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.
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Authors | Kazuaki Matsumoto, Akari Shigemi, Ayumi Takeshita, Erika Watanabe, Yuta Yokoyama, Kazuro Ikawa, Norifumi Morikawa, Yasuo Takeda |
Journal | International journal of antimicrobial agents
(Int J Antimicrob Agents)
Vol. 44
Issue 3
Pg. 242-7
(Sep 2014)
ISSN: 1872-7913 [Electronic] Netherlands |
PMID | 25108880
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved. |
Chemical References |
- Acetamides
- Anti-Bacterial Agents
- Oxazolidinones
- Linezolid
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Topics |
- Acetamides
(administration & dosage, adverse effects, pharmacokinetics, pharmacology)
- Adult
- Aged
- Aged, 80 and over
- Anti-Bacterial Agents
(administration & dosage, adverse effects, pharmacokinetics, pharmacology)
- Area Under Curve
- Female
- Humans
- Linezolid
- Male
- Metabolic Clearance Rate
- Microbial Sensitivity Tests
- Middle Aged
- Models, Statistical
- Oxazolidinones
(administration & dosage, adverse effects, pharmacokinetics, pharmacology)
- Plasma
(chemistry)
- Thrombocytopenia
(chemically induced)
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