scholarly journals Population Pharmacokinetics of Arbekacin in Patients Infected with Methicillin-Resistant Staphylococcus aureus

2006 ◽  
Vol 50 (11) ◽  
pp. 3754-3762 ◽  
Author(s):  
Yusuke Tanigawara ◽  
Reiko Sato ◽  
Kunihiko Morita ◽  
Mitsuo Kaku ◽  
Naoki Aikawa ◽  
...  

ABSTRACT Arbekacin, a derivative of dibekacin, is an aminoglycoside developed and widely used in Japan for the treatment of patients infected with methicillin-resistant Staphylococcus aureus (MRSA). The population pharmacokinetics of arbekacin was investigated in the Japanese, using 353 patients infected with MRSA and 50 healthy or renally impaired volunteers. The age of the study population ranged from 8 to 95 years, and weight ranged from 10.8 to 107 kg. In total, 1,581 serum arbekacin concentrations were measured (primarily from routine patient care) and used to perform the present pharmacokinetic analysis. Drug concentration-time data were well described by a two-compartment open model. Factors influencing arbekacin pharmacokinetics were investigated using a nonlinear mixed-effect model analysis. The best-developed model showed that drug clearance (CL) was related to creatinine clearance (CLCR), age, and body weight (WT), as expressed by CL (liter/h) = 0.0319CLCR + (26.5/age) (CLCR < 80 ml/min) and CL (liter/h) = 0.0130 CLCR + 0.0342WT + (26.5/age) (CLCR ≥ 80 ml/min). The volume of distribution for the central and peripheral compartments was different in healthy subjects and infected patients, and this difference was more pronounced among disease types. The elderly subjects (aged 80 years or over) exhibited, on average, a 19% greater volume for the central compartment. The volumes for the peripheral compartment were 50.6 liters in patients with pneumonia and 24.3 liters in patients with sepsis. The population pharmacokinetic parameters of arbekacin obtained here are useful for optimal use of this aminoglycoside in the treatment of MRSA-infected patients.

Drug Research ◽  
2020 ◽  
Vol 70 (05) ◽  
pp. 199-205
Author(s):  
Takahiro Nishimura ◽  
Haruichi Kohno ◽  
Hideaki Nagai ◽  
Daisuke Maruoka ◽  
Yuichi Koike ◽  
...  

AbstractIn Japan, tuberculosis has been recognized as one of the major infections requiring urgent measures because of its high morbidity rate even now especially in elderly people suffering from tuberculosis during the past epidemic and its reactivation. Hence, many Japanese clinicians have made efforts to suppress the onset of tuberculosis and treat it effectively. The objectives of this study are to (1) identify covariate(s) that may explain the variation of rifampicin, which is the key antitubercular agent, under the steady-state by evaluating its population pharmacokinetics and (2) to propose an appropriate dosing method of rifampicin to Japanese patients. For this purpose, serum concentration–time data were obtained from 138 patients receiving rifampicin (300–450 mg) and isoniazid (300–400 mg) every day over 14 days, and analyzed using nonlinear mixed effects model. Thereby, population pharmacokinetic parameters were estimated followed by elucidating relations between the parameters and statistical factors. The analysis adopted one-compartment model including Lag-time by assuming that the absorption process is 0+1st order. The analyses demonstrate that meal affected the bioavailability, primary absorption rate constant, and zero order absorption time in the constructed model. A body weight calculated from the power model was selected as the covariate by the Stepwise Covariate Model method and found to highly affect the clearance in the range from −31.6% to 47.4%. We conclude that the dose in Japanese tuberculous patients can be well estimated by the power model formula and should be taken into consideration when rifampicin is administered.


