Real-World Evidence of Factors Affecting Cannabidiol Exposure in Children with Drug-Resistant Developmental and Epileptic Encephalopathies.

The identification of factors that affect cannabidiol (CBD) systemic exposure may aid in optimizing treatment efficacy and safety in clinical practice. In this study, we aimed to correlate CBD plasma concentrations at a steady state to demographic, clinical, and pharmacological characteristics as well as seizure frequency after the administration of a purified CBD oil solution in a real-world setting of children with drug-resistant developmental and epileptic encephalopathies (DEEs). Patients receiving oral CBD pharmaceutical products at maintenance were enrolled. Venous blood samples were drawn before the CBD morning dose, 12 h apart from the last evening dose (C0 or CBD trough concentration). A linear mixed-effect analysis was implemented to assess the correlation between C0 and clinical, laboratory, pharmacological, and lifestyle factors. Fifteen females and seven males with a median age of 12.8 years (ranging between 4.7 and 17.2) were included. The median CBD dose was 8.8 mg/kg/day (ranging between 2.6 and 22.5), and the CBD C0 median (range) was 48.2 ng/mL (3.5-366.3). The multivariate model showed a 109.6% increase in CBD C0 in patients with concomitant levothyroxine (ß = 0.74 ± 0.1649, p < 0.001), 56.8% with food (ß = 0.45 ± 0.1550, p < 0.01), and 116.0% after intake of a ketogenic diet (ß = 0.77 ± 0.3141, p < 0.05). All patients included were responders without evidence of an association between C0 and response status. In children with DEEs, systemic concentrations of CBD may be significantly increased when co-administered with levothyroxine, food, or a ketogenic diet.

Population pharmacokinetics of sublingually administered tacrolimus in infants and young children with liver transplantation.

AIMS: Pharmacokinetics of tacrolimus after sublingual administration is not characterized in paediatric liver transplant patients. Therefore, we aimed to develop a population pharmacokinetic model of sublingually administered tacrolimus in patients who cannot swallow the capsules due to their age, sedation status and/or mechanical ventilation during the first weeks post-transplantation. METHODS: Demographic, clinical and pharmacological variables, including tacrolimus whole blood concentrations obtained from therapeutic drug monitoring and data from dense-sampling pharmacokinetic profiles, were recorded in 26 paediatric patients with biliary atresia who underwent liver transplantation between 2016 and 2021. Population pharmacokinetic analysis was performed with NONMEM v7.4. RESULTS: Disposition of tacrolimus was best characterized by a 2-compartment model with clearance achieving half of the maximum elimination capacity (CLMAX  = 4.1 L/h) at 4.6 days post-transplantation (T50 ). Compared to sedated patients, nonsedated status showed an increased first-order absorption rate constant (1.1 vs. 0.1 h-1 ) and a 24% reduction in bioavailability (FNS ) at 14 days post-transplant. The model was able to explain the oral absorption pattern in nonsedated patients as the result of gut bioavailability (0.9) and hepatic extraction ratio, with the latter being responsible for first-pass effects. Estimates of interindividual variability remained moderate (25.9% for the gut bioavailability) to high (79.8% for the apparent volume of distribution of the central compartment, and 101% for T50 ). CONCLUSION: A population pharmacokinetic model of sublingually administered tacrolimus in paediatric patients was developed to characterize different absorption mechanisms. Once the model is externally validated, the effect of post-transplant time on clearance and the sedation status may be considered in routine dosing management.

[Performance evaluation of a precision dosing service for vancomycin in a tertiary level pediatric hospital]. / Una evaluación de desempeño del servicio de dosificación de precisión para vancomicina en un hospital pediátrico de nivel terciario.

Background: Plasma level-based therapeutic drug monitoring of vancomycin is recommended in the treatment of complex pediatric infections in order to increase the probability of achieving safe and effective pharmacotherapy. Objective: To retrospectively evaluate the activities and performance of pharmacotherapeutic optimization based on vancomycin levels at a tertiary pediatric hospital between 2007 and 2020. Métodos: Vancomycin levels of pediatric patients were analyzed, assessing care quality indicators and analytical verifications, as well as aspects related to teaching and research. The predictive performance of vancomycin levels was evaluated after adjustment of the therapeutic regimen using a population pharmacokinetic optimization program (BestDose v1.126) considering the coefficient of determination (R2), the mean absolute percentage error (MAPE), and the root mean square error (RMSE). Results: 13269 vancomycin level determinations were analyzed; 70% were trough levels and 81% belonged to patients in the intensive care units. Forty percent of the trough levels were within the therapeutic range when adjusted without software. Three hundred seventy-four pharmacotherapeutic interventions, of which 97% were accepted by the treating physician; 75% of the post-adjustment trough levels were within the therapeutic range, compared to 40% when the approach was empirical, a difference that was statistically significant (p=0.03). The values associated with predictive performance (n subgroup of patients = 91) were: R2=0.61, MAPE=28.16%, and RMSE=3.3, which all showed to be adequate. Conclusion: The performance of therapeutic vancomycin monitoring and related pharmacokinetic clinical activities showed to be good.

