Nitrofurantoin
Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026
A nitrofuran antibiotic used exclusively for the treatment and prophylaxis of uncomplicated urinary tract infections. Active against most common UTI pathogens including E. coli (resistance remains low), Enterococcus faecalis, S. saprophyticus, and Klebsiella. Does not achieve therapeutic serum or tissue concentrations, so it is only effective for lower urinary tract (bladder) infections.
Exploratory record, not a reviewed medical publication.
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This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.
What the research says.
A quick, data-only summary. The full evidence, dosing, and sources are below.
A nitrofuran antibiotic used exclusively for the treatment and prophylaxis of uncomplicated urinary tract infections. NutriStack rates the supporting evidence as strong. Common adult dosing is Macrobid: 100 mg every 12 hours x 5 days; Macrodantin: 50-100 mg QID x 7 days; prophylaxis: 50-100 mg at bedtime (as prescribed by your physician), though a prescriber sets the actual dose. This profile indexes 10 sources.
- Nausea (most common, reduced with macrocrystal form)
- Headache
- Flatulence
- Severe renal impairment (CrCl <30 mL/min), inadequate urinary drug concentration and increased toxicity risk
- Pregnancy at term (38-42 weeks), risk of hemolytic anemia in neonate
The bottom line
Evidence rating strong. Most-documented uses: first-line treatment for uncomplicated lower uti (cystitis), uti prophylaxis (recurrent infections), low resistance rates (multi-target mechanism). 10 sources indexed (2015–2025), with 0 interaction records on file.
How it works, mechanistically.
Core mechanism
A prodrug that is reduced by bacterial nitroreductases to form highly reactive electrophilic intermediates. These intermediates attack bacterial ribosomal proteins, DNA, and other macromolecules through multiple mechanisms simultaneously, inhibiting protein synthesis, aerobic energy metabolism, DNA synthesis, RNA synthesis, and cell wall synthesis. This multi-target mechanism results in a very low rate of resistance development.
Dosing & protocol.
Take with food to increase absorption and reduce GI upset. Food increases bioavailability by approximately 40%. The macrocrystal form (Macrobid) has slower dissolution, providing more sustained urinary levels and fewer GI side effects.10
Full safety detail.
Side effects
- Nausea (most common, reduced with macrocrystal form)
- Headache
- Flatulence
- Brown-orange urine discoloration (harmless)
- Pulmonary toxicity (acute hypersensitivity or chronic fibrosis with prolonged use)
- Peripheral neuropathy (with prolonged use or renal impairment)
- Hepatotoxicity (rare)
Contraindications
- Severe renal impairment (CrCl <30 mL/min), inadequate urinary drug concentration and increased toxicity risk
- Pregnancy at term (38-42 weeks), risk of hemolytic anemia in neonate
- Infants under 1 month (risk of hemolytic anemia)
- Known hypersensitivity to nitrofurantoin1,2
- G6PD deficiency (risk of hemolytic anemia)5
- History of pulmonary reactions to nitrofurantoin4,1
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Meta-analyses & systematic reviews
1- 1Nitrofurantoin revisited: a systematic review and meta-analysis of controlled trialsPMIDHuttner A, Verhaegh EM, Harbarth S et al. · The Journal of antimicrobial chemotherapy · 2015
Huttner A, Verhaegh EM, Harbarth S et al.. Nitrofurantoin revisited: a systematic review and meta-analysis of controlled trials. The Journal of antimicrobial chemotherapy. 2015
Randomized controlled trials
1- 2Design of Two Phase III, Randomized, Multicenter Studies Comparing Gepotidacin with Nitrofurantoin for the Treatment of Uncomplicated Urinary Tract Infection in Female ParticipantsPMIDPerry C, Hossain M, Powell M et al. · Infectious diseases and therapy · 2022
Perry C, Hossain M, Powell M et al.. Design of Two Phase III, Randomized, Multicenter Studies Comparing Gepotidacin with Nitrofurantoin for the Treatment of Uncomplicated Urinary Tract Infection in Female Participants. Infectious diseases and therapy. 2022
Reviews & position papers
