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Clinical Pharmacokinetics Feb 2020Pharmacokinetics (PK) are severely altered in critically ill patients due to changes in volume of distribution (Vd) and/or drug clearance (Cl). This affects the target...
BACKGROUND
Pharmacokinetics (PK) are severely altered in critically ill patients due to changes in volume of distribution (Vd) and/or drug clearance (Cl). This affects the target attainment of antibiotics in critically ill children. We aimed to identify gaps in current knowledge and to compare published PK parameters and target attainment of antibiotics in critically ill children to healthy children and critically ill adults.
METHODS
Systematic literature search in PubMed, EMBASE and Web of Science. Articles were labelled as relevant when they included information on PK of antibiotics in critically ill, non-neonatal, pediatric patients. Extracted PK-parameters included Vd, Cl, (trough) concentrations, AUC, probability of target attainment, and elimination half-life.
RESULTS
50 relevant articles were identified. Studies focusing on vancomycin were most prevalent (17/50). Other studies included data on penicillins, cephalosporins, carbapenems and aminoglycosides, but data on ceftriaxone, ceftazidime, penicillin and metronidazole could not be found. Critically ill children generally show a higher Cl and larger Vd than healthy children and critically ill adults. Reduced target-attainment was described in critically ill children for multiple antibiotics, including amoxicillin, piperacillin, cefotaxime, vancomycin, gentamicin, teicoplanin, amikacin and daptomycin. 38/50 articles included information on both Vd and Cl, but a dosing advice was given in only 22 articles.
CONCLUSION
The majority of studies focus on agents where TDM is applied, while other antibiotics lack data altogether. The larger Vd and higher Cl in critically ill children might warrant a higher dose or extended infusions of antibiotics in this patient population to increase target-attainment. Studies frequently fail to provide a dosing advice for this patient population, even if the necessary information is available. Our study shows gaps in current knowledge and encourages future researchers to provide dosing advice for special populations whenever possible.
Topics: Acute Kidney Injury; Adolescent; Aminoglycosides; Anti-Bacterial Agents; Area Under Curve; Carbapenems; Cephalosporins; Child; Child, Preschool; Critical Illness; Drug Monitoring; Female; Half-Life; Humans; Infant; Infusions, Intravenous; Male; Penicillins; Vancomycin; Young Adult
PubMed: 31432468
DOI: 10.1007/s40262-019-00813-w -
Drug Metabolism and Disposition: the... Nov 2015Modeling and simulation of drug disposition has emerged as an important tool in drug development, clinical study design and regulatory review, and the number of... (Review)
Review
Modeling and simulation of drug disposition has emerged as an important tool in drug development, clinical study design and regulatory review, and the number of physiologically based pharmacokinetic (PBPK) modeling related publications and regulatory submissions have risen dramatically in recent years. However, the extent of use of PBPK modeling by researchers, and the public availability of models has not been systematically evaluated. This review evaluates PBPK-related publications to 1) identify the common applications of PBPK modeling; 2) determine ways in which models are developed; 3) establish how model quality is assessed; and 4) provide a list of publically available PBPK models for sensitive P450 and transporter substrates as well as selective inhibitors and inducers. PubMed searches were conducted using the terms "PBPK" and "physiologically based pharmacokinetic model" to collect published models. Only papers on PBPK modeling of pharmaceutical agents in humans published in English between 2008 and May 2015 were reviewed. A total of 366 PBPK-related articles met the search criteria, with the number of articles published per year rising steadily. Published models were most commonly used for drug-drug interaction predictions (28%), followed by interindividual variability and general clinical pharmacokinetic predictions (23%), formulation or absorption modeling (12%), and predicting age-related changes in pharmacokinetics and disposition (10%). In total, 106 models of sensitive substrates, inhibitors, and inducers were identified. An in-depth analysis of the model development and verification revealed a lack of consistency in model development and quality assessment practices, demonstrating a need for development of best-practice guidelines.
