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The United Kingdom: Nitrofurantoin: reminder of the risks of pulmonary and hepatic adverse drug reactions (English only)
 
Medicines and Healthcare products Regulatory Agency (MHRA) announces that healthcare professionals prescribing nitrofurantoin should be alert to the risks of pulmonary and hepatic adverse drug reactions and advise patients to be vigilant for the signs and symptoms in need of further investigation.

The MHRA has received a Coroner’s report following the death of a patient who experienced acute pulmonary damage and respiratory failure after being treated with nitrofurantoin for a urinary tract infection for a 10-day course. The Coroner raised concerns about the known risk of acute pulmonary damage following nitrofurantoin treatment and the need to highlight this to healthcare professionals and patients.

The potential for acute pulmonary damage with nitrofurantoin is well-documented in the product information for nitrofurantoin. The Summary of Product Characteristics (SmPC) states that acute, subacute and chronic pulmonary adverse reactions have been observed in patients treated with nitrofurantoin. Symptoms of acute pulmonary reactions usually include fever, chills, cough, chest pain, dyspnoea, pulmonary infiltration with consolidation or pleural effusion on chest X-ray, and eosinophilia. For subacute pulmonary reactions, fever and eosinophilia occur less often than in the acute form.

Information from published studies on the frequency or severity of pulmonary adverse drug reactions in association with acute use of nitrofurantoin is limited. A precise estimate of frequency of these pulmonary adverse drug reactions and the frequency of fatal outcomes cannot be made, but evidence from observational studies suggests that the pulmonary pulmonary adverse drug reactions in association with acute use of nitrofurantoin are infrequent.

If symptoms of pulmonary damage occur, nitrofurantoin should be discontinued immediately. The Patient Information Leaflet (PIL) advises patients that lung adverse reactions may occur and that patients should consult a doctor immediately if they notice symptoms of a lung reaction. Close monitoring of pulmonary conditions is advised for patients receiving long-term therapy (especially elderly people). Patients and carers should be reminded about the symptoms of pulmonary damage and the need to seek prompt medical advice if they experience these symptoms.

Following advice from the Pharmacovigilance Expert Advisory Group of the Commission on Human Medicines, Marketing Authorisation Holders for these medicines have been requested to strengthen the wording in the United Kingdom SmPC and PIL. These updates will include the advice that healthcare professionals should be vigilant for respiratory symptoms in patients taking nitrofurantoin, for any duration, and promptly investigate these symptoms, as they may indicate a pulmonary reaction.

MHRA also reminds healthcare professionals of the risk of hepatic adverse drug reactions and clarify advice on the frequency of monitoring. Nitrofurantoin can rarely cause hepatic reactions, including cholestatic jaundice, chronic active hepatitis, autoimmune hepatitis, and hepatic necrosis. Events with a fatal outcome have been reported. Nitrofurantoin should be discontinued immediately if hepatitis occurs.

The onset of hepatitis may be gradual and may not have obvious symptoms at first. It is important to monitor patients periodically for changes in biochemical tests that could indicate hepatic dysfunction and for clinical signs or symptoms of liver abnormality, especially in patients taking long-term nitrofurantoin. When scheduling periodic monitoring, take into account relevant local guidance, as well as any pre-existing conditions that might mask the symptoms of a hepatic reaction and the patient’s ability to recognise symptoms and seek advice in the event of a hepatic reaction. This periodic monitoring may be an opportunity to remind patients about the possible symptoms of hepatic reactions and to remind them to seek medical advice if they experience these symptoms.

Advice for healthcare professionals:
- Advise patients and caregivers to be vigilant for new or worsening respiratory symptoms while taking nitrofurantoin and promptly investigate any symptoms that may indicate a pulmonary adverse reaction.
- Pulmonary reactions may occur with short- or long-term use of nitrofurantoin, and increased vigilance for acute pulmonary reactions is required in the first week of treatment.
- Patients receiving long-term therapy, for example for recurrent urinary tract infections, should be closely monitored for new or worsening respiratory symptoms, especially if elderly.
- Immediately discontinue nitrofurantoin if new or worsening symptoms of pulmonary damage occur.
- Be vigilant for symptoms and signs of liver dysfunction in patients taking nitrofurantoin for any duration, but particularly with long-term use, and monitor patients periodically for signs of hepatitis and for changes in biochemical tests that would indicate hepatitis or liver injury.
- Use caution when prescribing nitrofurantoin in patients with pulmonary disease or hepatic dysfunction, which may mask the signs and symptoms of adverse reactions.
- Advise patients to read carefully the advice in the PIL about symptoms of possible pulmonary and hepatic reactions and to seek medical advice if they experience these symptoms.

Please refer to the following website in MHRA for details: http://www.gov.uk/drug-safety-update/nitrofurantoin-reminder-of-the-risks-of-pulmonary-and-hepatic-adverse-drug-reactions

In Hong Kong, there are 5 registered pharmaceutical products containing nitrofurantoin. All products are prescription-only medicines. So far, the Department of Health (DH) has received one case of adverse drug reaction related to nitrofurantoin, which was related to pulmonary embolism.

The risk of pulmonary reactions and hepatotoxicty with relevant precautions associated with the use of nitrofurantoin is documented in overseas reputable drug references such as the “Martindale: The Complete Drug Reference”. The DH will remain vigilant on safety update of the drug issued by other overseas drug regulatory authorities.

Ends/Thursday, Apr 27, 2023
Issued at HKT 18:00
 
 
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