What are Nitrofurantoin MR 100mg capsules?
Nitrofurantoin MR 100mg capsules are modified-release hard capsules containing 100mg of nitrofurantoin as a mix of macrocrystalline and monohydrate forms. The modified-release design slows absorption so the drug is cleared through the urine over 12 hours, which allows twice-daily rather than four-times-daily dosing. Each UK pack contains 6 capsules.
How Nitrofurantoin MR 100mg sits in UK UTI treatment
NICE NG109 list nitrofurantoin as first-line for uncomplicated lower UTI in non-pregnant women aged 16 and over. The alternatives:
- Trimethoprim 200mg BD for 3 days, where local resistance patterns favour it.
- Pivmecillinam, fosfomycin, cefalexin, second-line options.
- Pharmacy First (NHS England) PGD route, nitrofurantoin dispensed by a community pharmacist for women aged 16-64, where eligibility criteria are met.
Nitrofurantoin remains the preferred first-line because of low community resistance and minimal collateral damage to the gut microbiome.
Fast UTI treatment, how it works
UTIs tend to escalate quickly. Our same-day online consultation keeps the gap between symptoms and treatment short.
- Online UTI consultation reviewed by a UK prescriber within hours.
- Prescription issued and dispensed from our pharmacy.
- Standard 3-day course, start as soon as the pack arrives.
Eligibility, who can order Nitrofurantoin MR 100mg
This product is for women aged 16 and over with symptoms of uncomplicated lower UTI who meet the following criteria:
- Classic UTI symptoms, dysuria (burning), frequency, urgency, suprapubic discomfort, cloudy or smelly urine.
- No fever, flank pain, loin pain or nausea and vomiting (which may signal upper UTI/pyelonephritis).
- Not pregnant, not planning pregnancy in the next week, and not breastfeeding a baby under 1 month.
- eGFR above 45 mL/min/1.73m2 (your prescriber will ask about kidney function).
- No history of nitrofurantoin allergy or G6PD deficiency.
- Not on long-term suppressive antibiotic use without specialist review.
Men with suspected UTI, pregnant women, children under 16, and anyone with upper-tract or complicated UTI need prescriber-led assessment, often with urine culture, before treatment.
How to buy Nitrofurantoin MR 100mg at Courier Pharmacy
Buying Nitrofurantoin MR 100mg capsules through our UTI service is a four-step process:
- Step 1, complete a quick UTI consultation at courierpharmacy.co.uk/uti.
- Step 2, a UK prescriber reviews your symptoms and medical history.
- Step 3, if clinically appropriate, a private prescription is issued.
- Step 4, we dispense the 6-capsule pack and deliver by signed-for tracked UK delivery.
If nitrofurantoin is not suitable for you, we will explain why and suggest the next best step. Common alternatives include trimethoprim 200mg BD for 3 days, fosfomycin 3g single dose, or a GP referral if your symptoms suggest something more than lower UTI.
Dr Ada Jex-Cori, our brand pharmacist
Our brand pharmacist is Dr Ada Jex-Cori. She represents the spirit of what we do. Named for Ada Lovelace, Sophia Jex-Blake and Gerty Cori, she stands for evidence-led, unafraid-of-questions medicine.
“You’re not broken. The system is. We’re here to change that.”
UTIs are one of those classic examples where the system does not fit the user. Women often know within hours when a UTI is starting, but then face a two-day GP wait while symptoms get worse. Ada’s view is simple, listen to the patient, test where it changes the answer, treat quickly where it does not, and keep the review door open.
Frequently asked questions about Nitrofurantoin MR 100mg capsules
Am I eligible to order Nitrofurantoin MR 100mg?
You are eligible if you are a non-pregnant woman aged 16 and over with classic lower UTI symptoms (burning on urination, frequency, urgency, suprapubic discomfort) and no fever, flank pain or vomiting. Our online consultation screens for the common exclusion criteria.
How long does it take to work?
Most women feel noticeable relief within 24 to 48 hours. Finish the full 3-day course even if your symptoms clear quickly. If you feel no better by day 2, contact us for review, as you may need a different antibiotic.
Why is my urine orange-brown?
Nitrofurantoin and its metabolites colour the urine orange-brown. It is harmless, cosmetic only, and clears when you finish the course. It will not stain clothing permanently if washed as normal.
Why do I need to take it with food?
Food (particularly a meal with some fat) improves nitrofurantoin absorption by about 40%. Food also reduces nausea, which is the most common side effect. A glass of milk works as well as a full meal.
