scholarly journals Population Pharmacokinetics of Intramuscular Quinine in Children with Severe Malaria

2001 ◽  
Vol 45 (6) ◽  
pp. 1803-1809 ◽  
Author(s):  
Sanjeev Krishna ◽  
Nelamangala V. Nagaraja ◽  
Tim Planche ◽  
Tsiri Agbenyega ◽  
George Bedo-Addo ◽  
...  

ABSTRACT We present the first population pharmacokinetic analysis of quinine in patients with Plasmodium falciparum malaria. Ghanaian children (n = 120; aged 12 months to 10 years) with severe malaria received an intramuscular loading dose of quinine dihydrochloride (20 mg/kg of body weight). A two-compartment model with first-order absorption and elimination gave post hoc estimates for pharmacokinetic parameters that were consistent with those derived from non-population pharmacokinetic studies (clearance [CL] = 0.05 liter/h/kg of body weight; volume of distribution in the central compartment [V 1] = 0.65 liter/kg; volume of distribution at steady state = 1.41 liter/kg; half-life at β phase = 19.9 h). There were no covariates (including age, gender, acidemia, anemia, coma, parasitemia, or anticonvulsant use) that explained interpatient variability in weight-normalized CL and V 1. Intramuscular quinine was associated with minor, local toxicity in some patients (13 of 108; 12%), and 11 patients (10%) experienced one or more episodes of postadmission hypoglycemia. A loading dose of intramuscular quinine results in predictable population pharmacokinetic profiles in children with severe malaria and may be preferred to the intravenous route of administration in some circumstances.

2019 ◽  
Vol 8 (10) ◽  
pp. 1563 ◽  
Author(s):  
In-Kyung Song ◽  
SoJeong Yi ◽  
Hyeong-Seok Lim ◽  
Ji-Hyun Lee ◽  
Eun-Hee Kim ◽  
...  

Dexmedetomidine is a selective alpha-2 adrenergic agonist with concurrent sedative and analgesic effects, and it is being increasingly used in pediatric anesthesia and intensive care. This study aimed to investigate the pharmacokinetics of intravenous dexmedetomidine in mechanically ventilated children in the intensive care unit (ICU) after neurosurgery. Pediatric patients aged 2–12 years, who were mechanically ventilated in ICU after neurosurgery, were allocated into a low-dose (n = 15) or high-dose (n = 14) group. The low-dose group received dexmedetomidine at a loading dose of 0.25 µg/kg for 10 min, followed by a maintenance dose of 0.25 µg/kg/h for 50 min, whereas the high-dose group received dexmedetomidine at a loading dose of 0.5 µg/kg for 10 min, followed by a maintenance dose of 0.5 µg/kg/h for 50 min. Serial blood samples were collected for a pharmacokinetic analysis up to 480 min after the end of the infusion. The sedative effect of dexmedetomidine was assessed using the Bispectral Index and University of Michigan Sedation Scale. Adverse reactions, electrocardiography findings, and vital signs were monitored for a safety assessment. A population pharmacokinetic analysis was performed using non-linear mixed effects modeling. Dexmedetomidine induced a moderate-to-deep degree of sedation during infusion in both groups. The pharmacokinetics of dexmedetomidine were best described by a two-compartment disposition model with first-order elimination kinetics. The parameters were standardized for a body weight of 70 kg using an allometric power model. The population estimates (95% confidence interval) per 70 kg body weight were as follows: clearance of 81.0 (72.9–90.9) L/h, central volume of distribution of 64.2 (50.6–81.0) L, intercompartment clearance of 116.4 (90.6–156.0) L/h, and peripheral volume of distribution of 167 (132–217) L. No serious adverse reactions or hemodynamic changes requiring the discontinuation of dexmedetomidine were observed. Dexmedetomidine had increased clearance and volume of distribution in mechanically ventilated children in ICU after neurosurgery, thereby indicating the need to adjust the dosage to obtain a target plasma concentration.


