Nitrofurantoin guide
How to complete the prescribed lower-UTI course, take each dose with food, and spot lung, liver, nerve, or kidney warning signs.
How to use
- 01
Step 1
Take the exact formulation and course prescribed
Nitrofurantoin products are not all dosed alike. A common prolonged-release regimen is 100 mg twice daily for a product-specific course; immediate-release products may use a different frequency. Follow your label rather than substituting schedules.
- 02
Step 2
Take with food or milk
Swallow each dose with a meal or milk to improve absorption and tolerance. Space doses evenly and complete the prescribed course unless a clinician tells you to stop.
Dose schedule
- 01
Step 1
Every prescribed dose
Use the same formulation throughout. If a dose is missed, take it when remembered unless the next is near; do not take two doses together.
- 02
Step 2
Review response within 48–72 hours
Lower urinary symptoms should be reassessed if they worsen or do not begin to improve. Nitrofurantoin is not suitable for suspected kidney infection, and kidney function affects whether it can be used.
Side effects
Digestive and urine changes
Nausea, reduced appetite, abdominal discomfort, diarrhoea, or headache can occur. Urine may turn dark yellow or brown; this alone is usually harmless.
Rare serious reactions
New cough, breathlessness, fever, chest pain, yellow skin or eyes, numbness, tingling, weakness, or a severe rash needs prompt assessment. These can signal lung, liver, nerve, or allergic reactions.
04 · When to contact your doctor
Contact your doctor if
- Fever with flank or back pain, vomiting, confusion, pregnancy, or feeling acutely unwell
- New breathing symptoms, jaundice, severe rash, numbness, tingling, or weakness — stop and seek prompt advice
- Symptoms worsen, fail to improve within 2–3 days, or return after the course
Storage
Keep in the original package, away from moisture and direct heat, and out of children's reach. Follow the temperature limit on your pack and do not use it after the expiry date.
What to expect
Nitrofurantoin concentrates in urine and is used for selected susceptible lower urinary infections. It does not cover every bacterium and is not a kidney-infection treatment. Complete the prescribed course and seek reassessment if the expected early improvement does not occur.