scholarly journals Population pharmacokinetic study of teicoplanin in severely neutropenic patients.

1996 ◽  
Vol 40 (5) ◽  
pp. 1242-1247 ◽  
Author(s):  
O Lortholary ◽  
M Tod ◽  
N Rizzo ◽  
C Padoin ◽  
O Biard ◽  
...  
Keyword(s):  
Steady State ◽  
Trough Concentration ◽  
Linear Regression Analysis ◽  
Central Compartment ◽  
Population Pharmacokinetic ◽  
Mixed Effect ◽  
Elimination Half ◽  
Neutropenic Patients ◽  
The Mean ◽  
Volumes Of Distribution

The teicoplanin pharmacokinetics (PK) of 30 febrile and severely neutropenic patients (polymorphonuclear count, < 500/mm3) with hematologic malignancies were compared with those determined for five healthy volunteers (HV). Neutropenic patients were given piperacillin combined with amikacin, and teicoplanin was added to the regimen the day fever developed in patients suspected of having a staphylococcal infection or 48 h later. Teicoplanin was given intravenously at a dosage of 6 mg/kg of body weight at 0, 12, and 24 h and once a day thereafter. Five to eleven blood samples per patient were collected. Teicoplanin concentrations were measured by liquid chromatography. A bicompartmental model was fitted to the data by a nonlinear mixed-effect-model approach. Multiple-linear regression analysis was applied in an attempt to correlate PK parameters to nine covariates. The mean trough concentrations of teicoplanin 48 h after the onset of treatment and 24 h after the last injection (last trough) +/- standard deviations were 8.8 +/- 4.1 and 17.5 +/- 13.5 mg/liter, respectively. A significant increase was noted in the mean rate of elimination clearance of teicoplanin in neutropenic patients compared with that of HV (0.86 versus 0.73 liter/h, P = 0.002), as was the case with rates of distribution clearance (5.89 versus 4.94 liter/h, P = 0.002); the mean half-life of distribution was significantly shorter in patients than in HV (0.43 versus 0.61 h, P = 0.002). In contrast, the volumes of the central compartment (ca. 5.8 liters for both groups), the volumes of distribution at steady state (HV, 37.6 liters; patients, 55.9 liters), and the elimination half-lives (HV, 39.6 h; patients, 52.7 h) were not significantly different between HV and neutropenic patients. Interindividual variabilities of rates of clearance (coefficient of variation [CV], 43%) and elimination half-lives (CV, 56%) were mainly explained by the variabilities among rates of creatinine clearance. Interindividual variabilities of the volumes of the central compartment (CV, 33%) and the volumes of distribution at steady state (CV = 51%) were correlated to interindividual variabilities among numbers of leukocytes and the ages of patients, respectively. On the basis of the population PK model of teicoplanin, simulations were made to optimize the dosing schedule. A supplemental 6 mg/kg dose of teicoplanin at 36 h resulted in a trough concentration at 48 h of 16.0 +/- 4.5 mg/liter, with only 7% of patients having a trough concentration of less than 10 mg/liter, compared with 46% of patients on the usual schedule.

scholarly journals Evaluating the Relationship between Vancomycin Trough Concentration and 24-Hour Area under the Concentration-Time Curve in Neonates

2018 ◽  
Vol 62 (4) ◽  
pp. e01647-17 ◽  
Author(s):  
Sheng-Hsuan Tseng ◽  
Chuan Poh Lim ◽  
Qi Chen ◽  
Cheng Cai Tang ◽  
Sing Teang Kong ◽  
...  
Keyword(s):  
Steady State ◽  
Trough Concentration ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Time Curve ◽  
Content Type ◽  
Concentration Time ◽  
Vancomycin Trough ◽  
Trough Concentrations ◽  
The Relationship

