Side effects of nitrofurantoin

Keep taking the medicine, but speak to a doctor if the advice on how to cope does not help and a side effect is still bothering you or does not go away.

Common questions about nitrofurantoin

Nitrofurantoin works in a different way from other antibiotics.

When you take it by mouth, most of it gets filtered out of your blood and into your pee. This concentrates the medicine where the bacteria are that are causing the urinary tract infection.

Nitrofurantoin kills the bacteria by entering their cells and damaging their genetic material.

When will I feel better?

You should feel better within a few days.

It’s important that you keep taking nitrofurantoin until your course is finished. Do this even if you feel better. It will help stop the infection coming back.

If you’re taking nitrofurantoin to stop urinary tract infections coming back, you may not have any symptoms or feel unwell, but you will still need to carry on taking it for several months.

What if I do not get better?

Tell your doctor if you do not start feeling better after taking nitrofurantoin for 3 days, or if you start to feel worse at any time.

Will it give me thrush?

Some people get a fungal infection called thrush after taking a course of antibiotics like nitrofurantoin. It happens because antibiotics kill the normal harmless bacteria that help to protect you against thrush.

Ask your pharmacist or doctor for advice if this happens to you.

Will it affect my contraception?

Nitrofurantoin does not stop any type of contraception from working, including the combined pill, progestogen-only pill or emergency contraception.

However, if nitrofurantoin makes you sick (vomit) or you have severe diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Look on the pill packet to find out what to do.

• What to do if you’re sick or have diarrhoea when taking the combined pill
• What to do if you’re sick or have diarrhoea when taking the progestogen-only pill

Can I drive or ride a bike?

Nitrofurantoin can make you feel dizzy or sleepy. If this happens, do not drive or cycle until you feel better.

It’s an offence to drive a car if your ability to drive safely is affected. It’s your responsibility to decide if it’s safe to drive. If you’re in any doubt, do not drive.

Talk to your doctor or pharmacist if you’re unsure whether it’s safe for you to drive while taking nitrofurantoin. GOV.UK has more information on the law on drugs and driving.

Can I drink alcohol while taking nitrofurantoin?

Yes, you can drink alcohol with nitrofurantoin.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking nitrofurantoin.

Can drinking cranberry juice help urinary tract infections?

It’s unlikely that drinking cranberry juice or taking cranberry supplements helps treat or prevent urinary tract infections.

Can lifestyle changes help urinary tract infections?

It’s possible that a straightforward urinary tract infection will clear up on its own without any treatment. But it’s usually best to treat a urinary tract infection with an antibiotic, or it could spread to the kidneys and lead to more serious problems.

Once treated, there are many steps you can take to stop urinary tract infections coming back:

• avoid perfumed bubble bath, soap or talcum powder around your genitals – use plain, unperfumed varieties, and have a shower rather than a bath
• go to the toilet as soon as you need to pee, and always empty your bladder fully
• stay well hydrated – aim to drink 6 to 8 glasses of fluid a day (water, lower-fat milk and sugar-free drinks, including tea and coffee, all count)
• wipe your bottom from front to back when you go to the toilet
• empty your bladder as soon as possible after having sex
• do not use a contraceptive diaphragm or condoms with spermicidal lubricant on them – use another type of contraception instead
• wear underwear made from cotton, rather than synthetic material like nylon
• avoid tight jeans and trousers

More in Nitrofurantoin

Page last reviewed: 7 January 2022
Next review due: 7 January 2025

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Side effects of nitrofurantoin

Like all medicines, nitrofurantoin can cause side effects, although not everyone gets them.

Common side effects

There are things you can do to help cope with these common side effects of nitrofurantoin.

Feeling sick (nausea)

Taking nitrofurantoin with or after a meal or snack should help prevent this. It may also help if you avoid rich or spicy food.

Being sick (vomiting)

Have frequent sips of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee. Do not take any other medicines to treat vomiting without speaking to a pharmacist or doctor.

If you take the combined pill or progestogen-only pill and you’re being sick, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having strong-smelling pee. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor.

If you take the combined pill or progestogen-only pill and you have severe diarrhoea for more than 24 hours, your contraception may not protect you from pregnancy. Check the pill packet for advice.

Loss of appetite

Eat when you would usually expect to be hungry. If it helps, eat smaller meals more often than usual. Snack when you’re hungry. Have nutritious snacks that are high in calories and protein, such as dried fruit and nuts.

Make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Painkillers you can buy without a prescription, such as paracetamol and ibuprofen, are safe to take with nitrofurantoin. Speak to your doctor if these do not help or the headaches are severe.

Dizziness or feeling sleepy

If nitrofurantoin makes you feel dizzy, stop what you’re doing and sit or lie down until you feel better. Do not drive a car or ride a bike while you’re feeling dizzy or sleepy.

Keep taking the medicine, but speak to a doctor if the advice on how to cope does not help and a side effect is still bothering you or does not go away.

Nitrofurantoin may cause your pee to turn dark yellow or a brownish colour. This is normal and is not a reason to stop taking the medicine. Your pee will return to its usual colour once you stop taking nitrofurantoin.

Serious side effects

Serious side effects are rare and happen in less than 1 in 1,000 people.

Call a doctor or call 111 straight away if you have:

• a cough, coughing up blood or mucus, shortness of breath, pain when you breathe or a high temperature – these can be signs of lung problems
• pale poo and dark pee together, or the whites of your eyes turn yellow or your skin turns yellow (this may be less obvious on brown or black skin) – this can be a sign of liver or gallbladder problems
• bruising or bleeding you cannot explain (including nosebleeds), sore throat, a high temperature and feeling tired or generally unwell – these can be signs of blood problems
• severe headaches

Immediate action required: Call 999 or go to A&E if:

• you get chest pain or difficulty breathing – these can be signs of lung problems
• you get pins and needles, tingling sensations, numbness or weakness – these can be signs of nerve problems

Information:

Do not drive to A&E. Ask someone to drive you or call 999 and ask for an ambulance.

Bring all the medicines you take with you.

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to nitrofurantoin (anaphylaxis).

Immediate action required: Call 999 now if:

• your lips, mouth, throat or tongue suddenly become swollen
• you’re breathing very fast or struggling to breathe (you may become very wheezy or feel like you’re choking or gasping for air)
• your throat feels tight or you’re struggling to swallow
• your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
• you suddenly become very confused, drowsy or dizzy
• someone faints and cannot be woken up
• a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)

You or the person who’s unwell may also have a rash that’s swollen, raised, itchy, blistered or peeling.

These can be signs of a serious allergic reaction and may need immediate treatment in hospital.

Information:

Do not drive yourself to A&E.

The person you speak to at 999 will give you advice about what to do.

Other side effects

These are not all the side effects of nitrofurantoin. For a full list see the leaflet inside your medicines packet.

Information:

Reporting side effects

You can report any suspected side effect using the Yellow Card safety scheme.

More in Nitrofurantoin

Page last reviewed: 7 January 2022
Next review due: 7 January 2025

Support links

• Home
• Health A to Z
• Live Well
• Mental health
• Care and support
• Pregnancy
• NHS services
• Coronavirus (COVID-19)

• NHS App
• Find my NHS number
• View your GP health record
• View your test results
• About the NHS
• Healthcare abroad

• Other NHS websites
• Profile editor login

• About us
• Give us feedback
• Accessibility statement
• Our policies
• Cookies