Nitrofurantoin: Uses, Side Effects & Safety

What it is and what it's used for

Nitrofurantoin is an antibiotic used mainly for urinary tract infections (UTIs). It is most commonly prescribed for infections of the bladder (cystitis) in adults and children, and it is sometimes used in a low dose to help prevent repeated UTIs. In India it is a prescription-only medicine — it should never be bought or started on your own.

How it works (simple language)

Nitrofurantoin reaches high levels in the urine, which is why it is so useful for bladder infections. Inside the bacteria it is converted into active substances that damage the bacteria's vital structures and stop them from growing and multiplying. It works well against many of the common bacteria that cause UTIs, though your doctor may order a urine test to confirm it is the right choice for you.

Dosage forms available in India (general info only)

Nitrofurantoin is commonly available in India as 50 mg and 100 mg tablets or capsules, sold under several brand names that vary by manufacturer — your pharmacist can guide you on what is stocked. Taking it with food or milk reduces stomach upset and helps the medicine be absorbed better.

Never decide the dose yourself from this article. Always follow your doctor's prescription or the directions on the pack, and check with your pharmacist if you are unsure — especially for children, where the dose depends on the child's weight and age.

Side effects

Common: Nausea, vomiting, loss of appetite, diarrhoea, stomach pain, headache, dizziness, and brownish or dark-yellow urine (this colour change is harmless and disappears after you stop the medicine).

Serious — seek medical care: Tingling, numbness or burning in the hands and feet (signs of nerve damage); fever, chills, cough, chest pain or difficulty breathing (possible lung reaction); yellowing of the skin or eyes, unusual tiredness, or loss of appetite that does not go away (possible liver problem); signs of a severe allergic reaction such as rash, swelling of the face or lips, or wheezing; severe or bloody diarrhoea.

Precautions and warnings

• Prescription only. Never start, share, or stop this antibiotic on your own — and complete the full course even if you start feeling better.
• Take with food or milk to reduce stomach upset and improve absorption.
• Kidney problems: tell your doctor if you have reduced kidney function — the medicine works through the urine and may not suit everyone with kidney disease.
• Nerve symptoms: report tingling, numbness, or weakness in the hands or feet immediately; the risk is higher with long-term use, diabetes, or in older adults.
• Lung and liver watch: a persistent cough, breathing difficulty, chest pain, or yellowing of the skin during or after treatment needs prompt medical attention.
• G6PD deficiency: people with this inherited enzyme condition should tell their doctor, as the medicine may need extra caution.
• Driving and machinery: dizziness can occur, so be careful until you know how the medicine affects you.

Interactions (general)

Tell your doctor about ALL medicines you take, including herbal and ayurvedic products. Some antacids can reduce how well nitrofurantoin is absorbed, and medicines such as probenecid can raise its levels in the blood. It is best to avoid alcohol while being treated for an infection, and let your doctor know if you are due for urine tests, as nitrofurantoin can affect some urine glucose test results.

Pregnancy and breastfeeding (general guidance)

Nitrofurantoin is often used for UTIs during pregnancy, but it is usually avoided at or near the time of delivery because of a risk to the newborn's red blood cells. If you are pregnant, planning a pregnancy, or breastfeeding, consult your doctor first — do not decide on your own.

Storage

Store at room temperature, away from moisture and direct sunlight. Keep it in its original pack, out of the reach and sight of children, and do not use it after the expiry date printed on the pack.

When to see a doctor

See a doctor if your UTI symptoms (burning on urination, frequent urge to urinate, lower abdominal pain, fever) do not improve within a couple of days of starting treatment, or if they get worse. Seek emergency care for breathing difficulty, chest pain, swelling of the face or lips, a severe rash, yellowing of the skin or eyes, or bloody diarrhoea.

FAQs

1. Why has my urine turned brown or dark yellow?

This is a harmless and common effect of nitrofurantoin. The colour returns to normal after you finish the course. Keep drinking plenty of water as your doctor advised.

2. Can I buy nitrofurantoin without a prescription?

No. It is a prescription-only medicine in India. Urinary infections need proper diagnosis — treating yourself can hide a more serious infection and delay the right treatment.

3. Can it treat a kidney infection or infections elsewhere in the body?

Nitrofurantoin concentrates in the urine and works best for bladder infections. It is generally not the right choice for kidney tissue infections or infections outside the urinary tract — your doctor will choose the right antibiotic for your situation.

4. What should I do if I miss a dose?

Take it as soon as you remember, unless it is nearly time for your next dose. Do not take a double dose to make up for the missed one; ask your pharmacist if you are unsure.