Nitrofurantoin 100mg Modified-Release Capsules

Buy Nitrofurantoin 100mg MR Capsules to treat cystitis

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About Nitrofurantoin 100mg Modified-Release Capsules
  1. What is Nitrofurantoin?

    Nitrofurantoin is an antibiotic that is very effective in slowing the growth of bacteria in the body.

    It is commonly sold under the brand name Macrobid.

    It comes in the form of capsules or tablets that you swallow, or a liquid you drink.

    You need a prescription to buy Nitrofurantoin tablets.

    What is Nitrofurantoin used to treat?

    Nitrofurantoin is widely prescribed to treat urinary tract infections (UTIs) like kidney infections and cystitis. It can be taken by adults and children over 3 months old, although the dosage will differ for children.

    When you take Nitrofurantoin, your body will filter it out of your blood and into your urine very swiftly, meaning the medicine is concentrated on the area of infection, making it an ideal treatment for urine infections.

    You will normally be instructed to take it for between 3 and 7 days, depending on your individual problem.

    Why is Nitrofurantoin recommended to treat UTIs?

    Nitrofurantoin has been used in the successful treatment of UTIs for more than 60 years.

    Clinical studies have shown that Nitrofurantoin is also effective at preventing UTIs.  

    How does Nitrofurantoin treat cystitis?

    Nitrofurantoin is an antibiotic medicine that enters the cells of harmful bacteria and damages their genetic material. This kills the bacteria that causes the infection.

    Taken orally, Nitrofurantoin is mostly filtered out of your blood and into your urine, which means it is able to focus solely on killing the bacteria that is causing the UTI.

    Who can take Nitrofurantoin?

    While it is generally considered to be a very safe antibiotic, Nitrofurantoin may not be suitable for everyone. You should consult your doctor or pharmacist before you use this medicine to treat cystitis or any other infections if any of the below apply to you:

    • You have severe kidney disease
    • You have diabetes
    • You have any illnesses which cause severe weakness
    • You have anaemia
    • You have vitamin B deficiency
    • You have had an allergic reaction to Nitrofurantoin or any other medication in the past
    • You have any of these rare inherited conditions: porphyria or glucose-6-phosphate dehydrogenase (G6PD) deficiency

    This list may not be exhaustive. Before you start to take Nitrofurantoin, consult the patient information leaflet for a full list of precautions.

    Can you buy Nitrofurantoin over the counter?

    Nitrofurantoin is classed as a prescription-only medicine (POM), so it must be prescribed for you by a doctor.

    Can you buy Nitrofurantoin online in the UK?

    Nitrofurantoin requires a prescription to be purchased, so before you can complete your order, you will need to have an online consultation to make sure it is safe for you. When you have answered some questions about your condition and medical history, one of our prescribers will assess your answers to ensure Nitrofurantoin is a suitable treatment.

    Nitrofurantoin alternatives

    Trimethoprim is another effective antibiotic medication available to order from Medicine Direct. This medicine works to stop the bacteria that cause UTIs from being able to reproduce, making it easier for your immune system to fight the infection effectively.

    View our full range of treatments by visiting the Cystitis treatments page.

  2. Nitrofurantoin 100mg Dose and Directions

    Take Nitrofurantoin in the dose your doctor has prescribed for you. This dose will depend on the infection you are taking the medicine for.

    The normal doses can be seen below:



    To treat infections

    One 50mg capsule or one 100mg capsule four times a day for seven days.

    To prevent infections

    One 50mg capsule or one 100mg capsule at bedtime

    To prevent infections during surgery

    One 50mg capsule four times a day on the day of the operation and for the next three days

    If this medicine is prescribed for a child, the dose will be decided upon by their doctor and based on their weight.

    Nitrofurantoin must not be taken by children under 3 months old.

    How to take Nitrofurantoin

    Take Nitrofurantoin capsules with food or milk. This will make the medicine more effective.

    Swallow the capsules whole, do not crush, open or chew them.

    To treat urinary tract infections, you will normally be instructed to take it for between three and seven days.

    Always read the patient information leaflet for full instructions.

    How long do I need to take it for?

    To treat a urinary tract infection, you will normally be required to use Nitrofurantoin for between 3 and 7 days.

    To prevent a UTI like cystitis before having surgery, it is likely you will need to take it on the day you have the operation, and for the following three days.

    To stop a UTI like cystitis from coming back, you may be instructed to take it for several months.

  3. Nitrofurantoin Side Effects

    Not everyone will experience side effects when taking this medicine, but there are common adverse reactions you should take note of.

    If you suffer any of the below effects, you should keep taking the medicine but speak to your doctor if they persist:

    • Loss of appetite
    • Headaches
    • Feeling sick
    • Being sick or suffering diarrhoea
    • Dizziness or feeling drowsy

    This list may not be exhaustive. For comprehensive information on side effects, you should always make sure you read the patient information leaflet, which will accompany your medicine. 