Author(s):  
Ryan D Dunn ◽  
Ryan L Crass ◽  
Joseph Hong ◽  
Manjunath P Pai ◽  
Lynne C Krop

Abstract Purpose To compare methods of estimating vancomycin volume of distribution (V) in adults with class III obesity. Methods A retrospective, multicenter pharmacokinetic analysis of adults treated with vancomycin and monitored through measurement of peak and trough concentrations was performed. Individual pharmacokinetic parameter estimates were obtained via maximum a posteriori Bayesian analysis. The relationship between V and body weight was assessed using linear regression. Mean bias and root-mean-square error (RMSE) were calculated to assess the precision of multiple methods of estimating V. Results Of 241 patients included in the study sample, 159 (66.0%) had a BMI of 40.0–49.9 kg/m2, and 82 (34.0%) had a BMI of ≥50.0 kg/m2. The median (5th, 95th percentile) weight of patients was 136 (103, 204) kg, and baseline characteristics were similar between BMI groups. The mean ± S.D. V was lower in patients with a BMI of 40.0–49.9 kg/m2 than in those with a BMI of ≥50.0 kg/m2 (72.4 ± 19.6 L versus 79.3 ± 20.6 L, p = 0.009); however, body size poorly predicted V in regression analyses (R2 < 0.20). A fixed estimate of V (75 L) or use of 0.52 L/kg by total body weight yielded similar bias and error in this population. Conclusion Results of the largest analysis of vancomycin V in class III obesity to date indicated that use of a fixed V value (75 L) and use of a TBW-based estimate (0.52 L/kg) for estimation of vancomycin V in patients with a BMI of ≥40.0 kg/m2 have similar bias. Two postdistribution vancomycin concentrations are needed to accurately determine patient-specific pharmacokinetic parameters, estimate AUC, and improve the precision of vancomycin dosing in this patient population.


2021 ◽  
Vol 12 ◽  
Author(s):  
Bin Du ◽  
Yue Zhou ◽  
Bo-Hao Tang ◽  
Yue-E Wu ◽  
Xin-Mei Yang ◽  
...  

Objectives: Augmented renal clearance (ARC) of primarily renally eliminated antibacterial agents may result in subtherapeutic antibiotic concentrations and, as a consequence, worse clinical outcomes. Cefathiamidine is frequently used as empirical antimicrobial therapy in children with ARC, but pharmacokinetic studies in infants are lacking. This population pharmacokinetic study in infants with ARC was conducted to determine optimal dosing regimens of cefathiamidine.Methods: The population pharmacokinetics was conducted in 20 infants treated with cefathiamidine. Plasma samples of cefathiamidine were collected using opportunistic sampling, and the concentrations were detected by UPLC-MS/MS. Data analysis was performed to determine pharmacokinetic parameters and to characterize pharmacokinetic variability of cefathiamidine using nonlinear mixed effects modelling (NONMEM) software program.Results: The data (n = 36) from 20 infants (age range, 0.35–1.86 years) with ARC were fitted best with a 1-compartment model. Allometrically scaled weight and age as significant covariates influenced cefathiamidine pharmacokinetics. The median (range) values of estimated clearance and the volume of distribution were 0.22 (0.09–0.29) L/h/kg and 0.34 (0.24–0.41) L/kg, respectively. Monte Carlo simulations showed that the cefathiamidine doses of 100 mg/kg/day q12 h, 50 mg/kg/day q8 h and 75 mg/kg/day q6 h were chosen for bacteria with MIC 0.25, 0.5 and 2 mg/L, respectively.Conclusion: The population pharmacokinetic model of cefathiamidine for infants with ARC was developed. The PTA - based dosing regimens were recommended based on the final model.


2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Muaaz Munir ◽  
Huma Rasheed ◽  
Muhammad Imran Khokhar ◽  
Rizwan Rasul Khan ◽  
Hafiz Asad Saeed ◽  
...  

