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BACKGROUND: With advancements in CF drug development, people with cystic fibrosis (PwCF) now take a median of seven medications daily, increasing treatment complexity, risk of drug therapy problems (DTPs), and interference with treatment goals. Given that some of these DTPs can be prevented with preemptive pharmacogenetic testing, the overall goal of this study was to test the clinical utility of a multi-gene pharmacogenetics (PGx) panel in potentially reducing DTPs in PwCF. METHODS: A population based retrospective study of patients with CF was conducted at the University of Utah Health Care System. The patients were genotyped for CYP450 enzymes using a pharmacogenomic assay, and their drug utilization information was obtained retrospectively. This pharmacogenomic information was combined with clinical guidelines to predict the number of actionable PGx interventions in this patient cohort. RESULTS: A total of 52 patients were included in this study. In the patient sample, a minimum of one order of actionable PGx medication was observed in 75 % of the cases. Results revealed that 4.2 treatment modifications per 10 patients can be enabled with the help of a PGx intervention in this patient population. Additionally, our findings suggest that polymorphisms in CYP2D6 and CYP2C19 are most likely to be the primary contributors to DTP's within PwCF. CONCLUSION: This study provides evidence that the PGx panel has the potential to help alleviate the clinical burden of DTPs in PwCF and can assist in informing pharmacotherapy recommendations. Future research should validate these findings and evaluate which subgroups of PwCF would most benefit from pharmacogenetic testing.
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BACKGROUND: Gallstone disease (GD) is increasing in the world and has various complications. OBJECTIVE: This study aims to examine the relationship between GD and the risk of mortality from cardiovascular disease (CVD) and cancer using a systematic review and meta-analysis approach. METHODS: A comprehensive and systematic search was done in various databases, such as Web of Science (WOS), Scopus, MEDLINE/PubMed, Cochrane, and Embase. The search included studies published from 1980 to December 2023. Heterogeneity was assessed using Chi-square, I2, and forest plots, while publication bias was evaluated through Begg's and Egger's tests. All analyses were performed using Stata 15, with statistical significance set at p <0.05. RESULTS: A pooled analysis of five studies involving 161,671 participants demonstrated that individuals with GD had a significantly higher risk of mortality from CVD (RR 1.29, 95% CI: 1.11-1.50, p <0.001). Importantly, no evidence of publication bias was found based on the results of Begg's test (p =0.806) and Egger's test (p =0.138). Furthermore, the pooled analysis of seven studies, encompassing a total of 562,625 participants, indicated an increased risk of cancer mortality among individuals with GD (RR 1.45, 95% CI: 1.16-1.82, p <0.001). Similarly, no publication bias was detected through Begg's test (p =0.133) and Egger's test (p =0.089). CONCLUSION: In this study, the evidence of a significant association between GD and an elevated risk of mortality from CVD and cancer is provided. These findings suggest that implementing targeted interventions for individuals with gallstone disease could reduce mortality rates among these patients.
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AIMS: Whether and when glomerular filtration rate (GFR) in preterms catches up with term peers is unknown. This study aims to develop a GFR maturation model for (pre)term-born individuals from birth to 18 years of age. Secondarily, the function is applied to data of different renally excreted drugs. METHODS: We combined published inulin clearance values and serum creatinine (Scr) concentrations in (pre)term born individuals throughout childhood. Inulin clearance was assumed to be equal to GFR, and Scr to reflect creatinine synthesis rate/GFR. We developed a GFR function consisting of GFRbirth (GFR at birth), and an Emax model dependent on PNA (with GFRmax, PNA50 (PNA at which half of GFR max is reached) and Hill coefficient). The final GFR model was applied to predict gentamicin, tobramycin and vancomycin concentrations. RESULT: In the GFR model, GFRbirth varied with birthweight linearly while in the PNA-based Emax equation, GA was the best covariate for PNA50, and current weight for GFRmax. The final model showed that for a child born at 26 weeks GA, absolute GFR is 18%, 63%, 80%, 92% and 96% of the GFR of a child born at 40 weeks GA at 1 month, 6 months, 1 year, 3 years and 12 years, respectively. PopPK models with the GFR maturation equations predicted concentrations of renally cleared antibiotics across (pre)term-born neonates until 18 years well. CONCLUSIONS: GFR of preterm individuals catches up with term peers at around three years of age, implying reduced dosages of renally cleared drugs should be considered below this age.
