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Nitrofurantoin Uses, Dosage, Side Effects & Warnings | DrugsAtlas

Authoritative Clinical Reference

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

⚠️ 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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