Predictive Factors of Piperacillin Exposure and the Impact on Target Attainment after Continuous Infusion Administration to Critically Ill Patients.

Critically ill patients undergo significant pathophysiological changes that affect antibiotic pharmacokinetics. Piperacillin/tazobactam administered by continuous infusion (CI) improves pharmacokinetic/pharmacodynamic (PK/PD) target attainment. This study aimed to characterize piperacillin PK after CI administration of piperacillin/tazobactam in critically ill adult patients with preserved renal function and to determine the empirical optimal dosing regimen. A total of 218 piperacillin concentrations from 106 patients were simultaneously analyzed through the population PK approach. A two-compartment linear model best described the data. Creatinine clearance (CLCR) estimated by CKD-EPI was the covariate, the most predictive factor of piperacillin clearance (CL) interindividual variability. The mean (relative standard error) parameter estimates for the final model were: CL: 12.0 L/h (6.03%); central and peripheral compartment distribution volumes: 20.7 L (8.94%) and 62.4 L (50.80%), respectively; intercompartmental clearance: 4.8 L/h (26.4%). For the PK/PD target of 100% fT>1×MIC, 12 g of piperacillin provide a probability of target attainment > 90% for MIC < 16 mg/L, regardless of CLCR, but higher doses are needed for MIC = 16 mg/L when CLCR > 100 mL/min. For 100% fT>4×MIC, the highest dose (24 g/24 h) was not sufficient to ensure adequate exposure, except for MICs of 1 and 4 mg/L. Our model can be used as a support tool for initial dose guidance and during therapeutic drug monitoring.

Continuous Infusion of Piperacillin/Tazobactam and Meropenem in ICU Patients Without Renal Dysfunction: Are Patients at Risk of Underexposure?

BACKGROUND AND OBJECTIVES: Morbidity and mortality from serious infections are common in intensive care units (ICUs). The appropriateness of the antibiotic treatment is essential to combat sepsis. We aimed to evaluate pharmacokinetic/pharmacodynamic target attainment of meropenem and piperacillin/tazobactam administered at standard total daily dose as continuous infusion in critically ill patients without renal dysfunction and to identify risk factors of non-pharmacokinetic/pharmacodynamic target attainment. RESULTS: We included 118 patients (149 concentrations), 47% had microorganism isolation. Minimum inhibitory concentration (MIC) [median (interquartile range, IQR) values in isolated pathogens were: meropenem: 0.05 (0.02-0.12) mg/l; piperacillin: 3 (1-4) mg/l]. Pharmacokinetic/pharmacodynamic target attainments (100%fCss≥1xMIC, 100%fCss≥4xMIC and 100%fCss ≥ 8xMIC, respectively) were: 100%, 96.15%, 96.15% (meropenem) and 95.56%, 91.11%, 62.22% (piperacillin) for actual MIC; 98.11%, 71.70%, 47.17% (meropenem, MIC 2 mg/l), 95.83%, 44.79%, 6.25% (piperacillin, MIC 8 mg/l), 83.33%, 6.25%, 1.04% (piperacillin, MIC 16 mg/l) for EUCAST breakpoint of Enterobacteriaceae spp. and Pseudomonas spp. Multivariable linear analysis identified creatinine clearance (CrCL) as a predictive factor of free antibiotic concentrations (fCss) of both therapies (meropenem [ß = - 0.01 (95% CI - 0.02 to - 0.0; p = 0.043)] and piperacillin [ß = - 0.01 (95% CI - 0.02 to 0.01, p < 0.001)]). Neurocritical status was associated with lower piperacillin fCss [ß = - 0.36 (95% CI - 0.61 to - 0.11; p = 0.005)]. CONCLUSION: Standard total daily dose of meropenem allowed achieving pharmacokinetic/pharmacodynamic target attainments in ICU patients without renal dysfunction. Higher doses of piperacillin/tazobactam would be needed to cover microorganisms with MIC > 8 mg/l. CrCL was the most powerful factor predictive of fCss in both therapies.

Bayes-based dosing of infliximab in inflammatory bowel diseases: Short-term efficacy.

