The Medicines and Healthcare products Regulatory Agency (MHRA) has issued a reminder to healthcare professionals about possible adverse reactions to nitrofurantoin.

This follows the death of a patient who experienced acute pulmonary damage and respiratory failure after being treated with a 10-day course of nitrofurantoin for a urinary tract infection (UTI).

The Coroner raised concerns about the need to highlight the known risk of acute pulmonary damage following nitrofurantoin treatment to healthcare professionals and patients.

Nitrofurantoin, also known under the brand names Macrobid and Genfura, is an antibacterial agent used to treat uncomplicated UTIs and bladder and kidney infections, in adults and children over three months old.

The MHRA told clinicians to warn patients and caregivers to look out for new or worsening respiratory symptoms or signs of liver dysfunction in patients taking nitrofurantoin.

Risk of pulmonary adverse reaction to nitrofurantoin

Symptoms such as a fever, chills, cough, chest pain or shortness of breath could indicate a pulmonary adverse reaction, the MHRA said.

While there is limited evidence on the frequency or severity of pulmonary adverse drug reactions associated with nitrofurantoin, the MHRA said that observational studies suggested that such adverse reactions were infrequent.

But if symptoms of pulmonary damage do occur, the drug should be discontinued immediately, the MHRA added.

Risk of hepatic reactions to nitrofurantoin

The MHRA also issued a reminder of the risk of hepatic reactions and said that it wanted to ‘clarify’ its advice on the frequency of monitoring, ‘following discussions with NHS England’.

It said that nitrofurantoin can ‘rarely’ cause hepatic reactions, such as cholestatic jaundice, chronic active hepatitis, autoimmune hepatitis, and hepatic necrosis.

‘Events with a fatal outcome have been reported,’ the MHRA said, while adding that nitrofurantoin should be discontinued immediately if hepatitis occurs.

As the onset of hepatitis ‘may be gradual and may not have obvious symptoms at first’, the MHRA said that patients – especially those taking long-term nitrofurantoin – should be monitored periodically for changes in biochemical tests that could indicate hepatic dysfunction and for clinical signs or symptoms of liver abnormality.

It added that this periodic monitoring could be an opportunity to remind patients of the possible symptoms of hepatic reactions – such as yellowing of the skin or eyes, upper right abdominal pain, dark urine and pale or grey-coloured stools, itching or joint pain and swelling – and to encourage them to seek medical advice if they were to experience symptoms of an adverse reaction.

All suspected adverse drug reactions should be reported via the Yellow Card scheme, the MHRA added.