Early linezolid-associated lactic acidosis in a patient with Child's class C liver cirrhosis and end stage renal disease.

Linezolid, an oxazolidinone antibiotic, does not required dose adjustment in patients with Child's class A and B liver cirrhosis. The dose adjustment data for Child's class C liver cirrhosis is inadequate. We reported a case of Child's class C liver cirrhosis, in which lactic acidosis, an adverse effect related to prolonged use, occurred only after two weeks of linezolid treatment. A 63-year old male had underlying diseases, such as end-stage renal disease (ESRD) and Child's class C liver cirrhosis, and was admitted for hepatic encephalopathy management and liver transplantation evaluation. Spontaneous bacterial peritonitis and septic shock occurred during admission. Because ascites culture revealed vancomycin-resistant Enterococci (VRE), daptomycin was initially prescribed. Subsequently, VRE bacteremia occurred, and infective endocarditis was confirmed. Following treatment failure with daptomycin use, intravenous linezolid (600 mg q12h) was added for synergic effect. VRE bacteremia quickly resolved following linezolid treatment, and vasopressor use was reduced. Despite stable hemodynamics, lactic acidosis still persisted, and linezolid therapeutic drug monitoring was ordered. High linezolid trough concentration (49 mg/L) was found by therapeutic drug monitoring, and linezolid-associated lactic acidosis was highly suspected. Therefore, linezolid treatment was stopped and patient's lactic acid level returned to normal after one week. VRE bacteremia recurred after discontinuation of linezolid; therefore, linezolid was re-prescribed at the lower dose (600 mg). Linezolid trough concentration was within the therapeutic range this time (6.1 mg/L), and lactic acidosis did not occur when linezolid dose was reduced. Therefore, empirically decreased dose and therapeutic drug monitoring should be considered in patients with Child's class C liver cirrhosis and ESRD.