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Antibacterianos , Inulina , Recién Nacido , Niño , Humanos , Tasa de Filtración Glomerular , Vancomicina , Peso al Nacer , CreatininaRESUMEN
BACKGROUND: Rheumatoid arthritis (RA) and osteoarthritis (OA) are the most common forms of skeletal disease worldwide. OBJECTIVE: The current systematic review investigated the mechanisms of Silybum marianum, silymarin, and silibinin on RA and OA symptoms. METHODS: The PRISMA 2020 statement was used for reporting Items in this systematic review. The result was a list of five databases, including Web of Science, Cochrane Library, Embase, PubMed, and Scopus. After determining the inclusion and exclusion criteria, of 437 records identified, 21 studies were eligible. The data were extracted from the studies and imported into an Excel form, and finally, the effects, outcomes, and associated mechanisms were surveyed. RESULTS: Silybum marianum and its main constituents revealed immunomodulatory, anti-inflammatory, antioxidant, and anti-apoptotic properties in humans and laboratory animals. Moreover, they protect the joints against the cartilage matrix's hypocellularity and fibrillation, reduce synovitis, and inhibit degeneration of aggrecan and collagen-II in human chondrocytes. They also, through reducing inflammatory cytokines, show an analgesic effect. Although silymarin and silibinin have low absorption, their bioavailability can be increased with nanoparticles. CONCLUSION: In experimental studies, Silybum marianum, silymarin, and silibinin revealed promising effects on RA and OA symptoms. However, more clinical studies are needed in this field to obtain reliable results and clinical administration of these compounds.
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Artritis Reumatoide , Osteoartritis , Silibina , Silybum marianum , Silimarina , Humanos , Silybum marianum/química , Silimarina/uso terapéutico , Silimarina/farmacología , Artritis Reumatoide/tratamiento farmacológico , Osteoartritis/tratamiento farmacológico , Silibina/farmacología , Silibina/uso terapéutico , Animales , Antioxidantes/uso terapéutico , Antioxidantes/farmacología , Extractos Vegetales/uso terapéutico , Extractos Vegetales/farmacología , Antiinflamatorios/uso terapéutico , Antiinflamatorios/farmacologíaRESUMEN
OBJECTIVE: Information is needed to guide the design of randomized controlled trials (RCTs) evaluating L-citrulline therapy for premature infants with pulmonary hypertension associated with bronchopulmonary dysplasia (BPD-PH). Based on our single-dose pharmacokinetic study, we evaluated the ability of a multi-dose enteral L-citrulline strategy to achieve a target trough steady-state L-citrulline plasma concentration and its tolerability in premature infants. STUDY DESIGN: Plasma L-citrulline concentrations were measured in six premature infants receiving 60 mg/kg L-citrulline every 6 h for 72 h before the first and last L-citrulline doses. L-citrulline concentrations were compared to concentration-time profiles from our previous study. RESULTS: Target trough plasma L-citrulline concentrations were achieved in 2/6 subjects. No serious adverse events occurred. CONCLUSIONS: Multi-dose L-citrulline was well tolerated. These results will assist in the design of phase II RCTs evaluating L-citrulline dosage strategies to achieve target plasma L-citrulline concentrations in infants at risk for BPD-PH. CLINICAL TRIALS: gov ID: NCT03542812.
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Displasia Broncopulmonar , Hipertensión Pulmonar , Humanos , Lactante , Recién Nacido , Displasia Broncopulmonar/tratamiento farmacológico , Citrulina/uso terapéutico , Hipertensión Pulmonar/etiología , Hipertensión Pulmonar/complicaciones , Recien Nacido PrematuroRESUMEN
AIMS: We propose using glomerular filtration rate (GFR) as the physiological basis for distinguishing components of renal clearance. METHODS: Gentamicin, amikacin and vancomycin are thought to be predominantly excreted by the kidneys. A mixed-effects joint model of the pharmacokinetics of these drugs was developed, with a wide dispersion of weight, age and serum creatinine. A dataset created from 18 sources resulted in 27,338 drug concentrations from 9,901 patients. Body size and composition, maturation and renal function were used to describe differences in drug clearance and volume of distribution. RESULTS: This study demonstrates that GFR is a predictor of two distinct components of renal elimination clearance: (1) GFR clearance associated with normal GFR and (2) non-GFR clearance not associated with normal GFR. All three drugs had GFR clearance estimated as a drug-specific percentage of normal GFR (gentamicin 39%, amikacin 90% and vancomycin 57%). The total clearance (sum of GFR and non-GFR clearance), standardized to 70 kg total body mass, 176 cm, male, renal function 1, was 5.58 L/h (95% confidence interval [CI] 5.50-5.69) (gentamicin), 7.77 L/h (95% CI 7.26-8.19) (amikacin) and 4.70 L/h (95% CI 4.61-4.80) (vancomycin). CONCLUSIONS: GFR provides a physiological basis for renal drug elimination. It has been used to distinguish two elimination components. This physiological approach has been applied to describe clearance and volume of distribution from premature neonates to elderly adults with a wide dispersion of size, body composition and renal function. Dose individualization has been implemented using target concentration intervention.
