Side Effects Of Nitrofurantoin

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

Common side effects of nitrofurantoin

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.

There are things you can do to help cope with some of the common side effects of nitrofurantoin:

Keep taking the medicine, but tell your doctor if the advice on how to cope does not help and the side effects bother you or do not go away.

Serious side effects

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

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

• a cough, are coughing up blood or mucus, have 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

Call 999 or go to A&E if:

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).

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.

Other side effects

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

Reporting side effects

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

Visit the Yellow Card website for more information about reporting side effects.

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