Introducción: La dosificación de precisión a través del monitoreo de vancomicina basado en sus concentraciones plasmáticas (vancocinemia) es una práctica recomendada en el tratamiento de infecciones pediátricas de alta complejidad para aumentar la probabilidad de lograr una farmacoterapia segura y eficaz. Objetivo: Evaluar retrospectivamente las actividades y el desempeño relacionado a la optimización farmacoterapéutica basada en las vancocinemias (período 2007-2020) de un hospital pediátrico terciario. Métodos: Se analizaron las vancocinemias de pacientes pediátricos, estimándose indicadores de calidad asistencial y verificaciones analíticas, así como también aspectos relacionados a docencia e investigación. Se evaluó el desempeño predictivo de las concentraciones de vancomicina cuando se ajustaron los regímenes terapéuticos con un programa de optimización farmacocinética (BestDose v1.126) considerando el coeficiente de determinación (R2), el error porcentual absoluto medio (MAPE) y la raíz del error cuadrático medio (RMSE). Resultados: Se analizaron 13269 vancocinemias. El 70% fueron valles y el 81% pertenecieron a pacientes de Unidades de Cuidados Intensivos. El 40% de los valles se encontró dentro del margen terapéutico al ajustarse sin programa informático. Se realizaron 347 intervenciones farmacoterapéuticas, el 97% de las cuales fueron aceptadas por el médico tratante; el 75% de los valles posteriores al ajuste entraron en el margen terapéutico, valor significativamente mayor respecto al 40% de cuando el abordaje fue empírico (p=0.03). Los valores asociados al desempeño predictivo, (n subgrupo de pacientes = 91) fueron: R2=0.61, MAPE=28.16% y RMSE=3.3, mostrándose todos adecuados. Conclusión: Las actividades de monitoreo y farmacocinética clínica de vancomicina mostraron un buen rendimiento clínico. Resultados: Se analizaron 13269 vancocinemias. El 70% fueron valles y el 81% pertenecieron a pacientes de Unidades de Cuidados Intensivos. El 40% de los valles se encontró dentro del margen terapéutico al ajustarse sin programa informático. Se realizaron 347 intervenciones farmacoterapéuticas, el 97% de las cuales fueron aceptadas por el médico tratante; el 75% de los valles posteriores al ajuste entraron en el margen terapéutico, valor significativamente mayor respecto al 40% de cuando el abordaje fue empírico (p=0.03). Los valores asociados al desempeño predictivo, (n subgrupo de pacientes = 91) fueron: R2=0.61, MAPE=28.16% y RMSE=3.3, mostrándose todos adecuados. Conclusión: Las actividades de monitoreo y farmacocinética clínica de vancomicina mostraron un buen rendimiento clínico.

[Medicinal cannabis: beyond the myth, just another (herbal) drug]. / Cannabis medicinal: más allá del mito, solo otra droga (vegetal).

This editorial briefly explores some of the distinctions between drugs and pharmaceuticals, alongside definitions regarding Cannabis sativa and its use in the context of a newly legal industry. Furthermore, medical cannabis is considered with regard to its toxicity, its social uses, its pharmacological activity, its legal paradoxes, and the scientific revolution sparked by the study of the endocannabinoid system, which has gained a great deal of relevance for modern physiology and pharmacology.

En este editorial, se propone un breve recorrido por algunas distinciones entre drogas y fármacos y definiciones sobre Cannabis sativa y su uso en una nueva industria legal. Por otro lado, se aborda la toxicidad del cannabis medicinal, sus usos sociales, la acción farmacológica, las paradojas legales, y la revolución científica que ha generado el estudio del sistema endocannabinoide y que ha sido de gran relevancia para la fisiología y la farmacología moderna.

Integrative oncology: Addressing the global challenges of cancer prevention and treatment.

The increase in cancer incidence and mortality is challenging current cancer care delivery globally, disproportionally affecting low- and middle-income countries (LMICs) when it comes to receiving evidence-based cancer prevention, treatment, and palliative and survivorship care. Patients in LMICs often rely on traditional, complementary, and integrative medicine (TCIM) that is more familiar, less costly, and widely available. However, spheres of influence and tensions between conventional medicine and TCIM can further disrupt efforts in evidence-based cancer care. Integrative oncology provides a framework to research and integrate safe, effective TCIM alongside conventional cancer treatment and can help bridge health care gaps in delivering evidence-informed, patient-centered care. This growing field uses lifestyle modifications, mind and body therapies (eg, acupuncture, massage, meditation, and yoga), and natural products to improve symptom management and quality of life among patients with cancer. On the basis of this review of the global challenges of cancer control and the current status of integrative oncology, the authors recommend: 1) educating and integrating TCIM providers into the cancer control workforce to promote risk reduction and culturally salient healthy life styles; 2) developing and testing TCIM interventions to address cancer symptoms or treatment-related adverse effects (eg, pain, insomnia, fatigue); and 3) disseminating and implementing evidence-based TCIM interventions as part of comprehensive palliative and survivorship care so patients from all cultures can live with or beyond cancer with respect, dignity, and vitality. With conventional medicine and TCIM united under a cohesive framework, integrative oncology may provide citizens of the world with access to safe, effective, evidence-informed, and culturally sensitive cancer care.

