title: Pharmacokinetics of meropenem in critically ill patients with severe infections.
abstract: BACKGROUND
  Meropenem is an effective β-lactam antibiotic that is frequently used to treat serious infections in both intensive care unit (ICU) and febrile neutropenic hematology/oncology (Hem/Onc) patients. Studies suggest that to be effective, meropenem concentrations must be maintained above the inhibitory concentrations for the majority of a dosing interval. However, the pharmacokinetics (PK) of meropenem seem to differ in critically ill patients compared with healthy or less ill subjects used to select labeled dosing regimens.
  
  
  OBJECTIVE
  This study was designed to investigate meropenem PK in critically ill patients and to see how often standard dosing regimens produced adequate plasma concentrations. A secondary objective was to investigate how achieved concentrations were related to outcomes (morbidity and mortality) in these patients.
  
  
  METHODS
  Meropenem plasma concentrations over time were measured using a high pressure liquid chromatography assay in febrile Hem/Onc and ICU patients who were treated with standard meropenem dosing schedules. Outcomes such as fever control and survival were assessed in these patients and compared with individual meropenem PK data and with recommended target concentrations.
  
  
  RESULTS
  A total of 25 subjects including 10 febrile Hem/Onc and 15 ICU patients with a variety of serious illnesses and baseline renal function were studied. Mean peak concentrations were less variable than were pre-dose concentrations. Post peak and trough concentrations were often below recommended minimum inhibitory concentrations. Both clearance and volumes of distribution were greater than reported in less ill subjects, only in part explained by increased renal clearance. Therefore, serum concentrations often did not exceed recommended concentration targets even for moderately sensitive organisms. Inadequate concentrations were especially common in the mostly ill, febrile neutropenic Hem/Onc subjects and seemed to explain at least some therapeutic failures. Conversely, drug accumulation occurred in ICU subjects with decreased renal function.
  
  
  CONCLUSIONS
  Standard meropenem dosing regimens were inadequate in many critically ill febrile, neutropenic Hem/Onc, and septic ICU patients. These data suggest a role for meropenem concentration monitoring in such patients.
authors: Department of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany.
authors: Lutz
authors: L
authors: Binder
authors: Harald
authors: H
authors: Schwörer
authors: Sebastian
authors: S
authors: Hoppe
authors: Frank
authors: F
authors: Streit
authors: Silke
authors: S
authors: Neumann
authors: Annett
authors: A
authors: Beckmann
authors: Rolf
authors: R
authors: Wachter
authors: Michael
authors: M
authors: Oellerich
authors: Philip D
authors: PD
authors: Walson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000097:blood* / Q000493:pharmacokinetics* / Q000627:therapeutic use; D016638:Critical Illness; D005260:Female; D006801:Humans; D007239:Infections / Q000097:blood / Q000188:drug therapy* / Q000378:metabolism*; D007362:Intensive Care Units; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D013845:Thienamycins / Q000097:blood* / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D013845:Thienamycins; D000077731:Meropenem