ABSTRACT Bacterial sepsis is a major cause of morbidity and mortality in neonates, especially those involving methicillin-resistant Staphylococcus aureus (MRSA). Guidelines by the Infectious Diseases Society of America recommend the vancomycin 24-h area under the concentration-time curve to MIC ratio (AUC24/MIC) of >400 as the best predictor of successful treatment against MRSA infections when the MIC is ≤1 mg/liter. The relationship between steady-state vancomycin trough concentrations and AUC24 values (mg·h/liter) has not been studied in an Asian neonatal population. We conducted a retrospective chart review in Singapore hospitals and collected patient characteristics and therapeutic drug monitoring data from neonates on vancomycin therapy over a 5-year period. A one-compartment population pharmacokinetic model was built from the collected data, internally validated, and then used to assess the relationship between steady-state trough concentrations and AUC24. A Monte Carlo simulation sensitivity analysis was also conducted. A total of 76 neonates with 429 vancomycin concentrations were included for analysis. Median (interquartile range) was 30 weeks (28 to 36 weeks) for postmenstrual age (PMA) and 1,043 g (811 to 1,919 g) for weight at the initiation of treatment. Vancomycin clearance was predicted by weight, PMA, and serum creatinine. For MRSA isolates with a vancomycin MIC of ≤1, our major finding was that the minimum steady-state trough concentration range predictive of achieving an AUC24/MIC of >400 was 8 to 8.9 mg/liter. Steady-state troughs within 15 to 20 mg/liter are unlikely to be necessary to achieve an AUC24/MIC of >400, whereas troughs within 10 to 14.9 mg/liter may be more appropriate.

scholarly journals Pharmacokinetics of Miltefosine in Old World Cutaneous Leishmaniasis Patients

2008 ◽  
Vol 52 (8) ◽  
pp. 2855-2860 ◽  
Author(s):  
Thomas P. C. Dorlo ◽  
Pieter P. A. M. van Thiel ◽  
Alwin D. R. Huitema ◽  
Ron J. Keizer ◽  
Henry J. C. de Vries ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Half Life ◽  
Leishmania Major ◽  
The Body ◽  
Population Pharmacokinetic ◽  
Mixed Effect ◽  
Old World ◽  
Elimination Half Life ◽  
Elimination Half ◽  
End Of Treatment

ABSTRACT The pharmacokinetics of miltefosine in leishmaniasis patients are, to a great extent, unknown. We examined and characterized the pharmacokinetics of miltefosine in a group of patients with Old World (Leishmania major) cutaneous leishmaniasis. Miltefosine plasma concentrations were determined in samples taken during and up to 5 months after the end of treatment from 31 Dutch military personnel who contracted cutaneous leishmaniasis in Afghanistan and were treated with 150 mg miltefosine/day for 28 days. Samples were analyzed with a validated liquid chromatography-tandem mass spectrometry assay with a lower limit of quantification (LLOQ) of 4 ng/ml. Population pharmacokinetic modeling was performed with nonlinear mixed-effect modeling, using NONMEM. The pharmacokinetics of miltefosine could best be described by an open two-compartment disposition model, with a first elimination half-life of 7.05 days and a terminal elimination half-life of 30.9 days. The median concentration in the last week of treatment (days 22 to 28) was 30,800 ng/ml. The maximum duration of follow-up was 202 days after the start of treatment. All analyzed samples contained a concentration above the LLOQ. Miltefosine is eliminated from the body much slower than previously thought and is therefore still detectable in human plasma samples taken 5 to 6 months after the end of treatment. The presence of subtherapeutic miltefosine concentrations in the blood beyond 5 months after treatment might contribute to the selection of resistant parasites, and moreover, the measures for preventing the teratogenic risks of miltefosine treatment should be reconsidered.

scholarly journals Prediction of steady-state plasma concentrations of olanzapine in Chinese Han in patients based on a retrospective population pharmacokinetic model

2021 ◽  
Vol 20 (11) ◽  
pp. 2433-2441
Author(s):  
Xiaoyue Wang ◽  
Yong Han ◽  
Hong Zhou ◽  
Bin Cao ◽  
Miaomiao Zhu ◽  
...  
Keyword(s):  
Steady State ◽  
Smoking Status ◽  
Mental Health Center ◽  
Plasma Concentrations ◽  
Visual Predictive Check ◽  
Apparent Volume ◽  
Population Pharmacokinetic ◽  
Chinese Han ◽  
Mixed Effect ◽  
State Plasma

