Nitrofurantoin

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.

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.

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.

Serious 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

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.

Find out more about taking nitrofurantoin during pregnancy on the Bumps (Best Use of Medicines in Pregnancy) website

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.