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Summary
Nitrofurantoin is a synthetic derivative of imidazolinedione, used to treat uncomplicated urinary tract infections. It acts by inhibiting bacterial DNA, RNA and cell wall protein synthesis. It is used prophylactically as a urinary anti-infective agent against most gram-positive organism and for long-term suppression of infections. Nitrofurantoin-associated pulmonary injuries occur in 1% of patients, presenting with dyspnoea and dry cough, and it can mimic interstitial lung disease. We present a case of an 81-year-old woman with shortness of breath and cough 3 days after initiation of nitrofurantoin. CT of the chest revealed bilateral pleural effusion and extensive pulmonary interstitial prominence, suggesting pulmonary fibrosis. According to the Naranjo Adverse Drug Reaction Probability Scale score of 6, it was determined that nitrofurantoin was the probable cause, and immediate cessation of the medication showed a marked clinical improvement and resolution after 10 days.
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Background
Nitrofurantoin is an antimicrobial drug recommended as the first-line treatment for uncomplicated cystitis, urinary tract infection (UTI) and prophylaxis for recurrent UTI.1–3 It is the treatment of choice for patients with known allergy to trimethoprim–sulfamethoxazole. The most common side effects are gastrointestinal such as nausea, vomiting and diarrhoea, and very rarely can present with pulmonary toxicity.3 Pulmonary toxicity may range from acute, subacute or chronic.4 Both acute and subacute reactions are thought to be secondary to a hypersensitivity reaction and are dose independent. In contrast, chronic pulmonary reactions, which include diffuse interstitial pneumonitis and pulmonary fibrosis, are related to the total lifetime dosage. …
Footnotes
Contributors Summary and treatment: VKK. Background, investigations, outcome and follow-up: AB-B. Case presentation: EM. Differential diagnosis: GO. Discussion and learning points/take-home messages: EM and GO.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.