Daptomycin-Induced Severe Hyperkalemia With Normal Creatine Kinase in a Patient With Methicillin-Resistant Staphylococcus aureus Osteomyelitis

We report a case of an asymptomatic 60-year-old female who presented to the emergency department due to a home health measured serum potassium of 7.7 mmol/L (normal range: 3.6-5.0 mmol/L) and was admitted for severe hyperkalemia. She was recently started on a low dose of daily intravenous daptomycin to treat methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis of her sacral decubitus ulcers. Laboratory results showed normal creatine kinase (CK). Her elevated serum potassium levels reversed throughout her hospital stay and remained within normal range after daptomycin discontinuation, establishing a temporal relationship between daptomycin and hyperkalemia. To our knowledge, no other cases report daptomycin-induced severe hyperkalemia in the absence of rhabdomyolysis. Our case emphasizes the importance of considering hyperkalemia as an adverse effect of daptomycin, especially in elderly hospitalized patients.