What are nitrofurantoin MR Capsules?
nitrofurantoin capsules are an oral medication used to treat urinary tract infections. The active ingredient in
the capsules is nitrofurantoin, which is a type of antibiotic that works by stopping the growth of bacteria in
the urinary tract. This medication is typically taken twice a day for a period of 3 to 7 days, and should be
taken with plenty of water to help flush the bacteria from the urinary tract. Some possible side effects of
nitrofurantoin capsules include upset stomach, diarrhea, and dizziness.
In the UK, nitrofurantoin capsules
are classified as a prescription-only medication, meaning that they can only be obtained with a prescription.
UTIs can affect both men and women, we currently only offer treatment for women, as men usually need a
longer course to completely rid themselves of infection and can be the sign of something more serious. If you
are a man and require treatment visit your doctor or a clinic that specializes in sexual health.
It is the
first line choice of antibiotic and will usually clear the infection quickly getting you back to feeling normal
quickly.
As with any antibiotic it is important you complete the course even if you start to feel better.
Failing to complete the course can lead to reinfection and antibiotic resistance.
How to buy nitrofurantoin MR Capsules online
You can use our online prescription service to buy nitrofurantoin MR Capsules online in the UK with free and
next day delivery. We are a regulated GPhC registered pharmacy based in the UK. Any website that claims to sell
nitrofurantoin MR Capsules without a prescription is operating illegally and you could be purchasing counterfeit
/ fake medicine.
Upon completion of your order, our independent prescriber will then review your online
assessment. If your assessment is approved, our pharmacy team will then receive a prescription and dispense your
order, which will be dispatched the same day using your chosen delivery method.
How it works
nitrofurantoin MR Capsules contain the active ingredient Nitrofurantoin, which is an antibiotic. It is only used to treat UTIs as it is quickly filtered out of the blood into urine. This allows the medicine to act directly at the site of infection and kill the bacteria in your urinary tract. But it does mean that Nitrofurantoin will not work for other types of infections.
How to take nitrofurantoin MR Capsules
For an uncomplicated lower UTI in a non-pregnant adult woman, the usual course is one 100mg modified-release capsule twice daily for three days. Take it with food and water. Other patients, including pregnant women, may need a different course; follow your prescription label and do not choose the course length yourself.
Complete the prescribed course even if you feel better. Use it only for the infection it was prescribed for. Contact your doctor if symptoms worsen at any time or have not started to improve within 48 hours. You may need reassessment or a different treatment; do not extend the course yourself.
The modified-release capsule leaflet covers adults and children over 12 years, but the online service described here treats eligible women. Children, men and anyone pregnant with UTI symptoms should seek individual medical assessment. The dose and course must match that assessment.
How do I know if I have a UTI?
UTIs are common in both men and women. Common symptoms include:
- Dysuria (pain when urinating)
- Nocturia (needing to urinating more at night)
- Dark or cloudy urine with a strong smell
- Blood in your urine
- Needing to urinate more often
- Lower abdomen pain
- A high temperature
- A low temperature below 36C
UTIs are usually easily treated however if they are left untreated they can become more serious.
Get urgent medical advice for fever or shivering, a temperature below 36°C, pain in your side or back under the ribs, vomiting or feeling very unwell. These can be signs of a kidney infection or a more serious illness. Nitrofurantoin treats lower UTIs and is not suitable for a suspected kidney infection. Do not wait until the course is finished to seek help.
UTI symptom relief
Some ways to help relieve the symptoms of a urinary tract infection (UTI) include:
- Drink plenty of fluids to help flush out bacteria from the urinary tract
- Don't fight the urge to urinate (pee), go to the toilet if you get the urge to urinate
- Take over the counter medicines such as paracetamol and ibuprofen
- Apply a heat pad or warm compress to your lower belly to help relax the muscles in the urinary tract
- Check with your pharmacist before using cystitis remedies; some can interfere with nitrofurantoin
If you think you have a UTI these will only help relieve the symptoms and will not treat the cause.
How quickly does Nitrofurantoin work?
You should usually start feeling better within a day or two. Contact your doctor if symptoms worsen at any time or have not started to improve within 48 hours, even if you have not finished the course. Take the course prescribed unless a clinician tells you to stop; persistent symptoms may need tests or a different treatment.
What else can I take?
Painkillers are commonly taken alongside nitrofurantoin, such as Aspirin, Paracetamol or Ibuprofen.
Cystitis sachets that make urine less acidic can interfere with nitrofurantoin. Check with your pharmacist before using them. Cranberry products are not a treatment for an established UTI.
Should I take nitrofurantoin or Trimethoprim?
NICE guidelines first line choice for treating a UTI is Nitrofurantoin, as there is a lesser chance of
antibiotic resistance with nitrofurantoin than Trimethoprim.
