Thiamine
| Evidence Level: L3 | Predicted Indications: 10 |
Table of Contents
Thiamine: From Nutritional Supplementation to Hyperthyroidism
One-Sentence Summary
Thiamine (vitamin B1) is marketed in Singapore as a single-ingredient vitamin product, mainly in B-vitamin tablets and injections. The TxGNN model predicts it may be useful for hyperthyroidism, specifically as supportive repletion of the relative thiamine deficiency that a hypermetabolic state can cause, not as an antithyroid treatment. Support is limited to 1 small completed trial (12 patients) and case reports and observational literature.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not stated in the registration records |
| Predicted New Indication | Hyperthyroidism |
| TxGNN Prediction Score | 99.44% |
| Evidence Level | L3 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 10 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, thiamine is an essential vitamin that acts as a coenzyme in carbohydrate and oxidative energy metabolism. Its efficacy in correcting thiamine deficiency is well established, and mechanistically it may be applicable to hyperthyroidism.
Hyperthyroidism raises metabolic rate and thiamine turnover, which can cause relative thiamine deficiency. The literature describes the consequences: high-output heart failure resembling wet beriberi and Wernicke's encephalopathy, especially when severe vomiting accompanies hyperthyroidism in pregnancy. In this setting, thiamine would support patients as repletion of a secondary deficiency. It would not treat the thyroid disease itself.
Graves disease, the main cause of hyperthyroidism, ranks 8th among the predictions (score 98.15%). It shares the same rationale and the same limited evidence. Other predicted indications were considered, but the evidence for each is weaker or indirect:
- Pulmonary hypertension (score 98.97%) has the most clinical literature. Multiple case series and a prospective observational study describe thiamine-responsive pulmonary hypertension in thiamine-deficient infants. There is no RCT, and the finding applies only to deficient or at-risk populations. This is the only prediction at the "Proceed with Guardrails" stage.
- Open-angle glaucoma has only associative observational and mechanistic studies.
- Resistance to thyroid hormone, primary hereditary glaucoma, hyperthyroxinemia, kyphoscoliotic heart disease, peripheral vascular disease and neonatal thyrotoxicosis have no supporting evidence, or only indirect evidence, beyond the model prediction.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT02767245 | Not applicable | Completed | 12 | Pilot study of thiamine supplementation for cardiovascular function in severe hyperthyroidism. It also assessed the prevalence of thiamine deficiency. No results were available, and there was no randomised control design. |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 26567494 | 2015 | Case report/Review | Crit Care Nurs Clin North Am | High-output heart failure caused by thyrotoxicosis and beriberi |
| 7919625 | 1994 | Case series | Intern Med | High-output heart failure with pulmonary hypertension: improvement with antithyroid therapy in hyperthyroidism, and with thiamine in cardiac beriberi |
| 7416185 | 1980 | Case series | Am J Med | 23 Japanese patients with beriberi heart disease caused by relative thiamine deficiency |
| 18026802 | 2008 | Case report | J Gen Intern Med | Wernicke's encephalopathy associated with thyrotoxicosis |
| 32934066 | 2020 | Case report | Clin Med (Lond) | Wernicke's encephalopathy in pregnancy with hyperemesis and thyrotoxicosis |
| 32983708 | 2020 | Case report | Cureus | Wernicke's encephalopathy with transient gestational hyperthyroidism and hyperemesis gravidarum |
| 34995426 | 2021 | Case report | S D Med | Wernicke encephalopathy in a Graves' disease patient after sleeve gastrectomy |
| 22635085 | 2012 | Case report | Neuro Endocrinol Lett | Hyperthyroidism and hyperemesis gravidarum with Wernicke's encephalopathy |
| 19713670 | 2009 | Case report | Nihon Ronen Igakkai Zasshi | Severe pulmonary hypertension and heart failure in an elderly patient with Basedow's (Graves') disease |
| 21064291 | 1946 | Preclinical | Fed Proc | Effects of thiamine deficiency and thyroid status on rat heart muscle ATP |
No RCTs were identified. The evidence consists mainly of case reports and small series that describe thiamine deficiency complications in hyperthyroid patients.
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN12077P | DANEURON TABLET | Film-coated tablet | Not stated |
| SIN10891P | NEURO-B TABLET | Film-coated tablet | Not stated |
| SIN07635P | VITAMIN B FORTE TABLET | Film-coated tablet | Not stated |
| SIN06262P | NEUROBION INJECTION | Injection | Not stated |
| SIN11975P | CERNEVIT FOR INJECTION | Powder for injection solution | Not stated |
All 10 registrations are valid single-ingredient licences. The table shows 5 of them. Both oral and injectable forms are available.
Safety Considerations
Please refer to the package insert for safety information. The data compiled for this report did not include warnings or contraindications from the Singapore package inserts, and no drug interaction records were found.
Conclusion and Next Steps
Decision: Hold
Rationale: The hyperthyroidism prediction rests on one small, exploratory trial (12 patients, no results available) and case reports. Thiamine would support deficiency-related complications and would not treat the thyroid disease. Safety label data are also missing.
To proceed, the following is needed:
- Results from the completed pilot trial (NCT02767245), or a larger controlled study in thyrotoxic patients with confirmed thiamine deficiency
- Package insert warnings and contraindications from the Singapore regulator
- Mechanism of action data
- Approved indication text for the local registrations
- A separate evaluation of pulmonary hypertension in thiamine-deficient populations, where the observational evidence is stronger, as a possible alternative research direction
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.