scholarly journals Use of Pharmacokinetic and Pharmacodynamic Principles To Determine Optimal Administration of Daptomycin in Patients Receiving Standardized Thrice-Weekly Hemodialysis

2011 ◽  
Vol 55 (4) ◽  
pp. 1677-1683 ◽  
Author(s):  
Nimish Patel ◽  
Katie Cardone ◽  
Darren W. Grabe ◽  
Shari Meola ◽  
Christopher Hoy ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Monte Carlo ◽  
Body Weight ◽  
Infective Endocarditis ◽  
Population Model ◽  
Area Under The Curve ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Exposure Profile ◽  
Trough Concentrations

ABSTRACTThis study identified optimal daptomycin dosing for patients receiving thrice-weekly hemodialysis (HD). Twelve adult patients on HD received daptomycin at 6 mg/kg of body weight intravenously (i.v.) one time; plasma and dialysate samples were collected over 3 days. A 2-compartment model with separate HD and non-HD clearance terms was fit to the data. A series of 9,999-subject Monte Carlo simulations (MCS) was performed to identify HD dosing schemes providing efficacy and toxicity profiles comparable to those obtained for MCS employing the daptomycin population pharmacokinetic (PK) model derived from patients in theStaphylococcus aureusbacteremia-infective endocarditis (SAB-IE) study. For efficacy, we selected the HD dosing scheme which generated an area-under-the-curve (AUC) exposure profile comparable to that for the SAB-IE population model. For toxicity, we selected HD dosing schemes that minimized trough concentrations of ≥24.3 mg/liter. Separate HD dosing schemes were developed for each FDA-approved regimen and for two weekly interdialytic periods (48 and 72 h). Administration of the same parent daptomycin dose intra-HD and post-HD resulted in AUC, maximum concentration of drug in serum (Cmax), andCminvalues most comparable to those for SAB-IE simulations for the 48-hour interdialytic period. In contrast, all candidate HD dosing schemes provided AUC48-72values that were at least 50% lower than the SAB-IE AUC48-72values. Increasing the parent dose by 50% provided more comparable AUC48-72values while maintaining acceptableCminvalues. Administration of the daptomycin parent dose intra-HD or post-HD was optimal for the 48-h interdialytic period. For the 72-h interdialytic period, clinicians should consider increasing the dose by 50% to achieve more comparable AUC48-72values.

scholarly journals Is the Recommended Once-Daily Dose of Lamivudine Optimal in West African HIV-Infected Children?

2010 ◽  
Vol 54 (8) ◽  
pp. 3280-3286 ◽  
Author(s):  
Naïm Bouazza ◽  
Déborah Hirt ◽  
Christophe Bardin ◽  
Serge Diagbouga ◽  
Boubacar Nacro ◽  
...  
Keyword(s):  
Body Weight ◽  
Area Under The Curve ◽  
Compartment Model ◽  
Individual Characteristics ◽  
Pharmacokinetic Parameters ◽  
Population Pharmacokinetic ◽  
Parameter Estimates ◽  
Ratio Test ◽  
Once Daily ◽  
Time Courses

ABSTRACT We aimed in this study to describe lamivudine concentration-time courses in treatment-naïve children after once-daily administration, to study the effects of body weight and age on lamivudine pharmacokinetics, and to simulate an optimized administration scheme. For this purpose, lamivudine concentrations were measured in 49 children after at least 2 weeks of didanosine-lamivudine-efavirenz treatment. A total of 148 plasma lamivudine concentrations were measured, and a population pharmacokinetic model was developed with NONMEM. The influence of individual characteristics was tested using a likelihood ratio test. Children were divided into two groups, according to their pharmacokinetic parameters, thanks to tree regression analysis. For each patient, the area under the curve was derived from estimated individual pharmacokinetic parameters. Different once-daily doses were simulated in each group, to obtain the same exposure in children as the mean effective exposure in adults (8.9 mg/liter·h). A two-compartment model in which the slope of distribution is assumed to be equal to the absorption rate constant adequately described the data. Parameter estimates were standardized for a mean standard body weight using an allometric model. Children were then divided into 2 groups according to body weight: CL/F was significantly higher in children weighing less than 17 kg (1.12 liters/h/kg) than in children over 17 kg (0.95 liters/h/kg; P = 0.01). The target mean AUC of 8.9 mg/liters·h was obtained with a 10-mg/kg once-daily lamivudine (3TC) dose for children below 17 kg; the recommended dose of 8 mg/kg seems to be sufficient in children weighing more than 17 kg. These assumptions should be prospectively confirmed.