Background: Vancomycin is a narrow therapeutic agent, and it is necessary to optimize the dose to achieve safe therapeutic outcomes. The purpose of this study was to identify the significant covariates for vancomycin clearance and to optimize the dose among surgical patients in Pakistan.Methods: Plasma concentration data of 176 samples collected from 58 surgical patients treated with vancomycin were used in this study. A population pharmacokinetic model was developed on NONMEM® using plasma concentration–time data. The effect of all available covariates was evaluated on the pharmacokinetic parameters of vancomycin by stepwise covariate modeling. The final model was evaluated using bootstrap, goodness-of-fit plots, and visual predictive checks.Results: The pharmacokinetics of vancomycin followed a one-compartment model with first-order elimination. The vancomycin clearance (CL) and volume of distribution (Vd) were 2.45 L/h and 22.6 l, respectively. Vancomycin CL was influenced by creatinine clearance (CRCL) and body weight of the patients; however, no covariate was significant for its effect on the volume of distribution. Dose tailoring was performed by simulating dosage regimens at a steady state based on the CRCL of the patients. The tailored doses were 400, 600, 800, and 1,000 mg for patients with a CRCL of 20, 60, 100, and 140 ml/min, respectively.Conclusion: Vancomycin CL is influenced by CRCL and body weight of the patient. This model can be helpful for the dose tailoring of vancomycin based on renal status in Pakistani patients.


2016 ◽  
Vol 60 (11) ◽  
pp. 6550-6557 ◽  
Author(s):  
Abdulaziz S. Alobaid ◽  
Steven C. Wallis ◽  
Paul Jarrett ◽  
Therese Starr ◽  
Janine Stuart ◽  
...  

ABSTRACTOur objective was to describe the population pharmacokinetics of fluconazole in a cohort of critically ill nonobese, obese, and morbidly obese patients. Critically ill patients prescribed fluconazole were recruited into three body mass index (BMI) cohorts, nonobese (18.5 to 29.9 kg/m2), obese (30.0 to 39.9 kg/m2), and morbidly obese (≥40 kg/m2). Serial fluconazole concentrations were determined using a validated chromatographic method. Population pharmacokinetic analysis and Monte Carlo dosing simulations were undertaken with Pmetrics. Twenty-one critically ill patients (11 male) were enrolled, including obese (n= 6) and morbidly obese (n= 4) patients. The patients mean ± standard deviation (SD) age, weight, and BMI were 54 ± 15 years, 90 ± 24 kg, and 31 ± 9 kg/m2, respectively. A two-compartment linear model described the data adequately. The mean ± SD population pharmacokinetic parameter estimates were clearance (CL) of 0.95 ± 0.48 liter/h, volume of distribution of the central compartment (Vc) of 15.10 ± 11.78 liter, intercompartmental clearance from the central to peripheral compartment of 5.41 ± 2.28 liter/h, and intercompartmental clearance from the peripheral to central compartment of 2.92 ± 4.95 liter/h. A fluconazole dose of 200 mg daily was insufficient to achieve an area under the concentration-time curve for the free, unbound drug fraction/MIC ratio of 100 for pathogens with MICs of ≥2 mg/liter in patients with BMI of >30 kg/m2. A fluconazole loading dose of 12 mg/kg and maintenance dose of 6 mg/kg/day achieved pharmacodynamic targets for higher MICs. A weight-based loading dose of 12 mg/kg followed by a daily maintenance dose of 6 mg/kg, according to renal function, is required in critically ill patients for pathogens with a MIC of 2 mg/liter.


2019 ◽  
Vol 64 (1) ◽  
Author(s):  
James M. Kidd ◽  
Colleen M. Sakon ◽  
Louise-Marie Oleksiuk ◽  
Jeffrey J. Cies ◽  
Rebecca S. Pettit ◽  
...  