Purpose: To develop robust methods of establishing a population pharmacokinetics (Pop-PK) model of olanzapine, using existing hospital in-patient information, in order to predict the steady-state plasma concentration of olanzapine tablets in Chinese Han inpatients, thus providing guidance for individualized therapy for mental disorders.Methods: A retrospective study analyzing and predicting the steady-state plasma olanzapineconcentration was performed using nonlinear mixed-effect modeling (Phoenix® NLME8). The effects of ten potential covariates, including age, gender, Body Mass Index, fasting lipid, family history, alcohol and smoking status in 107 Chinese Han patients with steady-state plasma olanzapine concentration were collected from the hospital information system (HIS) in Wuhan Mental Health Center from Feb 2017 to Jul 2019.Results: The final model was validated using bootstrap and visual predictive check (VPC) and was found to fit the one-compartment mixed error model. Smoking status was found to be the only factor affecting olanzapine tablets clearance. The standard Pop-PK parameters apparent volume of distribution (VL/F) and clearance (CL/F) were 223 L and 12.4 Lꞏh-1, respectively.Conclusion: The Pop-PK model for olanzapine established with the data from HIS is effective inpredicting the plasma olanzapine tablets concentration of individual Chinese in-patients. This Pop-PK model approach can now be adapted to optimize other antipsychotic drugs.

Pharmacokinetics and renal toxicity of three once-a-day doses of amikacin in cows

2005 ◽  
Vol 53 (2) ◽  
pp. 231-240 ◽  
Author(s):  
H. Sumano ◽  
Lilia Gutierrez ◽  
C. Velazquez ◽  
Sayuri Hayashida
Keyword(s):  
Renal Toxicity ◽  
Day Treatment ◽  
Screening Method ◽  
Central Compartment ◽  
Single Daily Dose ◽  
Serum Concentrations ◽  
Maximum Serum ◽  
Elimination Half ◽  
Daily Dose ◽  
Volumes Of Distribution

Pharmacokinetic variables of amikacin in cows were determined after administration of amikacin sulphate either intravenously (IV) or intramuscularly (IM) at a dose of 25 mg/kg per day for three days. Amikacin concentrations at time zero and maximum serum concentrations were 240.8 µg/mL and 122.53 µg/mL, respectively. The elimination half-life remained unchanged during the three days of administration (T½ß = 1.33 ± 0.029 h for the IV route and T½ß = 2.75 ± 0.38 h for the IM route). Apparent volumes of distribution suggest limited distribution out of the central compartment (VdAUC = 0.154 ± 0.005 L/kg; Vdc = 36.50 ± 2.35 L; Vdss = 0.092 ± 0.004 L/kg). Bioavailability after IM administration was 95%. Serum profiles of urea, creatinine, albumin, electrolytes and pH after 5-day treatment with amikacin at a dose of 25 mg/kg per day IM revealed no changes. Assessment of diffusion of amikacin to milk by a commercially available screening method to detect antibiotic residues revealed that amikacin could not be detected by the fifth milking period after the last treatment. These results suggest that it would be rational to use a large single-daily dose of amikacin for future clinical trials in cows.

Dose-Ranging Pharmacokinetic Study of Ciprofloxacin after 200-, 300-, and 400-mg Intravenous Doses

1992 ◽  
Vol 26 (1) ◽  
pp. 8-10 ◽  
Author(s):  
David E. Nix ◽  
J. Michael Spivey ◽  
Allyn Norman ◽  
Jerome J. Schentag
Keyword(s):  
Steady State ◽  
Half Life ◽  
Total Body Clearance ◽  
Volume Of Distribution ◽  
Elimination Half Life ◽  
Elimination Half ◽  
The Mean ◽  
Total Body ◽  
Venous Irritation ◽  
Body Clearance

