Acute Cardiotoxicity Induced by 5-Fluorouracil Successfully Treated With Levosimendan: A Case Report.

Cardiotoxicity is a rare but potentially life-threatening complication of 5-fluorouracil (5-FU), commonly presenting as chest pain or acute heart failure. We present the case of a 48-year-old woman with colon cancer who developed acute decompensated heart failure within 48 hours of completing her first cycle of FOLFOX chemotherapy (5-FU, oxaliplatin, and leucovorin). Echocardiography revealed a left ventricular ejection fraction (LVEF) of 28% and markedly elevated pro-B-type natriuretic peptide levels (>14,700 pg/mL), confirming severe cardiac dysfunction. The patient was admitted to the intensive care unit and received continuous levosimendan infusion at 0.1 µg/kg/minute for 24 hours, along with norepinephrine support. This treatment resulted in significant clinical improvement, normalization of cardiac biomarkers, as documented by serial laboratory tests, and full recovery of renal and cardiac function. Follow-up echocardiography showed improvement in LVEF to 50%. Other differential diagnoses, such as ischemic heart disease, sepsis, and myocarditis, were ruled out through clinical, laboratory, and imaging findings. Although causality cannot be definitively established, this case highlights the potential utility of levosimendan in chemotherapy-related cardiotoxicity, particularly in patients requiring inotropic support. Only limited case-based literature exists regarding its use in this context. The patient remained clinically stable and asymptomatic during four weeks of outpatient follow-up. Further clinical studies are warranted to establish evidence-based recommendations.