Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
Patient leaflets and SmPCs, drug interaction checker, official dosages and NHS pharmacy opening hours — all in one place.
The electronic medicines compendium (emc) no longer publishes a Summary of Product Characteristics for this product, which usually means it is no longer marketed in the UK. The patient leaflet below is kept for reference, but the product may not be available.
If you were prescribed this medicine, other products containing Nitrofurantoin may still be available. Do not stop your treatment — ask your pharmacist or GP what to use instead.
FOR Nitrofurantoin (the active substance in Nitrofurantoin 100mg Prolonged-Release Capsules) is an antibiotic. It is used to prevent and treat infections of the bladder, kidney and other parts of the urinary tract.
E NITROFURANTOIN 100MG PROLONGED-RELEASE CAPSULES DO NOT TAKE Nitrofurantoin 100mg Prolonged-Release Capsules:
Driving and using machines: Nitrofurantoin 100mg Prolonged-Release Capsules may cause dizziness and drowsiness. You should not drive or operate machinery if you are affected this way until such symptoms go away. Nitrofurantoin 100mg Prolonged-Release Capsules contains lactose and sucrose If you have been told by your doctor that you are intolerant to some sugars and have to avoid them, contact your doctor before taking this medicine.
NITROFURANTOIN 100MG PROLONGED-RELEASE CAPSULES Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure. The recommended dose is: Adults and children over 12 years old: The normal dosage depends on the type of infection you have and instructions should be written on the label provided by the pharmacist. Consult your pharmacist or doctor if these instructions are not clear. The usual doses are:
Like all medicines, this medicine can cause side effects, although not everybody gets them. Most of them are mild and disappear when you stop taking Nitrofurantoin. If you experience any of the side effects detailed below or any other side effects, stop taking Nitrofurantoin and consult your doctor. All medicines can cause allergic reactions although serious allergic reactions are rare. If you notice any sudden wheeziness, difficulty in breathing, swelling of the eyelids, face or lips, rash or itching (especially affecting your whole body) STOP TAKING your medicine and go to a doctor immediately. Please note that while taking Nitrofurantoin your urine may become coloured dark yellow or brown. This is quite normal and not a reason to stop taking the medicine. If you notice any of the following side effects consult your doctor immediately:
NITROFURANTOIN 100MG PROLONGED-RELEASE CAPSULES Keep this medicine out of the sight and reach of children.
Do not store above 30°C (aluminium/aluminium). Do not store above 25°C (For PVC/polyethylene/aclar/aluminium blisters). Store in the original package to protect from light and moisture. Do not use this medicine after the expiry date which is stated on the carton after EXP. The expiry date refers to the last day of that month. Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help to protect the environment.
What Nitrofurantoin 100mg Prolonged-Release Capsules contains: The active substance is 100mg nitrofurantoin in each capsule. The other ingredients are talc, corn starch, lactose, carbopol, povidone, sugar and magnesium stearate. The capsule shell contains gelatin, quinoline yellow (E104), titanium dioxide (E171) and FD&C Blue No.2 (E132). The printing ink contains shellac, propylene glycol (E1520), titanium dioxide (E171) black iron oxide (E172), ammonium hydroxide (E527) and simethicone. What Nitrofurantoin 100mg Prolonged-Release Capsules looks like and contents of the pack: Nitrofurantoin 100mg Prolonged-Release Capsules has an opaque blue cap and opaque yellow body and bears the monogram "GS 100". The capsules are available in blister strips of 14. Marketing Authorisation Holder: Mercury Pharmaceuticals Ltd, Dashwood House, 69 Old Broad Street, London, EC2M 1QS, United Kingdom Manufacturer: Famar A.V.E., 7 Anthousa Avenue, 15344 Anthousa, Attiki, Greece This leaflet was last revised in April 2026.
Nitrofurantoin Mercury Pharma 100mg Prolonged-Release Capsules comes as capsule containing 100mg. Always follow the dose your doctor or pharmacist has given you, and read the leaflet that comes with the medicine.
The active substance in Nitrofurantoin Mercury Pharma 100mg Prolonged-Release Capsules is nitrofurantoin.
Medicines with the same active substance, strength and form include: Nitrofurantoin 100 mg Capsules, Nitrofurantoin 100 mg Hard Capsules, Nitrofurantoin 100 mg capsules. In total there are 9 equivalent products. They are interchangeable only if your prescriber or pharmacist says so.
This leaflet reproduces the patient information leaflet approved for Nitrofurantoin Mercury Pharma 100mg Prolonged-Release Capsules, as published on the electronic medicines compendium (emc). The version printed inside your medicine’s packaging is the one that applies to you.
Whether a medicine is available over the counter or on prescription only depends on its licence. Check the leaflet, or ask your pharmacist — they can tell you straight away.
The text above reproduces the patient information leaflet approved for this medicine, restructured for easier reading.
For the treatment of and prophylaxis against acute or recurrent, uncomplicated lower urinary tract infections or pyelitis either spontaneous or following surgical procedures. It is indicated in adults, children and infants over 12 years of age.