2006 ◽  
Vol 50 (11) ◽  
pp. 3763-3769 ◽  
Author(s):  
Reiko Sato ◽  
Yusuke Tanigawara ◽  
Mitsuo Kaku ◽  
Naoki Aikawa ◽  
Kihachiro Shimizu

ABSTRACT Arbekacin is widely used in Japan for the treatment of patients infected with methicillin-resistant Staphylococcus aureus (MRSA). In this study, we have determined the optimal concentration targets of arbekacin for both efficacy and safety. A pharmacokinetic-pharmacodynamic analysis was performed to relate exposure to the drug and clinical cure/improvement or nephrotoxicity. Since we have reported the population pharmacokinetic parameters for arbekacin in the preceding paper (Y. Tanigawara, R. Sato, K. Morita, M. Kaku, N. Aikawa, and K. Shimizu, Antimicrob. Agents Chemother. 50:3754-3762, 2006), individual exposure parameters, such as area under the concentration-time curve (AUC), peak concentration (C max), AUC/MIC, C max/MIC, and trough concentration (C min) were estimated by the Bayesian method. Logistic regression was used to describe the relationship between exposure to the drug and the probability of clinical cure/improvement or nephrotoxicity. For the clinical efficacy analysis, 174 patients confirmed to have an MRSA infection were evaluated. The C max, C min, and AUC of arbekacin were associated with the probability of clinical cure/improvement during monotherapy. It was shown that the probability of cure/improvement rose when the C max of arbekacin was increased, with an odds ratio of 6.7 for a change in C max from 7.9 to 12.5 μg/ml (P = 0.037). For the nephrotoxic risk analysis, 333 patients were included, regardless of whether a pathogen was identified. Logistic regression analysis revealed C min and AUC as risk factors of nephrotoxicity (P < 0.005). The estimated probabilities of arbekacin-induced nephrotoxicity were 2.5, 5.2, and 13.1% when the C min values were 1, 2, and 5 μg/ml, respectively. The present findings are useful for optimizing the individual dose of arbekacin for the treatment of MRSA-infected patients.


1998 ◽  
Vol 42 (7) ◽  
pp. 1783-1787 ◽  
Author(s):  
Bryan Facca ◽  
Bill Frame ◽  
Steve Triesenberg

ABSTRACT Ceftizoxime is a widely used beta-lactam antimicrobial agent, but pharmacokinetic data for use with clinically ill patients are lacking. We studied the population pharmacokinetics of ceftizoxime in 72 clinically ill patients at a community-based, university-affiliated hospital. A population pharmacokinetic model for ceftizoxime was created by using a prospective observational design. Ceftizoxime was administered by continuous infusion to treat patients with proven or suspected bacterial infections. While the patients were receiving infusions of ceftizoxime, serum samples were collected for pharmacokinetic analysis with the nonlinear mixed-effect modeling program NONMEM. In addition to clearance and volume of distribution, various comorbidities were examined for their influence on the kinetics. All 72 subjects completed the study, and 114 serum samples were collected. Several demographic and comorbidity variables, namely, age, weight, serum creatinine levels, congestive heart failure, and long-term ventilator dependency, had a significant impact on the estimate for ceftizoxime clearance. A mixture model, or two populations for estimation of ceftizoxime clearance, was discovered. One population presented with an additive clearance component of 1.6 liters per h. In addition, a maximizer function for serum creatinine levels was found. In summary, two models for ceftizoxime clearance, mixture and nonmixture, were found and are presented. Clearance for ceftizoxime can be estimated with commonly available clinical information and the models presented. From the clearance estimates, the dose of ceftizoxime to maintain the desired concentration in serum can be determined. Work is needed to validate the model for drug clearance and to evaluate its predictive performance.


2005 ◽  
Vol 49 (11) ◽  
pp. 4429-4436 ◽  
Author(s):  
Grant Langdon ◽  
Justin Wilkins ◽  
Lynn McFadyen ◽  
Helen McIlleron ◽  
Peter Smith ◽  
...  

