Nitrofurantoin Uses, Dosage, Side Effects & Warnings | DrugsAtlas
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Therapeutic Class
Antibacterial
Subclass
Urinary antiseptic (Nitrofuran derivative)
Speciality
Urology
Schedule (India)
Schedule H
Routes
Oral
Formulations
| Form | Strengths Available |
|---|---|
| Tablet (immediate-release) | 100 mg |
| Capsule (modified-release/SR) | 100 mg |
| Oral suspension | NOT AVAILABLE in India |
Adult indications
INDICATIONS + DOSING — FOR CLINICIAN USE ONLY
Primary Indications (Approved / Standard in India)
1. Uncomplicated Lower Urinary Tract Infection (Acute Cystitis)
Adults (≥18 years) — Non-pregnant females and selected males
| Parameter | Immediate-Release | Modified-Release (SR) |
|---|---|---|
| Starting dose | 50–100 mg every 6 hours | 100 mg twice daily |
| Titration | Not applicable | Not applicable |
| Usual maintenance dose | 50–100 mg every 6 hours | 100 mg twice daily |
| Maximum dose | 400 mg/day | 200 mg/day |
| Duration | 5–7 days | 5–7 days |
Clinical Notes:
- SR formulation preferred for improved compliance and GI tolerability
- Take with food to enhance absorption and reduce GI upset
- Not appropriate for pyelonephritis or prostatitis due to poor tissue penetration
- Obtain urine culture before initiating in recurrent cases
2. Prophylaxis of Recurrent Urinary Tract Infections
Adults — Recurrent cystitis in women (≥3 episodes/year)
| Parameter | Dosing |
|---|---|
| Starting dose | 50 mg once at bedtime |
| Titration | May increase to 100 mg once at bedtime if needed |
| Usual maintenance dose | 50–100 mg once at bedtime |
| Maximum dose | 100 mg/day |
| Duration | 3–6 months; reassess periodically |
Clinical Notes:
- Initiate only after culture-confirmed susceptibility
- Specialist review recommended before starting long-term prophylaxis
- Maintain adequate fluid intake throughout treatment
- Monitor for pulmonary and hepatic toxicity during prolonged use
Secondary Indications — Adults Only (Off-label)
| Indication | Dose | Duration | Supervision | Evidence |
|---|---|---|---|---|
| UTI prophylaxis post-urethral instrumentation/catheterisation | 100 mg 2–4 hours pre-procedure, then 100 mg at bedtime for 24 hours | Single-day | Specialist only | OFF-LABEL; Indian urology protocols |
| Asymptomatic bacteriuria in pregnancy (selected cases) | 100 mg twice daily (SR) or 50 mg QID (IR) | 5–7 days | Obstetric specialist | OFF-LABEL; ICMR antimicrobial guidelines supportive |
Paediatric indications
PAEDIATRIC DOSING (Specialist Only)
Primary Indications (Approved / Standard in India)
Uncomplicated Lower UTI (Culture-confirmed, Nitrofurantoin-sensitive organism)
| Age/Weight | Dose | Frequency | Duration | Maximum |
|---|---|---|---|---|
| 1–3 months | 5–7 mg/kg/day | Divided into 4 doses | 7 days | Based on weight |
| 3 months–12 years | 5–7 mg/kg/day | Divided into 4 doses | 7 days | 400 mg/day |
| >12 years | Adult dosing | As per adult regimen | 5–7 days | 400 mg/day |
Clinical Notes:
- Use immediate-release formulation only; SR not recommended in children
- Administer with food to improve tolerability
- Bitter taste may affect compliance — consider mixing with food/juice
UTI Prophylaxis (Chronic/Recurrent UTI — Specialist supervision mandatory)
| Parameter | Dosing |
|---|---|
| Starting dose | 1 mg/kg once at bedtime |
| Titration | May increase to 2 mg/kg if needed |
| Usual maintenance dose | 1–2 mg/kg once at bedtime |
| Maximum dose | 100 mg/day |
| Duration | Case-dependent; regular specialist review |
Secondary Indications — Paediatric Doses (Off-label)
Not applicable — no established off-label paediatric indications in Indian practice.
Safety Monitoring — Paediatrics
- Screen for G6PD deficiency before initiation in high-risk populations
- Monitor for haemolytic anaemia (pallor, jaundice, dark urine)
- Observe for GI symptoms and assess compliance
- Periodic CBC if prolonged prophylaxis (>4 weeks)
⚠️ CLEAR STATEMENT: Nitrofurantoin is CONTRAINDICATED in neonates <1 month due to immature enzyme systems and risk of haemolytic anaemia. Use only under paediatric/urology specialist supervision in children 1 month to 12 years.
Renal Adjustments
| eGFR (mL/min/1.73 m²) | Recommendation |
|---|---|
| ≥60 | Full dose; no adjustment required |
| 45–59 | Use with caution; short-term treatment only (≤7 days) |
| 30–44 | Avoid if possible; reduced efficacy and increased toxicity risk |
| <30 |
CONTRAINDICATED — ineffective urinary concentrations; toxicity risk
|
| Haemodialysis |
CONTRAINDICATED — drug removed; ineffective
|
| Peritoneal dialysis |
CONTRAINDICATED
|
Note: Therapeutic efficacy depends on adequate urinary drug concentrations, which are not achieved with impaired renal function.
