Rifampicin

Evidence Level: L4

Predicted Indications: 10

Rifampicin

Pharmacist Assessment Report

Rifampicin: From Pulmonary Tuberculosis to Conjunctivitis

One-Sentence Summary

Rifampicin is a broad-spectrum antibiotic originally used to treat pulmonary tuberculosis. The TxGNN model predicts it may be effective for conjunctivitis, but there are no registered clinical trials and only indirect literature (mainly older topical trachoma and chlamydial eye studies and susceptibility surveys) supporting this direction.

Quick Overview

Item	Content
Original Indication	Pulmonary tuberculosis
Predicted New Indication	Conjunctivitis
TxGNN Prediction Score	0.9995
Evidence Level	L4
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 in the data compiled for this report. Based on known information, rifampicin is a broad-spectrum antibacterial that inhibits bacterial RNA polymerase. It has activity against Gram-positive bacteria, Staphylococcus and Chlamydia, and its efficacy in tuberculosis is established.

Bacterial conjunctivitis is commonly caused by Staphylococcus, Streptococcus, Haemophilus and Chlamydia trachomatis. An antibacterial with activity against these organisms could plausibly be applied. The evidence is indirect, however: older studies used topical (eye ointment) rifampicin, whereas the only Australian product is an oral capsule. A topical ocular formulation and antimicrobial resistance (tuberculosis stewardship) concerns remain unresolved.

Note that the model also returned a near-duplicate entry, “conjunctivitis (disease)” (score 0.9960), which should be merged with this one. Their literature largely overlaps.

Clinical Trial Evidence

Currently no related clinical trials registered for conjunctivitis.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
1096630	1975	Controlled clinical study	Am J Ophthalmol	1% rifampicin or 1% tetracycline ointment vs boric acid ointment in endemic trachoma in Tunisian schoolchildren (10 weeks’ treatment)
322700	1977	Open trial	Br J Ophthalmol	1% rifampicin eye ointment vs chloramphenicol in 63 patients with chlamydial eye infection; 3 weeks was insufficient, 6-7 weeks gave about 90% clinical and microbiological cure
33457332	2020	Cross-sectional	Adv Biomed Res	Bacterial causes and antibiotic susceptibility of conjunctivitis isolates in Kashan, Iran
21191558	2010	In vitro study	Rev Esp Quimioter	Antibiotic susceptibility of Corynebacterium macginleyi strains causing conjunctivitis
30347565	2018	Susceptibility study	Zhonghua Yan Ke Za Zhi	Genetic typing and susceptibility of S. aureus from keratitis or conjunctivitis
8363150	1993	Microbiology study	An Esp Pediatr	Organisms and antibiotic sensitivity in 50 neonatal conjunctivitis samples
3191080	1988	Case series	Br J Ophthalmol	Marginal corneal abscesses in adult chlamydial ophthalmia
39336466	2024	Case report	Medicina (Kaunas)	Parinaud oculoglandular syndrome with Bartonella DNA detected in cornea and conjunctiva
1247775	1976	Report	BMJ	Ocular toxicity due to rifampicin (a safety signal)
5005929	1971	Review	Ann Ophthalmol	General review of rifampicin

Australia Market Information

ARTG Number	Product Name	Dosage Form	Approved Indication
ARTG 12189M	Rimycin 300	Capsule 300 mg (oral)	Not available in the data compiled for this report

Cytotoxicity

Rifampicin is an antibacterial, not an antineoplastic, so this section does not apply.

Safety Considerations

Contraindications suggested by the knowledge graph (these are drug-disease associations, not product label text): liver failure, acute liver failure, hepatitis and other liver disease; porphyria; gallbladder disease; blood disorders (thrombocytopenia, neutropenia, agranulocytosis, anaemia, pancytopenia, aplastic anaemia); diabetes mellitus and diabetic ketoacidosis; gout; peripheral neuropathy; substance abuse/dependence; slow acetylator status; non-infectious meningitis; anxiety and related disorders.
Drug Interactions: The interaction screen returned 100 interactions, and the 20 listed were all rated Moderate. These include rabeprazole, omeprazole, doxycycline, clarithromycin, metronidazole, metformin, pioglitazone, canagliflozin, chlorpropamide, bupropion, aprepitant, morphine, and several corticosteroids (hydrocortisone, dexamethasone, betamethasone, triamcinolone) and vitamin D analogues (cholecalciferol, calcifediol, calcitriol). Rifampicin is a strong enzyme inducer, so co-medications need review.
Ocular safety: Early reports describe ocular toxicity associated with rifampicin (PMIDs 1247775 and 1260294).

Please also refer to the TGA-approved Product Information (PI) for full warnings and contraindications.

Conclusion and Next Steps

Decision: Hold

Rationale: Support for conjunctivitis rests on a high model score, in vitro susceptibility data and a few 1970s topical-ointment studies, with no registered trials. The only Australian product is an oral capsule, and there are antimicrobial stewardship concerns.

To proceed, the following is needed:

Product Information warnings and contraindications for the Australian product
Mechanism of action data
A topical ocular formulation, or a justification for the oral route
Modern controlled trials against current standard-of-care eye antibiotics
A stewardship assessment on resistance risk for tuberculosis treatment
Merging of the duplicate “conjunctivitis” entries

Other predicted indications (for reference)

Rank	Predicted Indication	Score	Evidence Level	Comment	Decision
2	Multiple endocrine neoplasia	0.9986	L5	Prediction only	Hold
3	Acne (disease)	0.9974	L4	Evidence mostly concerns hidradenitis suppurativa (clindamycin + rifampicin), not acne vulgaris	Hold
5	HIV infectious disease	0.9959	L4	Phase 2/3 trials are TB/HIV co-infection and interaction studies, not anti-HIV efficacy	Research Question
7	Rheumatoid arthritis	0.9945	L3	Small 1980s-90s studies with limited, inconsistent benefit; one Phase 1 PK trial	Research Question

Disclaimer

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