scholarly journals Population Pharmacokinetic Analysis of Voriconazole and Anidulafungin in Adult Patients with Invasive Aspergillosis

2014 ◽  
Vol 58 (8) ◽  
pp. 4718-4726 ◽  
Author(s):  
Ping Liu ◽  
Diane R. Mould
Keyword(s):  
Invasive Aspergillosis ◽  
Area Under The Curve ◽  
Compartment Model ◽  
Population Pharmacokinetic Analysis ◽  
Institutional Review Boards ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Parameter Estimates ◽  
First Order ◽  
Two Compartment Model

ABSTRACTTo assess the pharmacokinetics (PK) of voriconazole and anidulafungin in patients with invasive aspergillosis (IA) in comparison with other populations, sparse PK data were obtained for 305 adults from a prospective phase 3 study comparing voriconazole and anidulafungin in combination versus voriconazole monotherapy (voriconazole, 6 mg/kg intravenously [IV] every 12 h [q12h] for 24 h followed by 4 mg/kg IV q12h, switched to 300 mg orally q12h as appropriate; with placebo or anidulafungin IV, a 200-mg loading dose followed by 100 mg q24h). Voriconazole PK was described by a two-compartment model with first-order absorption and mixed linear and time-dependent nonlinear (Michaelis-Menten) elimination; anidulafungin PK was described by a two-compartment model with first-order elimination. For voriconazole, the normal inverse Wishart prior approach was implemented to stabilize the model. Compared to previous models, no new covariates were identified for voriconazole or anidulafungin. PK parameter estimates of voriconazole and anidulafungin are in agreement with those reported previously except for voriconazole clearance (the nonlinear clearance component became minimal). At a 4-mg/kg IV dose, voriconazole exposure tended to increase slightly as age, weight, or body mass index increased, but the difference was not considered clinically relevant. Estimated voriconazole exposures in IA patients at 4 mg/kg IV were higher than those reported for healthy adults (e.g., the average area under the curve over a 12-hour dosing interval [AUC0–12] at steady state was 46% higher); while it is not definitive, age and concomitant medications may impact this difference. Estimated anidulafungin exposures in IA patients were comparable to those reported for the general patient population. This study was approved by the appropriate institutional review boards or ethics committees and registered on ClinicalTrials.gov (NCT00531479).

scholarly journals Population Pharmacokinetic Study of the Suitability of Standard Dosing Regimens of Amikacin in Critically Ill Patients with Open-Abdomen and Negative-Pressure Wound Therapy

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Cédric Carrié ◽  
Faustine Delzor ◽  
Stéphanie Roure ◽  
Vincent Dubuisson ◽  
Laurent Petit ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Body Weight ◽  
Monte Carlo Simulations ◽  
Critically Ill ◽  
Negative Pressure ◽  
Critically Ill Patients ◽  
Open Abdomen ◽  
Population Pharmacokinetic ◽  
Pressure Therapy ◽  
Dosing Regimens