Hepatic adjustment
Contraindications
- Known hypersensitivity to nitrofurantoin or any excipient
- Severe renal impairment (eGFR <30 mL/min/1.73 m²)
- G6PD deficiency (risk of haemolytic anaemia)
- Neonates <1 month of age
- Pregnancy at term (≥38 weeks gestation) — risk of neonatal haemolytic anaemia
- History of nitrofurantoin-induced pulmonary reactions (acute or chronic)
- History of nitrofurantoin-induced hepatotoxicity (cholestatic or hepatocellular)
- Severe hepatic impairment
- Anuria or oliguria
Cautions
- Elderly patients — reduced renal reserve; increased toxicity risk
- Moderate renal impairment (eGFR 30–59) — reduced efficacy
- Pre-existing pulmonary disease — increased susceptibility to pulmonary toxicity
- Pre-existing peripheral neuropathy — may worsen with nitrofurantoin
- Electrolyte imbalances or debilitated patients
- Diabetes mellitus — may interfere with urine glucose testing (false positive with copper reduction methods)
- Long-term use (>6 months) — requires close monitoring for pulmonary fibrosis and peripheral neuropathy
- Vitamin B deficiency, anaemia, or folate deficiency — may predispose to neurotoxicity
- Urine discolouration (harmless brown colour) — counsel patient to prevent unnecessary alarm
Pregnancy
| Aspect | Details |
|---|---|
| Overall safety | Generally safe in first and second trimesters; avoid at term |
| First trimester | Category B equivalent — acceptable when indicated |
| Second trimester | May be used when benefits outweigh risks |
| Third trimester (≥38 weeks) |
CONTRAINDICATED — risk of neonatal haemolytic anaemia
|
| G6PD-deficient fetus | Avoid throughout pregnancy if G6PD status unknown/positive |
| Preferred alternatives | Fosfomycin (single-dose), Cephalexin, Amoxicillin (if susceptible) |
| Monitoring | Maternal haemoglobin, reticulocyte count if prolonged use; neonatal bilirubin if used near term |
Lactation
| Aspect | Details |
|---|---|
| Compatibility | Compatible with breastfeeding at doses ≤100 mg/day |
| Levels in breast milk | Low (approximately 0.3% of maternal dose) |
| Infant considerations | Avoid if infant is <1 month old, premature, or G6PD deficient |
| Monitoring | Observe infant for jaundice, haemolysis (pallor, irritability), poor feeding |
| Preferred alternatives | Cephalexin, Amoxicillin (if organism susceptible) |
| Duration limit | Short-term use preferred; avoid >7 days without reassessment |
Elderly
| Aspect | Recommendation |
|---|---|
| Starting dose | 50 mg twice daily or 100 mg once daily (SR) |
| Titration | Not applicable; avoid dose escalation |
| Maximum dose | 200 mg/day |
| Duration | Short-term only (≤7 days); avoid long-term prophylaxis |
| Special considerations | Assess renal function before prescribing (eGFR often reduced) |
| Risks | Increased susceptibility to pulmonary toxicity, peripheral neuropathy, hepatotoxicity |
| Monitoring | Renal function, LFTs, respiratory symptoms |
Major drug interactions
| Interacting Drug | Effect | Mechanism | Management |
|---|---|---|---|
| Magnesium trisilicate antacids | Marked reduction in nitrofurantoin absorption | Physical adsorption in GI tract |
Avoid co-administration; separate by ≥2 hours
|
| Probenecid | Increased serum levels and toxicity; reduced urinary concentration | Inhibits tubular secretion |
Avoid combination
|
| Sulfinpyrazone | Similar to probenecid — increased toxicity risk | Inhibits tubular secretion |
Avoid combination
|
| Fluoroquinolones (Norfloxacin, Ciprofloxacin) | Potential in-vitro antagonism; reduced efficacy of both agents | Mechanism unclear |
Avoid combining for UTI treatment
|
| Live oral typhoid vaccine | Reduced vaccine efficacy | Antibacterial effect on vaccine strain |
Avoid concurrent use; complete antibiotic course before vaccination
|
Moderate drug interactions
| Interacting Drug | Effect | Management |
|---|---|---|
| Oral contraceptives | Theoretical risk of reduced efficacy (rare, via GI flora disruption) | Advise backup contraception during prolonged treatment |
| Methotrexate | Possible increased methotrexate plasma levels | Monitor for methotrexate toxicity (mucositis, myelosuppression) |
| Aluminium/calcium antacids | Minor reduction in absorption | Separate administration by 2 hours |
| Urine alkalinising agents (sodium bicarbonate, potassium citrate) | Reduced nitrofurantoin efficacy in alkaline urine | Avoid concurrent use; maintain acidic urine |
| Warfarin | Possible enhanced anticoagulant effect (rare reports) | Monitor INR if co-administered |
Common Adverse effects
- Nausea, vomiting (10–20%) — reduced with food intake and SR formulation
- Anorexia
- Abdominal discomfort, flatulence
- Diarrhoea
- Headache
- Dizziness
- Brown discolouration of urine (harmless)
- Mild skin rash
Serious Adverse effects
| Adverse Effect | Clinical Notes |
|---|---|
| Acute pulmonary reactions | Fever, dyspnoea, cough, eosinophilia within days to weeks; reversible on discontinuation |
| Chronic pulmonary toxicity | Interstitial pneumonitis, pulmonary fibrosis with prolonged use (>6 months); may be irreversible |
| Peripheral neuropathy | Paraesthesia, numbness, motor weakness; may be irreversible — discontinue immediately |
| Hepatotoxicity | Cholestatic or hepatocellular pattern; may present weeks to months after initiation |
| Haemolytic anaemia | Especially in G6PD-deficient patients; presents with pallor, jaundice, dark urine |
| Drug hypersensitivity | Drug fever, eosinophilia, lupus-like syndrome, anaphylaxis (rare) |
| Blood dyscrasias | Agranulocytosis, thrombocytopenia (rare) |
Serious Adverse effects
Serious Adverse effects
Serious Adverse effects
⚠️ All serious adverse effects require immediate discontinuation and appropriate investigation.
