Therapeutic Drug Monitoring of Linezolid in Drug-Resistant Tuberculosis Patients: Clinical Factors and Hematological Toxicities

Purpose: Previous studies have indicated that the development of severe adverse events is associated with linezolid peak concentration (C max ), but the factors affecting linezolid C max and evidences on therapeutic drug monitoring to anticipate toxicity in drug-resistant tuberculosis (DR-TB) patients have not been clarified clearly. This study aimed to explore the factors influencing linezolid C max and investigate the association between linezolid concentration and hematological toxicity. Patients and Methods: This study included patients with drug-resistant tuberculosis treated with linezolid from January 2022 to September 2023. We analyzed the factors affecting linezolid C max using chi-squared and binary logistic regression. The diagnostic utility of linezolid C max in predicting hematological toxicity was evaluated using receiver operating characteristic (ROC) analysis. Results: A total of 76 patients were enrolled in the study. 63.20% met the standard rates for linezolid C max . Age (P=0.036), weight (P=0.0016), and creatinine clearance (P=0.0223) significantly correlated with the C max . Hematological toxicity was observed in 46.05% (35/76) of patients, characterized by thrombocytopenia (31.58%, 24/76), anemia (6.58%, 5/76), and leukopenia (21.05%, 16/76). ROC curve analysis confirmed the predictive value of linezolid C max for thrombocytopenia with an area under curve of 0.728. Conclusion: Suboptimal linezolid C max was prevalent among patients with DR-TB, with age, weight, and renal function emerging as influential factors. Elevated linezolid C max increases the risk of thrombocytopenia. Meticulous monitoring of linezolid C max is imperative during anti-DR-TB therapy to tailor treatment and mitigate hematological toxicity. Keywords: linezolid, therapeutic drug monitoring, influencing factors, hematological toxicity