Nitrofurantoin – Specialist antibiotic for urinary tract infections.
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What is Nitrofurantoin?
Nitrofurantoin is a specialist antibiotic that concentrates in the urine, making it particularly effective for treating urinary tract infections. It’s often used when other antibiotics haven’t worked or for preventing recurrent UTIs.
Book an online consultation if you’re experiencing UTI symptoms such as burning during urination, frequent urination, or pelvic pain. Our GPs can assess your symptoms and prescribe appropriate treatment.
What is Nitrofurantoin used for?
- Urinary tract infections (UTIs)
- Cystitis (bladder infections)
- Prevention of recurrent UTIs
- Lower urinary tract infections
- Prophylaxis during urological procedures
How does Nitrofurantoin work?
A bacteriostatic and bactericidal antibiotic that concentrates in the urine, specifically targeting bacteria in the urinary tract.
Dosage and Administration
Adults
50-100 mg four times daily for acute infections, or 50-100 mg once daily for prevention.
Children
1-1.5 mg per kg body weight, four times daily—GP will calculate appropriate dose.
Important Notes
- Take with food or milk to reduce stomach upset and improve absorption.
- Complete the full course even if symptoms improve.
- Drink plenty of fluids to help flush bacteria from the urinary system.
- For prevention, usually taken as a single bedtime dose.
Side Effects
Common Side Effects
- Nausea and vomiting
- Loss of appetite
- Diarrhoea
- Headache
- Dizziness
- Drowsiness
Serious Side Effects
Seek immediate medical attention if you experience:
- Lung problems (pulmonary fibrosis with long-term use)
- Severe liver reactions
- Peripheral neuropathy (nerve damage)
- Severe allergic reactions
- Blood disorders
Important Warnings
- Not suitable for patients with severe kidney disease.
- May cause serious lung problems with long-term use—regular monitoring required.
- Tell your GP if you have glucose-6-phosphate dehydrogenase (G6PD) deficiency.
- Not recommended in pregnancy near term or during breastfeeding.
- May cause urine to turn dark yellow or brown—this is harmless.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- Antacids containing magnesium—may reduce absorption.
- Probenecid—may increase nitrofurantoin levels and toxicity.
- Quinolone antibiotics—may reduce effectiveness of both medications.
- Oral typhoid vaccine—may reduce vaccine effectiveness.
Frequently Asked Questions
Why is my urine a different colour?
Nitrofurantoin commonly turns urine dark yellow or brown. This is harmless and will return to normal when you stop taking the medication.
How quickly does Nitrofurantoin work for UTIs?
Most people start feeling better within 1-2 days, but it's important to complete the full course to prevent the infection from returning.
Can I take Nitrofurantoin long-term for recurrent UTIs?
Yes, it can be prescribed for long-term prevention, but requires regular monitoring by your GP for potential lung and liver side effects.
Why must I take it with food?
Taking Nitrofurantoin with food reduces stomach upset and actually improves how well your body absorbs the medication.
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14