Severe Transaminitis Without Rhabdomyolysis: An Unusual Presentation of Daptomycin-Induced Liver Injury.

Daptomycin is a lipopeptide antibiotic commonly used for methicillin-resistant Staphylococcus aureus infections. Abnormal liver function tests occur in approximately 3% of patients receiving daptomycin; severe isolated transaminitis is exceptionally rare. We report a 43-year-old man with methicillin-resistant Staphylococcus aureus bacteremia and multiple abscesses who developed marked transaminitis with aspartate aminotransferase and alanine aminotransferase levels peaking at 1,965 U/L and 2,253 U/L, respectively, within 6 days of initiating daptomycin therapy (8 mg/kg daily). Notably, the patient had no evidence of rhabdomyolysis, hyperbilirubinemia, or acute kidney injury. After excluding alternative etiologies and discontinuing daptomycin on hospital day 10, liver enzymes normalized within 13 days without additional intervention. This case highlights the importance of monitoring hepatic function in patients receiving daptomycin and recognizing isolated hepatotoxicity as a rare but significant adverse effect.