Nitrofurantoin
Capsule
Quick Summary
Nitrofurantoin is a first-choice treatment for uncomplicated urinary tract infections in many guidelines.
Medical Uses
How it's taken
Take it with food or milk.
Take it for the full course, even if you feel better, unless your doctor tells you otherwise. Don't share antibiotics or keep leftovers.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Nausea
Take with food.
Dark yellow or brown urine
Harmless.
Headache
Sometimes.
Interactions
Antacids containing magnesium
Reduce absorption.
Critical Warnings
Kidney problems
Not suitable if kidney function is poor.
Lung or nerve problems
Rarely with long use; report breathlessness or tingling.
Severe allergic reaction
Black Box Warning: Swelling of the face or throat, difficulty breathing or a widespread rash: get emergency help.
Antibiotic resistance
Using antibiotics when they aren't needed makes them less effective for everyone.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Nitrofurantoin: drug information(opens in a new tab) · MedlinePlus, US National Library of Medicine
- Nitrofurantoin: antibiotic to treat bacterial infections(opens in a new tab) · NHS