Nitrofurantoin is specifically indicated for the treatment of infections when due to susceptible strains of Escherichia coli, Enterococci, Staphylococci, Citrobacter, Klebsiella and Enterobacter.
Most strains of Proteus and Serratia are resistant. All Pseudomonas strains are resistant.
Nitrofurantoin 100mg Prolonged-Release Capsules is not indicated for the treatment of associated renal cortical or perinephric abscesses.
Posology
Adults and children over 12 years of age.
The dose should be taken with food or milk (e.g. at meal times).
Acute or recurrent uncomplicated UTI and pyelitis -100mg twice daily for seven days.
Surgical Prophylaxis - 100 mg twice daily on the day of the procedure and 3 days thereafter.
Elderly
Provided there is no significant renal impairment, in which nitrofurantoin is contraindicated, the dosage should be that for any normal adult.
See precaution and risks to elderly patients associated with long term therapy (see section 4.8).
Children under 12 years
Nitrofurantoin 100mg Prolonged-Release Capsules is a fixed dosage and is therefore not suitable for children under 12 years
Renal impairment
Nitrofurantoin is contraindicated in patients with renal dysfunction and in patients with an eGFR below of less than 45 ml/minute (see sections 4.3 & 4.4).
Method of administration
For oral use
• Hypersensitivity to the active substance, other nitrofurans or to any of the excipients listed in section 6.1.
• Patients suffering from renal dysfunction with an eGFR below 45 ml/minute.
• G6PD deficiency (see also Section 4.6)
• Acute porphyria.
• In infants under three months of age as well as pregnant patients at term (during labour and delivery) because of the theoretical possibility of haemolytic anaemia in the foetus or in the newborn infant due to immature erythrocyte enzyme systems.
Nitrofurantoin is not effective for the treatment of parenchymal infections of a unilaterally functioning kidney. A surgical cause for infection should be excluded in recurrent or severe cases.
Nitrofurantoin may be used with caution as short-course therapy only for the treatment of uncomplicated lower urinary tract infection in individual cases with an eGFR between 30-44 ml/min to treat resistant pathogens, when the benefits are expected to outweigh the risks.
Since pre-existing conditions may mask hepatic or pulmonary adverse reactions, nitrofurantoin should be used with caution in patients with pulmonary disease, hepatic dysfunction, neurological disorders and allergic diathesis.
Peripheral neuropathy and susceptibility to peripheral neuropathy, which may become severe or irreversible has occurred and may be life threatening. Therefore, treatment should be stopped at the first signs of neural involvement (paraesthesiae).
Nitrofurantoin should be used with caution in patients with anaemia, diabetes mellitus, electrolyte imbalance, debilitating conditions, and vitamin B (particularly folate) deficiency.
Pulmonary adverse reactions
Acute, subacute and chronic pulmonary reactions have been observed in patients treated with nitrofurantoin. If these reactions occur, nitrofurantoin should be discontinued immediately. Signs of pulmonary damage include difficulty and or pain when breathing, shortness of breath and coughing up blood or mucus.
Chronic pulmonary reactions
Chronic pulmonary reactions (including pulmonary fibrosis and diffuse interstitial pneumonitis) can develop insidiously and can often occur in elderly patients. Close monitoring of the lung diseaseof patients receiving long-term therapy is indicated (especially in the elderly).
Acute pulmonary reactions
Pulmonary reactions may be acute and usually occur within the first week of treatment. Increased vigilance for respiratory symptoms in patients who have just started therapy is warranted (especially in the elderly).
Urine may be coloured yellow or brown after taking Nitrofurantoin. Patients on Nitrofurantoin are susceptible to false positive urinary glucose (if tested for reducing substances).
Nitrofurantoin should be discontinued at any signs of haemolysis in those with suspected glucose-6-phosphate dehydrogenase deficiency.
Gastrointestinal reactions may be minimised by taking the drug with food or milk, or by adjustment of dosage.
Hepatotoxicity
Hepatic reactions, including hepatitis, autoimmune hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis, occur rarely. Fatalities have been reported. The onset of chronic active hepatitis may be insidious, and patients should be monitored periodically for changes in biochemical tests that would indicate liver injury. If hepatitis occurs, the drug should be withdrawn immediately and appropriate measures should be taken.
For long term treatment monitor the patient closely for appearance of hepatic or pulmonary symptoms and other evidence of toxicity.
Discontinue treatment with nitrofurantoin if otherwise unexplained pulmonary, hepatotoxic, haematological or neurological syndromes occur.
Excipients
Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.
Patients with rare hereditary problems of fructose intolerance, glucose-galactose malabsorption or sucrase-isomaltase insufficiency should not take this medicine.