OBJECTIVE: To assess the pharmacokinetics and tolerance of ciprofloxacin after the administration of single intravenous doses of 200, 300, and 400 mg. DESIGN: Double-blind, three-period, randomized, crossover trial. SETTING: Private, university-affiliated, hospital-based, clinical research center. PATIENTS: Normal healthy male volunteers, 18–40 years of age. INTERVENTIONS: Subjects received 200-, 300-, and 400-mg single intravenous doses of ciprofloxacin via 30-minute infusions in random sequence. MAIN OUTCOME MEASURES: Serum ciprofloxacin concentrations were determined by HPLC after each dose and the results were used to derive pharmacokinetic parameters. Tolerance was assessed by reported and observed adverse events, urine microscopic examinations for crystals, and examination of intravenous infusion sites. RESULTS: The mean area under the time curve (AUC) values displayed linearity with respect to the administered dose. No statistical differences were observed in total body clearance, steady-state volume of distribution, or elimination half-life with respect to dose administered. The mean total body clearance, steady-state volume of distribution, or elimination half-life ranged from 36 to 41 L/h, 146 to 169 L, and 3.5 to 3.7 h for the 200-, 300-, and 400-mg doses, respectively. Adverse effects, including venous irritation (four subjects) and crystalluria (two subjects), were mild and did not require withdrawal of any subject from the study. CONCLUSIONS: Intravenous ciprofloxacin in doses ranging from 200 to 400 mg demonstrated linear pharmacokinetics. These single doses were well tolerated, although cases of transient venous irritation and crystalluria were observed.

scholarly journals Micafungin population PK analysis in plasma and peritoneal fluid in septic patients with intra-abdominal infections: a prospective cohort study

2021 ◽  
Author(s):  
Nicolas Garbez ◽  
Litaty Mbatchi ◽  
Steven C. Wallis ◽  
Laurent Muller ◽  
Jeffrey Lipman ◽  
...  
Keyword(s):  
Peritoneal Fluid ◽  
Central Compartment ◽  
Population Pharmacokinetic Analysis ◽  
Peritoneal Exudate ◽  
Fat Free Mass ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Parameter Estimates ◽  
The Mean ◽  
Abdominal Infections

Objectives: To describe the pharmacokinetics (PK) of micafungin in plasma and peritoneal fluid in septic patients with intra-abdominal infections. Methods: Twelve patients with secondary peritonitis in septic shock receiving 100 mg micafungin once daily were included. Total micafungin plasma and peritoneal fluid were subject to a population pharmacokinetic analysis using Pmetrics®. Monte Carlo simulations were performed considering total AUC0-24h/MIC ratios in plasma. Results: Micafungin concentrations in both plasma and peritoneal exudate were best described by a three-compartmental PK model with the fat free mass (FFM) as a covariate of clearance (CL) and volume of the central compartment (Vc). The mean parameter estimates (standard deviation, SD) were 1.18 (0.40) L/h for CL and 12.85 (4.78) L for Vc. The mean peritoneal exudate/plasma ratio (SD) of micafungin was 25% (5%) on day 1 and 40% (8%) between day 3-5. Dosing simulations supported the use of standard 100 mg daily dosing for C. albicans (FFM < 60 kg), C. glabrata (FFM < 50 kg) and C. tropicalis (FFM < 30 kg) on the second day of therapy. Conclusions: There is a moderate penetration of micafungin into peritoneal cavity (25 to 40%). For empirical treatment, a dose escalation of at least a loading dose of 150 mg depending on the FFM of patients and Candida species is suggested to be effective from the first day of therapy.

CPX-351 Population Pharmacokinetics in Pediatric and Adult Patients with Acute Myeloid Leukemia (AML)

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 1-1
Author(s):  
Qi Wang ◽  
Todd M. Cooper ◽  
Michael J. Absalon ◽  
E. Anders Kolb ◽  
Grygoriy Vasilinin ◽  
...  
Keyword(s):  
Goodness Of Fit ◽  
Plasma Concentrations ◽  
Structural Models ◽  
Central Compartment ◽  
Population Pharmacokinetic ◽  
Extrinsic Factors ◽  
Mixed Effect ◽  
First Order ◽  
Population Pk ◽  
Study Type

