Nitrofurantoin at a glance
Medicine class
Nitrofuran antibacterial.
Main role
Treatment or prevention of susceptible, uncomplicated urinary tract infections.
Taking it
Take with food or milk to improve absorption and reduce stomach upset.
What is Nitrofurantoin used for?
Selected UK products are licensed for urinary infections caused by susceptible organisms.
Acute or recurrent uncomplicated lower urinary tract infection.
Prevention or suppression of recurrent uncomplicated urinary tract infection.
Some selected products also include uncomplicated pyelitis and prevention around urinary-tract procedures.
It is not suitable for renal cortical or perinephric abscesses.
How does Nitrofurantoin work?
Bacteria activate nitrofurantoin into reactive compounds that disrupt several bacterial enzymes, proteins and genetic material. It produces antibacterial concentrations in urine while blood and tissue concentrations remain low.
Nitrofurantoin preparations and strengths
Capsule
Route: Oral
Strengths: 50 mg, 100 mg
Modified-release capsule
Route: Oral
Strengths: 100 mg
Tablet
Route: Oral
Strengths: 50 mg, 100 mg
How to take Nitrofurantoin
Follow the dispensing label and instructions for the formulation supplied.
Take with or immediately after food, or with milk.
Swallow tablets and capsules whole; do not chew or break them.
Do not drive, cycle or operate machinery if dizzy or drowsy.
Nitrofurantoin side effects
Common or expected effects
- Nausea or stomach upset
- Vomiting or diarrhoea
- Reduced appetite
- Headache
- Dizziness or drowsiness
- Dark yellow or brown urine, which is usually harmless
Get urgent medical advice
- New or worsening cough, breathlessness, chest discomfort, fever or coughing blood or mucus
- Yellow skin or eyes, dark urine, pale stools, itching or upper abdominal discomfort
- Unexplained bruising or bleeding, sore throat, fever or marked tiredness
- Tingling, numbness, weakness or other signs of peripheral nerve injury
- Haemolysis, particularly with G6PD deficiency
- Severe allergic or blistering skin reaction
Nitrofurantoin in pregnancy
Nitrofurantoin can be prescribed during pregnancy when clinically appropriate. UK patient guidance generally recommends avoiding it towards the end of pregnancy where an effective alternative is available. Selected product information contraindicates use during labour and delivery because of possible haemolysis in the newborn. Discuss treatment with the prescriber rather than stopping it without advice.
Nitrofurantoin interactions
Tell the prescriber or pharmacist about medicines, pharmacy products and supplements, particularly:
Magnesium-containing antacids
Some products, particularly those containing magnesium trisilicate, can reduce nitrofurantoin absorption.
Urine-alkalinising cystitis remedies and carbonic anhydrase inhibitors
Making urine less acidic can reduce nitrofurantoin's antibacterial activity.
Common questions about Nitrofurantoin
Answers are fully visible for fast scanning and source review.
Is nitrofurantoin a penicillin antibiotic?
No. It is a nitrofuran antibiotic and is chemically unrelated to penicillins.
Why is kidney function checked?
Adequate renal function is needed to deliver nitrofurantoin into urine. Impairment can reduce effectiveness and increase systemic adverse effects.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.