Nitrofurantoin: important safety advice

Last Updated: Monday, 12 October 2026

Nitrofurantoin is an antibiotic used to treat bladder infections and prevent repeated urinary tract infections (UTIs).

The MHRA, the UK medicines regulator, has reminded patients that nitrofurantoin can sometimes cause serious side effects affecting the lungs or liver. These can happen during short courses or long-term treatment.

Symptoms affecting your lungs

Stop taking nitrofurantoin and seek medical advice immediately if you develop:

• New or worsening breathlessness.
• A cough that does not go away.
• Coughing up blood or mucus.
• Pain or discomfort when breathing.

Call 999 if you have severe difficulty breathing.

Symptoms affecting your liver

Seek medical advice promptly if you notice:

• Yellow skin or yellow whites of your eyes.
• Pain in the upper right side of your tummy.
• Dark urine together with pale or grey stools.
• Itching, or joint pain and swelling.

If you cannot reach your GP, contact NHS 111. Do not wait for a routine medication review if you develop these symptoms.

Taking nitrofurantoin long term?

Attend your monitoring appointments and blood tests.

If you have questions or concerns, contact your GP practice to book a medication review with a clinician.

Read the full MHRA alert.