Topics: Animals; Computer Simulation; Drug Interactions; Humans; Models, Biological; Pharmaceutical Preparations; Pharmacokinetics
PubMed: 26296709
DOI: 10.1124/dmd.115.065920 -
British Journal of Clinical Pharmacology Sep 2015It is common to advise that analgesics, and especially non-steroidal anti-inflammatory drugs (NSAIDs), be taken with food to reduce unwanted gastrointestinal adverse... (Review)
Review
AIMS
It is common to advise that analgesics, and especially non-steroidal anti-inflammatory drugs (NSAIDs), be taken with food to reduce unwanted gastrointestinal adverse effects. The efficacy of single dose analgesics depends on producing high, early, plasma concentrations; food may interfere with this. This review sought evidence from single dose pharmacokinetic studies on the extent and timing of peak plasma concentrations of analgesic drugs in the fed and fasting states.
METHODS
A systematic review of comparisons of oral analgesics in fed and fasting states published to October 2014 reporting kinetic parameters of bioavailability, time to maximum plasma concentration (tmax ), and its extent (Cmax ) was conducted. Delayed-release formulations were not included.
RESULTS
Bioavailability was not different between fasted and fed states. Food typically delayed absorption for all drugs where the fasting tmax was less than 4 h. For the common analgesics (aspirin, diclofenac, ibuprofen, paracetamol) fed tmax was 1.30 to 2.80 times longer than fasted tmax . Cmax was typically reduced, with greater reduction seen with more rapid absorption (fed Cmax only 44-85% of the fasted Cmax for aspirin, diclofenac, ibuprofen and paracetamol).
CONCLUSION
There is evidence that high, early plasma concentrations produces better early pain relief, better overall pain relief, longer lasting pain relief and lower rates of remedication. Taking analgesics with food may make them less effective, resulting in greater population exposure. It may be time to rethink research priorities and advice to professionals, patients and the public.
Topics: Acetaminophen; Administration, Oral; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Biological Availability; Dipyrone; Drug Liberation; Food-Drug Interactions; Humans
PubMed: 25784216
DOI: 10.1111/bcp.12628 -
Pharmacotherapy Sep 2022Vancomycin is commonly used to treat methicillin-resistant Staphylococcus aureus infections and is known to cause nephrotoxicity. Previous Vancomycin Consensus... (Meta-Analysis)
Meta-Analysis Review
Vancomycin is commonly used to treat methicillin-resistant Staphylococcus aureus infections and is known to cause nephrotoxicity. Previous Vancomycin Consensus Guidelines recommended targeting trough concentrations but the 2020 Guidelines suggest monitoring vancomycin area under the curve (AUC) given the reduced risk of acute kidney injury (AKI) at similar levels of efficacy. This meta-analysis compares vancomycin-induced AKI incidence using AUC-guided dosing strategies versus trough-based monitoring. Literature was queried from Medline (Ovid), Web of Science, and Google Scholar from database inception through November 5, 2021. Interventional or observational studies reporting the incidence of vancomycin-induced AKI between AUC- and trough-guided dosing strategies were included. In the primary analysis, the Vancomycin Consensus Guidelines definition for AKI was used if reported; otherwise, the Risk, Injury, and Failure; and Loss, and End-stage kidney disease (RIFLE) or Kidney Disease Improving Global Outcomes (KDIGO) definitions were used. The incidence of nephrotoxicity was evaluated between the two strategies using a Mantel-Haenszel random-effects model, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Subgroup analyses for adjusted ORs and AKI definitions were performed. Heterogeneity was identified using Cochrane's Q test and I statistics. A total of 10 studies with 4231 patients were included. AUC-guided dosing strategies were associated with significantly less vancomycin-induced AKI than trough-guided strategies [OR 0.625, 95% CI (0.469-0.834), p = 0.001; I = 25.476]. A subgroup analysis of three studies reporting adjusted ORs yielded similar results [OR 0.475, 95% CI (0.261-0.863), p = 0.015]. Stratification by AKI definition showed a significant reduction in AKI with the Vancomycin Consensus Guidelines definition [OR 0.552, 95% CI (0.341-0.894), p = 0.016] but failed to find significance in the alternative definitions. Area under the curve-guided dosing strategies are associated with a lower incidence of vancomycin-induced AKI versus trough-guided dosing strategies (GRADE, low). Limitations included the variety of AKI definitions and the potential for confounding bias.