ABSTRACT Adults with cystic fibrosis (CF) frequently harbor Staphylococcus aureus, which is increasingly antibiotic resistant. Telavancin is a once-daily rapidly bactericidal antibiotic active against methicillin-, linezolid-, and ceftaroline-resistant S. aureus. Because CF patients experience alterations in pharmacokinetics, the optimal dose of telavancin in this population is unknown. Adult CF patients (n = 18) admitted for exacerbations received 3 doses of telavancin 7.5 mg/kg of body weight (first 6 patients) or 10 mg/kg (final 12 patients) every 24 h (q24h). Population pharmacokinetic models with and without covariates were fitted using the nonparametric adaptive grid algorithm in Pmetrics. The final model was used to perform 5,000-patient Monte Carlo simulations for multiple telavancin doses. The best fit was a 2-compartment model describing the volume of distribution of the central compartment (Vc) as a multiple of total body weight (TBW) and the volume of distribution of the central compartment scaled to total body weight (Vθ) normalized by the median observed value (Vc = Vθ × TBW/52.1) and total body clearance (CL) as a linear function of creatinine clearance (CRCL) (CL = CLNR + CLθ × CRCL), where CLNR represents nonrenal clearance and CLθ represents the slope term on CRCL to estimate renal clearance. The mean population parameters were as follows: Vθ, 4.92  ± 0.76 liters · kg−1; CLNR, 0.59  ± 0.30 liters · h−1; CLθ, 5.97 × 10−3 ± 1.24 × 10−3; Vp (volume of the peripheral compartment), 3.77  ± 1.41 liters; Q (intercompartmental clearance), 4.08  ± 2.17 liters · h−1. The free area under the concentration-time curve (fAUC) values for 7.5 and 10 mg/kg were 30  ± 4.6 and 52  ± 12 mg · h/liter, respectively. Doses of 7.5 mg/kg and 10 mg/kg achieved 76.5% and 100% probability of target attainment (PTA) at a fAUC/MIC threshold of >215, respectively, for MIC of ≤0.12 mg/liter. The probabilities of reaching the acute kidney injury (AKI) threshold AUC (763 mg · h · liter−1) for these doses were 0% and 0.96%, respectively. No serious adverse events occurred. Telavancin 10 mg/kg yielded optimal PTA and minimal risk of AKI, suggesting that this FDA-approved dose is appropriate to treat acute pulmonary exacerbations in CF adults. (The clinical trial discussed in this study has been registered at ClinicalTrials.gov under identifier NCT03172793.)


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1071-1071
Author(s):  
Mirjam Nadine Trame ◽  
Lesley Mitchell ◽  
Christoph Male ◽  
Jeffrey S. Barrett ◽  
Georg Hempel ◽  
...  

Abstract Abstract 1071 Poster Board I-93 Introduction: Enoxaparin, a low-molecular-weight-heparin (LMWH), is used off-label in children to prevent symptomatic thromboembolism when acute anticoagulation or secondary prevention is required due to venous thrombosis or stroke. This investigation was conducted because of concerns of altered pharmacokinetics and a lack of safety and efficacy data when used in children. Patients and Methods: Data of 126 children and adolescents with a median age of 5.9 years receiving enoxaparin either as a once or twice daily dosing regimen were analyzed. Children < 12 months of age received a starting dose of 1.5 mg/kg followed by a maintenance dose of 1.3 mg/kg. Children > 12 months of age were started on 1 mg/kg followed by a maintenance dose of 1 mg/kg. Blood samples were drawn after patients reached steady-state on their maintenance dose at baseline prior to the next dose, and at 2, 4, 8 and 12 hours after administration. The median enoxaparin concentration in our population resulted in a median anti-factor Xa activity of 0.4 U/ml (range 0 – 1 U/ml anti-factor Xa). By means of population pharmacokinetics using nonlinear mixed-effects modelling (NONMEM) plasma concentration-time data were analyzed. Several covariates such as age, body weight and body surface area were tested on their effects on the pharmacokinetic parameters. Results: Using a two-compartment model the enoxaparin kinetics were described sufficiently. By using body weight and age as covariates for clearance (CL) and central volume of distribution (V1) the best results were obtained. The final population estimates of enoxaparin resulted to be: CL 7.11 ml h-1 kg-1 ± 14.3%, V1 7.31 ml kg-1 ± 33.5%, intercompartimental clearance (Q) 194 ml h-1 ± 24.7%, peripheral volume of distribution (V2) 45.1 l ± 52.5% and absorption rate (ka) 0.0799 h-1 ± 21.7% (estimates ± standard errors). Interindividual variability (IIV) was found to be 75.6% for CL and 78.4% for Q, respectively. Figure 1 shows the predicted activity time-course versus the measured activities for a representative patient. The model is capable of describing all aging and dosing groups of our childhood population (neonates, infants to adolescents). Conclusion: The high IIV in CL and Q in our population underlines the need for monitoring the activity and individualizing the dose. Further population pharmacokinetic/-dynamic investigations should be conducted to predict target enoxaparin levels or other new antithrombotic drugs for more safety and efficacy during antithrombotic therapy when used in children. Disclosures: Off Label Use: Enoxaparin (LMWH) is used off-label in children to prevent symptomatic thromboembolism..