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Antibacterianos , Vancomicina , Recién Nacido , Adulto , Humanos , Masculino , Anciano , Antibacterianos/farmacocinética , Vancomicina/farmacocinética , Amicacina/farmacocinética , Gentamicinas/farmacocinética , Tasa de Filtración Glomerular , Tasa de Depuración Metabólica , CreatininaRESUMEN
The liver is important in detoxifying organisms from xenobiotics, supporting immune functions, and metabolizing lipids and glucose. In addition, a growing number of drug-induced liver injuries and diseases associated with liver dysfunction make the development of phytodrugs targeting multiple liver functions particularly crucial. Therefore, we investigated the effects of a novel chicory extract prepared from aerial parts of the wild Cichorium intybus L. plant (CE) on liver enzymes and on lipid and glucose metabolism in rats with acute liver injury or hyperlipidemia. A single subcutaneous injection of mercury chloride induced an acute liver injury. Hyperlipidemia was induced by a single intraperitoneal injection of Tween-80 or by feeding rats with cholesterol and mercazolil for 28 days. Under varying regimens, the experimental rats received 100 mg/kg b.w. or 500 mg/kg b.w. of CE. CE treatment ameliorated acute liver injury by reducing liver enzyme activity, bilirubin, glucose, and lipid levels. Treatment of hyperlipidemic rats with CE effectively reduced serum lipid and glucose levels. The data obtained in this study suggest that chicory-based phytodrugs may be used to effectively treat acute liver injury and for the prophylaxis or treatment of diseases such as hyperlipidemia, type 2 diabetes, and metabolic syndrome. Clinical trials are needed to prove the effectiveness of chicory extract in human patients.
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BACKGROUND: Depression and anxiety are the most common mental disorders worldwide. OBJECTIVE: We aimed to review silymarin and silibinin effects and underlying mechanisms in the central nervous system (CNS) for depression and anxiety treatment. METHODS: The research protocol was prepared based on following the PRISMA statement. An extensive search was done in essential databases such as PubMed, Cochrane Library, Web of Science (ISI), Embase, and Scopus. Considering the study inclusion and exclusion criteria, 17 studies were finally included. The desired information was extracted from the studies and recorded in Excel, and the consequences and mechanisms were reviewed. RESULTS: Silymarin and silibinin upregulated brain-derived neurotrophic factor (BDNF) and improved neural stem cells (NSCs) proliferation in the cortex and hippocampus. They also increased neurochemical serotonin (5-HT), dopamine (DA), and norepinephrine (NE) levels. Silymarin and silibinin reduced malondialdehyde (MDA) formation and increased glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT) activities. In addition, silymarin and silibinin reduced interleukin (IL)-6, IL-1ß, and IL-12ß, reducing tumor necrosis factor α (TNF-α) induced neuroinflammation. CONCLUSION: Silymarin and silibinin exert anti-depression and anxiolytic effects by regulating neurotransmitters, endocrine, neurogenesis, and immunologic systems. Therefore, as natural and complementary medicines, they can be used to reduce the symptoms of depression and anxiety; However, more clinical studies are needed in this field.
