Background Linezolid is an oxazolidinone antibiotic used in the treatment of Gram‐positive bacterial infections. However, its prolonged use is often limited by adverse effects, including thrombocytopenia. Therapeutic drug monitoring (TDM) has been proposed to individualize linezolid dosing to mitigate such adverse effects. This study presents a case of linezolid‐induced thrombocytopenia successfully managed with TDM and dose individualization in a patient receiving linezolid as chronic suppressive therapy for cardiac implantable electronic device (CIED) infection. Methods A 92‐year‐old female with a history of recurrent Corynebacterium striatum bacteremia and complex cardiovascular conditions who completed a six‐week course of intravenous therapy and were placed on chronic suppressive therapy with oral linezolid. Given the risk of thrombocytopenia, TDM was utilized to guide linezolid dosing. Platelet counts and linezolid trough levels were regularly monitored, and dose adjustments were made accordingly. Results Upon initiation of linezolid (600 mg daily), the patient’s baseline platelet count was 150 × 10 9 /L. On day 19, platelet counts declined to 73 × 10 9 /L. Linezolid was temporarily withheld, and TDM revealed a supratherapeutic trough level of 10.26 mcg/mL. The dosage was adjusted to 300 mg once daily, leading to the stabilization of platelet counts at 140 × 10 9 /L. Subsequent monitoring showed a trough level within the target range (7.62 mcg/mL) with no further episodes of thrombocytopenia or additional adverse effects out to day 172. Conclusion This case highlights the utility of TDM in managing linezolid‐induced thrombocytopenia, particularly in patients requiring prolonged therapy. TDM enabled precise dose adjustments, ensuring therapeutic efficacy while minimizing toxicity. The findings support the broader implementation of TDM in linezolid therapy to enhance patient safety and treatment outcomes, particularly in long‐term therapy or deep‐seated infections.
Concannon et al. (Thu,) studied this question.