ABSTRACT The aim was to assess the appropriateness of recommended regimens for empirical MIC coverage in critically ill patients with open-abdomen and negative-pressure therapy (OA/NPT). Over a 5-year period, every critically ill patient who received amikacin and who underwent therapeutic drug monitoring (TDM) while being treated by OA/NPT was retrospectively included. A population pharmacokinetic (PK) modeling was performed considering the effect of 10 covariates (age, sex, total body weight [TBW], adapted body weight [ABW], body surface area [BSA], modified sepsis-related organ failure assessment [SOFA] score, vasopressor use, creatinine clearance [CLCR], fluid balance, and amount of fluids collected by the NPT over the sampling day) in patients who underwent continuous renal replacement therapy (CRRT) or did not receive CRRT. Monte Carlo simulations were employed to determine the fractional target attainment (FTA) for the PK/pharmacodynamic [PD] targets (maximum concentration of drug [Cmax]/MIC ratio of ≥8 and a ratio of the area under the concentration-time curve from 0 to 24 h [AUC0–24]/MIC of ≥75). Seventy critically ill patients treated by OA/NPT (contributing 179 concentration values) were included. Amikacin PK concentrations were best described by a two-compartment model with linear elimination and proportional residual error, with CLCR and ABW as significant covariates for volume of distribution (V) and CLCR for CL. The reported V) in non-CRRT and CRRT patients was 35.8 and 40.2 liters, respectively. In Monte Carlo simulations, ABW-adjusted doses between 25 and 35 mg/kg were needed to reach an FTA of >85% for various renal functions. Despite an increased V and a wide interindividual variability, desirable PK/PD targets may be achieved using an ABW-based loading dose of 25 to 30 mg/kg. When less susceptible pathogens are targeted, higher dosing regimens are probably needed in patients with augmented renal clearance (ARC). Further studies are needed to assess the effect of OA/NPT on the PK parameters of antimicrobial agents.

scholarly journals Pharmacokinetics of Ceftaroline in Normal Body Weight and Obese (Classes I, II, and III) Healthy Adult Subjects

2015 ◽  
Vol 59 (7) ◽  
pp. 3956-3965 ◽  
Author(s):  
Julie Ann Justo ◽  
Stockton M. Mayer ◽  
Manjunath P. Pai ◽  
Melinda M. Soriano ◽  
Larry H. Danziger ◽  
...  
Keyword(s):  
Body Weight ◽  
Healthy Adult ◽  
Plasma Concentrations ◽  
Area Under The Curve ◽  
Total Body Weight ◽  
Pharmacokinetic Profile ◽  
Volume Of Distribution ◽  
Population Pharmacokinetic ◽  
Ceftaroline Fosamil ◽  
Plasma And Urine Samples

ABSTRACTThe pharmacokinetic profile of ceftaroline has not been well characterized in obese adults. The purpose of this study was to evaluate the pharmacokinetics of ceftaroline in 32 healthy adult volunteers aged 18 to 50 years in the normal, overweight, and obese body size ranges. Subjects were evenly assigned to 1 of 4 groups based on their body mass index (BMI) and total body weight (TBW) (ranges, 22.1 to 63.5 kg/m2and 50.1 to 179.5 kg, respectively). Subjects in the lower-TBW groups were matched by age, sex, race/ethnicity, and serum creatinine to the upper-BMI groups. Serial plasma and urine samples were collected over 12 h after the start of the infusion, and the concentrations of ceftaroline fosamil (prodrug), ceftaroline, and ceftaroline M-1 (inactive metabolite) were assayed. Noncompartmental and population pharmacokinetic analyses were used to evaluate the data. The mean plasma ceftaroline maximum concentration and area under the curve were ca. 30% lower in subjects with a BMI of ≥40 kg/m2compared to those <30 kg/m2. A five-compartment pharmacokinetic model with zero-order infusion and first-order elimination optimally described the plasma concentration-time profiles of the prodrug and ceftaroline. Estimated creatinine clearance (eCLCR) and TBW best explained ceftaroline clearance and volume of distribution, respectively. Although lower ceftaroline plasma concentrations were observed in obese subjects, Monte Carlo simulations suggest the probability of target attainment is ≥90% when the MIC is ≤1 μg/ml irrespective of TBW or eCLCR. No dosage adjustment for ceftaroline appears to be necessary based on TBW alone in adults with comparable eCLCR. Confirmation of these findings in infected obese patients is necessary to validate these findings in healthy volunteers. (This study has been registered at ClinicalTrials.gov under registration no. NCT01648127.)

