Most cited article - PubMed ID 28650911
Creatinine Clearance Estimations for Vancomycin Maintenance Dose Adjustments
The objective of this study was to develop a population pharmacokinetic model for linezolid in hematooncological patients with sepsis, and to propose dosing optimization based on pharmacokinetic covariates that would lead to improved achievement of the PK/PD target. Therapeutic drug monitoring data from hematooncological patients treated with linezolid for suspected or proven sepsis were analyzed. A pharmacokinetic population model for linezolid was constructed using a nonlinear mixed-effects modeling approach. Monte Carlo simulations were then used to compare various dosing regimens in terms of PK/PD target attainment. A total of 197 linezolid serum concentrations obtained from 22 patients were included in the analysis. Patients' age was found to be the most predictive covariate for linezolid pharmacokinetics. In a patient with a median age of 59 years, the volume of distribution and clearance of linezolid were 46.2 L and 12.1 L/h, respectively. During the first 4 days of therapy, linezolid clearance decreased by 33%. The probability of PK/PD target attainment increased through the individualization of the dose according to the patient's age, administration of a loading dose, and administration of linezolid via continuous infusion. For this scenario, an easy-to-use nomogram was designed.
- Keywords
- Monte Carlo simulation, PK/PD target, age, nonlinear mixed‐effects modeling, oxazolidinone, therapeutic drug monitoring,
- MeSH
- Anti-Bacterial Agents * pharmacokinetics administration & dosage MeSH
- Models, Biological * MeSH
- Adult MeSH
- Gram-Positive Bacterial Infections * drug therapy microbiology blood diagnosis MeSH
- Middle Aged MeSH
- Humans MeSH
- Linezolid * pharmacokinetics administration & dosage MeSH
- Monte Carlo Method MeSH
- Drug Monitoring methods MeSH
- Retrospective Studies MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Sepsis * drug therapy microbiology diagnosis blood MeSH
- Age Factors MeSH
- Dose-Response Relationship, Drug MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Male MeSH
- Aged, 80 and over MeSH
- Aged MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Anti-Bacterial Agents * MeSH
- Linezolid * MeSH
AIM: The aim of this study was to develop a vancomycin population pharmacokinetic model in adult obese patients and propose covariate-based dosing individualization in order to maximize the achievement of the newly recommended PK/PD target, according to a revised consensus guideline from 2020. METHODS: Therapeutic drug monitoring data from initial vancomycin therapy (first 3 days of treatment) in adult obese (BMI ≥ 30 kg/m2) patients from 2013 to 2022 were analyzed using a non-linear mixed-effects modeling method, and Monte Carlo simulations were then used to find the optimal dosage maximizing the PK/PD target attainment. RESULTS: A total of 147 vancomycin serum levels obtained from 138 patients were included in the analysis. Based on the covariate model diagnosis among all tested variables, no reliable predictor of vancomycin volume of distribution (Vd) was identified, while clearance (CL) was positively correlated with eGFR and lean body mass. Creatinine-based eGFR predicted vancomycin CL better than cystatin C-based eGFR. The median (interquartile range) value from conditional modes of individual estimates of Vd, CL, and elimination half-life in our population was 74.0 (70.5-75.4) L, 6.65 (4.95-8.42) L/h, and 7.7 (6.0-10.0) h, respectively. CONCLUSION: We proposed dosing individualization based on the covariate found in order to maximize the achievement of the newly recommended PK/PD target of the AUC/MIC ratio of 400-600. Clinical pharmacy/pharmacology interventions may lead to an improvement in vancomycin dosing with a reflection in PK/PD target attainment.
Peritonitis is a limiting complication of peritoneal dialysis, which is treated by intraperitoneal administration of antibiotics. Various dosing strategies are recommended for intraperitoneally administered vancomycin, which leads to large differences in intraperitoneal vancomycin exposure. Based on data from therapeutic drug monitoring, we developed the first-ever population pharmacokinetic model for intraperitoneally administered vancomycin to evaluate intraperitoneal and plasma exposure after dosing schedules recommended by the International Society for Peritoneal Dialysis. According to our model, currently recommended dosing schedules lead to possible underdosing of a large proportion of patients. To prevent this, we suggest avoiding intermittent intraperitoneal vancomycin administration, and for the continuous dosing regimen, we suggest a loading dose of 20 mg/kg followed by maintenance doses of 50 mg/L in each dwell to improve the intraperitoneal exposure. Vancomycin plasma level measurement on the fifth day of treatment with subsequent dose adjustment would prevent it from reaching toxic levels in the few patients who are susceptible to overdose.
The aim of this prospective study was to evaluate the pharmacokinetics of ganciclovir in lung transplant recipients, to explore its covariates, and to propose an individualized dosing regimen. Ganciclovir was administered according to the protocol in a standardized intravenous dose of 5 mg/kg twice daily. Serum ganciclovir concentrations were monitored as a trough and at 3 and 5 h after dosing. Individual ganciclovir pharmacokinetic parameters were calculated in a two-compartmental pharmacokinetic model, while regression models were used to explore the covariates. Optimal loading and maintenance doses were calculated for each patient. In lung transplant recipients (n = 40), the median (IQR) ganciclovir total volume of distribution and clearance values were 0.65 (0.52-0.73) L/kg and 0.088 (0.059-0.118) L/h/kg, respectively. We observed medium-to-high inter-individual but negligible intra-individual variability in ganciclovir pharmacokinetics. The volume of distribution of ganciclovir was best predicted by height, while clearance was predicted by glomerular filtration rate. Bodyweight-normalized clearance was significantly higher in patients with cystic fibrosis, while distribution half-life was reduced in this subgroup. On the basis of the observed relationships, practical nomograms for individualized ganciclovir dosing were proposed. The dosing of ganciclovir in patients with cystic fibrosis requires special caution, as their daily maintenance dose should be increased by approximately 50%.
