Analysis of thrombocytopenic effects and population pharmacokinetics of linezolid: a dosage strategy according to the trough concentration target and renal function in adult patients

Kazuaki Matsumoto, Akari Shigemi, Ayumi Takeshita, Erika Watanabe, Yuta Yokoyama, Kazuro Ikawa, Norifumi Morikawa, Yasuo Takeda

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The pharmacokinetic/pharmacodynamic (PK/PD) index for the efficacy of linezolid is a 24-h area under the plasma drug concentration-time curve (AUC₂₄)/minimum inhibitory concentration (MIC) ratio of ≥100. The main adverse event associated with administration of linezolid is thrombocytopenia. Therefore, the aims of the present study were to define PD thresholds that would minimise linezolid-induced thrombocytopenia and to perform a population PK analysis to identify factors influencing the pharmacokinetics of linezolid. Population PK analysis revealed that creatinine clearance (CLCr) significantly affected linezolid pharmacokinetics: the mean parameter estimate of drug clearance (CL; in L/h)=0.0258 × CLCr + 2.03. A strong correlation (r=0.970) was found between AUC₂₄ and trough plasma concentrations (Cmin) [AUC₂₄=18.2 × Cmin + 134.4]. The Cmin value for AUC₂₄=200 (in the case of MIC=2 μg/mL) was estimated to be 3.6 μg/mL. Regarding safety, Cmin was a significant predictor of thrombocytopenia during treatment, and its threshold to minimise linezolid-induced thrombocytopenia was 8.2 μg/mL. A Kaplan-Meier plot revealed that the median time from initiation of therapy to the development of thrombocytopenia was 15 days. Therefore, the target Cmin range was 3.6-8.2 μg/mL. The following formula to achieve a target Cmin in patients with different degrees of renal function was proposed based on these results: initial daily dose (mg/day)=CL × AUC₂₄=(0.0258 × CLCr + 2.03)×(18.2 × Cmin + 134.4). This recommended initial dosage and subsequent dosage adjustment for the target concentration range should avoid adverse events, thereby enabling effective linezolid-based therapies to be continued.

Original languageEnglish
Pages (from-to)242-247
Number of pages6
JournalInternational Journal of Antimicrobial Agents
Volume44
Issue number3
DOIs
Publication statusPublished - 2014 Sep 1
Externally publishedYes

Keywords

  • Linezolid
  • Population pharmacokinetics
  • Therapeutic drug monitoring
  • Thrombocytopenia

ASJC Scopus subject areas

  • Microbiology (medical)
  • Pharmacology (medical)
  • Infectious Diseases

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