Trimethoprim is still a good choice and will produce good results in most women with some finding better results
using it. Trimethoprim is also a good alternative for those with certain medical conditions such as kidney
problems or if your urine sample has been tested and shows the bacteria is not antibiotic resistant.
nitrofurantoin and pregnancy
Nitrofurantoin can be prescribed during pregnancy, but a UTI in pregnancy needs assessment by a doctor or midwife. Treatment is usually for seven days, rather than the three-day course used for uncomplicated UTIs in non-pregnant women. It is generally avoided towards the end of pregnancy because of a small risk to the baby's red blood cells; your prescriber may choose another antibiotic, particularly after 28 weeks. Follow their advice rather than stopping or changing treatment yourself.
nitrofurantoin and breastfeeding
If your baby is healthy, nitrofurantoin can usually be taken while breastfeeding after checking with your doctor or pharmacist. Small amounts pass into milk. Do not take it while breastfeeding if your baby has jaundice, high bilirubin levels or G6PD deficiency. Contact your healthcare professional if your baby feeds less well, is sick, has diarrhoea or develops oral thrush.
nitrofurantoin side effects
The most common side effect of nitrofurantoin is you urine changing colour to a dark yellow or a brownish
colour. This is completely normal and you should continue to take the medicine. It will return back to its
normal colour after the course is completed.
Other side effects include:
- Nausea (feeling sick)
- Vomiting (being sick)
- Diarrhoea
- Loss of appetite
- Headaches
- Dizziness
For a full list of side effects, read the patient information leaflet. Stop nitrofurantoin and get urgent medical advice if you develop a new cough, breathlessness, pain when breathing or coughing up blood or mucus. Lung reactions can happen during a short course as well as longer treatment.
Seek urgent advice for yellow skin or eyes, dark urine with pale stools, unexplained bruising or bleeding, or new persistent tingling or numbness. Call 999 for severe breathing difficulty, chest pain or signs of a severe allergic reaction.
nitrofurantoin alternatives
An alternative to nitrofurantoin is Trimethoprim. nitrofurantoin is usually the first line for UTIs as there is less resistance to it. Trimethoprim is still used in some women and some women will find it works better then nitrofurantoin.
Frequently asked questions
What are the possible side effects of nitrofurantoin?
Some possible side effects of nitrofurantoin include: nausea, vomiting, diarrhoea, loss of appetite, headache, dizziness, rash. More serious side effects include: Yellowing of the skin or whites of the eyes (jaundice), unusual bruising or bleeding, confusion or hallucinations, chest pain or difficulty breathing. If these side effects occur contact your doctor immediately.
How should I take nitrofurantoin?
nitrofurantoin capsules are usually taken twice a day with food and a glass of water. Taking it with food helps to prevent side effects and the water will help the antibiotic work.
Can I drink alcohol while taking nitrofurantoin?
Yes you can drink alcohol while taking nitrofurantoin.
Can I buy nitrofurantoin over the counter?
No they must be prescribed.
Can I take nitrofurantoin if I'm pregnant or breastfeeding?
A doctor can prescribe nitrofurantoin during pregnancy, usually as a seven-day course, but may choose another antibiotic towards the end of pregnancy. Ask your doctor or midwife about any UTI symptoms rather than using the usual three-day course yourself. During breastfeeding it can usually be used if your baby is healthy, but not if the baby has jaundice, high bilirubin levels or G6PD deficiency. Check with your doctor or pharmacist first.
What should I do if I miss a dose of nitrofurantoin?
If you have missed a dose take it as soon as you remember unless it is time to take your next dose. If it is time for your next dose skip the missed dose.
Is it safe to buy nitrofurantoin from your pharmacy?
We are a General Pharmaceutical Council (GPhC) registered pharmacy and we source all our pharmaceutical products from reputable wholesalers, the same wholesalers that provide the medicines used to fill NHS prescriptions.
If you buy them from an unregistered pharmacy you may be wasting your money at best or at worse harm yourself buying and taking fake tablets. Always check to make sure where you are buying them from are registered with the GPhC.Do nitrofurantoin capsules expire?
Yes, like most medicines it has a shelf life and will become less effective if it is left unused. Always check the expiry date of any medicines you are taking before you take them, the expiry date refers the end of the month. If you find your medication has expired, you can post them to us, bring them to us or take them to your nearest pharmacy for safe disposal.
How should I store nitrofurantoin capsules?
They should be stored in a dry area below 30°C and kept out of direct sunlight. Storing the tablets incorrectly could result in the tablets becoming less effective.
Is this the same as Macrobid?
Yes, Macrobid is no longer available, they are now a generic item and contain the same active ingredient as Macrobid used too.
Sources and further information
- NHS: nitrofurantoin during pregnancy and breastfeeding (checked 8 September 2026)
- MHRA: MacroBID 100mg prolonged-release capsules professional information (checked 8 September 2026)
- Summary of Product Characteristics (SPC)
- Further product information
- NHS: nitrofurantoin and other medicines (accessed 8 September 2026)
- NICE: lower urinary tract infection treatment and reassessment (accessed 8 September 2026)
- MHRA: nitrofurantoin lung and liver safety advice (accessed 8 September 2026)