3- 3Plain language summary: efficacy and safety of gepotidacin, a new oral antibiotic, compared with nitrofurantoin, a commonly used oral antibiotic, for treating uncomplicated urinary tract infectionPMIDWagenlehner F, Perry CR, Hooton TM et al. · Future microbiology · 2025
Wagenlehner F, Perry CR, Hooton TM et al.. Plain language summary: efficacy and safety of gepotidacin, a new oral antibiotic, compared with nitrofurantoin, a commonly used oral antibiotic, for treating uncomplicated urinary tract infection. Future microbiology. 2025
- 4Nitrofurantoin-Induced Pulmonary Toxicity: Mechanisms, Diagnosis, and ManagementPMIDKaye AD, Shah SS, LaHaye L et al. · Toxics · 2025
Kaye AD, Shah SS, LaHaye L et al.. Nitrofurantoin-Induced Pulmonary Toxicity: Mechanisms, Diagnosis, and Management. Toxics. 2025
- 5Nitrofurantoin and glucose-6-phosphate dehydrogenase deficiency: a safety reviewPMIDRecht J, Chansamouth V, White NJ et al. · JAC-antimicrobial resistance · 2022
Recht J, Chansamouth V, White NJ et al.. Nitrofurantoin and glucose-6-phosphate dehydrogenase deficiency: a safety review. JAC-antimicrobial resistance. 2022
Reference material
5- 6Gupta K et al. International clinical practice guidelines for the treatment of acute uncomplicated cystitis and pyelonephritis in women: a 2010 update by IDSA and ESCMID. Clin Infect Dis. 2011.Source linkedPMID
- 7McKinnell JA et al. Nitrofurantoin compares favorably to recommended agents as empirical treatment of uncomplicated urinary tract infections in a decision and cost analysis. Mayo Clin Proc. 2011.Source linkedPMID
- 8Ibrahim T et al. Safety and efficacy of gepotidacin in urinary tract infection: a GRADE-assessed systematic review and meta-analysis. J Antimicrob Chemother. 2026.Source linkedPMID
- 9Konwar M, Gogtay NJ, Ravi R et al.. Evaluation of efficacy and safety of fosfomycin versus nitrofurantoin for the treatment of uncomplicated lower urinary tract infection (UTI) in women - A systematic review and meta-analysis. Journal of chemotherapy (Florence, Italy). 2022Source linkedPMID
- 10Huttner A, Kowalczyk A, Turjeman A et al.. Effect of 5-Day Nitrofurantoin vs Single-Dose Fosfomycin on Clinical Resolution of Uncomplicated Lower Urinary Tract Infection in Women: A Randomized Clinical Trial. JAMA. 2018Source linkedPMID
Common questions.
Quick answers about Nitrofurantoin, drawn from the data on this page.
What is Nitrofurantoin?
A nitrofuran antibiotic used exclusively for the treatment and prophylaxis of uncomplicated urinary tract infections. Active against most common UTI pathogens including E. coli (resistance remains low), Enterococcus faecalis, S. saprophyticus, and Klebsiella. Does not achieve therapeutic serum or tissue concentrations, so it is only effective for lower urinary tract (bladder) infections.
What is Nitrofurantoin used for?
Commonly cited benefits of Nitrofurantoin include: First-line treatment for uncomplicated lower UTI (cystitis); UTI prophylaxis (recurrent infections); Low resistance rates (multi-target mechanism); Minimal impact on gut and vaginal flora; Well-tolerated for short courses. NutriStack rates the overall evidence as strong.
What is a typical dose of Nitrofurantoin?
A typical adult dose of Nitrofurantoin is Macrobid: 100 mg every 12 hours x 5 days; Macrodantin: 50-100 mg QID x 7 days; prophylaxis: 50-100 mg at bedtime (as prescribed by your physician). The commonly recommended form is Oral capsules (Macrobid macrocrystals/monohydrate preferred) or suspension. These are general ranges, not personalized advice; confirm the right dose with a clinician.
What are the side effects of Nitrofurantoin?
Reported side effects include nausea (most common, reduced with macrocrystal form), headache, flatulence, brown-orange urine discoloration (harmless), pulmonary toxicity (acute hypersensitivity or chronic fibrosis with prolonged use), peripheral neuropathy (with prolonged use or renal impairment). This is educational information; check with a healthcare professional before use.
How strong is the evidence for Nitrofurantoin?
NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.
Use this with your stack
Nitrofurantoin in NutriStack.
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