scholarly journals Pharmacokinetics of intravenous sildenafil in children with palliated single ventricle heart defects: effect of elevated hepatic pressures

2015 ◽  
Vol 26 (2) ◽  
pp. 354-362 ◽  
Author(s):  
Kevin D. Hill ◽  
Mario R. Sampson ◽  
Jennifer S. Li ◽  
Robert D. Tunks ◽  
Scott R. Schulman ◽  
...  
Keyword(s):  
Drug Exposure ◽  
Structural Model ◽  
Single Ventricle ◽  
Heart Defects ◽  
Model Development ◽  
Area Under The Curve ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Mixed Effect ◽  
The Impact

AbstractAimsSildenafil is frequently prescribed to children with single ventricle heart defects. These children have unique hepatic physiology with elevated hepatic pressures, which may alter drug pharmacokinetics. We sought to determine the impact of hepatic pressure on sildenafil pharmacokinetics in children with single ventricle heart defects.MethodsA population pharmacokinetic model was developed using data from 20 single ventricle children receiving single-dose intravenous sildenafil during cardiac catheterisation. Non-linear mixed effect modelling was used for model development, and covariate effects were evaluated based on estimated precision and clinical significance.ResultsThe analysis included a median (range) of 4 (2–5) pharmacokinetic samples per child. The final structural model was a two-compartment model for sildenafil with a one-compartment model for des-methyl-sildenafil (active metabolite), with assumed 100% sildenafil to des-methyl-sildenafil conversion. Sildenafil clearance was unaffected by hepatic pressure (clearance=0.62 L/hour/kg); however, clearance of des-methyl-sildenafil (1.94×(hepatic pressure/9)−1.33 L/hour/kg) was predicted to decrease ~7-fold as hepatic pressure increased from 4 to 18 mmHg. Predicted drug exposure was increased by ~1.5-fold in subjects with hepatic pressures ⩾10 versus <10 mmHg (median area under the curve=533 versus 792 µg*h/L).DiscussionElevated hepatic pressure delays clearance of the sildenafil metabolite – des-methyl-sildenafil – and increases drug exposure. We speculate that this results from impaired biliary clearance. Hepatic pressure should be considered when prescribing sildenafil to children. These data demonstrate the importance of pharmacokinetic assessments in patients with unique cardiovascular physiology that may affect drug metabolism.

Population pharmacokinetic (PK)/pharmacodynamic (PD) modeling and simulations for exposure‐;tumor response relationships: Motesanib in a phase II thyroid cancer (TC) trial

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14528-e14528
Author(s):  
J. Lu ◽  
L. Claret ◽  
L. Sutjandra ◽  
M. Kuchimanchi ◽  
D. Stepan ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Thyroid Cancer ◽  
Monte Carlo Simulations ◽  
Tumor Size ◽  
Tumor Response ◽  
Area Under The Curve ◽  
Population Pharmacokinetic ◽  
Phase 2 ◽  
Population Pk ◽  
The Difference

