Nitrofurantoin
First-line for uncomplicated cystitis. 100 mg modified-release twice daily for 3 days in women. Not for pyelonephritis or eGFR below 45.
On this page
Uses
- Uncomplicated lower UTI (cystitis).
- Prophylaxis of recurrent UTI (specialist).
- Not for pyelonephritis (doesn't reach the kidney).
Adult dose
| Indication | Dose |
|---|---|
| Cystitis, women | 100 mg modified-release twice daily for 3 days |
| Cystitis, men or pregnancy | 100 mg modified-release twice daily for 7 days |
| Immediate-release form | 50 mg 4 times daily |
Children's dose
3 months and over: 750 micrograms/kg 4 times daily for 3–7 days.
Kidney and liver
Avoid if eGFR below 45 (short courses may be used with caution at 30–44 per guidance).
Pregnancy and breastfeeding
Can be used in pregnancy, but avoid at term (neonatal haemolysis).
Side effects and cautions
- Nausea, brown urine.
- Rare lung reactions and liver injury with long-term use.
- Haemolysis in G6PD deficiency.
Frequently asked questions
Can nitrofurantoin treat pyelonephritis?
No. It doesn't reach adequate levels in kidney tissue.
Is nitrofurantoin safe in pregnancy?
Yes, except near term.
Used in these guides
Sources
Doses on this page are typical doses from the sources above. Always confirm with a current drug reference, the product leaflet and your hospital protocol, especially in children, pregnancy and kidney or liver disease.
For FCPS Part 1
Revising for FCPS Part 1? Nitrofurantoin is covered in our textbook chapter Antimicrobials in pregnancy, with practice MCQs.