Can I drink alcohol with Nitrofurantoin MR 100mg?
No direct interaction, but alcohol irritates the bladder and can prolong UTI symptoms. We recommend avoiding alcohol until the course is finished and symptoms have resolved.
Can I take it with the contraceptive pill?
Yes. A 3-day course of nitrofurantoin does not reduce the effectiveness of combined oral contraceptives. You do not need extra contraception during the course.
Why only 3 days?
NICE NG109 and UK Health Security Agency guidance support a 3-day course for uncomplicated lower UTI in women. Shorter courses mean lower antibiotic exposure, fewer side effects, and less contribution to resistance. Longer courses are reserved for men, pregnant women, upper UTI, and complicated infections.
What if the course does not work?
Contact us or your GP. We will arrange a urine culture to identify the organism and its sensitivities. Alternatives include trimethoprim 200mg BD, fosfomycin 3g single dose, pivmecillinam or cefalexin, depending on the result.
Can I get Nitrofurantoin from Pharmacy First on the NHS?
Yes, if you are a woman aged 16-64 with uncomplicated lower UTI, your local pharmacy may supply nitrofurantoin for free under the NHS Pharmacy First service in England. Our private service is useful when you prefer online, same-day delivery, or when the Pharmacy First criteria do not fit (for example age 65 or over, specific medical history).
Does Nitrofurantoin treat kidney infection?
No. Nitrofurantoin reaches high concentrations only in urine, not in kidney tissue, so it does not treat pyelonephritis (upper UTI). Signs of kidney infection include fever, loin or flank pain, nausea and vomiting. If you have these, see a GP urgently or call NHS 111, do not self-treat with nitrofurantoin.
Can men take Nitrofurantoin MR 100mg?
Yes, but UTI in men is less common and often needs a different approach including prostate examination. Nitrofurantoin can be prescribed but we recommend a GP review rather than online supply for men.
Can I take it if I am pregnant?
Up to 36 weeks of pregnancy, yes, with GP or midwife supervision. From 36 weeks onwards, nitrofurantoin is contraindicated because of risk of haemolytic anaemia in the newborn. We do not supply nitrofurantoin to pregnant women through this online service, see your GP or midwife instead.
Can I take it if I am breastfeeding?
If your baby is over 1 month old, generally yes, under medical supervision. Nitrofurantoin passes into breast milk in small amounts. Avoid in babies under 1 month and in any infant with suspected G6PD deficiency. We recommend GP review rather than online supply for breastfeeding women.
What if I have kidney problems?
Nitrofurantoin is contraindicated at eGFR below 45 for a full course. Short courses may be acceptable at eGFR 30 to 44 under prescriber judgement, per the MHRA 2014 Drug Safety Update. Our online consultation asks about kidney function and recent blood tests.
Can I take it with other antibiotics?
Avoid combining nitrofurantoin with quinolones (ciprofloxacin, levofloxacin), as they antagonise each other. Other antibiotic combinations should only be used under prescriber guidance.
What about recurrent UTIs?
If you have had 3 or more UTIs in 12 months, speak to your GP. Options include non-antibiotic measures (hydration, hygiene, D-mannose, cranberry extract), vaginal oestrogen in postmenopausal women, standby prescriptions, or prophylactic low-dose nitrofurantoin or methenamine hippurate.
How quickly will my order arrive?
Orders placed before 12pm with an approved prescription are usually dispatched on the same day (provided there are no stock issues) by signed-for tracked UK delivery, usually arriving the next working day. Weekend and public holiday dispatch runs the next working day.
Is Nitrofurantoin a controlled drug?
No. Nitrofurantoin is a prescription-only medicine (POM) but it is not a controlled drug. There are no safe-custody or CD-register requirements.
What is Nitrofurantoin used for?
Nitrofurantoin is a prescription-only antibiotic used mainly for acute uncomplicated lower urinary tract infection (lower UTI, cystitis) in women. It is also used off-label for recurrent UTI prevention under specialist supervision.
Nitrofurantoin dosage for UTI how many days?
For a non-pregnant woman aged 16 and over with uncomplicated lower UTI, the standard course is 100mg modified-release twice a day for 3 days (total 6 capsules). For men, pregnant women up to 36 weeks, and complicated UTI, courses run 7 days under prescriber supervision.
How long does Nitrofurantoin take to work on a UTI?
Most women notice symptom relief within 24 to 48 hours. Burning on urination and urgency usually ease first, with full resolution by the end of the 3-day course. Finish all 6 capsules even if you feel better early.