CPX-351 (Vyxeos®; daunorubicin and cytarabine liposome for injection), a dual-drug liposomal encapsulation of daunorubicin and cytarabine at a 1:5 synergistic ratio, is approved by the US FDA and EMA for the treatment of adults with newly diagnosed therapy-related AML or AML with myelodysplasia-related changes. Recently, CPX-351 was used in pediatric patients (pts) with relapsed AML (JCO 2020, ASH 2019, ASH 2018). A population pharmacokinetic (PK) analysis of plasma concentrations of cytarabine and daunorubicin following IV administration of CPX-351 was performed to assess sources of variability in PK and to determine if age-based dose adjustments may be warranted, particularly in pediatric pts. The PK population consisted of 250 pts with advanced hematologic malignancies from 7 studies and included 46 (18%) pediatric pts (1-17 y) and 204 (82%) adults (≥18 y). The population included 148 (59%) males, mainly of white origin (82%). Nonlinear mixed-effect modeling was performed using NONMEM®. Model evaluation and selection were assessed using a standard model discrimination process that included statistical criteria (eg, objective function value) and pertinent graphical representations of goodness-of-fit. Separate PK models were developed for cytarabine and daunorubicin; intrinsic and extrinsic factors were evaluated as covariates. The intrinsic factors included body weight, body mass index, age, sex, race, white blood cell count, and markers of renal function (creatinine clearance, serum creatinine) and hepatic function (bilirubin, aspartate and alanine aminotransferases, alkaline phosphatase). The extrinsic factors included study type (adult vs pediatric/young adult) and formulation (frozen vs lyophilized). Based on previous population PK models developed for adults, the PK models for cytarabine and daunorubicin used 2-compartment structural models, with drug input into the central compartment, first-order distribution between the central and peripheral compartments, and first-order elimination from the central compartment. Two-compartment structural models with body surface area (BSA) as an allometric scalar provided minimum bias in estimates of systemic clearance (CL) and volume of distribution for the central compartment (Vc). Based on the final population PK models, the estimates of CL and Vc in adults were 0.101 L/h and 4.76 L, respectively, for cytarabine and 0.140 L/h and 4.04 L for daunorubicin. The population estimates of CL and Vc for cytarabine in children, adolescents, and young adults (&lt;22 y) were 0.073 L/h and 3.91 L, respectively, for cytarabine and 0.093 L/h and 3.28 L for daunorubicin. The population PK models included an allometric component that accounted for differences in BSA. The exponent for the effect of BSA on CL was 0.948 and 0.876 for cytarabine and daunorubicin, respectively, suggesting a faster clearance in pts with higher BSA. These differences in CL are expected to be offset by BSA-based dosing of CPX-351. Bilirubin and formulation (frozen) remained statistically significant covariates on the CL of daunorubicin. All tested covariates were eventually excluded from the population PK models, except BSA, bilirubin, study type, and formulation, which have a small effect on PK and are not expected to result in detectable changes in clinical safety or efficacy. Age was evaluated both as a continuous and categorical variable (1-5, 6-11, and 12-17 y) and was not a significant covariate for cytarabine and daunorubicin CL and Vc. Study type was identified as a significant covariate for CL and Vc for cytarabine and daunorubicin, which was possibly due to a change in analytical site for pediatric studies. Mean AUC0-48 values of cytarabine in pts aged 1-5, 6-11, and 12-17 y (135 U/m2) were similar (2767, 2783, and 2806 μg·h/mL, respectively) and approximately 40% higher than that observed in pts ≥18 y (100 U/m2, 1928 μg·h/mL), proportional to the 35% higher dose in pediatric pts. Mean AUC0-48 values of daunorubicin in pts aged 1-5, 6-11, and 12-17 y (135 U/m2) were similar (967, 896, and 982 μg·h/mL, respectively) and approximately 40% higher than that observed in pts ≥18 y (100 U/m2, 615 μg·h/mL), proportional to the 35% higher dose in pediatric pts. The results of this population PK analysis indicated exposures to CPX-351 in pediatric pts were not affected by age and were similar to those in adults when administered at the same BSA-normalized dose. Disclosures Wang: Jazz Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Cooper:Celgene: Other: Spouse was an employee of Celgene (through August 2019). Absalon:Jazz Pharmaceuticals: Research Funding. OffLabel Disclosure: Yes, in this study, CPX-351 was also evaluated in pediatric AML

scholarly journals Caspofungin Weight-Based Dosing Supported by a Population Pharmacokinetic Model in Critically Ill Patients