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Silimarina , Humanos , Silimarina/farmacología , Silimarina/uso terapéutico , Silibina/uso terapéutico , Silibina/farmacología , Depresión/tratamiento farmacológico , Antioxidantes/farmacología , Antioxidantes/uso terapéutico , Trastornos de Ansiedad/tratamiento farmacológico , Trastornos de Ansiedad/patología , Hipocampo/patología , Glutatión/farmacologíaRESUMEN
AIMS: To investigate the pharmacokinetics and safety of prolonged paracetamol use (>72 h) for neonatal pain. METHODS: Neonates were included if they received paracetamol orally or intravenously for pain treatment. A total of 126 samples were collected. Alanine aminotransferase and bilirubin were measured as surrogate liver safety markers. Paracetamol and metabolites were measured in plasma. Pharmacokinetic parameters for the parent compound were estimated with a nonlinear mixed-effects model. RESULTS: Forty-eight neonates were enrolled (38 received paracetamol for >72 h). Median gestational age was 38 weeks (range 25-42), and bodyweight at inclusion was 2954 g (range 713-4750). Neonates received 16 doses (range 4-55) over 4.1 days (range 1-13.8). The median (range) dose was 10.1 mg/kg (2.9-20.3). The median oxidative metabolite concentration was 14.6 µmol/L (range 0.12-113.5) and measurable >30 h after dose. There was no significant difference (P > .05) between alanine aminotransferase and bilirubin measures at <72 h or >72 h of paracetamol treatment or the start and end of the study. Volume of distribution and paracetamol clearance for a 2.81-kg neonate were 2.99 L (% residual standard error = 8, 95% confidence interval 2.44-3.55) and 0.497 L/h (% residual standard error = 7, 95% confidence interval 0.425-0.570), respectively. Median steady-state concentration from the parent model was 50.3 µmol/L (range 30.6-92.5), and the half-life was 3.55 h (range 2.41-5.65). CONCLUSION: Our study did not provide evidence of paracetamol-induced liver injury nor changes in metabolism in prolonged paracetamol administration in neonates.
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Acetaminofén , Analgésicos no Narcóticos , Recién Nacido , Humanos , Lactante , Acetaminofén/efectos adversos , Estudios de Cohortes , Alanina Transaminasa , Dolor/tratamiento farmacológico , BilirrubinaRESUMEN
Prescription drug use is prevalent during pregnancy, yet there is limited knowledge about maternal-fetal safety and efficacy of this drug use because pregnant individuals have historically been excluded from clinical trials. Underrepresentation has resulted in a lack of data available to estimate or predict fetal drug exposure. Approaches to study fetal drug pharmacology are limited and must be evaluated for feasibility and accuracy. Anatomic and physiological changes throughout pregnancy fluctuate based on gestational age and can affect drug pharmacokinetics (PK) for both mother and fetus. Drug concentrations have been studied throughout different stages of gestation and at or following delivery in tissue and fluid biospecimens. Sampling amniotic fluid, umbilical cord blood, placental tissue, meconium, umbilical cord tissue, and neonatal hair present surrogate options to quantify and characterize fetal drug exposure. These sampling methods can be applied to all therapeutics including small molecule drugs, large molecule drugs, conjugated nanoparticles, and chemical exposures. Alternative approaches to determine PK have been explored, including physiologically based PK modeling, in vitro methods, and traditional animal models. These alternative approaches along with convenience sampling of tissue or fluid biospecimens can address challenges in studying maternal-fetal pharmacology. In this narrative review, we 1) present an overview of the current understanding of maternal-fetal drug exposure; 2) discuss biospecimen-guided sampling design and methods for measuring fetal drug concentrations throughout gestation; and 3) propose methods for advancing pharmacology research in the maternal-fetal population.
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BACKGROUND AND OBJECTIVE: Contradictory pharmacokinetic (PK) results have been observed between obese adults and obese adolescents, with absolute clearance (CL) reported to be either unaltered, lower, or higher in obese adolescents compared to obese adults. This study investigates the PK of vancomycin in adolescents and adults who are overweight or obese. METHODS: Data from 125 overweight and obese adolescents (aged 10-18 years, weight 28.3-188 kg) and 81 overweight and obese adults (aged 29-88 years, weight 66.7-143 kg) were analysed using population PK modelling. In addition to age, sex, renal function estimates, and regular weight descriptors, we evaluated standard weight (WTstandard, defined as weight for length, age, and sex in adolescents and weight for length in adults) and excess weight (WTexcess, defined as total body weight (TBW) minus WTstandard) as covariates in order to distinguish between weight resulting from length versus weight resulting from obesity. RESULTS: Analyzing adolescents and adults together, vancomycin CL was found to increase with TBW and decrease with increasing age (p < 0.001). A covariate analysis investigating adolescents and adults separately found that vancomycin CL increased with WTstandard in adolescents and adults, albeit with different functions, with adolescents having a higher CL per WTstandard than adults. Moreover, in this separate model, adolescent males had 21% higher CL than adolescent females of the same WTstandard, while in adults, CL decreased with increasing age (p < 0.001). CONCLUSION: There are apparent differences in vancomycin CL in overweight and obese adults versus overweight and obese adolescents, implying that dosing of vancomycin cannot be directly extrapolated between these populations.
