Reversible Severe Cardiomyopathy Associated With Supratherapeutic Vancomycin Levels: A Case Report.

Vancomycin is a widely used glycopeptide antibiotic, and while nephrotoxicity and infusion-related reactions are well-established adverse effects, direct reversible cardiomyopathy associated with extreme vancomycin levels has not been previously reported in humans. We describe a 59-year-old woman treated for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia who developed acute heart failure, hypotension, and severe left ventricular systolic dysfunction (ejection fraction 27%) while her vancomycin level exceeded 80 mg/L. Multiple left ventricular thrombi were also identified, likely representing a secondary complication of profound systolic dysfunction, with a possible contributory prothrombotic effect of supratherapeutic vancomycin levels. Extensive evaluation excluded ischemic, infectious, autoimmune, and other drug-induced causes of cardiomyopathy. As serial hemodialysis sessions gradually removed vancomycin, cardiac function improved, with the ejection fraction increasing to 44%. The temporal relationship, laboratory findings, and Naranjo scoring support a probable causal association between supratherapeutic vancomycin exposure and reversible cardiomyopathy. This case highlights a potentially underrecognized adverse effect. It emphasizes the importance of therapeutic drug monitoring and cardiac assessment when vancomycin levels become markedly elevated, especially in patients with impaired renal clearance.