ABSTRACT This study was designed to describe the population pharmacokinetics of rifapentine (RFP) and 25-desacetyl RFP in a South African pulmonary tuberculosis patient population. Special reference was made to studying the influence of previous exposure to rifampin (RIF) and the variability in pharmacokinetic parameters between patients and between occasions and the influence of different covariates. Patients were included in the study if they had been receiving first-line antimycobacterial therapy (rifampin, isoniazid, pyrazinamide, and ethambutol) for not less than 4 weeks and not more than 6 weeks and were divided into three RFP dosage groups based on weight: 600 mg, <45 kg; 750 mg, 46 to 55 kg; and 900 mg, >55 kg. Participants received a single oral dose of RFP together with concomitant antimycobacterial agents, excluding RIF, on study days 1 and 5 after they ingested a soup-based meal. The RFP and 25-desacetyl RFP concentration-time data were analyzed by nonlinear mixed-effect modeling using NONMEM. The pharmacokinetics of the parent drug were modeled separately, and the individual pharmacokinetic parameters were used as inputs for the 25-desacetyl RFP pharmacokinetic model. A one-compartment disposition model was found to best describe the data for both the parent and the metabolite, and the metabolite was assumed to be formed only from the central compartment of the parent drug. Prior treatment with RIF did not alter the pharmacokinetics of RFP but appeared to increase the excretion of 25-desacetyl RFP in a nonlinear fashion. The RFP oral clearance and volume of distribution were found to increase by 0.049 liter/h and 0.691 liter, respectively, with a 1-kg increase from the median weight of 50 kg. The oral clearance of 25-desacetyl RFP was found to be 35% lower in female patients. The model developed here describes the population pharmacokinetics of RFP and its primary metabolite in tuberculosis patients and includes the effects of prior administration with RIF and covariate factors.


2019 ◽  
Vol 104 (6) ◽  
pp. e42.2-e42
Author(s):  
Z Li ◽  
Z Jiao

The main goal of our study was to characterize the population pharmacokinetics of vancomycin in critically ill Chinese neonates to develop a pharmacokinetic model and investigate factors that have significant influences on the pharmacokinetics of vancomycin in this population.1 2 The study population consisted of 80neonates in the neonatal intensive care unit (ICU)from which 165 trough and peak concentrations of vancomycin were obtained.Nonlinear mixed effect modeling was used to develop a population pharmacokinetic model for vancomycin.4 The stability and predictive ability of the final model were evaluated based on diagnostic plots, normalized prediction distribution errorsandthe bootstrap method.Serum creatinine (Scr) and body weight were significant covariates on the clearance of vancomycin.5 6 The average clearance was 0.309L/h for a neonate with Scr of 23.3mmol/L and body weight of 2.9 kg. No obvious ethnic differences in the clearance of vancomycin were found relative to the earlier studies of Caucasian neonates. Moreover, the established model indicated that in patients with a greater renal clearance status, especially Scr < 15mmol/L,current guideline recommendationswould likely not achieve therapeuticarea under the concentration-time curve over24 h/minimum inhibitoryconcentration (AUC24h/MIC) ≥ 400.3 The exceptions to this areBritish National Formulary (2016–2017), Blue Book (2016) and Neofax (2017). Recommended dose regimensfor neonates with differentScrlevelsandpostmenstrual ageswere estimatedbased on Monte Carlo simulations andthe established model.These findings will be valuable for developing individualized dosage regimens in the neonatal ICU setting.ReferencesAbdel HO, Al OS, Nazer LH., Mubarak S, Le, J. Vancomycin pharmacokinetics and predicted dosage requirements in pediatric cancer patients. Journal of Oncology Pharmacy Practice 2015;22(3):448–453doi: 10.1177/1078155215591386Anderson, B. J., Allegaert, K., Jn, V. D. A., Cossey, V., &amp;Holford, N. H. ( 2007). Vancomycin pharmacokinetics in preterm neonates and the prediction of adult clearance. British Journal of Clinical Pharmacolog;63(1):75–84. doi: 10.1111/j.1365-2125.2006.02725.xAllegaert K, Anderson BJ, Jn, VDA, Vanhaesebrouck, S., & De, Z. F. ( 2007). Renal drug clearance in preterm neonates: relation to prenatal growth. Therapeutic Drug Monitoring, 29(3), 284–291. doi: 10.1097/FTD.0b013e31806db3f5Byon, W., Smith, M. K., Chan, P., Tortorici, M. A., Riley, S., & Dai, H., et al. ( 2013). Establishing best practices and guidance in population modeling: an experience with an internal population pharmacokinetic analysis guidance. CptPharmacometrics & Systems Pharmacology,2(7), e51. doi: 10.1016/j.cmpb.2010.04.018Capparelli, E. V., Lane, F. R., Romanowski, G. L., Pharm, M. F., Murray, W., & Sousa, P., et al. ( 2001). The influences of renal function and maturation on vancomycin elimination in newborns and infants. Journal of Clinical Pharmacology, 41(9), 927–934.Centers for Disease Control and Prevention. ( 2009). WHO Child Growth Standards. http://www.who.int/childgrowth/en. [EB/OL] 2017-09-12Disclosure(s)Nothing to disclose


