S3337 An Unusual Case of Drug-Induced Liver Injury Secondary to Nitrofurantoin Use

Abstract

Introduction: Nitrofurantoin is a commonly prescribed antibiotic for uncomplicated urinary tract infections (UTI). One of nitrofurantoin's rare, however significant, adverse effects is idiosyncratic drug-induced liver injury (DILI). Case Description/Methods: A 24-year-old obese female with a past medical history of GERD presented to the emergency department complaining of epigastric pain with nausea and vomiting for the past few hours. The patient was recently diagnosed with a UTI and took nitrofurantoin (50 mg every 6 hours) for the past 3 days. Blood tests on admission were significant for direct bilirubin of 0.7 mg/dL, total bilirubin of 1.9 mg/dL, AST of >717 U/L, and ALT of 476 U/L. The patient had liver function tests (LFTs) a week ago, which were normal. Toxicology labs were negative for acetylsalicylic acid, acetaminophen, and alcohol. Viral workups, including Hepatitis tests, were negative for hepatitis A, B, C, and E and showed immunity for hepatitis A with IgG positive/IgM negative. Autoimmune workup including antinuclear antibodies (ANA), Anti-smooth muscle, anti-mitochondrial, and anti-LK- antibodies were negative. Ultrasound showed stones within the gallbladder. Nitrofurantoin was immediately discontinued, and after 3 days in the hospital, symptoms subsided. Repeat LFTs showed enzyme values trending towards normal (Table 1). The patient was educated to follow up with PCP for repeat LFTs and chances of possible relapse with similar medications on discharge. Discussion: DILI can be a rare and fatal adverse effect of nitrofurantoin use. There is a higher risk of developing DILI from taking nitrofurantoin for female patients with increased age, reduced renal function, or increased duration of treatment with the drug. DILI generally presents in two forms with nitrofurantoin, acute and chronic. Acute DILI can present with fever, rash, eosinophilia, hepatomegaly, jaundice, abdominal pain, nausea, malaise, pulmonary signs, anorexia, and elevated liver enzymes. Most cases of acute DILI due to nitrofurantoin will resolve on their own after discontinuation of the drug but should be monitored in case chronic liver injury develops. Severe cases may require treatment with steroids, N-acetylcysteine, or transplantation. Our patient presented with signs of liver damage after starting a course of nitrofurantoin for a lower urinary tract infection. Once treatment was discontinued, the patient’s condition improved, consistent with DILI. Table 1. - Patients lab results post discontinuation of Nitrofurantoin on day 1 Parameters Day 1 Day 2 Day 3 Normal Values Platelets 245,000 250,000 225,000 150,000-400,000/mm3 Total Bilirubin 1.9 1.7 1.6 0.1-1.0 mg/dL Direct Bilirubin 0.7 0.8 0.6 0.0-0.3 mg/dL AST > 717 406 135 8-20 U/L ALT 476 520 331 8-20 U/L Alkaline Phosphatase 120 129 104 20-70 U/L Glucose 90 123 86 Fasting: 70-110 mg/dL 2-h postprandial: < 120 mg/dL Albumin 4.5 4.1 3.7 3.5-5.5 g/dL INR 1.0 1.2 1.2 0.8-1.2 secs BUN 11 5 6 7-18 mg/dL Creatinine 0.8 0.8 0.7 0.6-1.2 mg/dL Sodium 135 138 137 136-145 mEq/L Potassium 5.8 3.7 3.8 3.5-5.0 mEq/L Chloride 103 106 106 95-105 mEq/L ASA < 5.0 5.0-20.0 mg/dL Acetaminophen < 1 5.0-20.0 mg/dL Alcohol < 0.01 Gammaglobulin wnl