Can you drink on Nitrofurantoin?
No direct interaction between nitrofurantoin and alcohol. However, alcohol irritates the bladder and can worsen UTI symptoms, so we recommend avoiding alcohol until the course is finished and symptoms have cleared.
Nitrofurantoin 100mg dosage for UTI how many days?
100mg twice a day for 3 days is the NICE NG109 first-line regimen for uncomplicated lower UTI in women. One capsule in the morning, one in the evening, with food.
Can you drink alcohol with Nitrofurantoin?
There is no pharmacological interaction, so a small amount of alcohol will not stop the antibiotic working or make you ill. We still advise avoiding alcohol until the UTI is fully resolved, as alcohol can prolong bladder symptoms.
Nitrofurantoin can you drink alcohol?
No pharmacological interaction, but we recommend avoiding alcohol during a UTI course. Alcohol dehydrates and irritates the bladder, which can mask or extend your symptoms.
Can you drink alcohol on Nitrofurantoin?
Short answer, yes without a direct interaction. Better answer, avoid alcohol during the course. Hydration and bladder rest help your recovery as much as the antibiotic itself.
How long do Nitrofurantoin side effects last?
Common side effects (nausea, headache, orange urine) usually last only while you are taking the capsules and clear within 1 to 3 days of finishing the course. Rare pulmonary or neurological side effects can persist longer and need urgent review.
Is Nitrofurantoin safe in pregnancy?
Yes up to 36 weeks of pregnancy under GP or midwife supervision. From 36 weeks onwards, during labour, and in breastfeeding mothers of babies under 1 month, nitrofurantoin is contraindicated because of neonatal haemolytic anaemia risk. We do not supply nitrofurantoin to pregnant women through our online pathway, see your GP or midwife.
How long does it take for Nitrofurantoin to work?
Symptom relief typically starts within 24 to 48 hours. The 3-day course fully clears a straightforward UTI in around 80 to 90% of cases. If you feel no better by day 2, contact us for review and possible urine culture.
Can Nitrofurantoin cause thrush?
Possibly, like any antibiotic, nitrofurantoin can disturb the vaginal microbiome and trigger thrush. The risk is lower with nitrofurantoin than with broader-spectrum antibiotics because it acts mainly in the urine. If you develop thrush, over-the-counter clotrimazole or fluconazole usually clears it.
Can I drink on Nitrofurantoin?
Technically yes, there is no pharmacological interaction. However, we recommend avoiding alcohol during the course because alcohol irritates the bladder, worsens dehydration, and can prolong UTI symptoms.
Can I drink alcohol with Nitrofurantoin?
No formal contraindication, but we advise against it. Alcohol dehydrates you, which concentrates urine and worsens burning on urination. Save the drink for after the course finishes.
Does Nitrofurantoin contain penicillin?
No. Nitrofurantoin is a nitrofuran antibiotic, chemically unrelated to penicillin. It is safe to take if you have a penicillin allergy. Always tell your prescriber about every allergy before any antibiotic.
Can you take paracetamol with Nitrofurantoin?
Yes. Paracetamol has no interaction with nitrofurantoin and is useful for UTI pain or any mild fever. Follow the standard adult dose (up to 1g four times daily, maximum 4g in 24 hours).
What are Nitrofurantoin tablets used for?
For acute uncomplicated lower urinary tract infection (cystitis) in women and, less commonly, for UTI prevention in people with recurrent infections. UK Nitrofurantoin is dispensed as capsules rather than tablets.
How long for Nitrofurantoin to work?
Serum and urine levels rise within hours of the first dose. Symptom improvement usually within 24 to 48 hours. Full resolution by the end of the 3-day course in most women.
What is Nitrofurantoin?
Nitrofurantoin is a UK-licensed nitrofuran antibiotic used for lower UTI. The modified-release 100mg capsule is taken twice a day. It reaches high concentrations in urine, which is where it kills the bacteria.
What does Nitrofurantoin treat?
It treats acute uncomplicated lower urinary tract infection (cystitis), especially in women. It is active against E. coli, Staphylococcus saprophyticus and most Enterococcus and Klebsiella strains. It does not treat kidney infection, non-urinary infections or Pseudomonas and Proteus organisms.
Is Nitrofurantoin a strong antibiotic?
Nitrofurantoin is narrow-spectrum, meaning it targets urinary pathogens specifically rather than many bacteria at once. For lower UTI in women it is highly effective (80 to 90% cure rate), but it is not a broad-spectrum "strong" antibiotic suitable for infections elsewhere in the body.