1996 ◽  
Vol 40 (3) ◽  
pp. 575-580 ◽  
Author(s):  
B G Reigner ◽  
H A Welker

A metaanalysis was conducted on data from 172 subjects (healthy volunteers and uninfected patients) included in 10 pharmacokinetic studies of fleroxacin after oral administration. The objectives of this analysis were (i) to estimate the typical values of two key pharmacokinetic parameters, clearance over systemic availability (CL/F) and volume of distribution over systemic availability (V/F), after the administration of therapeutic doses and (ii) to study qualitatively and quantitatively the factors which influence the elimination and distribution of fleroxacin. The main pharmacokinetic parameters, CL/F and V/F, were analyzed separately by a standard two-stage approach. The covariates investigated were predicted creatinine clearance (CLCR), age, gender, body surface area, body weight, and lean body weight (LBW). The predicted CL/F and V/F were 83.5 ml/min and 101 liters, respectively, for a typical male subject (CLCR, 70 ml/min; LBW, 54 kg; age, 54 years). Modeling of CL/F indicated that this parameter increases linearly with CLCR, decreases linearly with age, and is 10.8 ml/min lower in females than in males. The best model for V/F showed a linear increase with LBW and a linear decrease with age. V/F was found to be 20.4 liters greater in males than in females. In conclusion, this metaanalysis has shown that CLCR, age, and gender influence the elimination of fleroxacin from the body, whereas V/F is influenced by LBW, age, and gender.


1998 ◽  
Vol 42 (4) ◽  
pp. 849-856 ◽  
Author(s):  
Michel Tod ◽  
Olivier Lortholary ◽  
Delphine Seytre ◽  
Rémi Semaoun ◽  
Bernard Uzzan ◽  
...  

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.


2013 ◽  
Vol 118 (4) ◽  
pp. 853-862 ◽  
Author(s):  
Stanislas Grassin-Delyle ◽  
Roland Couturier ◽  
Emuri Abe ◽  
Jean Claude Alvarez ◽  
Philippe Devillier ◽  
...  

Abstract Background: Pediatric cardiac surgery patients are at high risk for bleeding, and the antifibrinolytic drug tranexamic acid (TA) is often used to reduce blood loss. However, dosing schemes remain empirical as a consequence of the absence of pharmacokinetic study in this population. The authors’ objectives were thus to investigate the population pharmacokinetics of TA in pediatric cardiac surgery patients during cardiopulmonary bypass (CPB). Methods: Twenty-one patients were randomized to receive TA either continuously (10 mg/kg followed by an infusion of 1 mg·kg−1·h−1 throughout the operation, and 10 mg/kg into the CPB) or discontinuously (10 mg/kg, then 10 mg/kg into the CPB and 10 mg·kg−1·h−1 at the end of CPB). Serum concentrations were measured at eight time points with chromatography–mass spectrometry and the data were modeled using Monolix (Lixoft, Orsay, France). Results: Tranexamic acid pharmacokinetics was ascribed to a two-compartment open model. The main covariate effects were body weight and CPB. Representative pharmacokinetic parameters adjusted to a 70-kg body weight were as follows: systemic clearance, 2.45 l/h; volume of distribution in the central compartment, 14.1 l; intercompartmental clearance, 5.74 l/h; and peripheral volume, 32.8 l. In accordance with this model, the authors proposed a weight-adjusted dosing scheme to maintain effective TA concentrations in children during surgery, consisting of one loading dose followed by a continuous infusion. Conclusions: The authors report for the first time the pharmacokinetics of TA in children undergoing cardiac surgery with CPB, and propose a dosing scheme for optimized TA administration in those children.


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