1. Increased absorption with food or agents delaying gastric emptying.
2. Decreased absorption with magnesium trisilicate.
3. Decreased renal excretion of Nitrofurantoin by probenecid and sulfinpyrazone.
4. Decreased anti-bacterial activity by carbonic anhydrase inhibitors and urine alkalisation.
5. Anti-bacterial antagonism by quinolone anti-infectives.
6. Interference with some tests for glucose in urine.
7. As Nitrofurantoin belongs to the group of Antibacterials, it will have the following resulting interactions:
• Typhoid Vaccine (oral): Antibacterials inactivate oral typhoid vaccine.
Pregnancy
Animal studies with nitrofurantoin have shown no teratogenic effects, however study in rats has shown reproductive toxicity (see section 5.3). Nitrofurantoin has been in extensive clinical use since 1952 and its suitability in human pregnancy has been well documented. However, as with all other drugs, the maternal side effects may adversely affect course of pregnancy. The drug should be used at the lowest dose as appropriate for a specific indication, only after careful assessment.
Nitrofurantoin is however contraindicated in infants under three months of age and in pregnant women during labour and delivery because of the possible risk of haemolysis of the infants immature red cells.
Breast-feeding
Breast feeding an infant known or suspected to have an erythrocyte enzyme deficiency (including G6PD deficiency), must be temporarily avoided, since Nitrofurantoin is detected in trace amounts in breast milk.
Fertility
No data available
Nitrofurantoin 100mg Prolonged-Release Capsules may cause dizziness and drowsiness. Patients should be advised not to drive or operate machinery if affected in this way until such symptoms go away.
A tabulated list of undesirable effects is outlined below:
The undesirable effects are listed according to organ systems and following frequencies:
Rare (≥1/10,000 to <1/1,000)
Not known (cannot be estimated from the available data)
System organ class
Frequency
Adverse reaction
Infections and infestations
Not known
Superinfections by fungi or resistant organisms such as Pseudomonas. However, these are limited to the genitourinary tract
Blood and lymphatic system disorders
Rare
Not known
Aplastic anaemia
Agranulocytosis, leucopenia, granulocytopenia, haemolytic anaemia, thrombocytopenia,glucose¬6-phosphatedehydrogenase deficiency anaemia, megaloblasticanaemia and eosinophilia
Immune system disorders
Not known
Anaphylaxis, , angioneuroticoedema , cutaneous vasculitis and allergic skin reactions
Psychiatric disorders
Not known
psychotic reactions, depression, euphoria, confusion
Nervous system disorders
Not known
Benign intracranial hypertension, peripheral neuropathy including optic neuritis (sensory as well as motor involvement), nystagmus, vertigo, dizziness, headache and drowsiness.
Cardiac disorders
Rare
Collapse and cyanosis
Respiratory, thoracic and mediastinal disorders
Not known
Pulmonary fibrosis; possible association with lupus-erythematous-like syndrome.
acute pulmonary reactions *
subacute pulmonary reactions, *
chronic pulmonary reactions, *
cough, dyspnoea,
Gastrointestinal disorders
Not known
Sialaodenitis, pancreatitis, , anorexia, emesis, abdominal pain, diarrhea and nausea
Hepatobiliary disorders
Not known
Chronic active hepatitis**, hepatic necrosis, autoimmune hepatitis, cholestatic jaundice
Skin and subcutaneous tissue disorders
Not known
Lupus-like syndrome associated with pulmonary reaction.
Drug Rash With Eosinophilia And Systemic Symptoms (DRESS syndrome), exfoliative dermatitis and erythema multiforme (including Stevens-Johnson Syndrome), maculopapular, erythematous or eczematous eruptions,urticaria, rash, and pruritis, Transient alopecia
Renal and urinary disorders
Not known
Interstitial nephritis, yellow or brown discolouration of urine,
General disorders and administration site conditions
Not known
Asthenia, fever, chills, drug fever and arthralgia
Investigations
Not known
False positive urinary glucose
* Acute pulmonary reactions are commonly manifested by fever, chills, cough, chest pain, dyspnoea, pulmonary infiltration with consolidation or pleural effusion on chest x-ray, and eosinophilia. In subacute pulmonary reactions, fever and eosinophilia occur less often than in the acute form.
Chronic pulmonary reactions occur rarely in patients who have received continuous therapy for six months or longer and are more common in elderly patients. Changes in ECG have occurred, associated with pulmonary reactions
**Can be fatal
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the MHRA yellow card scheme website: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
Symptoms
Symptoms and signs of overdose include gastric irritation, nausea and vomiting.
Management
There is no specific antidote. However, Nitrofurantoin can be haemodialysed. Standard treatment is by induction of emesis or by gastric lavage in cases of recent ingestion. Monitoring of full blood count, liver function tests and pulmonary function, are recommended. A high fluid intake should be maintained to promote urinary excretion of the drug.
Ask anything about Nitrofurantoin Mercury Pharma 100mg Prolonged-Release Capsules. The assistant answers only from this leaflet — if the leaflet does not cover it, it will say so. It does not give medical advice.
Answers come from the patient leaflet published on the electronic medicines compendium (emc). They are not medical advice. Ask a pharmacist or your GP if you are unsure. For urgent help call NHS 111, or 999 in an emergency.
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