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 nitrofuran-class antibiotic, widely used as a first-line treatment for uncomplicated urinary tract infections (UTIs). The TxGNN model predicts it may be effective for Rheumatoid Arthritis, with 0 clinical trials and 12 publications currently associated with this direction — however, a careful review reveals that this evidence reflects adverse event co-occurrence rather than any therapeutic relationship, and the prediction is assessed as a likely false positive.

Quick Overview

Item	Content
Original Indication	Urinary tract infections (UTI)
Predicted New Indication	Rheumatoid Arthritis
TxGNN Prediction Score	99.89%
Evidence Level	L5
India Market Status	✗ Not marketed
Number of Registrations	0
Recommended Decision	Hold

Why is This Prediction Reasonable?

Currently, detailed mechanism of action data is not available. Based on known information, Nitrofurantoin is a nitrofuran-class antibiotic whose efficacy in treating urinary tract infections is well established. Its antimicrobial activity is generally understood to involve the generation of reactive intermediates by bacterial nitroreductases, which then cause widespread damage to bacterial DNA, ribosomes, and cell wall proteins.

The link between Nitrofurantoin and rheumatoid arthritis (RA) does not stem from any direct mechanistic rationale. The 12 associated publications document co-occurrence in the context of pulmonary adverse events: both Nitrofurantoin and several RA-associated drugs (e.g., methotrexate, gold salts) can independently cause drug-induced pulmonary fibrosis, and RA itself predisposes patients to interstitial lung disease. This shared clinical territory has led to their co-mention in the literature — not in the context of RA treatment, but in the context of overlapping lung toxicity.

One observational study (PMID 31222078) examined whether antibiotic use is associated with RA flare frequency, suggesting a possible pathogenic role of infections in RA. This indirect hypothesis — that clearing infections might reduce RA disease triggers — is speculative and does not constitute evidence that Nitrofurantoin itself treats RA. The mechanistic case for repurposing is extremely weak. The TxGNN prediction is most likely driven by literature co-occurrence and is assessed as a false positive.

Clinical Trial Evidence

Currently no related clinical trials registered.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
31222078	2019	Self-controlled case series	Scientific Reports	Studied antibiotic exposure and RA flare frequency in 31,992 RA patients (UK CPRD); identifies a possible infection-RA link — not specific to Nitrofurantoin and does not evaluate therapeutic efficacy
3335140	1988	Retrospective cohort	Chest	57 RA patients hospitalized for interstitial lung fibrosis; Nitrofurantoin mentioned as a co-cause of drug-induced fibrosis alongside RA-associated lung disease — adverse event context
35145797	2022	Case report	Cureus	94-year-old female with RA on long-term methotrexate developed irreversible pulmonary fibrosis after receiving Nitrofurantoin for recurrent UTIs; documents a dangerous drug–drug interaction, not RA treatment
15195196	2004	Review	Saudi Medical Journal	Review of drug-induced pulmonary fibrosis; lists Nitrofurantoin among causative agents and notes RA as an independent predisposing systemic disease
25362778	2014	Review	La Revue du praticien	Drug-induced interstitial lung diseases; Nitrofurantoin cited alongside minocycline as antibiotics associated with subacute or chronic interstitial pneumonia patterns
41635325	2026	Case report	Cureus	Autoimmune hepatitis workup; Nitrofurantoin listed among common drug-induced liver injury causes, and RA mentioned as a co-existing autoimmune condition — no therapeutic link
899886	1977	Observational	Acta Medica Scandinavica	Short-term Nitrofurantoin therapy for bacteriuria screening in middle-aged women; RA is not mentioned; inclusion appears to be a database artifact
11937933	2002	Case report	Annales de Dermatologie et de Vénéréologie	Phenylbutazone-induced sialadenitis; Nitrofurantoin mentioned among drugs that can induce salivary gland inflammation — incidental co-mention with no RA relevance
8104358	1993	Case report	Revue de Pneumologie Clinique	Gold salt-induced immunoallergic pneumonia in a 62-year-old RA patient; discusses CD4 alveolitis differential; Nitrofurantoin cited in the broader drug-induced lung disease context
4608019	1974	Review	Der Internist	Synopsis of alveolitis and pulmonary fibrosis; Nitrofurantoin listed among known causative agents; no connection to RA treatment

India Market Information

Nitrofurantoin currently has no registered products in India. No authorization records were found in the regulatory database (total registrations: 0).

Safety Considerations

Drug Interactions (172 total interactions identified; key interactions listed below):

Interacting Drug	Severity	Notes
Metronidazole	Moderate	Potential for increased systemic adverse effects when co-administered
Balsalazide	Moderate	Interaction reported; clinical significance to be assessed
Rosuvastatin	Moderate	May affect statin exposure; monitor for myopathy signs
Simvastatin	Moderate	May affect statin exposure; monitor for myopathy signs
Naltrexone	Moderate	Interaction reported; monitor clinical response
Picosulfuric acid	Moderate	Interaction reported; separate administration timing if possible
Anticholinergics (Hyoscyamine, Atropine, Scopolamine, Dicyclomine, Trospium, etc.)	Minor	May delay gastric emptying and increase Nitrofurantoin absorption
Magnesium-containing antacids (Magaldrate, Magnesium carbonate, Magnesium hydroxide, Magnesium oxide)	Minor	May reduce Nitrofurantoin absorption; administer separately

Please refer to the package insert for complete warnings and contraindications.

Conclusion and Next Steps

Decision: Hold

Rationale: All available evidence indicates that the TxGNN prediction linking Nitrofurantoin to rheumatoid arthritis is a false positive, driven by literature co-occurrence in the context of pulmonary adverse events — not by any demonstrated or plausible therapeutic mechanism. There are zero clinical trials, no mechanistic hypothesis connecting Nitrofurantoin to RA pathophysiology, and every identified publication describes either adverse events or epidemiological associations unrelated to RA treatment. Critically, Nitrofurantoin is itself a known inducer of pulmonary fibrosis and drug-induced liver injury, both of which overlap with RA-associated complications — making any repurposing attempt potentially harmful rather than beneficial.

To proceed, the following would be needed:

A clearly articulated mechanistic hypothesis (e.g., immunomodulation via nitroreductase pathways or microbiome-mediated RA trigger suppression) supported by preclinical evidence
In vitro or in vivo studies demonstrating anti-inflammatory or disease-modifying activity in RA models
Safety re-evaluation addressing the known pulmonary fibrosis risk — especially in RA patients already on methotrexate or other DMARDs with overlapping lung toxicity profiles
Clarification of contraindication boundaries: Nitrofurantoin is contraindicated in patients with eGFR < 45 mL/min, which is relevant given the prevalence of renal impairment in long-standing RA patients on nephrotoxic DMARDs
Full MOA data from DrugBank to enable proper mechanistic linkage analysis
Disclaimer

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