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Sobrepeso , Obesidad Infantil , Masculino , Femenino , Adolescente , Humanos , Adulto , Vancomicina , Aumento de Peso , Modelos BiológicosRESUMEN
Infants, children, and adolescents are at risk of experiencing a multitude of gastrointestinal disorders (GID). These disorders can adversely affect the quality of life or be life-threatening. Various interventions that span the conventional and complementary therapeutic categories have been developed. Nowadays, parents increasingly seek complementary options for their children to use concurrently with conventional therapies. Due to the high prevalence and morbidity of diarrhea, constipation, and irritable bowel syndrome (IBS) in children, in this review, we decided to focus on the current state of the evidence for conventional and complementary therapies used for the treatment of these diseases in children. Diarrhea treatment focuses on the identification of the cause and fluid management. Oral rehydration with supplementation of deficient micronutrients, especially zinc, is well established and recommended. Some probiotic strains have shown promise in reducing the duration of diarrhea. For the management of constipation, available clinical trials are insufficient for conclusive recommendations of dietary modifications, including increased use of fruit juice, fiber, and fluid. However, the role of laxatives as conventional treatment is becoming more established. Polyethylene glycol is the most studied, with lactulose, milk of magnesia, mineral oil, bisacodyl, and senna presenting as viable alternatives. Conventional treatments of the abdominal pain associated with IBS are poorly studied in children. Available studies investigating the effectiveness of antidepressants on abdominal pain in children with IBS were inconclusive. At the same time, probiotics and peppermint oil have a fair record of benefits and safety. The overall body of evidence indicates that a careful balance of conventional and complementary treatment strategies may be required to manage gastrointestinal conditions in children.
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Background: Esophageal cancer is a cancerous tumor that develops in the esophagus. It is the 10th most common cancer and has a low survival rate. Esophageal adenocarcinoma (EAC) is increasing in incidence globally. Those with EAC are affected by Barrett's esophagus metaplasia, which is attributed to genetic predisposition and is more common in men. Studies suggest that gastric acid suppressants, like proton pump inhibitors and histamine-2 receptor antagonists, have anticancer properties and reduce EAC. However, other research has suggested that they are not cancer-protective, and the use of antisecretory drugs is a risk factor for developing EAC. Objective: This systematic review and meta-analysis investigated the properties and risk factors associated with using gastric acid suppressants in patients with EAC. Methods: This meta-analysis used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Information from selected articles, including the lead author's name, year of publication, study setting, sample size, and gender, was extracted and recorded into an Excel (Microsoft, Redmond, Washington) form. Statistical data included odds ratio, hazard ratio, and/or risk ratio, with a 95% CI associated with patients with EAC and receiving gastric acid suppressants. Data were compared with individuals not receiving treatment. Publication bias was assessed using Begg's and Egger's tests. Statistical analyzes used Stata 14.0 (Stata LLC, College Station, Texas). Results: The initial electronic literature search retrieved 3761 titles/abstracts. Extensive screening selected 20 articles for analysis. Odds ratios associated with EAC in the individuals using gastric acid suppressants were 0.77 (95% CI, 0.49-1.22; Pâ¯=â¯0.274) and 0.67 (95% CI, 0.39-1.29; Pâ¯=â¯0.240) for proton pump inhibitors and 1.02 (95% CI, 0.44-2.36; Pâ¯=â¯0.967) for histamine-2 receptor antagonists. Conclusions: The results found that gastric acid suppressants do not have a protective role in EAC and are not risk factors. Future studies of confounding variables and risk factors are needed to understand what affects EAC development.
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Although effective in treating actinic damage, topical photodynamic therapy (PDT) has been shown to be immunosuppressive through unknown mechanisms, which could potentially limit its effectiveness. Multiple types of environmental stressors, including PDT, can produce the immunosuppressive lipid mediator platelet-activating factor (PAF). Because PAF can produce subcellular microvesicle particles (MVPs), these studies tested whether PDT can generate PAF and MVP release and whether these are involved in PDT-induced immunosuppression. Previously, topical PDT using blue light and 5-aminolevulinic acid was found to be a potent stimulus for PAF production in mice and human skin explants and human patients, and we show that experimental PDT also generates high levels of MVP. PDT-generated MVPs were independent of the PAF receptor but were dependent on the MVP-generating enzyme acid sphingomyelinase. Patients undergoing topical PDT treatment to at least 10% of body surface area showed local and systemic immunosuppression as measured by inhibition of delayed-type hypersensitivity reactions. Finally, using a murine model of contact hypersensitivity, PDT immunosuppression was blocked by genetic and pharmacologic inhibition of acid sphingomyelinase and genetic inhibition of PAF receptor signaling. These studies describe a mechanism involving MVP through which PDT exerts immunomodulatory effects, providing a potential target to improve its effectiveness.
