Case Report: Persistent Elevation in Creatine Phosphokinase Associated with High-Dose Daptomycin Therapy

Abstract

Objective To report a persistent elevation in creatine phosphokinase (CPK) associated with high-dose daptomycin therapy that did not resolve following discontinuation of daptomycin. Summary A 34-year-old male with HIV/AIDS and stage IV Burkitt lymphoma was admitted for pain management. The patient's initial hospital course was complicated by left brachial deep vein thrombosis (DVT), Clostridium difficile colitis, and pancytopenia. The patient later developed severe sepsis and septic shock secondary to methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), Candida albicans, and Escherichia coli infection. High-dose daptomycin (12 mg/kg) was initiated to treat MRSA and VRE bacteremia. The patient's baseline CPK was 118 U/L, which increased to 327 U/L following 2 days of therapy. The patient's CPK continued to increase to 1648 U/L on day 10 of daptomycin, thereby necessitating a discontinuation of daptomycin and the initiation of linezolid. Six days after discontinuation of therapy, the patient's CPK remained elevated at 1940 U/L. Discussion A Naranjo scale score of 6 was calculated, indicating that daptomycin was the probable cause for the increase in CPK. Although daptomycin is known to cause elevations in CPK, there are limited published data describing this adverse event with high-dose daptomycin therapy. Conclusion High-dose daptomycin is becoming more frequently used in clinical practice, so clinicians should monitor for and report any adverse events associated with this dosing strategy.