Can you drink alcohol while taking Nitrofurantoin?
No pharmacological interaction. However, alcohol can worsen bladder symptoms and dehydration, so we recommend avoiding it until the course is finished and symptoms have resolved.
How long does Nitrofurantoin take to work?
Noticeable relief in 24 to 48 hours for most women, full resolution by the end of the 3-day course. If you feel no better by day 2, contact us or your GP for review.
Does Nitrofurantoin make you urinate more?
Not directly. The UTI itself makes you urinate more. As the infection clears over 24 to 48 hours, urinary frequency returns to normal. We recommend drinking plenty of water during the course, which can temporarily increase urine output.
Nitrofurantoin how long to work?
24 to 48 hours for symptom relief. 3 full days for the complete course. Do not stop early even if you feel better by day 2.
How quickly does Nitrofurantoin work?
Serum and urine concentrations rise within hours of the first capsule. Clinical improvement in burning, urgency and frequency typically starts within 24 hours and progresses over the full 3 days.
How long does Nitrofurantoin stay in your system?
Nitrofurantoin has a short half-life of around 20 to 60 minutes. Most of a dose is cleared from blood within 4 to 6 hours and from urine within 24 hours of the last capsule. The orange urine colour clears within 1 to 2 days.
How many hours apart should I take Nitrofurantoin?
Roughly 12 hours apart. Take one capsule in the morning (with breakfast) and one in the evening (with dinner). Keeping to a regular schedule keeps urine concentrations high enough to kill the bacteria.
Can I buy Nitrofurantoin over the counter?
No. Nitrofurantoin is a prescription-only medicine (POM) in the UK and cannot be bought over the counter. However, you can access it quickly through NHS Pharmacy First (for women 16-64 with uncomplicated lower UTI) or through our private online UTI consultation.
How long after taking Nitrofurantoin can you drink alcohol?
Since there is no direct interaction, you can technically drink from the day after your last capsule. For comfort, we suggest waiting until symptoms have fully resolved, usually 48 to 72 hours after the course ends.
Is Nitrofurantoin a penicillin?
No. Nitrofurantoin is a nitrofuran antibiotic, not related to penicillin. If you have a penicillin allergy, nitrofurantoin is generally safe to take. Always inform your prescriber of all allergies.
Does Nitrofurantoin make you sleepy?
Occasionally, yes. Drowsiness and dizziness are listed as common side effects. If you feel drowsy, do not drive or operate machinery until you know how it affects you. The effect usually settles after the first day or two.
Can Nitrofurantoin treat UTI?
Yes, it is the NICE NG109 first-line antibiotic for uncomplicated lower UTI in non-pregnant women aged 16 and over. 100mg twice a day for 3 days clears around 80 to 90% of straightforward infections.
How to take Nitrofurantoin
Swallow one 100mg modified-release capsule with food twice a day, roughly 12 hours apart, for 3 days. Do not crush or open the capsule. Drink plenty of water during the course. Expect orange-brown urine, this is harmless.
What can you not take with Nitrofurantoin?
Avoid magnesium trisilicate antacids (they reduce absorption, separate by 2 hours) and quinolone antibiotics such as ciprofloxacin (which antagonise nitrofurantoin). Also avoid stacking with other medicines that cause peripheral neuropathy or pulmonary toxicity (vincristine, amiodarone, methotrexate) without prescriber review.
Is Nitrofurantoin an antibiotic?
Yes. Nitrofurantoin is a narrow-spectrum antibiotic in the nitrofuran class. It is used specifically for urinary tract infections because it concentrates in urine but not in most body tissues.
Nitrofurantoin how long does it take to work?
Within hours in your urine, within 24 to 48 hours for symptom improvement, and the full 3-day course clears a straightforward UTI in most women.
Where can I buy Nitrofurantoin?
At any UK-registered pharmacy against a valid NHS or private prescription. For a quick private supply, complete our online UTI consultation at courierpharmacy.co.uk. For free NHS supply, ask your community pharmacist about Pharmacy First.
Nitrofurantoin dose for UTI female?
For a non-pregnant woman aged 16 and over with uncomplicated lower UTI, 100mg modified-release twice a day for 3 days. For complicated UTI, pyelonephritis, pregnancy or recurrent UTI, dosing is different and needs prescriber review.
Can I buy Nitrofurantoin online?
Yes, through a UK-registered online pharmacy following a prescriber-led consultation. Our UTI consultation at courierpharmacy.co.uk screens for suitability and issues a private prescription where appropriate. We cannot sell nitrofurantoin without that consultation.