Topics: Humans; Acute Kidney Injury; Anti-Bacterial Agents; Area Under Curve; Electrolytes; Methicillin-Resistant Staphylococcus aureus; Microbial Sensitivity Tests; Retrospective Studies; Vancomycin
PubMed: 35869689
DOI: 10.1002/phar.2722 -
Nutrition Reviews Jan 2018Vitamin D is frequently prescribed as a supplement, yet its absorption remains poorly understood.
CONTEXT
Vitamin D is frequently prescribed as a supplement, yet its absorption remains poorly understood.
OBJECTIVE
This systematic review was performed to evaluate data on mechanisms involved in the intestinal absorption of vitamin D.
DATA SOURCES
PubMed, Embase, and Cochrane Library databases were searched.
STUDY SELECTION
The following studies were included: experimental laboratory studies of vitamin D absorption through the enterocyte brush-border membrane; absorption tests that used radiolabeled vitamin D; and clinical trials in adults that investigated a single dose of cholecalciferol or ergocalciferol and reported at least 2 measurements of serum cholecalciferol, ergocalciferol, or 25-hydroxyvitamin D.
DATA EXTRACTION
From 2069 articles identified, 46 met the inclusion criteria.
RESULTS
Different methods were employed to evaluate vitamin D absorption. Recent research suggests that vitamin D absorption is not an exclusive simple diffusion process. Vitamin D was better absorbed when it was consumed with fat-containing meals, but absorption also occurred without fat or oily vehicles. Factors that modified cholesterol absorption also altered vitamin D absorption.
CONCLUSION
Vitamin D is probably absorbed through passive diffusion and a mechanism involving membrane carriers, especially cholesterol transporters, although data remain scarce. Some data suggest that fat, when consumed concomitantly with vitamin D, improves vitamin D absorption.
Topics: Animals; Humans; Intestinal Absorption; Mice; Vitamin D
PubMed: 29025082
DOI: 10.1093/nutrit/nux034 -
European Journal of Drug Metabolism and... Jul 2021Short bowel syndrome is a clinical condition defined by malabsorption of nutrients and micronutrients, most commonly following extensive intestinal resection. Due to a...
BACKGROUND AND OBJECTIVES
Short bowel syndrome is a clinical condition defined by malabsorption of nutrients and micronutrients, most commonly following extensive intestinal resection. Due to a loss of absorptive surfaces, the absorption of orally administered drugs is also often affected. The purpose of this study was to systematically review the published literature and examine the effects of short bowel syndrome on drug pharmacokinetics and clinical outcomes.
METHODS
Studies were identified through searches of databases MEDLINE, EMBASE, Web of Science, and SCOPUS, in addition to hand searches of studies' reference lists. Two reviewers independently assessed studies for inclusion, yielding 50 studies involving 37 different drugs in patients with short bowel syndrome.
RESULTS
Evidence of decreased drug absorption was observed in 29 out of 37 drugs, 6 of which lost therapeutic effect, and 14 of which continued to demonstrate clinical benefit through drug monitoring.
CONCLUSIONS
The influence of short bowel syndrome on drug absorption appears to be drug-specific and dependent on the location and extent of resection. The presence of a colon in continuity may also influence drug bioavailability as it can contribute significantly to the absorption of drugs (e.g., metoprolol); likewise, drugs that have a wide absorption window or are known to be absorbed in the colon are least likely to be malabsorbed. Individualized dosing may be necessary to achieve therapeutic efficacy, and therapeutic drug monitoring, where available, should be considered in short bowel syndrome patients, especially for drugs with narrow therapeutic indices.