AIMS: Therapeutic drug monitoring of infliximab can guide clinical decisions in patients with loss of response and in those who can benefit from a de-intensification. The aim of this study was to determine the impact of therapeutic drug monitoring combined with Bayesian forecasting methodology on clinical response in a real-world dataset of patients suffering from inflammatory bowel disease. METHODS: We performed a single-centre prospective study with one-group pre-test/post-test design in 108 adult inflammatory bowel disease patients treated with model-based dosing of infliximab maintenance treatment. We recorded clinical activity scores (Harvey-Bradshaw index and partial Mayo) and inflammatory biomarkers per patient. RESULTS: The initial infliximab regimen was maintained in 49 (45.4%) patients and was adjusted in 59 (54.6%) patients (34 treatment intensifications, 9 de-intensifications and 16 treatment discontinuations or therapy replacements). The median time from intervention to index measurement was 126 (103-160) days. The overall proportion of patients in clinical remission increased from 65.7% to 80.4% (P < .0001) and the median infliximab trough concentrations increased from 3.21 (0.99-5.45) to 5.13 mg/L (3.57-6.53) (P < .0001). In the intensified group, the remission rate increased from 35.3% to 61.8% (P = .001) and the percentage of patients in clinical remission or with mild symptoms increased from 76.5% to 94.1%. In the de-intensification cohort, no patients experienced an increase in the Harvey-Bradshaw index or partial Mayo scores, and all patients maintained an infliximab trough concentration of >5 mg/L. CONCLUSION: In our cohort of inflammatory bowel disease patients, Bayes-based optimized dosing improved the short-term efficacy of infliximab treatment.

OTAC: Optimización de la Terapia Antibiótica en el paciente Crítico. Antibióticos betalactámicos en perfusión continua / OTAC: Optimization of Antibiotic Therapy in Critically ill Patients. Using beta-lactam antibiotics by continuous infusion

Objetivo: Determinar el porcentaje de pacientes, a los que se les administró dosis estándar de piperacilina/tazobactam o meropenem en perfusión continua, que alcanzaban el índice farmacocinético/farmacodinámico diana definido como el 100% del intervalo de administración en que las concentraciones de antibiótico libre fueron cuatro veces iguales o superiores a la concentración mínima inhibitoria (100% fT ≥ 4 x CMI). Método: Datos preliminares obtenidos de un estudio clínico prospectivo que analiza el comportamiento farmacocinético/farmacodinámico de los antibióticos betalactámicos administrados en perfusión continua en pacientes críticos. Se realizó en unidades de cuidados intensivos de un hospital universitario de tercer nivel, desde junio de 2015 a mayo de 2017. Criterios de inclusión: adultos con función renal correcta (filtrado glomerular según la fórmula CKD-EPI ≥ 60 ml/min/1,73 m2) y tratados con dosis estándar de antibióticos betalactámicos en perfusión continua. Las concentraciones en estado de equilibrio estacionario fueron determinadas mediante cromatografía líquida acoplada a espectrometría de masas (UHPLC-MS/MS). Se utilizaron valores de concentración mínima inhibitoria teóricos para microorganismos más resistentes (piperacilina/ tazobactam: 16 mg/l para Pseudomonas aeruginosa y 8 mg/l para Enterobacteriaceae; meropenem: 2 mg/l, independientemente del microorganismo). Además, se realizó un subanálisis de los pacientes con aislamiento microbiológico (concentraciones mínimas inhibitorias reales). Resultados: Se incluyeron 61 pacientes (25 meropenem y 36 piperacilina/tazobactam). Edad media 59 años (15), mediana de filtrado glomerular 95 ml/min/1,73 m2 (83-115). Mediana de concentraciones en estado de equilibrio estacionario libre: 16 mg/l (11-29) meropenem y 40 mg/l (2151) piperacilina. El 88% de los pacientes tratados con meropenem alcanzaron el objetivo farmacocinético/farmacodinámico, sin diferencias entre Enterobacteriaceae y Pseudomonas. En el caso de piperacilina/tazobactam, el 61% y el 11% de los pacientes alcanzaron la diana, considerando Enterobacteriaceae y Pseudomonas como microorganismo sospechoso. Un total de 35 (57%) pacientes presentaron aislamiento microbiológico. El 94% de ellos alcanzaron la diana, sin diferencias entre los dos antibióticos. Conclusiones: Ante la sospecha de infecciones por microorganismos con concentraciones mínimas inhibitorias elevadas (Pseudomonas aeruginosa o enterobacterias), se observa que dosis convencionales de meropenem en perfusión continua son suficientes para lograr la diana 100% fT≥ 4 x MIC. Sin embargo, se requerirían dosis superiores de piperacilina/tazobactam. En casos de aislamiento microbiológico, dosis estándar de ambos antibióticos fueron suficientes para lograr la diana. La monitorización farmacocinética es altamente recomendable para la optimización terapéutica

Objective: To determine the percentage of patients given standard doses of piperacillin/tazobactam or meropenem by continuous infusion who achieved the target pharmacokinetic/pharmacodynamic index, which was defined as free concentrations four times more than the minimum inhibitory concentration (MIC) for 100% of the dosing interval (100% fT≥ 4 x MIC). Method: Preliminary data from a larger prospective clinical study analysing the pharmacokinetic/pharmacodynamic behaviour of ß-lactams antibiotics Continuous infusion (CI) in critical patients. The study was conducted in the intensive care units of a tertiary university hospital for adults (June 2015-May 2017). Inclusion criteria: normal renal function (glomerular renal function (GFR) CKD-EPI formula ≥ 60 mL/min/1.73 m2) and treatment with standard dose ß-lactams CI. Concentrations at steady state (Css) conditions were determined using UHPLC-MS/MS. We selected the highest susceptible MIC for all likely organisms according to European Commitee on Antimicrobial Susceptibility Testing's (i.e. piperacillin/tazobactam: 8 mg/L for enterobacteriaceae and 16 mg/L for Pseudomonas aeruginosa; meropenem: 2 mg/L for any microorganism). In addition, a subanalysis of patients was conducted using actual MIC values. Results: 61 patients were enrolled (25 to meropenem and 36 to piperacillin/tazobactam). Average age was 59 (15) years and median GFR rate was 95 mL/min/1.73 m2 (83-115). Median meropenem and piperacillin free concentrations were 16 mg/L (11-29) and 40 mg/L (21-51), respectively. 88% of patients treated with meropenem reached the PK/PD target, without differences between both microorganisms. For piperacillin/tazobactam, 61% and 11% of patients reached the target, with enterobacteriaceae and Pseudomonas as suspected microorganisms, respectively. The pathogen was isolated in 35 (57%) patients: 94% reached the target PK/ PD, without differences between both antibiotic therapies. Conclusions: Standard doses of meropenem CI are sufficient to achieve a PK/PD target of 100% fT≥ 4 x MIC in suspected infections with high MICs (Pseudomonas aeruginosa or enterobacteriaceae). However, higher doses of piperacillin/tazobactam could be considered to achieve this goal. In patients with isolated microorganisms, a standard dose of both antibiotic therapies would be sufficient to achieve the target. Therapeutic drug monitoring is highly recommended for therapeutic optimization

OTAC: Optimization of Antibiotic Therapy in Critically ill Patients. Using beta-lactam antibiotics by continuous infusion.

OBJECTIVE: To determine the percentage of patients given standard doses of piperacillin/tazobactam or meropenem by continuous  infusion who achieved the target pharmacokinetic/pharmacodynamic  (PK/PD) index, which was defined as free concentrations four times  more than the minimum inhibitory concentration (CMI) for 100% of the  dosing interval (100% fT≥ 4 x MIC). METHOD: Preliminary data from a larger prospective clinical study  analysing the PK/PD behaviour of ß-lactams antibiotics continuous  infusion (CI) in critical patients. The study was conducted in the  intensive care units of a tertiary university hospital for adults (June  2015-May 2017). Inclusion criteria: normal renal function (glomerular  renal function (GFR) CKD-EPI formula ≥ 60 mL/min/1.73 m2) and  treatment with standard dose ß-lactams CI. Concentrations at steady  state (Css) conditions were determined using UHPLC-MS/MS. We  selected the highest susceptible MIC for all likely organisms according to  European Commitee on Antimicrobial Susceptibility Testing's (i.e.  piperacillin/tazobactam: 8 mg/L for enterobacteriaceae and 16 mg/L for  Pseudomonas aeruginosa; meropenem: 2 mg/L for any  microorganism). In addition, a subanalysis of patients was conducted using actual MIC values. RESULTS: 61 patients were enrolled (25 to meropenem and 36 to  piperacillin/tazobactam). Average age was 59 (15) years and median  GFR rate was 95 mL/min/1.73 m2 (83-115). Median meropenem and  piperacillin free concentrations were 16 mg/L (11-29) and 40 mg/L (21- 51), respectively. 88% of patients treated with meropenem reached the  PK/PD target, without differences between both microorganisms. For  piperacillin/tazobactam, 61% and 11% of patients reached the target,  with enterobacteriaceae and Pseudomonas as suspected  microorganisms, respectively. The pathogen was isolated in 35 (57%)  patients: 94% reached the target PK/PD, without differences between  both antibiotic therapies. CONCLUSIONS: Standard doses of meropenem CI are sufficient to  achieve a PK/PD target of 100% fT≥ 4 x MIC in suspected infections  with high MICs (Pseudomonas aeruginosa or enterobacteriaceae).  However, higher doses of piperacillin/tazobactam could be considered to  achieve this goal. In patients with isolated microorganisms, a  standard dose of both antibiotic therapies would be sufficient to achieve  the target. Therapeutic drug monitoring is highly recommended for  therapeutic optimization.

Objetivo: Determinar el porcentaje de pacientes, a los que se les  administró dosis estándar de piperacilina/tazobactam o meropenem en  perfusión continua, que alcanzaban el índice  farmacocinético/farmacodinámico diana definido como el 100% del  intervalo de administración en que las concentraciones de antibiótico  libre fueron cuatro veces iguales o superiores a la concentración mínima  inhibitoria (100% fT ≥ 4 x CMI).Método: Datos preliminares obtenidos de un estudio clínico prospectivo que analiza el comportamiento  farmacocinético/farmacodinámico de los antibióticos betalactámicos  administrados en perfusión continua en pacientes críticos. Se realizó en  unidades de cuidados intensivos de un hospital universitario de tercer  nivel, desde junio de 2015 a mayo de 2017. Criterios de inclusión:  adultos con función renal correcta (filtrado glomerular según la fórmula  CKD-EPI ≥ 60 ml/min/1,73 m2) y tratados con dosis estándar de  antibióticos betalactámicos en perfusión continua. Las concentraciones  en estado de equilibrio estacionario fueron determinadas mediante  cromatografía líquida acoplada a espectrometría de masas (UHPLC- MS/MS). Se utilizaron valores de concentración mínima  inhibitoria  teóricos para microorganismos más resistentes (piperacilina/ tazobactam: 16 mg/l para Pseudomonas aeruginosa y 8 mg/l para Enterobacteriaceae; meropenem: 2 mg/l, independientemente del  microorganismo). Además, se realizó un subanálisis de los pacientes con aislamiento microbiológico (concentraciones mínimas inhibitorias  reales).Resultados: Se incluyeron 61 pacientes (25 meropenem y 36  piperacilina/ tazobactam). Edad media 59 años (15), mediana de  filtrado glomerular 95 ml/min/1,73 m2 (83-115). Mediana de  concentraciones en estado de equilibrio estacionario libre: 16 mg/l (11- 29) meropenem y 40 mg/l (21-51) piperacilina. El 88% de los pacientes  tratados con meropenem alcanzaron el objetivo  farmacocinético/farmacodinámico, sin diferencias entre Enterobacteriaceae y Pseudomonas. En el caso de  piperacilina/tazobactam, el 61% y el 11% de los pacientes alcanzaron la  diana, considerando Enterobacteriaceae y Pseudomonas como  microorganismo sospechoso. Un total de 35 (57%) pacientes  presentaron aislamiento microbiológico. El 94% de ellos alcanzaron la  diana, sin diferencias entre los dos antibióticos.Conclusiones: Ante la sospecha de infecciones por microorganismos con concentraciones mínimas inhibitorias elevadas  (Pseudomonas aeruginosa o enterobacterias), se observa que dosis  convencionales de meropenem en perfusión continua son suficientes  para lograr la diana 100% fT≥ 4 x MIC. Sin embargo, se requerirían  dosis superiores de piperacilina/tazobactam. En casos de aislamiento  microbiológico, dosis estándar de ambos antibióticos fueron suficientes  para lograr la diana. La monitorización farmacocinética es altamente  recomendable para la optimización terapéutica.

Contribution of infliximab population pharmacokinetic model for dose ptimization in ulcerative colitis patients

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Individualización de la terapia con infliximab: monitorización farmacocinética / Individualized infliximab therapy: pharmacokinetic monitoring

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¿Existe dificultad para mantener los objetivos de hemoglobina en pacientes prediálisis tratados con agentes estimulantes de la eritropoyesis? / Is there a difficulty in maintaining haemoglobin target levels in pre-dialysis patients treated with erythropoiesis-stimulating agents?

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