Nitrofurantoin

證據等級: L5

預測適應症: 10 個

Nitrofurantoin: From Urinary Tract Infection to Rheumatoid Arthritis

One-Sentence Summary

Nitrofurantoin is a long-established antibacterial primarily used to treat urinary tract infections (the drug is not currently marketed in South Africa, with 0 SAHPRA registrations on record). The TxGNN model predicts a possible link to Rheumatoid Arthritis, with a prediction score of 99.89%, but 0 clinical trials and 12 publications are currently associated with this pairing — and critically, the literature retrieved is predominantly about nitrofurantoin-induced harm (pulmonary fibrosis, autoimmune-type reactions), not therapeutic benefit.

Quick Overview

Item	Content
Original Indication	Urinary tract infection (established antibacterial use; not captured in the supplied registration data)
Predicted New Indication	Rheumatoid Arthritis
TxGNN Prediction Score	99.89%
Evidence Level	L4
South Africa Market Status	Not marketed
Number of SAHPRA Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Detailed mechanism-of-action data for nitrofurantoin is not available in this evidence pack (flagged as a High-severity data gap, DG002). Based on known pharmacology, nitrofurantoin is a nitrofuran-class antibacterial that is reduced by bacterial flavoproteins into reactive intermediates that damage bacterial DNA, ribosomal proteins, and metabolic enzymes — a mechanism specific to bacterial cell biology, with no established immunomodulatory or anti-rheumatic pathway.

Unlike a typical repurposing case where the original and new indications share a plausible pharmacological link, the literature surfaced here does not support a therapeutic connection between nitrofurantoin and rheumatoid arthritis (RA). Instead, the retrieved publications point in the opposite direction: one cohort study found antibiotic exposure (including nitrofurans) associated with flares of RA rather than benefit; several case reports and reviews describe nitrofurantoin-induced pulmonary fibrosis, including a documented case where the drug caused irreversible lung injury specifically in an RA patient already on methotrexate; and RA itself is independently recognized as a risk factor for interstitial lung disease, compounding this risk.

Given this, the high TxGNN score is best interpreted as a graph-embedding artifact — nitrofurantoin and RA are likely connected in the knowledge graph through shared “lung/pulmonary complication” or “autoimmune” nodes rather than through any genuine therapeutic mechanism. This is a pattern seen across nearly all of this drug’s top 10 predicted indications (see Conclusion), several of which are instead documented adverse-reaction associations (e.g., methemoglobinemia) rather than repurposing candidates.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
31222078	2019	Self-controlled case series (Cohort)	Scientific Reports	Antibiotic use (including nitrofurans) was associated with flares of RA in a UK cohort of 31,992 patients — an inverse signal, not supportive of benefit
15195196	2004	Review	Saudi Medical Journal	Lists nitrofurantoin among drugs causing pulmonary fibrosis; notes RA itself predisposes to the same condition
35145797	2022	Case Report	Cureus	Irreversible pulmonary fibrosis from methotrexate + nitrofurantoin interaction in a 94-year-old RA patient treated for UTI
25362778	2014	Review	La Revue du praticien	Nitrofurantoin listed among antibiotics causing drug-induced interstitial lung disease
3335140	1988	Cohort/Retrospective	Chest	RA patients hospitalized for interstitial lung fibrosis had poor prognosis; drug not a treatment in this context
11937933	2002	Case Report	Annales de Dermatologie et de Vénéréologie	Drug-induced sialadenitis case series naming nitrofurantoin among culprit drugs (not RA-related)
899886	1977	Cohort/Screening study	Acta Medica Scandinavica	Short-term nitrofurantoin therapy outcomes for bacteriuria; no RA relevance
41635325	2026	Case Report	Cureus	Autoimmune hepatitis workup listing nitrofurantoin among drugs to rule out as cause, alongside RA as a differential diagnosis
8104358	1993	Case Report	Revue de Pneumologie Clinique	Gold-salt–induced pneumonitis case (RA context); nitrofurantoin not the causative agent
4608019	1974	Review	Der Internist	General review of alveolitis/pulmonary fibrosis mentioning nitrofurantoin as one causative drug class

South Africa Market Information

No SAHPRA registrations are on record for nitrofurantoin in this dataset (total_licenses = 0; market status: Not marketed).

Safety Considerations

Please refer to the SAHPRA-approved Professional Information (PI) for safety information. Report adverse drug reactions to SAHPRA.

Signals identified during this evidence review (not from formal PI data, but recurring across the retrieved literature and worth flagging for any repurposing assessment):

Multiple reports of nitrofurantoin-induced pulmonary fibrosis/interstitial lung disease, with one case of irreversible injury when combined with methotrexate in an RA patient (PMID 35145797).
Documented methemoglobinemia induction (photoactivation-related, and in neonatal case reports) associated with nitrofurantoin elsewhere in this evidence pack’s predicted-indication list — a mechanistic contraindication signal, not a treatment rationale.
Nitrofurantoin appears among drugs implicated in drug-induced autoimmune hepatitis differentials.

Conclusion and Next Steps

Decision: Hold

Rationale: The 99.89% TxGNN score is not supported by the retrieved evidence — there are no clinical trials, and the 12 literature hits are predominantly reports of nitrofurantoin causing harm (pulmonary fibrosis, flares, hepatic/hematologic adverse reactions) rather than evidence of benefit in RA. The drug is also not currently marketed in South Africa (0 SAHPRA registrations), which is an independent barrier to any near-term clinical use regardless of the efficacy question.

To proceed, the following is needed:

SAHPRA/TFDA-approved Professional Information (warnings, contraindications) — currently a Blocking data gap (DG001)
Confirmed mechanism of action data to assess biological plausibility (High-severity data gap, DG002)
A genuine positive pharmacological hypothesis linking nitrofurantoin to RA pathogenesis (none currently identified)
If pursued further, prospective safety monitoring given the documented pulmonary and hematologic signal, particularly in patients on concomitant methotrexate
Disclaimer

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