Tetracycline
| Evidence Level: L4 | Predicted Indications: 10 |
Table of Contents
Tetracycline: From Bacterial Infections to Punctate Epithelial Keratoconjunctivitis
One-Sentence Summary
Tetracycline is a broad-spectrum antibiotic originally used for infections such as urinary tract infection, bronchitis, acne, gonorrhoea, pharyngitis, conjunctivitis and pneumonia. The TxGNN model predicts it may be effective for punctate epithelial keratoconjunctivitis, but there are currently 0 clinical trials and only 1 publication (a 1992 case report) supporting this direction, so the evidence is weak.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Bacterial infections (urinary tract infection, bronchitis, acne, gonorrhoea, pharyngitis, conjunctivitis, pneumonia, etc.). Singapore licence texts have no indication wording recorded. |
| Predicted New Indication | Punctate epithelial keratoconjunctivitis |
| TxGNN Prediction Score | 99.58% |
| Evidence Level | L4 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 3 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, tetracycline is a member of the tetracycline antibiotic class. Its efficacy against many bacterial infections, including chlamydial conjunctivitis and trachoma, is well established, and mechanistically it may be applicable to punctate epithelial keratoconjunctivitis.
The original indications already include conjunctivitis, so an ocular surface link is plausible. Tetracyclines are also known for anti-inflammatory and matrix metalloproteinase (MMP)-inhibiting effects, which could matter for corneal epithelial disease.
However, the only supporting paper is a 1992 report of two patients who developed punctate epithelial keratitis after chlamydial follicular conjunctivitis that had been treated with oral tetracycline or doxycycline. It is an indirect observation and does not show that tetracycline treats the condition. No trials are registered.
Clinical Trial Evidence
Currently no related clinical trials registered.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 1424659 | 1992 | Case report | Cornea | Two patients with chlamydial follicular conjunctivitis were treated with oral tetracycline or doxycycline, and the follicles resolved. Both later had recurrent bilateral punctate epithelial keratitis. |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN00969P | TETRACYCLINE MC CAPSULE 250 mg | Capsule | Not recorded |
| SIN02053P | BEATACYCLINE CAPSULE 250 mg | Capsule | Not recorded |
| SIN08514P | BIOTINE OINTMENT 3% w/w | Ointment | Not recorded |
Safety Considerations
- Contraindication signals (from a knowledge graph, not label text): These include liver failure, liver disease, kidney disease, kidney failure, uremia, epilepsy, neutropenia, agranulocytosis, G6PD deficiency, blood coagulation disease, Clostridium difficile colitis, diabetes mellitus, diabetic ketoacidosis and atrial fibrillation, among others. They need confirmation against the package insert.
- Drug Interactions: 100 interactions were identified. The main ones graded Major are:
- Isotretinoin
- Acitretin
- Aminolevulinic acid
Moderate interactions include ethinylestradiol, amoxicillin, ampicillin, aluminium hydroxide, bismuth subcitrate potassium and aminophylline. Examples of minor interactions are acetazolamide, hydrochlorothiazide and amiloride.
Please also refer to the package insert for the full safety information.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction score is high, but the only evidence is a single indirect 1992 case report with no registered trials, so the evidence is at model-prediction/case level (L4). Package-insert safety data have not yet been obtained, and the Singapore licences do not record approved indications.
To proceed, the following is needed:
- Package insert warnings and contraindications from the HSA website
- Detailed mechanism of action data
- Literature review specific to the ocular route (a topical or ophthalmic formulation is not among the Singapore registrations, only oral capsules and a 3% ointment)
- Comparative evidence versus current standard treatment for punctate epithelial keratoconjunctivitis
- Clinical studies (at least a pilot) specifically on this indication
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.