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Determinants of gentamicin concentrations in critically ill patients: a population pharmacokinetic analysis. Int J Antimicrob Agents 2016; 49:204-211. [PMID: 28038961 DOI: 10.1016/j.ijantimicag.2016.10.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/20/2016] [Accepted: 10/30/2016] [Indexed: 11/23/2022]
Abstract
When treating critically ill patients with gentamicin for severe infection, peak concentrations (Cmax) determine clinical efficacy and trough concentrations (Cmin) determine toxicity. Despite administration of body weight-standardised starting doses, a wide range of Cmax is generally observed. Furthermore, in therapeutic drug monitoring, several measures of renal function are used to predict appropriate Cmin and gentamicin dosing intervals, but the most accurate predictor is not known. This study aimed to quantify the impact of several patient parameters on gentamicin Cmax values and to determine which measure of renal function best predicts gentamicin clearance (CL). Clinical data and serum gentamicin levels were retrospectively collected from all critically ill patients treated with gentamicin at our intensive care unit between 1 January and 30 June 2011. Data were analysed using non-linear mixed-effects modelling (NONMEM v.7.1.2). A two-compartmental model was developed based on 303 gentamicin concentration-time data from 44 critically ill patients. Serum albumin levels explained 25% of interindividual variability in the volume of distribution (Vd). Creatinine clearance calculated from the creatinine concentration in a 6-h urine portion (CalcCLCr) resulted in acceptable estimation of gentamicin CL, whilst serum creatinine (SCr) and creatinine clearance estimated by the Cockcroft-Gault formula (CGCLCr) overestimated gentamicin CL and therefore underestimated Cmin. In conclusion, low albumin concentrations resulted in a larger Vd and lower Cmax of gentamicin. These results suggest that use of a higher gentamicin starting dose in critically ill patients with hypoalbuminaemia may prevent underdosing. Urinary CalcCLCr is a better predictor of Cmin than SCr or CGCLCr.
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Allou N, Bouteau A, Allyn J, Snauwaert A, Valance D, Jabot J, Bouchet B, Galliot R, Corradi L, Montravers P, Augustin P. Impact of a high loading dose of amikacin in patients with severe sepsis or septic shock. Ann Intensive Care 2016; 6:106. [PMID: 27807818 PMCID: PMC5093100 DOI: 10.1186/s13613-016-0211-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Accepted: 10/24/2016] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The therapeutic effect of aminoglycosides is highest and optimal when the peak plasma concentration (C max)/minimal inhibitory concentration (MIC) ratio is between 8 and 10. The French guidelines recommend to use high doses of aminoglycosides for empiric antibiotic therapy in patients suffering from severe sepsis or septic shock. In clinical practice, the recommended target is an amikacin C max between 60 and 80 mg/L, which corresponds to approximately 8 times the MIC breakpoint, as defined by the European Committee on Antimicrobial Susceptibility Testing. The aim of this study was to assess the incidence and impact on mortality of an amikacin concentration between 60 and 80 mg/L in patients suffering from severe sepsis or septic shock. METHODS This was a prospective observational cohort study conducted in two intensive care units (ICU). Patients receiving amikacin at a loading dose of 30 mg/kg for severe sepsis or septic shock were enrolled in the cohort. The target C max for amikacin was between 60 and 80 mg/L, as recommended by French guidelines (i.e. C max/MIC breakpoint = 8-10). RESULTS Over the study period, the amikacin C max was <60 mg/L, between 60 and 80 mg/L, and >80 mg/L in 20 (18.2%), 46 (41.8%) and 44 (40%) of the 110 selected patients, respectively. Mortality rate was 40, 28.3 and 56.8% in the groups of patients with C max < 60 mg/L, 60 mg/L < C max < 80 mg/L and C max > 80 mg/L, respectively. Following multivariate analysis, mortality rate was significantly lower in the group of patients with amikacin C max between 60 and 80 mg/L than in the group of patients with amikacin C max > 80 mg/L (P = 0.004). The multivariate analysis also revealed that the factors independently associated with a higher in-ICU mortality rate were age (P = 0.02) and norepinephrine dose (P = 0.0001). CONCLUSIONS With a loading dose of 30 mg/kg of amikacin, concentration was potentially suboptimal (C max < 60 mg/L) in only 18.2% of patients. The pharmacodynamic target (60 mg/L < C max < 80 mg/L) recommended by French guidelines was reached in 41.8% of patients and was associated with reduced in-ICU mortality. But amikacin overexposure (i.e. C max > 80 mg/L) was frequent and potentially associated with increased mortality.