Monitoring requirements
| Phase | Parameters |
|---|---|
|
Baseline
|
Serum creatinine, eGFR, LFTs (ALT, AST, ALP, bilirubin), CBC, G6PD status (in high-risk populations) |
|
During treatment (acute course)
|
Clinical response; GI tolerance; symptom resolution by day 3–5 |
|
Short-term use (≤2 weeks)
|
Repeat LFTs only if baseline abnormal or symptoms develop |
|
Long-term prophylaxis
|
LFTs and CBC every 4–6 weeks for first 3 months, then every 2–3 months |
|
Chronic use (>6 months)
|
Pulmonary function assessment (clinical symptoms, CXR if symptomatic); neurological examination for neuropathy |
|
Special situations
|
Chest X-ray if new respiratory symptoms; nerve conduction studies if paraesthesia develops |
Brands in India
| Brand Name | Manufacturer | Formulation |
|---|---|---|
| Martifur | Sanofi | Tablet 100 mg |
| Niftas | Alkem | Tablet/Capsule 100 mg |
| Urifast | Aristo | Tablet 100 mg |
| Macpar | FDC Ltd | Tablet 100 mg |
| Furadantin | — | Tablet 100 mg |
| Nitrofur-SR | Various | Modified-release capsule 100 mg |
Note: No significant FDCs available or recommended.
Price range (INR)
| Formulation | Price Range | Notes |
|---|---|---|
| Tablet 100 mg (immediate-release) | ₹5–₹12 per tablet | NLEM listed; NPPA price-controlled |
| Capsule 100 mg (modified-release/SR) | ₹10–₹20 per capsule | Not under NLEM price control |
| Government supply (Jan Aushadhi) | ₹2–₹4 per tablet | Available at subsidised rates |
Clinical pearls
- Lower UTI only: Nitrofurantoin achieves high urinary concentrations but poor tissue penetration — not suitable for pyelonephritis, prostatitis, or systemic infections.
- Renal function is critical: Efficacy drops significantly and toxicity rises when eGFR <45 mL/min — always check renal function before prescribing.
- SR formulation improves compliance: Twice-daily dosing with modified-release reduces GI side effects and improves adherence compared to QID immediate-release.
- Counsel about urine colour: Brown discolouration is harmless but alarming — proactive counselling prevents unnecessary discontinuation.
- Watch for pulmonary toxicity: Any new cough, dyspnoea, or fever during treatment warrants immediate discontinuation and chest imaging.
- Avoid near term in pregnancy: Contraindicated after 38 weeks due to risk of neonatal haemolysis — switch to cephalexin or fosfomycin.
- G6PD screening: Consider screening in communities with high G6PD prevalence (tribal populations, certain ethnic groups) before initiating therapy.
Version
RxIndia v1.0 — 03 May 2025
Reference
-
- CDSCO approved prescribing information
- Indian Pharmacopoeia 2022
- National List of Essential Medicines (NLEM) 2022
- ICMR Antimicrobial Treatment Guidelines 2023
- API Textbook of Medicine (11th Edition)
- AIIMS UTI Management Protocols
- IAP Guidelines for Paediatric UTI Management
- WHO Essential Medicines List (supportive, paediatric dosing)
- Goodman & Gilman's The Pharmacological Basis of Therapeutics (pharmacokinetic references)
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Clinical Responsibility
This platform is designed strictly for healthcare professionals. Data provided is synthesized from authoritative pharmacological sources and clinical registries. Do not use for consumer medical decisions. Always verify critical dosing and contraindications with official institutional protocols and peer-reviewed journals.
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