e14528 Background: Motesanib is a highly selective, oral inhibitor of VEGF receptors 1, 2, and 3; PDGFR; and Kit that is being investigated for its antitumor activity. In a phase 2 monotherapy study, a response rate of 14% (per RECIST) was observed in patients (pts) with differentiated thyroid cancer (DTC; NEJM 359:31–42, 2008) compared with 1% in pts with medullary TC (MTC; Endocr Soc Ann Meeting 2007, abstract OR39–3). We evaluated the relationship between motesanib PK and tumor response, investigated whether differences in PK between MTC and DTC pts contributed to the observed difference in response, and simulated tumor response with different dose regimens in pts with TC. Methods: Data from the phase 2 TC trial were used for PK/PD modeling. The study enrolled 93 DTC and 91 MTC pts who received motesanib 125 mg once daily (QD). Motesanib concentrations were fitted to a 2- compartment population PK model. Estimates of pts’ PK parameters were used to calculate concentration and steady-state area under the curve values for motesanib, which were used as the exposure measures in population PK/PD modeling (ie, longitudinal exposure-tumor response modeling of drug effect on tumor growth dynamics). Monte Carlo simulations were used to evaluate the potential effect of doses other than 125 mg QD (75 mg and 100 mg QD) on tumor response in TC pts. Results: Clearance in MTC pts was 40% faster than in DTC pts (74 vs 44 L/h). The fit was significantly improved (P<0.001) when exposure instead of dose was used in the model. The exposure-tumor response model that incorporated the difference in exposure described change in tumor size well in both MTC and DTC populations. Clinical trial simulations using the preliminary model based on week 24 data predicted that DTC pts would achieve 19.7%, 15.7%, and 11.3% reductions in tumor size at week 24 following doses of 125 mg QD, 100 mg QD, and 75 mg QD, respectively. The actual change in median tumor size at week 24 following 125-mg QD dosing in DTC pts included in the PK/PD analysis was 17.9%. Conclusions: The use of 125 mg QD motesanib in DTC pts was supported by PK/PD modeling and Monte Carlo simulations. Differences in PK may explain the difference in tumor response observed in MTC and DTC patient populations. [Table: see text]

scholarly journals Efficacy of Ceftaroline against Methicillin-Susceptible Staphylococcus aureus Exhibiting the Cefazolin High-Inoculum Effect in a Rat Model of Endocarditis

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Kavindra V. Singh ◽  
Truc T. Tran ◽  
Esteban C. Nannini ◽  
Vincent H. Tam ◽  
Cesar A. Arias ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Body Weight ◽  
Infective Endocarditis ◽  
Rat Model ◽  
Type A ◽  
Treated Group ◽  
Content Type ◽  
High Inoculum ◽  
Inoculum Effect

ABSTRACT Certain Staphylococcus aureus strains exhibit an inoculum effect (InE) with cefazolin (CFZ) that has been associated with therapeutic failures in high-inoculum infections. We assessed the in vitro activities of ceftaroline (CPT), CFZ, and nafcillin (NAF) against 17 type A β-lactamase (βla)-producing, methicillin-susceptible S. aureus (MSSA) strains, including the previously reported TX0117, which exhibits the CFZ InE, and its βla-cured derivative, TX0117c. Additionally, we determined the pharmacokinetics of CPT in rats after single intramuscular doses of 20 and 40 mg/kg of body weight and evaluated the activities of CPT (40 mg/kg every 8 h [q8h]), CFZ, and NAF against TX0117 and TX0117c in a rat model of infective endocarditis. No InE was observed for CPT or NAF, whereas a marked InE was detected for CFZ (MIC, 8 to ≥128 μg/ml). CPT and NAF treatment against TX0117 resulted in mean bacterial counts of 2.3 and 2.1 log10 CFU/g in vegetations, respectively, compared to a mean of 5.9 log10 CFU/g in the CFZ-treated group (CPT and NAF versus CFZ, P = 0.001; CPT versus NAF, P = 0.9830). Both CFZ and CPT were efficacious against the βla-cured derivative, TX0117c, compared to time zero (t 0) (P = <0.0001 and 0.0015, respectively). Our data reiterate the in vivo consequences of the CFZ InE and show that CPT is not affected by this phenomenon. CPT might be considered for high-inoculum infections caused by MSSA exhibiting the CFZ InE.