Topics: Administration, Oral; Biological Availability; Humans; Intestinal Absorption; Pharmaceutical Preparations; Pharmacokinetics; Short Bowel Syndrome
PubMed: 34196913
DOI: 10.1007/s13318-021-00696-y -
Anesthesiology Dec 2020Several models describing the pharmacokinetics of ketamine are published with differences in model structure and complexity. A systematic review of the literature was... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Several models describing the pharmacokinetics of ketamine are published with differences in model structure and complexity. A systematic review of the literature was performed, as well as a meta-analysis of pharmacokinetic data and construction of a pharmacokinetic model from raw data sets to qualitatively and quantitatively evaluate existing ketamine pharmacokinetic models and construct a general ketamine pharmacokinetic model.
METHODS
Extracted pharmacokinetic parameters from the literature (volume of distribution and clearance) were standardized to allow comparison among studies. A meta-analysis was performed on studies that performed a mixed-effect analysis to calculate weighted mean parameter values and a meta-regression analysis to determine the influence of covariates on parameter values. A pharmacokinetic population model derived from a subset of raw data sets was constructed and compared with the meta-analytical analysis.
RESULTS
The meta-analysis was performed on 18 studies (11 conducted in healthy adults, 3 in adult patients, and 5 in pediatric patients). Weighted mean volume of distribution was 252 l/70 kg (95% CI, 200 to 304 l/70 kg). Weighted mean clearance was 79 l/h (at 70 kg; 95% CI, 69 to 90 l/h at 70 kg). No effect of covariates was observed; simulations showed that models based on venous sampling showed substantially higher context-sensitive half-times than those based on arterial sampling. The pharmacokinetic model created from 14 raw data sets consisted of one central arterial compartment with two peripheral compartments linked to two venous delay compartments. Simulations showed that the output of the raw data pharmacokinetic analysis and the meta-analysis were comparable.
CONCLUSIONS
A meta-analytical analysis of ketamine pharmacokinetics was successfully completed despite large heterogeneity in study characteristics. Differences in output of the meta-analytical approach and a combined analysis of 14 raw data sets were small, indicative that the meta-analytical approach gives a clinically applicable approximation of ketamine population parameter estimates and may be used when no raw data sets are available.
Topics: Adult; Anesthetics, Dissociative; Child; Humans; Ketamine
PubMed: 32997732
DOI: 10.1097/ALN.0000000000003577 -
Clinical Pharmacokinetics Aug 2015Tramadol hydrochloride is used worldwide as an analgesic drug with a unique dual function. The metabolic enzymes cytochrome P450 (CYP) 3A4, CYP2B6, and CYP2D6 and the... (Review)
Review
BACKGROUND AND OBJECTIVE
Tramadol hydrochloride is used worldwide as an analgesic drug with a unique dual function. The metabolic enzymes cytochrome P450 (CYP) 3A4, CYP2B6, and CYP2D6 and the various transporters [adenosine triphosphate-binding cassette B1/multidrug resistance 1/P-glycoprotein, organic cation transporter 1, serotonin transporter (SERT), norepinephrine transporter (NET)] and receptor genes (opioid receptor μ 1 gene) give possible genetic differences that might affect the pharmacokinetics and/or pharmacodynamics of tramadol. Therefore, the aim of this review is to present a systematic walkthrough of all possible genetic factors involved in the pharmacology of tramadol.
METHOD
A systematic literature search was conducted in PubMed and EMBASE involving all metabolic enzymes, drug transporters and receptors, as well as SERT and NET that are involved in the pharmacokinetics and pharmacodynamics of tramadol. An additional search on population pharmacokinetics with genetic factors as covariates was performed separately.
RESULTS
A total of 56 studies (45 cohort and case-control studies, three case reports, six in vitro studies, and two animal studies) were included.
CONCLUSION
In this systematic review, the current knowledge on all possible genetic factors that might influence the metabolism or clinical efficacy of tramadol has been collected and summarized. Only the effect of CYP2D6 polymorphisms on the metabolism of tramadol and the consequent effect on pain relief has been thoroughly studied and sufficiently established as clinically relevant.
