[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/) › Nitrofurantoin

[Pharmacology](https://durgical.com/en/pharmacology/) · [Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/)

# Nitrofurantoin

A first-line oral drug for uncomplicated cystitis that acts only in the bladder. Long courses can harm the lungs, liver and nerves.

Updated 2026-11-01

- Class: [Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/)
- Target: Bacterial ribosomal proteins and other macromolecules (after reduction by bacterial flavoproteins)
- ATC code: J01XE01
- WHO Model List of Essential Medicines

## Mechanism of action

Bacterial flavoproteins reduce nitrofurantoin to reactive intermediates that attack ribosomal proteins and other macromolecules, disrupting protein synthesis, metabolism and cell-wall building. Because several targets are hit at once, resistance develops slowly. It reaches useful levels only in urine.

- Filtered and concentrated in the urine
- Bacterial flavoproteins reduce it
- Reactive products damage ribosomes and enzymes
- Bacteria in the bladder die

## Pharmacokinetics

**Absorption**
Absorbed by mouth; food increases absorption and tolerance.

**Distribution**
Low blood and tissue levels; high in urine.

**Elimination**
Urine, partly unchanged; it can turn the urine brown.

## Indications

- Acute uncomplicated cystitis (WHO «Access» antibiotic) [Urinary tract infection (acute cystitis) →](https://durgical.com/en/conditions/urinary-tract-infection/)
- Prevention of recurrent urinary tract infection in selected patients

## Adverse effects

### Common

- Nausea, loss of appetite and headache
- Brown urine
- Rash

### Serious (rare, important)

- Acute pulmonary reactions (fever, cough, breathlessness) and chronic interstitial pneumonitis or fibrosis with long use
- Hepatitis, cholestatic jaundice and liver necrosis
- Peripheral neuropathy, which may be severe or permanent
- Haemolytic anaemia, especially in G6PD deficiency

## Contraindications

- Significantly reduced kidney function, oliguria or anuria (too little reaches the urine and toxicity rises)
- Pregnancy at term (38–42 weeks), labour and delivery, and newborns under one month (haemolysis)
- Previous cholestatic jaundice or liver dysfunction with nitrofurantoin

## Key interactions

**Antacids with magnesium trisilicate**
Reduce absorption.

**Probenecid and other uricosurics**
Block its tubular secretion: lower urinary levels and more toxicity.

## What is monitored

- Breathing symptoms and chest findings, especially with long-term use
- Liver tests and kidney function in long courses
- Numbness or tingling

## Administration and safety

- Given with food to improve absorption and reduce nausea
- Capsules are swallowed whole
- Not used for pyelonephritis or bloodstream infection

## Nursing care

- Explain that brown urine is harmless
- Teach to report cough, breathlessness, fever, yellow skin or tingling
- Check kidney function before starting
- Ask about pregnancy stage

## Pregnancy and breastfeeding

Used for cystitis in pregnancy, but avoided at term, during labour and near delivery because of newborn haemolysis.

## Memory aid

«Nitro for the bladder, never for the kidney»: it fills the bladder, not the kidney or the blood.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is nitrofurantoin not used for pyelonephritis?

It reaches useful levels only in the bladder urine, not in kidney tissue or blood.

## Which lung problem can appear with long-term nitrofurantoin?

Chronic interstitial pneumonitis or pulmonary fibrosis.

## Why is it contraindicated at the end of pregnancy?

It can cause haemolytic anaemia in the newborn, whose red cells are vulnerable.

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## Related drugs

- [Fosfomycin](https://durgical.com/en/pharmacology/fosfomycin/)
- [Methenamine](https://durgical.com/en/pharmacology/methenamine/)
- [Trimethoprim](https://durgical.com/en/pharmacology/trimethoprim/)

## Related conditions

- [Urinary tract infection (acute cystitis)](https://durgical.com/en/conditions/urinary-tract-infection/)

[← Back to the class: Urinary antiseptics](https://durgical.com/en/pharmacology/classes/urinary-antiseptics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - NITROFURANTOIN- MONOHYDRATE/MACROCRYSTALS capsule](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=35c0a6d8-ff85-4d9b-9ad3-ae20808119dd) (DailyMed (U.S. National Library of Medicine), 2026); [Nitrofurantoin: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682291.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/?query=nitrofurantoin) (World Health Organization, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/nitrofurantoin/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/nitrofurantoin/