Nitrofurantoin is an antibiotic used to treat lower urinary tract infections (UTIs), such as cystitis. It belongs to a group of medications called ‘nitrofuran antibiotics’.

It is the first choice treatment for uncomplicated UTIs like cystitis, with many people noticing an improvement in their symptoms within 2 to 3 days.

When you take nitrofurantoin, it filters out from the blood into your urine. Here, it can enter and kill off the bacteria responsible for the infection by damaging its genetic material.

Nitrofurantoin targets the site of the infection in the urinary tract, making it specific for bladder and kidney infections. So, it will not work for other bacterial infections elsewhere in the body.

How effective is nitrofurantoin?

Studies show nitrofurantoin was more effective than trimethoprim in treating acute uncomplicated cystitis. In the study, a 5-day course of nitrofurantoin cured 84% of cases compared to 79% for trimethoprim. Further research shows that nitrofurantoin has cure rates between 79% and 92%.

If nitrofurantoin doesn’t clear up your UTI it can be a sign of antibiotic resistance, when bacteria develop ways to block the action of an antibiotic and continue to live. Nitrofurantoin resistance is low (less than 3%) but you may still need a broad-spectrum antibiotic that is effective against a wider range of bacteria. If you feel nitrofurantoin isn’t working for you, speak to your doctor for advice.

Always take nitrofurantoin exactly as your doctor has prescribed. They will tell you how long you need to take nitrofurantoin capsules for and at what dose.

The usual dose is:

• To treat a UTI: 2 x 100mg capsule 2 times a day
• To prevent a UTI: 1 x 100mg capsule before bed

When taking nitrofurantoin capsules:

• swallow them whole with food or milk – taking it with either option will help it work more effectively than taking it only with water
• space your doses evenly throughout the day
• swallow them with food to help lower the risk of side effects

When to take nitrofurantoin

If you have been prescribed nitrofurantoin to treat cystitis, you’ll usually need to take 2 x 100 mg capsules twice a day. You should leave 12 hours between each dose. For example, take your first dose at 8am and your second dose at 8pm.

If you have been prescribed nitrofurantoin to stop cystitis from coming back, take the capsule just before you go to bed.

How often to take nitrofurantoin

To treat cystitis you’ll usually take the capsules twice a day, once in the morning and once in the evening.

How long do you need to take nitrofurantoin for?

Usually, a 3-day or 7-day course of nitrofurantoin is prescribed for UTIs. Some people may need to take nitrofurantoin for longer if they have a more severe infection. Your doctor will advise you about how long you need to take nitrofurantoin for.

What should I do if I miss a dose?

If you forget to take nitrofurantoin, take your missed dose as soon as you remember unless it’s nearly time to take your next one. If it is, just skip your missed dose and take your normal dose at the usual time. If you miss several doses, speak to your doctor as it may not be effective and there is a higher chance of a recurrent infection.

You must not take 2 doses at the same time to make up for a missed dose.

You may find it useful to set an alarm to remind you to take your doses to help avoid missing them.

You will need a prescription to buy nitrofurantoin capsules for cystitis. You can request nitrofurantoin online from trusted services like Superdrug Online Doctor or you may be able to get a prescription on the NHS.

Can I buy nitrofurantoin online?

Yes, nitrofurantoin for cystitis can be requested from Superdrug Online Doctor. Just:

• complete a short online questionnaire about your health and lifestyle
• order your preferred treatment and make payment

Then:

• one of our doctors will review your answers to the questionnaire and your order to see if it is suitable for you
• if approved, your order will be delivered to your address in plain packaging or to a Superdrug Pharmacy for collection
• if our doctors do not feel nitrofurantoin is right for you, they will contact you via your account with other suitable treatment options

Can I buy nitrofurantoin over the counter?

No, it isn’t possible to buy nitrofurantoin over-the-counter because you need a prescription from a doctor.

Can I get nitrofurantoin on the NHS?

It may be possible to get nitrofurantoin capsules on the NHS but you will need to make an appointment with your GP to get a prescription.

The NHS will use the same prescribing criteria as our doctors to check whether nitrofurantoin is right for you.

Like all medications, nitrofurantoin can cause side effects but not everyone will get them.

