Erythromycin
| Evidence Level: L4 | Predicted Indications: 10 |
Table of Contents
Erythromycin: From Bacterial Infections to Punctate Epithelial Keratoconjunctivitis
One-Sentence Summary
Erythromycin is a macrolide antibiotic originally used for acne, otitis media, streptococcal and staphylococcal infections, pneumonia, gonorrhoea, pertussis, urethritis and conjunctivitis. The TxGNN model predicts it may be effective for punctate epithelial keratoconjunctivitis, but there are 0 clinical trials and only 1 publication (a review) supporting this direction, so the evidence is indirect.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Acne, infectious otitis media, streptococcal infection, bacterial pneumonia, staphylococcal infection, gonorrhoea, pertussis, urethritis, conjunctivitis and others (knowledge-graph indications; no approved indication text is available from Singapore licences) |
| Predicted New Indication | Punctate epithelial keratoconjunctivitis |
| TxGNN Prediction Score | 99.89% |
| Evidence Level | L4 |
| Singapore Market Status | ✓ Marketed |
| Number of Registrations | 7 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Currently, detailed mechanism of action data is not available. Based on known information, erythromycin is a macrolide antibiotic with both antibacterial and anti-inflammatory activity. Its efficacy in bacterial infections, including conjunctivitis and staphylococcal infections, is established, and mechanistically it may be applicable to bacterial or staphylococcal-associated ocular surface disease.
The one retrieved paper concerns chronic blepharokeratoconjunctivitis in children, a condition in which macrolides are used. This is indirect evidence. No clinical trial tests erythromycin for punctate epithelial keratoconjunctivitis specifically, and the high model score has not yet been confirmed by clinical data.
Other predictions in the same list include several that are weaker:
- Acute contagious conjunctivitis largely overlaps with an existing indication, so it is not a true repurposing candidate.
- Lymphogranuloma venereum has the strongest mechanistic link (erythromycin is active against Chlamydia trachomatis). However, the evidence is review-level only, and doxycycline is first-line.
- Necrotizing ulcerative gingivitis, polyclonal hyperviscosity syndrome, hyperamylasemia, postinfectious vasculitis and the broad post-infectious categories have only historical, indirect or no supporting evidence.
Clinical Trial Evidence
Currently no related clinical trials registered for punctate epithelial keratoconjunctivitis.
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 11495307 | 2001 | Review | Journal of Pediatric Ophthalmology and Strabismus | Describes the history, symptoms, clinical signs and treatment of chronic blepharokeratoconjunctivitis in children; indirect support |
Singapore Market Information
| Authorization Number | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| SIN11952P | ERYCYN-250 Tablet 250 mg | Film-coated tablet | Not stated in the data |
| SIN11245P | RETORIN Powder for Suspension 200 mg/5 ml | Powder for suspension | Not stated in the data |
| SIN00126P | ERYSOL for Oral Suspension 200 mg/5 ml | Granule for suspension | Not stated in the data |
| SIN07545P | ERMYCIN 250 Tablet 250 mg | Film-coated tablet | Not stated in the data |
| SIN00578P | ERYSON Tablets 250 mg | Enteric-coated tablet | Not stated in the data |
Two more valid licences are registered (7 in total): EROGRAN for Oral Suspension (SIN08042P) and ERYSON Lotion 2% (SIN10446P). All 7 are single-ingredient products, and none is cancelled. No ophthalmic formulation is listed among the Singapore products, which matters for an ocular indication.
Safety Considerations
- Contraindications and risk conditions (from the knowledge graph, not label text):
- Cardiac rhythm: long QT syndrome (including familial), torsades de pointes
- Metabolic: porphyria (inherited porphyria, porphyrin metabolism disease)
- Organ disease: kidney disease, liver disease, gallbladder disease, haematologic disease, folic acid deficiency anaemia
- Gastrointestinal: Clostridium difficile colitis, perinatal necrotizing enterocolitis
- Skin: exfoliative dermatitis, dermatitis
- Neuromuscular: myasthenia gravis (including adult-onset), neuromuscular junction disease
- Hearing: hearing disorder, auditory system disease
- Other: pyoureter
- Drug Interactions: 100 interactions were identified. Examples:
- Major: loperamide, clarithromycin
- Moderate: famotidine, cimetidine, hydrocortisone, dexamethasone, betamethasone, budesonide, triamcinolone, pioglitazone, chlorpropamide, aprepitant, alosetron, balsalazide, bisacodyl, picosulfuric acid, polyethylene glycol with electrolytes
- Minor: amoxicillin
Please refer to the package insert for full warnings and contraindications.
Conclusion and Next Steps
Decision: Hold
Rationale: The prediction score is very high (99.89%), but there are no clinical trials and only one indirect review for punctate epithelial keratoconjunctivitis. Evidence is at L4, and no ophthalmic erythromycin product is among the Singapore registrations.
To proceed, the following is needed:
- Clinical studies (ideally controlled trials) of erythromycin in punctate epithelial keratoconjunctivitis or closely related ocular surface disease
- Mechanism of action data (MOA), including its anti-inflammatory effects on the ocular surface
- Package insert warnings and contraindications from HSA
- Confirmation of an ophthalmic formulation or route, since the current Singapore products are oral or topical skin lotion
- Comparison with existing standard therapy for this condition
- If a more actionable candidate is wanted, consider reviewing lymphogranuloma venereum, which has the strongest mechanistic rationale but still lacks trial evidence and is behind doxycycline as first-line treatment
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.