Recurrent acute nitrofurantoin-induced pulmonary toxicity.

Nitrofurantoin may be used for prophylaxis of recurrent urinary tract infections in women; however, this agent has been associated with acute, subacute, and chronic pulmonary adverse reactions. The acute reaction occurs in about 1/5,000 women after their first exposure to the drug. We report the occurrence of two successive, highly probable (by Naranjo score) nitrofurantoin-induced acute pulmonary reactions in the same patient. On day 4 of prophylaxis with nitrofurantoin 100 mg/day (to prevent urinary tract infections), the patient developed intense substernal pain and pressure. On day 8, she experienced intense substernal burning. She went to the emergency department, where she vomited and was hypotensive and febrile. Her chest radiograph showed bilateral infiltrates. The patient was diagnosed with pneumonia and was prescribed levofloxacin; she stopped taking the nitrofurantoin. Her symptoms subsided over the next 3 days. Ten days later, the patient restarted the nitrofurantoin, and she returned to the emergency department after again experiencing sudden intense substernal burning, nausea, vomiting, shivering, and weakness. Nitrofurantoin was discontinued; her symptoms resolved quickly, and prophylaxis with trimethoprim-sulfamethoxazole was begun. After 1 year, the patient had experienced no further pulmonary symptoms or urinary tract infections. Drug toxicity must be considered in patients who develop pulmonary symptoms while taking nitrofurantoin. Symptoms are often misdiagnosed as other ailments, potentially subjecting patients to unnecessary treatments and delaying discontinuation of nitrofurantoin. Patients should be advised to contact a physician if breathing difficulties or unusual symptoms develop while taking nitrofurantoin, as this could result in earlier recognition of this drug reaction.