Fosfomycin-induced liver injury in a 17-year-old patient: A case report.

PURPOSE: To describe a case of severe acute hepatitis in an adolescent in whom fosfomycin was identified as the highly probable cause of drug-induced liver injury (DILI) and to highlight the potential hepatotoxicity of fosfomycin.

SUMMARY: A previously healthy 17-year-old male presented with nausea, vomiting, fever, and progressive epigastric pain over 3 days, accompanied by fatigue and malaise. Laboratory testing revealed marked hepatocellular injury, coagulopathy, metabolic acidosis, mild pre-renal acute kidney injury, and elevated inflammatory markers. Imaging demonstrated hepatomegaly with ascites, without biliary obstruction or vascular abnormalities. Extensive evaluation excluded viral hepatitis, autoimmune liver disease, Wilson's disease, ischemic hepatitis, zoonotic infections, and other potential hepatotoxic exposures. Within the 15 days before symptom onset, the patient had completed a 7-day course of oral fosfomycin 500 mg every 8 hours for renal colic-associated dysuria, with no other medications linked to liver injury. Clinical deterioration with hypotension and oliguria required admission to the intensive care unit, where the patient improved with supportive management during a 4-day stay. Using the Roussel-Uclaf Causality Assessment Method (RUCAM), the score was 9, indicating a highly probable association between fosfomycin and the liver injury. Levels of liver enzymes gradually normalized, and the patient was discharged with full recovery.

CONCLUSION: Although fosfomycin is widely used and generally well tolerated, clinicians should remain vigilant for this rare but potentially serious adverse effect. Early recognition and prompt discontinuation of the suspected agent are essential. Reporting uncommon adverse reactions helps strengthen pharmacovigilance and supports safer therapeutic decision-making.