title: Gentamicin in hemodialyzed critical care patients: early dialysis after administration of a high dose should be considered.
abstract: Gentamicin is a widely used antibiotic in the intensive care unit (ICU). Its dosage is difficult to adapt to hemodialyzed ICU patients. The FDA-approved regimen consists of the administration of 1 to 1.7 mg/kg of gentamicin at the end of each dialysis session. Better pharmacokinetic management could be obtained if gentamicin were administered just before the dialysis session. We performed Monte Carlo simulations (MCS) to determine the best gentamicin pharmacokinetic profile (high peak and low trough concentrations). Then, 6 mg/kg of gentamicin was infused into 10 ICU patients over a period of 30 min. A 4-h-long hemodialysis session was started 30 min after the end of the infusion. Pharmacokinetic samples were regularly collected over 24 h. A one-compartment model with zero-order input and first-order elimination was developed in Nonmem version VI to analyze patients' measured gentamicin concentration-versus-time profiles. Finally, additional MCS were performed to compare the regimen chosen with the FDA-approved gentamicin regimen. High peak concentrations (C(max), 31.8 ± 16.8 mg/liter) were achieved. The estimated C(24) and C(48) values (concentrations 24 and 48 h, respectively, after the beginning of the infusion) were 4.1 ± 2.3 and 1.8 ± 1.2 mg/liter, respectively. The volume of distribution was 0.21 ± 0.06 liter/kg. MCS confirmed that the dosing regimen chosen achieved the target C(max) whereas the FDA-approved regimen did not (31.0 ± 10.9 versus 8.8 ± 3.1 mg · liter(-1)). Moreover, the C(24) values were similar while the AUC(0-24) values were moderately increased (190.8 ± 65.0 versus 135 ± 42.2 mg · h · liter(-1)). Therefore, administration of 6 mg/kg of gentamicin before hemodialysis to critically ill patients achieves a high C(max) and an acceptable AUC, maximizing pharmacokinetic/pharmacodynamic endpoints.
authors.affiliation: Medical Intensive Care Unit, University Hospital of Poitiers, Poitiers, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Veinstein
authors.forename: Nicolas
authors.initials: N
authors.lastname: Venisse
authors.forename: Julie
authors.initials: J
authors.lastname: Badin
authors.forename: Michel
authors.initials: M
authors.lastname: Pinsard
authors.forename: René
authors.initials: R
authors.lastname: Robert
authors.forename: Antoine
authors.initials: A
authors.lastname: Dupuis
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D015992:Body Mass Index; D001835:Body Weight; D003422:Critical Care; D016638:Critical Illness; D004334:Drug Administration Schedule; D054796:Drug Dosage Calculations; D005839:Gentamicins / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use; D006439:Hemodynamics; D006801:Humans; D009010:Monte Carlo Method; D006435:Renal Dialysis
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins