Pharmacokinetics and Monte Carlo Simulations of Doripenem in Patients with Febrile Neutropenia

2012 ◽  
Vol 46 (10) ◽  
pp. 1281-1286 ◽  
Author(s):  
Gary E Stein ◽  
Grace Kulhanek ◽  
Curtis L Smith ◽  
Joseph L Kuti ◽  
David P Nicolau ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Febrile Neutropenia ◽  
Drug Exposure ◽  
Elimination Rate ◽  
Pharmacokinetic Parameters ◽  
Gram Negative Bacteria ◽  
Time Curve ◽  
Gram Negative ◽  
Probability Estimates ◽  
Drug Concentrations

Background: Doripenem is a group 2 carbapenem with enhanced in vitro activity against gram-negative bacteria including Pseudomonas aeruginosa. There is a paucity of pharmacokinetic/pharmacodynamic data on doripenem in patients with febrile neutropenia. Objective: To conduct a pharmacokinetic evaluation of 2 doses of doripenem in patients with febrile neutropenia and provide probability estimates of attaining effective drug exposure against common gram-negative pathogens. Methods: We obtained multiple blood samples from 12 adults with febrile neutropenia who were receiving either 500 mg or 1000 mg of intravenous doripenem over 4 hours every B hours. Following at least 2 doses, serum concentrations were measured in each subject at 1, 4, 6, and 8 hours after initiation of a dose by a validated high-performance liquid chromatography assay. The derived pharmacokinetic parameters from these serum levels were used to perform a 5000-patient Monte Carlo simulation against bacteria with minimal inhibitory concentrations (MICs) of 0.008-64 mg/L to determine probability estimates of the time in which unbound drug concentrations remain above the MIC (fT>MIC). Results: The mean pharmacokinetic parameters in these patients were a volume of distribution of 43.9 L, an elimination rate constant of 0.37 h-1, a total clearance of 14.4 L/h, and an area under the concentration-time curve of 57.6 mg·h/L. An optimal probability of target attainment (40% fT>MIC) of 90% was obtained against bacteria with MICs ≤2 mg/L and ≤4 mg/L with 500-mg and 1000-mg doses, respectively. Adverse events associated with doripenem were not observed. Conclusions: The findings from this analysis of doripenem suggest that higher doses, as well as prolonged infusions, may be necessary to optimally treat selected gram-negative bacteria (eg, P. aeruginosa) in patients with febrile neutropenia.

scholarly journals The postantibiotic effect of imipenem: relationship with drug concentration, duration of exposure, and MIC.

1997 ◽  
Vol 41 (8) ◽  
pp. 1735-1737 ◽  
Author(s):  
W J Munckhof ◽  
D Olden ◽  
J D Turnidge
Keyword(s):  
Escherichia Coli ◽  
Drug Concentration ◽  
Drug Exposure ◽  
Gram Negative Bacteria ◽  
Postantibiotic Effect ◽  
Gram Positive ◽  
Time Curve ◽  
Gram Negative ◽  
Concentration Time ◽  
Drug Concentrations

The postantibiotic effect (PAE) of imipenem against Escherichia coli was measured at a wide variety of drug concentrations and times of exposure. We observed that the area under the concentration-time curve of drug exposure (AUC), the product of time of exposure and concentration of drug, is a much better predictor of the duration of the PAE than either parameter alone. We also measured the PAE of imipenem against strains of gram-positive and gram-negative bacteria for which MICs varied widely. The E50, the AUC required to produce 50% of the maximum PAE, is correlated with the MIC and is independent of species. This may explain why the duration of the PAE differs for bacteria of the same species for which MICs are different.

scholarly journals Impact of Nonlinear Interactions of Pharmacokinetics and MICs on Sputum Bacillary Kill Rates as a Marker of Sterilizing Effect in Tuberculosis

2014 ◽  
Vol 59 (1) ◽  
pp. 38-45 ◽  
Author(s):  
Emmanuel Chigutsa ◽  
Jotam G. Pasipanodya ◽  
Marianne E. Visser ◽  
Paul D. van Helden ◽  
Peter J. Smith ◽  
...  
Keyword(s):  
Drug Exposure ◽  
Sputum Sample ◽  
Bactericidal Effect ◽  
Multivariate Adaptive Regression Splines ◽  
Pharmacokinetic Parameters ◽  
Time Curve ◽  
Content Type ◽  
Drug Concentrations ◽  
Adaptive Regression ◽  
Rate Of Decline

ABSTRACTThe relationships between antituberculosis drug exposure and treatment effects on humans receiving multidrug therapy are complex and nonlinear. In patients on treatment, an analysis of the rate of decline in the sputum bacillary burden reveals two slopes. The first is the α-slope, which is thought to reflect bactericidal effect, followed by a β-slope, which is thought to reflect sterilizing activity. We sought to characterize the effects of standard first-line treatment on sterilizing activity. Fifty-four patients receiving combination therapy for pulmonary tuberculosis in a clinical trial had drug concentrations measured andMycobacterium tuberculosisisolates available for MIC identification. Sputum sample cultures were performed at baseline and weekly for 8 weeks. A time-to-event model based on the days to positivity in the liquid cultures was used to estimate the β-slope. The pharmacokinetic parameters of rifampin, isoniazid, ethambutol, and pyrazinamide were determined for each patient. Multivariate adaptive regression splines analyses, which simultaneously perform linear and nonlinear analyses, were used to identify the relationships between the predictors and the β-slope. The potential predictors examined included HIV status, lung cavitation, 24-h area under the concentration-time curve (AUC), peak drug concentration (Cmax), AUC/MIC ratio,Cmax/MIC ratio, and the time that that concentration persisted above MIC. A rifampinCmaxof >8.2 mg/liter and a pyrazinamide AUC/MIC of >11.3 were key predictors of the β-slope and interacted positively to increase the β-slope. In patients with a rifampin AUC of <35.4 mg · h/liter, an increase in the pyrazinamide AUC/MIC and/or ethambutolCmax/MIC increased the β-slope, while increasing isoniazidCmaxdecreased it, suggesting isoniazid antagonism. Antibiotic concentrations and MICs interact in a nonlinear fashion as the main drivers of a sterilizing effect. The results suggest that faster speeds of sterilizing effect might be achieved by omitting isoniazid and by increasing rifampin, pyrazinamide, and ethambutol exposures. However, isoniazid and ethambutol exposures may only be of importance when rifampin exposure is low. These findings need confirmation in larger studies. (This study has been registered atcontrolled-trials.comunder registration no. ISRCTN80852505.)

#43: Monotherapy Experience in Pediatric Patients with High-risk Febrile Neutropenia

2021 ◽  
Vol 10 (Supplement_1) ◽  
pp. S19-S19
Author(s):  
Valentina Gutiérrez ◽  
Ximena Claverie
Keyword(s):  
High Risk ◽  
Febrile Neutropenia ◽  
Fungal Infections ◽  
Clinical Signs ◽  
Empiric Therapy ◽  
Fourth Generation ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Third Line ◽  
Clinical Worsening

Abstract Background Fever during neutropenia is a common occurrence in children with cancer. In a systematic review of RCTs of pediatric febrile neutropenia, compared monotherapy with aminoglycoside-containing combination therapy found no significant differences in failure rates, infection-related mortality, or overall mortality. The updated pediatric-specific guidelines recommend initiation of empirical antibiotic monotherapy using an antipseudomonal β-lactam, a fourth-generation cephalosporin, or a carbapenem for pediatric high-risk febrile neutropenia. However, local epidemiology and resistance patterns should be evaluated regularly. Our local hospital epidemiology does not have Pseudomonas aeruginosa isolates, therefore, we used ceftriaxone as monotherapy in patients with high-risk febrile neutropenia without other risk factors. The goal of our investigation is to describe the experience of using third-generation cephalosporins in these patients. Methods Descriptive study of high-risk febrile neutropenia episodes in patients admitted to the Pediatric Oncology Unit of Hospital Dr. Sótero del Río, Santiago, Chile. We included patients ≤15 years from June 2016 until November 2019. Results We found a total of 133 high-risk febrile neutropenia episodes corresponding to 50 patients, 78% were leukemia and 22% were solid tumor patients. Of the 133 episodes, 92 (69%) had clinical signs at admission, mostly respiratory in 46 (50%) of the cases, 18 (29%) had mucositis and 13 (14%) had diarrhea. Of 133 episodes, 41 (31%) did not have any source at clinical examination. Eighty-six (65%) cases started ceftriaxone at admission, 28 (33%) maintained ceftriaxone for 7 days of treatment with good clinical response. Of this group 58 (67%) patients changed treatment: 32 (37%) cases started second-line antibiotics for clinical worsening, 19 (22%) cases required second- and third-line antibiotics for persistent fever and clinical worsening, and 7 (8%) received third-line antibiotics from the start for past microbiological history. Sixteen (12%) cases of total evolved with sepsis requiring intensive care unit management. We had 30 (23%) episodes with positive blood culture, 11 (37%) due to gram-positive bacteria, 16 (53%) gram-negative bacteria, and 3 (10%) cases of fungal infections. Of the gram-negative bacteria, 7 (44%) were ESBL producers, without P. aeruginosa isolates. One case died (0.7%) for refractory sepsis due to gram-negative bacteria. Conclusion Although we did not have P. aeruginosa isolates, due to the spread of ESBL strains, monotherapy with ceftriaxone is not a good option as initial therapy for high-risk febrile neutropenia patients. The empiric therapy has to be evaluated regularly and should always be based on local epidemiology.

scholarly journals Pharmacokinetics of intramuscularly administered aminosidine in healthy subjects.

1997 ◽  
Vol 41 (5) ◽  
pp. 982-986 ◽  
Author(s):  
T P Kanyok ◽  
A D Killian ◽  
K A Rodvold ◽  
L H Danziger
Keyword(s):  
Healthy Subjects ◽  
Randomized Clinical Trials ◽  
Elimination Rate ◽  
Pharmacokinetic Parameters ◽  
Multiple Drug ◽  
Time Data ◽  
Time Curve ◽  
First Order ◽  
Significant Difference

Aminosidine is an older, broad-spectrum aminoglycoside antibiotic that has been shown to be effective in in vitro and animal models against multiple-drug-resistant tuberculosis and the Mycobacterium avium complex. The objective of this randomized, parallel trial was to characterize the single-dose pharmacokinetics of aminosidine sulfate in healthy subjects (eight males, eight females). Sixteen adults (mean [+/- standard deviation] age, 27.6 +/- 5.6 years) were randomly allocated to receive a single, intramuscular aminosidine sulfate injection at a dose of 12 or 15 mg/kg of body weight. Serial plasma and urine samples were collected over a 24-h period and used to determine aminosidine concentrations by high-performance liquid chromatographic assay. A one-compartment model with first-order input, first-order output, and a lag time (Tlag) and with a weighting factor of 1/y2 best described the data. Compartmental and noncompartmental pharmacokinetic parameters were estimated with the microcomputer program WinNonlin. One subject was not included (15-mg/kg group) because of the lack of sampling time data. On average, subjects attained peak concentrations of 22.4 +/- 3.2 microg/ml at 1.34 +/- 0.45 h. All subjects had plasma aminosidine concentrations below 2 microg/ml at 12 h, and all but two subjects (one in each dosing group) had undetectable plasma aminosidine concentrations at 24 h. The dose-adjusted area under the concentration-time curve from 0 h to infinity of aminosidine was identical for the 12- and 15-mg/kg groups (9.29 +/- 1.5 versus 9.29 +/- 2.2 microg x h/ml per mg/kg; P = 0.998). Similarly, no significant differences (P > 0.05) were observed between dosing groups for peak aminosidine concentration in plasma, time to peak aminosidine concentration in plasma, Tlag, apparent clearance, renal clearance, elimination rate constant, and elimination half-life. A significant difference was observed for the volume of distribution (0.35 versus 0.41 liters/kg; P = 0.037) between the 12 and 15 mg/kg dosing groups. Now that comparable pharmacokinetic profiles between dosing groups have been demonstrated, therapeutic equivalency testing via in vitro pharmacokinetic and pharmacodynamic modelling and randomized clinical trials in humans should be conducted.

scholarly journals Bloodstream infections in patients with hematologic malignancies and febrile neutropenia - a single center experience

2021 ◽  
Vol 74 (3-4) ◽  
pp. 83-89
Author(s):  
Marina Dragicevic-Jojkic ◽  
Ivana Urosevic ◽  
Amir El Farra ◽  
Borivoj Sekulic ◽  
Ivanka Percic ◽  
...  
Keyword(s):  
Febrile Neutropenia ◽  
Fatal Outcome ◽  
Antibiotic Sensitivity ◽  
Bloodstream Infections ◽  
Hematologic Malignancies ◽  
High Rate ◽  
Antibiotics Resistance ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Acinetobacter Spp

Introduction. Bacterial blood infections during febrile neutropenia episodes are urgent medical conditions which were and still are the main cause of morbidity and mortality among patients with hematologic malignancies. The aim of this study was to determine the incidence and clinical characteristics of bacteremia, infectious agents, presence and incidence of antibiotic resistance, as well as the treatment outcome of bloodstream infections in patients with hematologic malignancies. Material and Methods. A three-year retrospective study included 107 patients with hematologic malignancies and positive blood culture results during febrile neutropenia. Results. The most common isolates were Gram-negative bacteria (58.5%), with Escherichia coli being the most frequent pathogen. The Gram-negative microorganisms were mostly sensitive to carbapenems in 70.7%, whereas sensitivity to other antibiotics was as follows: piperacillin/ tazobactam 62%, amikacin 58.5%, and third-generation cephalosporins 50.5%. Acinetobacter spp. was sensitive only to colistin (94.1%). The antibiotic sensitivity among Gram-positive bacteria was highest to linezolid (97.1%), followed by teicoplanin (81.4%) and vancomycin (81.4%). In our patients, the mortality rate during the first 28 days from the moment of positive isolates was high (37.4%). Most patients died within the first seven days. Bacterial blood infections caused by Gram-negative bacteria were associated with significantly higher mortality (?2 = 4.92, p = 0.026). Acinetobacter spp. was isolated in almost half of the patients with fatal outcome, of whom 62.5% died in the first 24 hours. Conclusion. Bacterial bloodstream infections are severe complications with a high rate of mortality in febrile neutropenic hematological patients. Gram-negative bacteria were the most common isolates in our Clinic, with high mortality. It is of utmost importance to constantly monitor the resistance of bacteria to antibiotics, as well as to prevent and control the spread of resistant strains. Antibiotics resistance patterns should regularly be followed.

scholarly journals Pharmacokinetics, Safety, and Tolerability of Cefiderocol, a Novel Siderophore Cephalosporin for Gram-Negative Bacteria, in Healthy Subjects

2018 ◽  
Vol 62 (3) ◽  
Author(s):  
Yutaka Saisho ◽  
Takayuki Katsube ◽  
Scott White ◽  
Hiroyuki Fukase ◽  
Jingoro Shimada
Keyword(s):  
Healthy Subjects ◽  
Active Drug ◽  
Single Subject ◽  
Gram Negative Bacteria ◽  
Multiple Dosing ◽  
Time Curve ◽  
Gram Negative ◽  
Time Zero ◽  
Concentration Time ◽  
Dose Study

ABSTRACT Cefiderocol is a novel parenteral siderophore cephalosporin that shows potent efficacy against various Gram-negative bacteria, including carbapenem-resistant strains, in vitro and in preclinical models of infection. The aim of the present study was to evaluate the pharmacokinetics (PK), safety, and tolerability of cefiderocol after both single and multiple dosing by intravenous infusion over 60 min in healthy adult subjects. A single-ascending-dose study at doses of 100, 250, 500, 1,000, and 2,000 mg was conducted in 40 healthy Japanese males and females (6 individuals receiving the active drug and 2 individuals receiving a placebo per cohort). A multiple-ascending-dose study at doses of 1,000 (two groups) and 2,000 mg every 8 h (q8h) was conducted in 30 healthy Japanese and Caucasian males (8 individuals receiving the active drug and 2 individuals receiving a placebo per cohort). There were no serious or clinically significant adverse events (AEs) observed in either study. A single subject receiving 1,000 mg cefiderocol q8h was withdrawn due to AEs. Dose-proportional increases in the maximum plasma concentration ( C max ), the area under the concentration-time curve (AUC) from time zero to the time of the last quantifiable concentration after dosing, and the area under the concentration-time curve extrapolated from time zero to infinity were observed across the dose range of 100 to 2,000 mg. The mean plasma half-life of cefiderocol was 1.98 to 2.74 h. Cefiderocol was primarily excreted unchanged in the urine (61.5% to 68.4% of the dose). There was little accumulation of C max and AUC by dosing q8h, and the PK of cefiderocol did not change with multiple dosing. This study indicates that single and multiple intravenous doses of cefiderocol at up to 2,000 mg are well tolerated in healthy subjects and exhibit linear PK at doses up to 2,000 mg.

scholarly journals Paritaprevir and Ritonavir Liver Concentrations in Rats as Assessed by Different Liver Sampling Techniques

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Charles S. Venuto ◽  
Marianthi Markatou ◽  
Yvonne Woolwine-Cunningham ◽  
Rosemary Furlage ◽  
Andrew J. Ocque ◽  
...  
Keyword(s):  
Surgical Resection ◽  
Needle Aspiration ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Sprague Dawley ◽  
Time Curve ◽  
Tissue Samples ◽  
Drug Concentrations ◽  
Sprague Dawley Rats ◽  
Liquid Chromatography Tandem Mass

ABSTRACT The liver is crucial to pharmacology, yet substantial knowledge gaps exist in the understanding of its basic pharmacologic processes. An improved understanding for humans requires reliable and reproducible liver sampling methods. We compared liver concentrations of paritaprevir and ritonavir in rats by using samples collected by fine-needle aspiration (FNA), core needle biopsy (CNB), and surgical resection. Thirteen Sprague-Dawley rats were evaluated, nine of which received paritaprevir/ritonavir at 30/20 mg/kg of body weight by oral gavage daily for 4 or 5 days. Drug concentrations were measured using liquid chromatography-tandem mass spectrometry on samples collected via FNA (21G needle) with 1, 3, or 5 passes (FNA1, FNA3, and FNA5); via CNB (16G needle); and via surgical resection. Drug concentrations in plasma were also assessed. Analyses included noncompartmental pharmacokinetic analysis and use of Bland-Altman techniques. All liver tissue samples had higher paritaprevir and ritonavir concentrations than those in plasma. Resected samples, considered the benchmark measure, resulted in estimations of the highest values for the pharmacokinetic parameters of exposure (maximum concentration of drug in serum [C max] and area under the concentration-time curve from 0 to 24 h [AUC0–24]) for paritaprevir and ritonavir. Bland-Altman analyses showed that the best agreement occurred between tissue resection and CNB, with 15% bias, followed by FNA3 and FNA5, with 18% bias, and FNA1 and FNA3, with a 22% bias for paritaprevir. Paritaprevir and ritonavir are highly concentrated in rat liver. Further research is needed to validate FNA sampling for humans, with the possible derivation and application of correction factors for drug concentration measurements.

Limited Sampling Strategies to Estimate the Area under the Concentration-time Curve

2012 ◽  
Vol 51 (05) ◽  
pp. 383-394 ◽  
Author(s):  
M. Fukumoto ◽  
L. Bax ◽  
A. Kohno ◽  
Y. Morishita ◽  
H. Tsuruta
Keyword(s):  
Rate Constant ◽  
Elimination Rate ◽  
Estimation Method ◽  
Pharmacokinetic Parameters ◽  
Good Precision ◽  
Sampling Strategies ◽  
Time Curve ◽  
New Methods ◽  
Limited Sampling ◽  
Concentration Time

SummaryBackground: Over 100 limited sampling strategies (LSSs) have been proposed to reduce the number of blood samples necessary to estimate the area under the concentration-time curve (AUC). The conditions under which these strategies succeed or fail remain to be clarified.Objectives: We investigated the accuracy of existing LSSs both theoretically and numerically by Monte Carlo simulation. We also proposed two new methods for more accurate AUC estimations.Methods: We evaluated the following existing methods theoretically: i) nonlinear curve fitting algorithm (NLF), ii) the trapezium rule with exponential curve approximation (TZE), and iii) multiple linear regression (MLR). Taking busulfan (BU) as a test drug, we generated a set of theoretical concentration-time curves based on the identified distribution of pharmacokinetic parameters of BU and re-evaluated the existing LSSs using these virtual validation profiles. Based on the evaluation results, we improved the TZE so that unrealistic parameter values were not used. We also proposed a new estimation method in which the most likely curve was selected from a set of pre-generated theoretical concentration-time curves.Results: Our evaluation, based on clinical profiles and a virtual validation set, revealed: i) NLF sometimes overestimated the absorption rate constant Ka, ii) TZE overestimated AUC over 280% when Ka is small, and iii) MLR underestimated AUC over 30% when the elimination rate constant Ke is small. These results were consistent with our mathematical evaluations for these methods. In contrast, our two new methods had little bias and good precision.Conclusions: Our investigation revealed that existing LSSs induce different but specific biases in the estimation of AUC. Our two new LSSs, a modified TZE and one using model concentration-time curves, provided accurate and precise estimations of AUC.

scholarly journals Comparative Study on Pharmacokinetics of Four Long-Acting Injectable Formulations of Enrofloxacin in Pigs

2021 ◽  
Vol 7 ◽  
Author(s):  
Salah Uddin Ahmad ◽  
Jichao Sun ◽  
Fusheng Cheng ◽  
Bing Li ◽  
Safia Arbab ◽  
...  
Keyword(s):  
Comparative Study ◽  
High Performance ◽  
Pasteurella Multocida ◽  
Plasma Concentrations ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Reference Formulation ◽  
Time Curve ◽  
Drug Concentrations ◽  
Long Acting

A comparative study on pharmacokinetics of four long-acting enrofloxacin injectable formulations was investigated in 36 healthy pigs after intramuscular injection according to the recommended single dose @ 2.5 mg/kg body weight. The drug concentrations in the plasma were computed using high-performance liquid chromatography (HPLC) with fluorescence detection. WinNonLin5.2.1 software was used to analyze the experimental data and compared it under one-way ANOVA using SPSS software with a 95% confidence interval (CI). The main pharmacokinetic parameters, that is, the maximum plasma concentrations (Cmax), the time to maximum concentration (Tmax), area under the time curve concentration (AUCall) and Terminal half-life (T1/2) were 733.84 ± 129.87, 917.00 ± 240.13, 694.84 ± 163.49, 621.98 ± 227.25 ng/ml, 2.19 ± 0.0.66, 1.50 ± 0.37, 2.89 ± 0.24, 0.34 ± 0.13 h, 7754.43 ± 2887.16, 8084.11 ± 1543.98, 7369.42 ± 2334.99, 4194.10 ± 1186.62 ng h/ml, 10.48 ± 2.72, 10.37 ± 2.38, 10.20 ± 2.81, and 10.61 ± 0.86 h for 10% enrofloxacin (Alkali), 20% enrofloxacin (Acidic), Yangkang and control drug Nuokang® respectively. There were significant differences among Cmax, Tmax, and AUCall of three formulations compare with that of the reference formulation. No significant differences were observed among the T1/2 for tested formulations compare with the reference formulation. The pharmacokinetic parameters showed that the tested formulations were somewhat better compared to the reference one. The calculated PK/PD indices were effective for bacteria such as Actinobacillus pleuropneumoniae and Pasteurella multocida with values higher than the cut-off points (Cmax/MIC90≥10–12 and AUC/MIC90 ≥ 125). However, they were not effective against bacteria like Haemophilus parasuis, Streptococcus suis, E. coli, and Bordetella bronchiseptica where lower values were obtained.

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