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Fotoquimioterapia , Esfingomielina Fosfodiesterasa , Humanos , Ratones , Animales , Esfingomielina Fosfodiesterasa/metabolismo , Esfingomielina Fosfodiesterasa/farmacología , Piel/metabolismo , Ácido Aminolevulínico , Tolerancia Inmunológica , Inmunosupresores/farmacología , Fármacos FotosensibilizantesRESUMEN
Sepsis remains one of the leading causes of death among pediatric patients with burn injuries. Despite limited vancomycin pharmacokinetic (PK) information within this population, it is widely used to treat severe burn injuries. Those with severe burns are at risk of nephrotoxicity, with an incidence of acute kidney injury (AKI) over 50%. Delivering an effective vancomycin dose and avoiding unnecessary toxicity is essential for improved patient outcomes. This was a retrospective analysis of 115 children aged 0.2 months to 18 years with severe burns, >10% total body surface area. Vancomycin was given via intravenous infusion; blood samples were drawn between 6- and 12-hour postinfusion. A population pharmacokinetic model was developed using nonlinear mixed-effect modeling (Monolix, version 2016R1). A one-compartment model described a steady-state volume of distribution (V), dependent on weight. Vancomycin clearance (CL) was influenced by age and estimated creatinine clearance (CrCL). The study population's (median age = 4 years, median weight = 20 kg, median total body surface area (%TBSA) = 40%) median V and CL were calculated to be 1.25 L/kg (95% CI, 1.04-1.46) and 0.15 L/h/kg (95% CI, 0.126-0.165), respectively. The PK model was explicitly developed to characterize the impact of physiological changes in children under 18 years of age and the percentage of the burn surface area using limited data. The analysis determined that weight, age, and estimated CrCL were important covariates in predicting vancomycin PK with high variability in CL and V.
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Quemaduras , Sepsis , Humanos , Niño , Adolescente , Preescolar , Vancomicina , Antibacterianos , Quemaduras/tratamiento farmacológico , Estudios Retrospectivos , Sepsis/tratamiento farmacológicoRESUMEN
BACKGROUND: Options to treat pulmonary hypertension (PH) in neonates with bronchopulmonary dysplasia (BPD) are few and largely ineffective. Improving the bioavailability of nitric oxide (NO) might be an efficacious treatment for BPD-PH. When administered orally, the NO-L-arginine precursor, L-citrulline, increases NO production in children and adults, however, pharmacokinetic (PK) studies of oral L-citrulline have not been performed in infants and children. OBJECTIVES: This study characterized the PK of enterally administered L-citrulline in neonates at risk of developing BPD-PH to devise a model-informed dosing strategy. METHODS AND RESULTS: Ten premature neonates (≤ 28 weeks gestation) were administered a single dose of 150 mg/kg (powder form solubilized in sterile water) oral L-citrulline at 32 ± 1 weeks postmenstrual age. Due to the need to limit blood draws, time windows were used to maximize the sampling over the dosing interval by assigning neonates to one of two groups (ii) samples collected pre-dose and at 1- and 2.5-h post-dose, and (ii) pre-dose and 0.25- and 3-h post-dose. The L-arginine concentrations (µmol/L) and the L-citrulline (µmol/L) plasma concentration-time data were evaluated using non-compartmental analysis (Phoenix WinNonlin version 8.1). Optimal dosage strategies were derived using a simulation-based methodology. Simulated doses of 51.5 mg or 37.5 mg/kg given four times a day produced steady-state concentrations close to a target of 50 µmol/L. The volume of distribution (V/F) and clearance (CL/F) were 302.89 ml and 774.96 ml/h, respectively, with the drug exhibiting a half-life of 16 minutes. The AUC from the time of dosing to the time of last concentration was 1473.3 h*µmol/L, with Cmax and Tmax of 799 µmol/L and 1.55 h, respectively. CONCLUSION: This is the first PK study in neonates presenting data that can be used to inform dosing strategies in future randomized controlled trials evaluating enteral L-citrulline as a potential treatment to reduce PH associated with BPD in premature neonates. REGISTRATION: Clinical trials.gov Identifier: NCT03542812.