2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Anne-Grete Märtson ◽  
Kim C. M. van der Elst ◽  
Anette Veringa ◽  
Jan G. Zijlstra ◽  
Albertus Beishuizen ◽  
...  
Keyword(s):  
Critically Ill ◽  
Rate Constant ◽  
Critically Ill Patients ◽  
Population Pharmacokinetic Model ◽  
Pharmacokinetic Model ◽  
Central Compartment ◽  
Peripheral Compartment ◽  
Population Pharmacokinetic ◽  
Content Type ◽  
The Mean

ABSTRACT The objective of this study was to develop a population pharmacokinetic model and to determine a dosing regimen for caspofungin in critically ill patients. Nine blood samples were drawn per dosing occasion. Fifteen patients with (suspected) invasive candidiasis had one dosing occasion and five had two dosing occasions, measured on day 3 (±1) of treatment. Pmetrics was used for population pharmacokinetic modeling and probability of target attainment (PTA). A target 24-h area under the concentration-time curve (AUC) value of 98 mg·h/liter was used as an efficacy parameter. Secondarily, the AUC/MIC targets of 450, 865, and 1,185 were used to calculate PTAs for Candida glabrata, C. albicans, and C. parapsilosis, respectively. The final 2-compartment model included weight as a covariate on volume of distribution (V). The mean V of the central compartment was 7.71 (standard deviation [SD], 2.70) liters/kg of body weight, the mean elimination constant (Ke) was 0.09 (SD, 0.04) h−1, the rate constant for the caspofungin distribution from the central to the peripheral compartment was 0.44 (SD, 0.39) h−1, and the rate constant for the caspofungin distribution from the peripheral to the central compartment was 0.46 (SD, 0.35) h−1. A loading dose of 2 mg/kg on the first day, followed by 1.25 mg/kg as a maintenance dose, was chosen. With this dose, 98% of the patients were expected to reach the AUC target on the first day and 100% of the patients on the third day. The registered caspofungin dose might not be suitable for critically ill patients who were all overweight (≥120 kg), over 80% of median weight (78 kg), and around 25% of lower weight (≤50 kg). A weight-based dose regimen might be appropriate for achieving adequate exposure of caspofungin in intensive care unit patients.

scholarly journals Population Pharmacokinetic Study of Amikacin Administered Once or Twice Daily to Febrile, Severely Neutropenic Adults

1998 ◽  
Vol 42 (4) ◽  
pp. 849-856 ◽  
Author(s):  
Michel Tod ◽  
Olivier Lortholary ◽  
Delphine Seytre ◽  
Rémi Semaoun ◽  
Bernard Uzzan ◽  
...  
Keyword(s):  
Body Weight ◽  
Creatinine Clearance ◽  
Volume Of Distribution ◽  
Pharmacokinetic Parameters ◽  
Population Pharmacokinetic ◽  
Ratio Test ◽  
Dosing Regimen ◽  
Mixed Effect ◽  
Neutropenic Patients ◽  
Kinetics Of