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Affiliation(s)
- Nicolas Allou
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Astrid Bouteau
- Département d’Anesthésie Réanimation, AP-HP, Centre Hospitalier Universitaire Bichat-Claude-Bernard, 46, rue Henri-Huchard, 75018 Paris, France
| | - Jérôme Allyn
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Aurélie Snauwaert
- Département d’Anesthésie Réanimation, AP-HP, Centre Hospitalier Universitaire Bichat-Claude-Bernard, 46, rue Henri-Huchard, 75018 Paris, France
| | - Dorothée Valance
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Julien Jabot
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Bruno Bouchet
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Richard Galliot
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Laure Corradi
- Réanimation polyvalente, Hôpital Felix Guyon, Centre Hospitalier Universitaire Felix Guyon, Allée des Topazes, Bellepierre, 97405 Saint Denis, France
| | - Philippe Montravers
- Département d’Anesthésie Réanimation, AP-HP, Centre Hospitalier Universitaire Bichat-Claude-Bernard, 46, rue Henri-Huchard, 75018 Paris, France
| | - Pascal Augustin
- Département d’Anesthésie Réanimation, AP-HP, Centre Hospitalier Universitaire Bichat-Claude-Bernard, 46, rue Henri-Huchard, 75018 Paris, France
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Influence of Renal Replacement Modalities on Amikacin Population Pharmacokinetics in Critically Ill Patients on Continuous Renal Replacement Therapy. Antimicrob Agents Chemother 2016; 60:4901-9. [PMID: 27270279 DOI: 10.1128/aac.00828-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 05/27/2016] [Indexed: 01/31/2023] Open
Abstract
The objective of this study was to describe amikacin pharmacokinetics (PK) in critically ill patients receiving equal doses (30 ml/kg of body weight/h) of continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodiafiltration (CVVHDF). Patients receiving amikacin and undergoing CVVH or CVVHDF were eligible. Population pharmacokinetic analysis and Monte Carlo simulation were undertaken using the Pmetrics software package for R. Sixteen patients (9 undergoing CVVH, 11 undergoing CVVHDF) and 20 sampling intervals were analyzed. A two-compartment linear model best described the data. Patient weight was the only covariate that was associated with drug clearance. The mean ± standard deviation parameter estimates were 25.2 ± 17.3 liters for the central volume, 0.89 ± 1.17 h(-1) for the rate constant for the drug distribution from the central to the peripheral compartment, 2.38 ± 6.60 h(-1) for the rate constant for the drug distribution from the peripheral to the central compartment, 4.45 ± 2.35 liters/h for hemodiafiltration clearance, and 4.69 ± 2.42 liters/h for hemofiltration clearance. Dosing simulations for amikacin supported the use of high dosing regimens (≥25 mg/kg) and extended intervals (36 to 48 h) for most patients when considering PK/pharmacodynamic (PD) targets of a maximum concentration in plasma (Cmax)/MIC ratio of ≥8 and a minimal concentration of ≤2.5 mg/liter at the end of the dosing interval. The mean clearance of amikacin was 1.8 ± 1.3 liters/h by CVVHDF and 1.3 ± 1 liters/h by CVVH. On the basis of simulations, a strategy of an extended-interval high loading dose of amikacin (25 mg/kg every 48 h) associated with therapeutic drug monitoring (TDM) should be the preferred approach for aminoglycoside treatment in critically ill patients receiving continuous renal replacement therapy (CRRT). (This study is a substudy of a trial registered at ClinicalTrials.gov under number NCT01403220.).
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Allou N, Charifou Y, Augustin P, Galas T, Valance D, Corradi L, Martinet O, Vandroux D, Allyn J. A study to evaluate the first dose of gentamicin needed to achieve a peak plasma concentration of 30 mg/l in patients hospitalized for severe sepsis. Eur J Clin Microbiol Infect Dis 2016; 35:1187-93. [DOI: 10.1007/s10096-016-2652-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/18/2016] [Indexed: 12/25/2022]
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