This NHS content is written for people in England. Medicine names, availability, prescribing and services may differ in other countries.
Nitrofurantoin
What it's forNitrofurantoin
How it's used (previously Dosage and administration)Nitrofurantoin
Side effectsNitrofurantoin
Who it's forNitrofurantoin
InteractionsNitrofurantoin can be used to treat urinary tract infections such as cystitis, and sometimes it's used to prevent them coming back.
Nitrofurantoin usually comes as tablets, capsules and a liquid you swallow. Follow the instructions that come with your medicine.
Side effects of nitrofurantoin include feeling sick, headaches or sometimes turning your pee dark yellow or brown. More serious side effects are rare.
Nitrofurantoin is suitable for most adults and children over 3 months old, but always check before taking it because it's not suitable for everyone.
Taking nitrofurantoin with other medicines, such as antacids or medicines for glaucoma, can cause problems. Always check before taking it.
What nitrofurantoin is for
Nitrofurantoin is used to treat urinary tract infections (UTIs) such as cystitis.
It may also be prescribed to help prevent UTIs.
How to take nitrofurantoin
Nitrofurantoin usually comes as capsules, tablets and a liquid you swallow.
How much you need to take and for how long depends on why you're taking it. Most people need to take it for 3 to 7 days.
Nitrofurantoin can also be prescribed for long-term use if you get UTIs that keep coming back, or as a single-use medicine. You may only need to use it once to prevent a UTI before surgery, for example, or before coming into contact with a known trigger.
When taking nitrofurantoin:
- the dose will depend on the type of capsule or tablet you're taking – some are slow release (prolonged release) which means you do not have to take them as often
- swallow the tablets or capsules whole – do not break or chew them
- try to space your doses evenly throughout the day if you're taking more than 1 dose a day
- use the syringe or spoon that comes with the liquid medicine to measure the right dose
- you can take it with food or a glass of milk – this makes it easier for the medicine to work
Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to take it or have any problems taking it.
Important
If you're taking nitrofurantoin for an infection you already have, it's important to keep taking your medicine until you've finished it all, even if you start to feel better.
If you miss a dose of nitrofurantoin
If you forget to take a dose of nitrofurantoin, take it as soon as you remember, unless it's nearly time for your next dose.
If it's nearly time for your next dose, skip the dose you missed and take your next dose at the usual time.
Do not take 2 doses to make up for a forgotten dose.
If you take too much nitrofurantoin
Taking an extra dose of nitrofurantoin is unlikely to cause problems, but it's important to get medical advice if you take too much as it can sometimes be dangerous.
Speak to a pharmacist as soon as possible if:
- you've taken more than your prescribed dose of nitrofurantoin
If you're unable to speak to a pharmacist, or you took too much of your medicine on purpose, call NHS 111 for advice.
Find a pharmacyInformation
If you're told to go to A&E, do not drive. Ask someone to drive you or call 999 and ask for an ambulance.
Bring the nitrofurantoin packet or leaflet inside it, any remaining medicine, and any other medicines you take.
Side effects of nitrofurantoin
Like all medicines, nitrofurantoin can cause side effects, although not everyone gets them.
Side effects
Side effects of nitrofurantoin can include:
- nausea (feeling sick)
- diarrhoea
- loss of appetite
- headaches
- turning your pee a dark yellow or brownish colour
Side effects usually go away when you stop taking the medicine.
Nitrofurantoin will not usually affect your ability to drive, ride a bike or use machinery.
Speak to a pharmacist or doctor if:
- you have any side effects that bother you or do not go away
They may be able to give you advice about how to reduce the side effects. Keep taking your medicine unless you’re advised to stop.
Find a pharmacySerious side effects
Nitrofurantoin can sometimes cause serious side effects.
Possible serious side effects of nitrofurantoin include:
- lung problems – causing symptoms such as a cough, coughing up blood or mucus and breathing problems
- liver problems such as jaundice and hepatitis – causing yellowing of the eyes and skin (this may be harder to see on black or brown skin)
- an allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised, itchy rash or difficulty breathing
- blood problems – causing symptoms such as bruising or bleeding you cannot explain (including nosebleeds), sore throat, a high temperature and feeling tired or generally unwell
- severe headaches
Call 999 if:
- you're taking nitrofurantoin and might be having anaphylaxis
If you think you're having any other serious side effect, call NHS 111.
Who can and cannot take nitrofurantoin
Most adults and children over 3 months old can take nitrofurantoin.
But nitrofurantoin is not suitable for everyone. For example, it may not be suitable if:
- you've previously had an allergic reaction or other serious side effect from nitrofurantoin
- you have a lung condition
- you have severe kidney problems
- you have diabetes
- you have anaemia or vitamin B deficiency
- you have a condition that affects your blood called porphyria
Before taking nitrofurantoin, tell your doctor if you have any medical conditions.
Breastfeeding and nitrofurantoin
You can usually take nitrofurantoin while breastfeeding, but check with a pharmacist or doctor first.
It's rare for breastfed babies to get any side effects from medicine you're taking, but speak to a healthcare professional if you have any concerns about your baby or call NHS 111.
Pregnancy and nitrofurantoin
You can usually take nitrofurantoin before week 28 of pregnancy.
A doctor may not recommend nitrofurantoin after week 28 of pregnancy because it can affect your baby's red blood cells, but they will talk to you about the benefits and risks.
Nitrofurantoin is the best medicine to treat a UTI and it's important to treat them if you're pregnant.
Taking nitrofurantoin with other medicines, food and drink
There are some medicines, remedies and supplements that may not mix well with nitrofurantoin.
This includes some types of:
- medicines to treat indigestion, such as antacids
- medicines to treat certain infections, such as quinolones
- medicines, such as acetazolamide, to treat glaucoma
- medicines to treat cystitis that you buy from a pharmacy
Before taking nitrofurantoin, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.
Food, drink and alcohol with nitrofurantoin
You can eat and drink as normal while taking nitrofurantoin. It's best to take nitrofurantoin with food.
Content supplied by the NHS website, refreshed 19 October 2026. View the original NHS article ↗
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