scholarly journals Pharmacodynamic comparison of different antimicrobial regimens against Staphylococcus aureus bloodstream infections with elevated vancomycin minimum inhibitory concentration

2019 ◽  
Author(s):  
Thaina Miranda da Costa ◽  
Gabriel Trova Cuba ◽  
Priscylla Guimarães Migueres Morgado ◽  
David P. Nicolau ◽  
Simone Aranha Nouér ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Monte Carlo ◽  
Inhibitory Concentration ◽  
Area Under The Curve ◽  
Bloodstream Infections ◽  
Stochastic Simulations ◽  
High Dose ◽  
Percent Time ◽  
High Prevalence ◽  
Total Growth

Abstract Background Staphylococcus aureus is one of the major causes of bloodstream infections (BSI) worldwide, representing a major challenge for public health due to its resistance profile. Higher vancomycin minimum inhibitory concentrations (MIC) in S. aureus are associated with treatment failure and defining optimal empiric options for BSIs in settings where these isolates are prevalent is rather challenging. In silico pharmacodynamic models based on stochastic simulations (Monte Carlo) are important tools to estimate best antimicrobial regimens in different scenarios. We aimed to compare the pharmacodynamic profiles of different antimicrobials regimens for the treatment of S. aureus BSI in an environment with high vancomycin MIC. Methods Steady-state drug area under the curve ratio to MIC (AUC⁄MIC) or the percent time above MIC (fT>MIC) were modeled using a 5000-patient Monte Carlo simulation to achieve pharmacodynamic exposures against 110 consecutive S. aureus isolates associated with BSI. Results Cumulative fractions of response (CFRs) against all S. aureus isolates were 98% for ceftaroline; 79% and 92% for daptomycin 6 mg/kg q24h and for the high dose of 10 mg/kg q24h, respectively; 77% for linezolid 600 mg every 12h when MIC was read according to CLSI M100-S26 instructions, and 64% when MIC was considered at the total growth inhibition; 65% and 86% for teicoplanin, three loading doses of 400 mg every 12h followed by 400 mg every 24h and for teicoplanin 400 mg every 12h, respectively; 61% and 76% for vancomycin 1000 mg every 12h and every 8h, respectively. Conclusions Based on this model, ceftaroline and high-dose daptomycin regimens delivered best pharmacodynamic exposures against S. aureus BSIs. Teicoplanin higher dose regimen achieves the best CFR (86%) among glycopeptides, although optimal threshold was not achieved, and vancomycin performance is critically affected by S. aureus vancomycin MIC ≥ 2 mg/L. Linezolid effectiveness (CFR of 73%) is also affected by high prevalence of isolates with higher MICs. These data show the need to continually evaluate the pharmacodynamic profiles of antimicrobials for empiric treatment of these infections.

scholarly journals 1532. Population Pharmacokinetic (PPK) Modeling and Simulation of Long-Acting (LA) Cabotegravir (CAB) to Inform Strategies Following Dosing Interruptions in HIV-1-Infected Subjects

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S558-S558 ◽  
Author(s):  
Kelong Han ◽  
Mark Baker ◽  
Parul Patel ◽  
David Margolis ◽  
William Spreen ◽  
...  
Keyword(s):  
Modeling And Simulation ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Strand Transfer ◽  
Phase 3 ◽  
Once Daily ◽  
Minimal Impact ◽  
Treatment And Prevention ◽  
Trough Concentrations ◽  
Hiv 1