Does Nitrofurantoin treat UTI?
Yes, it is first-line for lower UTI in women per NICE NG109. It does not treat kidney infection (pyelonephritis), prostatitis, or non-urinary infections.
How to take Nitrofurantoin for UTI
One 100mg modified-release capsule twice a day with food, roughly 12 hours apart, for 3 days. Drink plenty of water. Expect orange-brown urine. Finish the full course even if symptoms clear early.
Disclaimer
Educational content, not a substitute for medical advice. This page is published by Courier Pharmacy as educational product information. It is not personalised medical advice, and it does not replace a consultation with your prescriber, pharmacist or GP. Always follow the dose and schedule written on your prescription.
UK-licensed Patient Information Leaflet is the authoritative source. Nitrofurantoin MR 100mg is a UK-licensed medicine. The Patient Information Leaflet supplied in the carton is the authoritative patient-facing document for the specific pack you receive. Always read the PIL before use.
Prescription-only medicine. Nitrofurantoin MR 100mg is a prescription-only medicine (POM) under the Human Medicines Regulations 2012. It is not a Controlled Drug. Do not share, sell or supply this medicine to anyone else, as it is prescribed specifically for you.
Antibiotic stewardship. Antibiotic resistance is a public health priority. Use antibiotics only when prescribed, complete the course as directed, and never save unused antibiotics for a future UTI. If your symptoms persist beyond 48 hours of treatment, or if they come back soon after, contact your prescriber for a urine culture before taking more antibiotics.
Pregnancy and breastfeeding. We do not supply nitrofurantoin to pregnant or breastfeeding women through our online service. If you may be pregnant or are breastfeeding, speak to your GP or midwife for assessment and treatment.
Red flag symptoms. Nitrofurantoin treats lower UTI only. If you develop fever, flank or back pain, nausea or vomiting, blood in your urine, or severe abdominal pain during the course, stop treatment and seek urgent review. Call NHS 111 for advice or 999 for a life-threatening emergency.
References
- National Institute for Health and Care Excellence (2018, updated 2024). Urinary tract infection (lower): antimicrobial prescribing. NICE guideline NG109. Available at: https://www.nice.org.uk/guidance/ng109
- National Institute for Health and Care Excellence (accessed 2026). Clinical Knowledge Summary: Urinary tract infection (lower), women. Available at: https://cks.nice.org.uk/topics/urinary-tract-infection-lower-women/
- National Institute for Health and Care Excellence (2018, updated 2024). Pyelonephritis (acute): antimicrobial prescribing. NICE guideline NG111. Available at: https://www.nice.org.uk/guidance/ng111
- Electronic Medicines Compendium (emc) (2026) [Summary of Product Characteristics for product 15362]. Available at: https://www.medicines.org.uk/emc/product/15362/smpc (Accessed: 13 October 2026).
- Electronic Medicines Compendium (emc) (2026) [Patient information leaflet for product 15362]. Available at: https://www.medicines.org.uk/emc/files/pil.15362.pdf (Accessed: 13 October 2026).
- British National Formulary (accessed 2026). Nitrofurantoin. Available at: https://bnf.nice.org.uk/drugs/nitrofurantoin/
- Medicines and Healthcare products Regulatory Agency (2014). Nitrofurantoin now contraindicated in most patients with an estimated glomerular filtration rate of less than 45 mL/min/1.73m2. Drug Safety Update. Available at: https://www.gov.uk/drug-safety-update/nitrofurantoin-now-contraindicated-in-most-patients-with-an-estimated-glomerular-filtration-rate-egfr-of-less-than-45-ml-min-1-73m2
- Medicines and Healthcare products Regulatory Agency (accessed 2026). Nitrofurantoin: reminder of the risks of pulmonary and hepatic adverse drug reactions. Available at: https://www.gov.uk/drug-safety-update/nitrofurantoin-reminder-of-the-risks-of-pulmonary-and-hepatic-adverse-drug-reactions
- NHS England (2024). NHS Pharmacy First service, clinical pathway for uncomplicated urinary tract infection in women. Available at: https://www.england.nhs.uk/primary-care/pharmacy/pharmacy-services/pharmacy-first/
- National Health Service (accessed 2026). Urinary tract infections (UTIs). Available at: https://www.nhs.uk/conditions/urinary-tract-infections-utis/
- Medicines and Healthcare products Regulatory Agency. Yellow Card scheme. Available at: https://yellowcard.mhra.gov.uk