Common nitrofurantoin side effects include:

• feeling sick (nausea)
• being sick (vomiting)
• diarrhoea
• loss of appetite
• headaches
• dizziness
• tiredness

Rare side effects of nitrofurantoin are:

• loss of consciousness
• anaemia (low red blood cell count)

You should stop taking nitrofurantoin and call a doctor or 111 if you experience any of the following:

• a cough, coughing up blood or mucous, shortness of breath, pain when you breathe, or a high temperature
• pale stool and dark urine together
• the whites of your eyes or your skin turns yellow
• unexplained bruising or bleeding
• severe headaches

Call 999 or go to A&E straight away if you get any of these serious allergic reaction side effects :

• chest pain or difficulty breathing
• pins and needles, tingling sensations, numbness, or weakness
• swollen lips, mouth, tongue or throat
• fast breathing
• your skin, lips, or tongue turn blue, grey, or pale
• sudden confusion, drowsiness, dizziness
• skin rash that is swollen, raised, itchy, blistered, or peeling

How long do nitrofurantoin side effects last?

The side effects of nitrofurantoin are usually mild and should go away within a few days, especially if you’re only on a 3-day course. If they do not disappear after your course has finished, speak to your doctor.

What to do if you get nitrofurantoin side effects

Taking nitrofurantoin with food can help to reduce the risk of side effects.

If you do get nitrofurantoin side effects and are finding them difficult to manage, speak to your doctor for advice. They may recommend a different dose or an alternative cystitis medication.

You can also report any side effects, including those not listed in the patient information leaflet, to the Yellow Card Scheme.

Nitrofurantoin isn’t suitable for everyone.

Do not take nitrofurantoin if you:

• are allergic to any of the ingredients in the capsule
• have kidney disease and it affects how they work
• are in the final stages of pregnancy (third trimester)
• have a blood disorder called porphyria
• are deficient in an enzyme called glucose-6-phosphate dehydrogenase (G6PD)
• are breastfeeding a baby with a G6PD deficiency

Before taking nitrofurantoin, tell your doctor if you:

• are diabetic
• have any illness that causes severe weakness
• are anaemic
• have a history of allergic reactions
• have kidney problems
• have lung disease

Nitrofurantoin and pregnancy

Nitrofurantoin can normally be used during pregnancy but not during the third trimester or labour because it may affect the baby at this point.

Let your doctor know if you are pregnant, think you might be or are planning on becoming pregnant, or are breastfeeding before taking nitrofurantoin.

Nitrofurantoin and alcohol

Although alcohol may not interact with nitrofurantoin and affect its effectiveness, it is recommended that you avoid alcohol while taking nitrofurantoin antibiotics to give your body the best chance to clear the infection. Alcohol may also increase the risk of side effects.

Nitrofurantoin and driving

Nitrofurantoin capsules can cause sleepiness. If you experience drowsiness or sleepiness you should avoid driving or operating machinery until these symptoms go away.

At Superdrug Online Doctor, we offer alternative cystitis treatments. They are:

• Fosfomycin sachets: a single-dose antibiotic sachet containing the active ingredient fosfomycin. These are only prescribed if nitrofurantoin is not suitable for you and is offered as a second-line treatment.

There are also some at-home remedies you can try to help manage the symptoms or prevent cystitis from coming back, such as:

• Painkillers: It is safe to take over-the-counter painkillers such as paracetamol or ibuprofen with nitrofurantoin to manage cystitis discomfort.
• Cranberry products: Some people use cranberry products like juice to prevent cystitis returning but there is no evidence so far that it can treat the infection once it has started.
• Cystitis sachets: Over-the-counter sachets that contain potassium citrate or sodium citrate can be used to help make your urine less acidic, reducing the discomfort you experience when you have cystitis.

If you are not sure if you have cystitis, you can request an at-home UTI TestCard. All you need to do is collect a urine sample, use the UTI test strips to check your sample and the TestCard app to receive your results within a few minutes.

Does nitrofurantoin affect sleep?

Sleep disturbances are not a known side effect of nitrofurantoin. However, nitrofurantoin can make you feel sleepy or drowsy and can cause loss of consciousness as a rare side effect.

If you feel sleepy while taking nitrofurantoin, you should avoid driving or operating machinery until these side effects have subsided.

Does nitrofurantoin make your pee bright?

Nitrofurantoin can change the appearance of your urine, making it turn dark yellow or brown. Once you have finished your course, your urine will return to its normal colour.

What food or drink should I avoid when taking nitrofurantoin?

There are no foods or drinks you need to avoid while taking nitrofurantoin, although it is recommended you avoid drinking alcohol. It is also recommended that you take the capsules with food or milk to increase their effectiveness.