  4. Nitrofurantoin Warnings and Drug Interactions

    Nitrofurantoin may interact with other medicines you are taking, whether these are prescription or non-prescription drugs you obtained from a pharmacy.

    Whether you are taking Nitrofurantoin to treat cystitis or another type of infection, you should inform your doctor and pharmacy if you are currently taking any of the below medicines:

    • Cystitis remedies you can purchase online or from a pharmacy such as Trimethoprim
    • Antibiotics called quinolones, such as nalidixic acid, ciprofloxacin, levofloxacin, norfloxacin, ofloxacin and moxifloxacin
    • Metronidazole 400mg tablets to treat Bacterial Vaginosis as taking both at the same time increases the risk of peripheral neuropathy
    • Indigestion remedies (antacids), particularly ones which contain magnesium
    • Certain medicines used to treat gout, including probenecid or sulfinpyrazone

    Read the patient information leaflet for full warnings. 

    Pregnancy and breastfeeding 

    If you are currently pregnant, trying to get pregnant or are breastfeeding, it is normally safe for you to use Nitrofurantoin. This medication goes straight into your urine, meaning that very little of it will pass through to the unborn baby.

    It may not be suitable for all breastfed babies. Speak to your doctor before taking Nitrofurantoin if you are breastfeeding; this is especially important if your baby has a rare condition called glucose-6-phosphate dehydrogenase (G6PD) deficiency.

    Do not take this medicine in the final stages of pregnancy, or during labour and childbirth, as this may affect the baby's blood.

    For more information on taking Nitrofurantoin during pregnancy, we recommend visiting BUMPS.

  5. Nitrofurantoin Ingredients

    The main active ingredient within this medicine is: Nitrofurantoin

    For a full list of the inactive ingredients, please read the Summary of Product Characteristics.

  6. How much does it cost to buy Nitrofurantoin online in the UK?

    Dosage Quantity Buy Online UK Price
    Nitrofurantoin 100mg tablets 6 tablets £17.99
  7. How long does it take to work?

    You should start to feel better after a few days of taking Nitrofurantoin. Do not stop taking Nitrofurantoin until you have completed the treatment course prescribed by your doctor, even if you feel better. This will provide the most effective treatment.

    Can I drink alcohol while taking Nitrofurantoin?

    It is safe to drink alcohol in moderate amounts while taking Nitrofurantoin.

    What should I do if it doesn’t work?

    If Nitrofurantoin has not improved your symptoms after three days, tell your doctor. They should also know if you feel worse while taking it.

    Will it affect my contraception?

    No, Nitrofurantoin does not impact any type of contraception. If you vomit or have diarrhoea after taking Nitrofurantoin, this may reduce the effectiveness of your contraception. If this happens, read the information that comes with your contraception for guidance on what to do.

    Is taking Nitrofurantoin for three days enough?

    This depends on why you need to take it. Most people are prescribed Nitrofurantoin for between 3 and 7 days. Always take Nitrofurantoin for as long as your doctor has told you to. Do not stop taking it early, even if you feel better.

    Can you prevent UTIs by drinking cranberry juice?

    Drinking cranberry juice is not likely to treat or prevent urinary tract infections from occurring.

    Can I make any lifestyle changes to prevent UTIs?

    There are certain actions you can take and things you can avoid which will lessen the risk of getting a urinary tract infection. A full list of preventative measures can be found on the NHS’s website.

    Can I get thrush from taking Nitrofurantoin?

    Thrush is a possible side effect while taking an antibiotic medicine like Nitrofurantoin. This is because antibiotics will also kill the good bacteria that stops thrush from developing, leaving you vulnerable to this problem. If you get any thrush symptoms, speak to your doctor.

    How long does Nitrofurantoin stay in your system?

    Nitrofurantoin has an elimination half-life of around 30 minutes. It is normally excreted through your urine after around 4-5 hours of being taken. This antibiotic is quickly filtered into your urine, allowing it to get to work very quickly.

    Does Nitrofurantoin affect fertility?

    No hard evidence exists to suggest that Nitrofurantoin has any effect on male or female fertility. However, if you are pregnant or trying to get pregnant, you should tell your doctor before you start taking it.

Written byHussain Abdeh MPharm: 2211840

Published on: 12/10/2020

Updated on: 03/06/2021

This content has been written by our Superintendent Pharmacist Hussain Abdeh and has been medically reviewed by our Pharmacist Sonia Khan

Hussain Abdeh Superintendent Pharmacist at Medicine Direct

Hussain Abdeh
MPharm: 2211840

Pharmacist Independent Prescriber

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