Abstract Background CAB is an integrase strand transfer inhibitor under investigation as an injectable LA formulation for the treatment and prevention of HIV, and as a tablet formulation as an oral lead-in (OLI) and bridging treatment for dose interruptions. The monthly injection regimen of CAB LA and rilpivirine (RPV) LA was noninferior to standard oral therapy in maintaining HIV-1 suppression in Phase 3 trials. PPK modeling and simulation was used to inform strategies for managing dosing interruptions. Methods A 2-compartment model with first-order oral and LA absorption and elimination adequately described the data from 1,647 healthy (28%) and HIV-infected (72%) adult subjects in 16 studies. Gender was a significant covariate on LA absorption; therefore, simulations of 5,000 virtual subjects were performed using a 4:1 male:female ratio to ensure 1,000 representative females and covariate sampling with replacement from the analysis dataset. One- to 12-week delays in dosing of the second, third, and fourth injection were simulated, and predicted troughs were compared with the 5th percentile (0.65 μg/mL) of trough concentrations following the first injection in Phase 3. Simulations of 1–2 months of oral bridging with CAB 30 mg once daily from time of a missed injection until CAB LA dosing resumed were performed, with the median Cmax (13.1 μg/mL) observed following oral CAB 60mg once daily in Phase 2b as an upper reference. Results Proportions of subjects predicted to achieve target plasma CAB trough concentrations are shown by length of delay and injection visit in Table 1. Oral bridging with CAB 30mg once daily starting at the time of a planned missed injection is predicted to provide exposures within ranges observed in clinical studies (Figure 1). Conclusion Dosing delays of up to one week appear to have minimal impact, but the effect is more likely to become problematic with longer delays, particularly in the first few months of dosing. Oral bridging provides therapeutic and safe exposures for planned interruptions in LA dosing. Regardless of use of oral bridging, simulations support resuming CAB LA dosing for interruptions <1 month (<2 months between injections) and reinitiating CAB LA with a loading dose and subsequent monthly injections for interruptions ≥ 1 month (≥ 2 months between injections). Disclosures All authors: No reported disclosures.

scholarly journals Developmental Pharmacokinetics of Lamivudine in 580 Pediatric Patients Ranging from Neonates to Adolescents

2011 ◽  
Vol 55 (7) ◽  
pp. 3498-3504 ◽  
Author(s):  
Naïm Bouazza ◽  
Déborah Hirt ◽  
Stéphane Blanche ◽  
Pierre Frange ◽  
Elisabeth Rey ◽  
...  
Keyword(s):  
Body Weight ◽  
Expectation Maximization Algorithm ◽  
Compartment Model ◽  
Population Pharmacokinetic Analysis ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Apparent Clearance ◽  
Routine Basis ◽  
Time Courses ◽  
Elimination Clearance

ABSTRACTLamivudine concentration-time courses were described for a very large range of ages to study the effects of body weight and maturation on lamivudine pharmacokinetics and to check the consistency of dosing recommendations. Lamivudine concentrations were monitored on a routine basis to produce concentrations similar to the known values in adults. Concentrations were measured in 580 children from 2 days to 18 years old. A total of 2,106 plasma lamivudine concentrations were measured, and a population pharmacokinetic analysis was performed using the stochastic approximation expectation maximization algorithm implemented in MONOLIX 3.1 software. A two-compartment model adequately described the data. After standardization for a mean standard body weight by using an allometric model, age also had a significant effect on clearance maturation. Typical population estimates (percent interindividual variability) standardized for 70 kg of the apparent clearance, including central and peripheral volumes of distribution, intercompartmental clearance, and absorption rate constant, were 31 liters·h−1(32%), 76.4 liters (77%), 129 liters, 5.83 liters·h−1, and 0.432 h−1, respectively. According to the model, elimination clearance (liters/h/70 kg) increases gradually during the first years of life. Theoretical doses needed to reach the range of 24 h of exposure observed in adults were calculated: to be closer to adult exposure, children should receive 4 mg/kg/day from birth to 8 weeks of age, 5 mg/kg/day from 8 to 16 weeks of age, 6 mg/kg from 16 to 25 weeks of age, 8 mg/kg/day from 25 weeks of age to 14 kg of body weight, 150 mg/day from 14 to 25 kg of body weight, 225 mg/day from 25 to 35 kg of body weight, and 300 mg/day thereafter.

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