Topics: Analgesics, Opioid; Animals; Biological Availability; Case-Control Studies; Clinical Studies as Topic; Cohort Studies; Cytochrome P-450 CYP2D6; Humans; Pain; Pharmacogenetics; Tramadol
PubMed: 25910878
DOI: 10.1007/s40262-015-0268-0 -
Journal of Clinical Epidemiology Jun 2019The objective of this study was to compare performance of logistic regression (LR) with machine learning (ML) for clinical prediction modeling in the literature. (Comparative Study)
Comparative Study Meta-Analysis
OBJECTIVES
The objective of this study was to compare performance of logistic regression (LR) with machine learning (ML) for clinical prediction modeling in the literature.
STUDY DESIGN AND SETTING
We conducted a Medline literature search (1/2016 to 8/2017) and extracted comparisons between LR and ML models for binary outcomes.
RESULTS
We included 71 of 927 studies. The median sample size was 1,250 (range 72-3,994,872), with 19 predictors considered (range 5-563) and eight events per predictor (range 0.3-6,697). The most common ML methods were classification trees, random forests, artificial neural networks, and support vector machines. In 48 (68%) studies, we observed potential bias in the validation procedures. Sixty-four (90%) studies used the area under the receiver operating characteristic curve (AUC) to assess discrimination. Calibration was not addressed in 56 (79%) studies. We identified 282 comparisons between an LR and ML model (AUC range, 0.52-0.99). For 145 comparisons at low risk of bias, the difference in logit(AUC) between LR and ML was 0.00 (95% confidence interval, -0.18 to 0.18). For 137 comparisons at high risk of bias, logit(AUC) was 0.34 (0.20-0.47) higher for ML.
CONCLUSION
We found no evidence of superior performance of ML over LR. Improvements in methodology and reporting are needed for studies that compare modeling algorithms.
Topics: Algorithms; Area Under Curve; Humans; Logistic Models; Models, Theoretical; Outcome Assessment, Health Care; Predictive Value of Tests; Sensitivity and Specificity; Supervised Machine Learning
PubMed: 30763612
DOI: 10.1016/j.jclinepi.2019.02.004 -
Therapeutic Drug Monitoring Feb 2020Linezolid is an antibiotic used to treat infections caused by drug-resistant gram-positive organisms, including vancomycin-resistant Enterococcus faecium, multi-drug...
Linezolid is an antibiotic used to treat infections caused by drug-resistant gram-positive organisms, including vancomycin-resistant Enterococcus faecium, multi-drug resistant Streptococcus pneumoniae, and methicillin-resistant Staphylococcus aureus. The adverse effects of linezolid can include thrombocytopenia and neuropathy, which are more prevalent with higher exposures and longer treatment durations. Although linezolid is traditionally administered at a standard 600 mg dose every 12 hours, the resulting exposure can vary greatly between patients and can lead to treatment failure or toxicity. The efficacy and toxicity of linezolid are determined by the exposure achieved in the patient; numerous clinical and population pharmacokinetics (popPK) studies have identified threshold measurements for both parameters. Several special populations with an increased need for linezolid dose adjustments have also been identified. Therapeutic Drug Monitoring (TDM) is a clinical strategy that assesses the response of an individual patient and helps adjust the dosing regimen to maximize efficacy while minimizing toxicity. Adaptive feedback control and model-informed precision dosing are additional strategies that use Bayesian algorithms and PK models to predict patient-specific drug exposure. TDM is a very useful tool for patient populations with sparse clinical data or known alterations in pharmacokinetics, including children, patients with renal insufficiency or those receiving renal replacement therapy, and patients taking co-medications known to interact with linezolid. As part of the clinical workflow, clinicians can use TDM with the thresholds summarized from the current literature to improve linezolid dosing for patients and maximize the probability of treatment success.
Topics: Anti-Bacterial Agents; Bayes Theorem; Drug Dosage Calculations; Drug Interactions; Drug Monitoring; Half-Life; Humans; Linezolid; Liver Failure; Metabolic Clearance Rate; Microbial Sensitivity Tests; Models, Biological; Pediatrics; Renal Insufficiency; Renal Replacement Therapy; Tuberculosis
PubMed: 31652190
DOI: 10.1097/FTD.0000000000000710