ABSTRACT Once-daily (o.d.) administration of 20 mg of amikacin per kg of body weight to neutropenic patients has been validated by clinical studies, but amikacin pharmacokinetics have been documented only for the 7.5-mg/kg twice-daily (b.i.d.) regimen in this population. In order to determine in neutropenic patients (i) the influence of the dosing regimen on the kinetics of amikacin, (ii) the linearity of kinetics of amikacin in the range of 7.5 to 20 mg/kg, and (iii) the influence of patient characteristics on the disposition of amikacin and (iv) to provide a rationale for dosing recommendations, we evaluated the population pharmacokinetics of amikacin administered to 57 febrile neutropenic adults (neutrophil count, <500/mm3) being treated for a hematological disorder and receiving amikacin at 7.5 mg/kg b.i.d. (n = 29) or 20 mg/kg o.d. (n = 28) and administered intravenously over 0.5 h. A total of 278 blood samples were obtained (1 to 14 samples per patient) during one or several administration intervals (1 to 47). Serum amikacin levels were measured by the enzyme-multiplied immunoassay technique. A mixed-effect modeling approach was used to fit a bicompartmental model to the data (NONMEM software). The influences of the dosing regimen and the demographic and biological indices on the pharmacokinetic parameters of amikacin were evaluated by the maximum-likelihood ratio test on the population model. The dosing regimen had no influence on amikacin pharmacokinetic parameters, i.e., the kinetics of amikacin were linear over the range of 7.5 to 20 mg/kg. Amikacin elimination clearance (CL) was only correlated with creatinine clearance or its covariates, namely, sex, age, body weight, and serum creatinine level. The interindividual variability of CL was 21%, while those of the central volume of distribution, the distribution clearance, and the tissue volume of distribution were 15, 30, and 25%, respectively. On the basis of the expected distribution of amikacin concentrations in this population, dosing recommendations as a function of creatinine clearance (CLCR) are proposed: for patients with normal renal function (CLCR of 80 to 130 ml/min), 20 mg/kg o.d. is recommended, whereas for patients with severe renal impairment (CLCR, 10 to 20 ml/min), a dosage of 17 mg/kg every 48 h is recommended.

scholarly journals Using Population Pharmacokinetic Modeling and Monte Carlo Simulations To Determine whether Standard Doses of Piperacillin in Piperacillin-Tazobactam Regimens Are Adequate for the Management of Febrile Neutropenia

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Fekade Bruck Sime ◽  
Uwe Hahn ◽  
Morgyn S. Warner ◽  
Ing Soo Tiong ◽  
Michael S. Roberts ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Febrile Neutropenia ◽  
Rate Constant ◽  
Central Compartment ◽  
Pharmacokinetic Analysis ◽  
Therapeutic Drug ◽  
Population Pharmacokinetic ◽  
Parameter Estimates ◽  
Target Attainment ◽  
Neutropenic Patients

ABSTRACT Changes in the pharmacokinetics of piperacillin in febrile neutropenic patients have been reported to result in suboptimal exposures. This study aimed to develop a population pharmacokinetic model for piperacillin and perform dosing simulation to describe optimal dosing regimens for hematological malignancy patients with febrile neutropenia. Concentration-time data were obtained from previous prospective observational pharmacokinetic and interventional therapeutic drug monitoring studies. Nonparametric population pharmacokinetic analysis and Monte Carlo dosing simulations were performed with the Pmetrics package for R. A two-compartment model, with between-subject variability for clearance (CL), adequately described the data from 37 patients (21 males, age of 59 ± 12 years [means ± standard deviations] and weight of 77 ± 16 kg). Parameter estimates were CL of 18.0 ± 4.8 liters/h, volume of distribution of the central compartment of 14.3 ± 7.3 liters, rate constant for piperacillin distribution from the central to peripheral compartment of 1.40 ± 1.35 h−1, and rate constant for piperacillin distribution from the peripheral to central compartment of 4.99 ± 7.81 h−1. High creatinine clearance (CLCR) was associated with reduced probability of target attainment (PTA). Extended and continuous infusion regimens achieved a high PTA of >90% for an unbound concentration of piperacillin remaining above the MIC (fT >MIC) of 50%. Only continuous regimens achieved >90% PTA for 100% fT >MIC when CLCR was high. The cumulative fraction of response (FTA, for fractional target attainment) was suboptimal (<85%) for conventional regimens for both empirical and directed therapy considering 50% and 100% fT >MIC. FTA was maximized with prolonged infusions. Overall, changes in piperacillin pharmacokinetics and the consequences on therapeutic dosing requirements appear similar to those observed in intensive care patients. Guidelines should address the altered dosing needs of febrile neutropenic patients exhibiting high CLCR or with known/presumed infections from high-MIC bacteria.

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