- Keywords
- covariates, cystic fibrosis, ganciclovir, lung transplant recipients, therapeutic drug monitoring,
- Publication type
- Journal Article MeSH
OBJECTIVES: Due to the high interindividual variability in vancomycin pharmacokinetics, optimisation of its dosing is still challenging. This study aimed to explore vancomycin pharmacokinetics in adult patients and to propose an easy applicable dosing nomogram for initial treatment. METHODS: Vancomycin pharmacokinetics was calculated in a two-compartmental model based on therapeutic drug monitoring data. A linear regression model was used to explore the relationship between vancomycin elimination half-life and glomerular filtration rate estimated according the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula. RESULTS: In the whole study population (n=66), vancomycin volume of distribution, clearance and half-life median (IQR) values were 0.69 (0.58-0.87) L/kg, 0.031 (0.022-0.050) L/h/kg and 14.4 (9.5-25.2) hours, respectively. Vancomycin half-life was associated with glomerular filtration rate (r2=0.4126, p<0.0001) according to the formula: t1/2 (h) = -0.247×eGFRCKD-EPI (mL/min/1.73 m2)+32.89. This relationship was used to construct a dosing nomogram. CONCLUSIONS: We propose an easy-to-use dosing nomogram for vancomycin therapy initiation that allows individualisation of the dosing interval with respect to the administered dose size and functional renal status.
- Keywords
- CKD-EPI, dosing nomogram, glomerular filtration, pharmacokinetics, therapeutic drug monitoring, vancomycin,
- MeSH
- Anti-Bacterial Agents * MeSH
- Adult MeSH
- Glomerular Filtration Rate MeSH
- Kidney physiology MeSH
- Humans MeSH
- Drug Monitoring MeSH
- Vancomycin * MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Anti-Bacterial Agents * MeSH
- Vancomycin * MeSH
The aim of this prospective PK study was to evaluate the pharmacokinetics of ciprofloxacin dosed within the first 36 h (early phase) and after 3 days of treatment (delayed phase) using individual and population PK analysis. The secondary aim of the study was to evaluate possible dosing implications of the observed PK differences between early and delayed phases to achieve a PK/PD target for ciprofloxacin of AUC24/MIC ≥ 125. Blood concentrations of ciprofloxacin (1 and 4 h after dose and trough) were monitored in critically ill adults in the early and delayed phases of the treatment. Individual and population PK analyses were performed. Complete concentration-time profiles in the early phase, delayed phase, and both phases were obtained from 29, 15, and 14 patients, respectively. No systematic changes in ciprofloxacin PK parameters between the early and delayed phases were observed, although variability was higher at the early phase. Both individual and population analyses provided similar results. Simulations showed that after standard dosing, it is practically impossible to reach the recommended ciprofloxacin PK/PD target (AUC/MIC ≥ 125) for pathogens with MIC ≥ 0.5 mg/L. A dosing nomogram utilizing patients' creatinine clearance and MIC values was constructed. Both individual and population analyses provided similar results. Therapeutic drug monitoring should be implemented to safeguard the optimal ciprofloxacin exposure.
- Keywords
- NONMEM, ciprofloxacin, covariates, dosing, pharmacokinetics, renal function,
- Publication type
- Journal Article MeSH
The study presents a novel vancomycin-releasing collagen wound dressing derived from Cyprinus carpio collagen type I cross-linked with carbodiimide which retarded the degradation rate and increased the stability of the sponge. Following lyophilization, the dressings were subjected to gamma sterilization. The structure was evaluated via scanning electron microscopy images, micro-computed tomography, and infrared spectrometry. The structural stability and vancomycin release properties were evaluated in phosphate buffered saline. Microbiological testing and a rat model of a wound infected with methicillin-resistant Staphylococcus aureus (MRSA) were then employed to test the efficacy of the treatment of the infected wound. Following an initial mass loss due to the release of vancomycin, the sponges remained stable. After 7 days of exposure in phosphate buffered saline (37°C), 60% of the material remained with a preserved collagen secondary structure together with a high degree of open porosity (over 80%). The analysis of the release of vancomycin revealed homogeneous distribution of the antibiotic both across and between the sponges. The release of vancomycin was retarded as proved by in vitro testing and further confirmed by the animal model from which measurable concentrations were observed in blood samples 24 hours after the subcutaneous implantation of the sponge, which was more than observed following intraperitoneal administration. The sponge was also highly effective in terms of reducing the number of colony-forming units in biopsies extracted from the infected wounds 4 days following the inoculation of the wounds with the MRSA solution. The presented sponges have ideal properties to serve as wound dressing for prevention of surgical site infection or treatment of already infected wounds.
- MeSH
- Anti-Bacterial Agents pharmacokinetics MeSH
- Wound Healing drug effects MeSH
- Carps MeSH
- Carbodiimides pharmacokinetics MeSH
- Collagen pharmacokinetics MeSH
- Rats MeSH
- Methicillin-Resistant Staphylococcus aureus drug effects MeSH
- Bandages MeSH
- Vancomycin pharmacokinetics MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Anti-Bacterial Agents MeSH
- Carbodiimides MeSH
- Collagen MeSH
- Vancomycin MeSH
