rather than a treatment candidate.

Conclusion and Next Steps

Decision: Hold

Rationale: For resistance to thyroid hormone, there are no trials, no publications and no plausible mechanistic link. The high model score is not enough to justify moving forward.

To proceed, the following is needed:

Mechanism of action data for thiamine, to test whether any link to thyroid hormone receptor signalling exists
Any preclinical or clinical studies directly addressing thiamine in this disorder
Safety information from the TGA Product Information, which was not available for this report
Approved indication text for the Australian licence
If the glaucoma prediction is pursued instead, prospective or interventional studies of thiamine in open-angle glaucoma
Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.