2019 ◽  
Vol 20 (7) ◽  
pp. 592-600 ◽  
Author(s):  
Zhiqi Wang ◽  
Nan Zhang ◽  
Chaoyang Chen ◽  
Shuqing Chen ◽  
Junyu Xu ◽  
...  

Background: The Pharmacokinetics of Methotrexate (MTX) has been reported to show significant intersubject variability. MTX is metabolized by SHMT1 and transported by OATP1B1 and OATP1B3 both of which show genetic polymorphisms. The non-genetic and genetic factors may influence the pharmacokinetics of MTX. Objective: This study aimed to determine the pharmacokinetic parameters of MTX in Chinese patients and to investigate the effect of various non-genetic factors and genetic variants of OATP1B1, OATP1B3 on MTX’s pharmacokinetics. Method: MTX concentration and clinical characteristics data were collected from 71 rheumatoid arthritis patients. For each patient, SLC19A1, SHMT1, OATP1B1, and OATP1B3 genotyping were tested. Population pharmacokinetic analysis was performed by Nonlinear Mixed-Effect Modeling (NONMEM). MTX pharmacokinetic properties analysis was executed using the one-compartment pharmacokinetic model which incorporated first-order conditional estimation methods with interaction. Besides, the impact of genetic factors and demographic factors on MTX disposition were explored. Results: All the genotypes of steady-state plasma concentrations and OATP1B1 rs4149056, OATP1B1 rs2306283, and OATP1B3 rs7311358 were determined. The detected blood drug concentration reached the standard. Genotypes were all measured. At the same time, the population pharmacokinetic model of methotrexate was obtained CL(L·h-1) =8.25× e0.167× SNP (SNP: SLCO1B1 388A/A=3; SLCO1B1 388A/G=2; SLCO1B1 388G/G=1); V(L)= 32.8; Ka(h- 1)=1.69. Conclusion: : In our study, it was showed that OATP1B1-388 G>A SNP had a significant effect on CL/F. The factor should be considered when determining MTX dosing. However, prospective studies with a large number of participants are needed to validate the results of this study.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Soon Min Lee ◽  
Seungwon Yang ◽  
Soyoung Kang ◽  
Min Jung Chang

AbstractThe pharmacokinetics of vancomycin vary among neonates, and we aimed to conduct population pharmacokinetic analysis to determine the optimal dosage of vancomycin in Korean neonates. From a retrospective chart review, neonates treated with vancomycin from 2008 to 2017 in a neonatal intensive care unit (NICU) were included. Vancomycin concentrations were collected based on therapeutic drug monitoring, and other patient characteristics were gathered through electronic medical records. We applied nonlinear mixed-effect modeling to build the population pharmacokinetic model. One- and two-compartment models with first-order elimination were evaluated as potential structural pharmacokinetic models. Allometric and isometric scaling was applied to standardize pharmacokinetic parameters for clearance and volume of distribution, respectively, using fixed powers (0.75 and 1, respectively, for clearance and volume). The predictive performance of the final model was developed, and dosing strategies were explored using Monte Carlo simulations with AUC0–24 targets 400–600. The patient cohort included 207 neonates, and 900 vancomycin concentrations were analyzed. Only 37.4% of the analyzed concentrations were within trough concentrations 5–15 µg/mL. A one-compartment model with first-order elimination best described the vancomycin pharmacokinetics in neonates. Postmenstrual age (PMA) and creatinine clearance (CLcr) affected the clearance of vancomycin, and model evaluation confirmed the robustness of the final model. Population pharmacokinetic modeling and dose optimization of vancomycin in Korean neonates showed that vancomycin clearance was related to PMA and CLcr, as well as body weight. A higher dosage regimen than the typical recommendation is suggested.


2009 ◽  
Vol 53 (7) ◽  
pp. 2918-2927 ◽  
Author(s):  
L. Zeng ◽  
C. E. Nath ◽  
E. Y. L. Blair ◽  
P. J. Shaw ◽  
K. Stephen ◽  
...  

ABSTRACT Acyclovir is effective in the prevention and treatment of herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections. The aim of this study was to characterize the population pharmacokinetics of acyclovir observed following treatment with intravenous acyclovir and oral valacyclovir (valaciclovir) in young people with malignancy. Plasma acyclovir concentration-time data were collected from 43 patients (age range, 9 months to 20 years) who had been given multiple doses of acyclovir (5 mg/kg of body weight) and/or valacyclovir (10 mg/kg). Nonlinear mixed-effect modeling was employed to analyze acyclovir population pharmacokinetics and identify influential covariates. Simulations (n = 1,000) were conducted to explore the ability of the current doses to maintain acyclovir concentrations above the recommended 50% inhibitory concentration for HSV or VZV (0.56 mg/liter or 1.125 mg/liter, respectively) for more than 12 h. A one-compartment pharmacokinetic model with first-order elimination best described the acyclovir concentration-time data. The population mean estimates for clearance (CL), volume of distribution (V), absorption rate (ka ), and bioavailability (F) were 3.55 liters/h, 7.36 liters, 0.63 h−1, and 0.60, respectively. Inclusion of body weight and estimated creatinine CL (CLCR) in the final model reduced the interindividual variabilities in CL and V from 61% to 24% and from 75% to 36%, respectively. Simulations revealed that with the use of the current doses, maximal efficacy can be achieved in over 45% of patients weighing 25 to 50 kg and with CLCR levels of 2.0 to 4.0 liters/h/m2, but only in a much smaller proportion of patients, with low weights (10 kg) and high CLCRs (5.5 liters/h/m2), suggesting that higher doses are required for this subgroup. This validated population pharmacokinetic model for acyclovir may be used to develop dosing guidelines for safe and effective antiviral therapy in young people with malignancy.


2016 ◽  
Vol 51 (3) ◽  
pp. 209-218 ◽  
Author(s):  
Eun Kyoung Chung ◽  
Megan R. Fleming ◽  
S. Christian Cheatham ◽  
Michael B. Kays

Background: Doripenem population pharmacokinetics and dosing recommendations are limited in obesity. Objective: To evaluate the population pharmacokinetics and pharmacodynamics of doripenem in obese patients. Methods: Hospitalized adults with a body mass index (BMI) ≥ 40 kg/m2 or total body weight (TBW) ≥45.5 kg over their ideal body weight received doripenem 500 mg every 8 hours, infused over 1 hour. Population pharmacokinetic analyses were performed using NONMEM, and Monte Carlo simulations were performed for 5 intermittent and prolonged infusion dosing regimens to calculate probability of target attainment (PTA) at 40% and 100% fT>MIC (free drug concentrations above the minimum inhibitory concentration). Results: A total of 20 patients were studied: 10 in an intensive care unit (ICU) and 10 in a non-ICU. A 2-compartment model with first-order elimination best described the serum concentration-time data. Doripenem clearance (CL) was significantly associated with creatinine CL (CRCL), volume of the central compartment with TBW and ICU residence, and volume of the peripheral compartment with TBW ( P < 0.05). Using 40% fT>MIC, PTA was >90% for all simulated dosing regimens at MICs ≤2 mg/L. Using 100% fT>MIC, prolonged infusions of 1 g every 6 hours and 2 g every 8 hours achieved >90% PTA at MICs ≤2 mg/L. Conclusions: CRCL, ICU residence, and TBW are significantly associated with doripenem pharmacokinetics. Currently approved dosing regimens provide adequate pharmacodynamic exposures at 40% fT>MIC for susceptible bacteria in obese patients. However, prolonged infusions of larger doses are needed if a higher pharmacodynamic target is desired.


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