Intensive Safety Monitoring of Rituximab (Biosimilar Novex® and the Innovator) in Pediatric Patients With Complex Diseases.

Although rituximab is widely used off-label for complex pediatric diseases, safety reports are limited. We aimed to report evidence of its use in clinical practice, to describe the incidence of adverse drug reactions (ADR) to rituximab biosimilar Novex® and innovator, and to identify risk factors for the development of ADR in a real-life follow-up cohort of pediatric patients with complex diseases. We conducted a prospective, longitudinal, observational, single-centre study in patients that received rituximab for any complex disease, and as part of an intensive pharmacovigilance program. Demographic, pharmacological, clinical, and drug-related data were collected for all patients. ADR-free survival, including infusion-related reactions (IRR) and delayed ADR (dADR), was estimated using Kaplan-Meier curves. Risk factors were evaluated by multivariable Cox regression models. In total, 77 patients (<19 y.o.) received 187 infusions of rituximab Novex® (n = 155) or innovator rituximab (n = 32) for neurologic (Neu), immune-hematologic-rheumatic (IHR), oncologic (O) diseases, and hematopoietic stem-cell transplantation (HSCT) or solid-organ transplantation (SOT). We recorded 29 IRR and 58 dADR that occurred in 27 (35.1%) and 29 (37.7%) patients, respectively. The respiratory tract was the most affected during IRR (29.6%) and hypogammaglobulinemia (37.9 %) was the most frequent dADR. First versus subsequent infusions (HR 5.4, CI95% 2.4-12.1, p<0.05), sex (boys vs. girls, HR 0.3, CI95% 0.1-0.8, and p<0.05), and diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 2.3, CI95% 1.02-5.4, and p < 0.05) were significantly associated with the development of IRR. For dADR, risk factors were diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 0.4, CI95% 0.2-0.9, and p < 0.05) and cumulative body surface area-normalized dosage (HR 1.0003, CI95% 1.0001-1.0006, and p < 0.05). The present is the largest real-world safety assessment of rituximab in Latin-American children with complex diseases supporting its use based on the overall acceptable safety. Identification of risk factors may contribute to optimization of off-label rituximab treatment in pediatrics.

Pharmacokinetics of cannabidiol in children with refractory epileptic encephalopathy.

Growing interest in the clinical use of cannabidiol (CBD) as adjuvant therapy for pediatric refractory epileptic encephalopathy emphasizes the need for drug treatment optimization. The aim of this study was to characterize the pharmacokinetics of CBD in pediatric patients with refractory epileptic encephalopathy receiving an oil-based oral solution. To evaluate CBD concentrations, six serial blood samples per patient were collected after the morning dose of CBD, at least 21 days after the beginning of treatment. Twelve patients who received a median (range) dose of 12.2 (5.3-19.4) mg/kg/d (twice daily) were included in the analysis. Median (range) CBD time to maximum plasma concentration, maximum plasma concentration, and area under the concentration versus time curve up to 6 hours after dosing were 3.2 hours (1.9-6.2), 49.6 ng/mL (14.4-302.0), and 226.3 ng ⋅ h/mL (70.5-861.3), respectively. CBD systemic exposure parameters were in the lower range of previous reports in pediatric patients receiving doses in a similar range. Most of our patients (83%) showed little CBD plasma level fluctuation during a dosing interval, comparable to that encountered after oral administration of an extended release drug delivery system. CDB administration was generally safe and well tolerated, and a novel levothyroxine-CBD interaction was recorded. Similar to other studies, large interindividual variability in CBD exposure was observed, encouraging the use of CBD therapeutic drug monitoring.

An Ultrafast Ultrahigh-Performance Liquid Chromatography Coupled With Tandem Mass Spectrometry Method for Cannabidiol Monitoring in Pediatric Refractory Epilepsy.

BACKGROUND: Cannabidiol (CBD) is a nonpsychoactive natural product that has been increasingly used as a promising new drug for the management of neurological conditions such as refractory epilepsy. Development of rapid and sensitive methods to quantitate CBD is essential to evaluate its pharmacokinetics in humans, particularly in children. The objective of this work was to develop and validate an ultrafast ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) method for CBD quantitation that is capable of detecting major CBD and tetrahydrocannabinol (THC) metabolites in the plasma of pediatric refractory epilepsy patients. METHODS: Eight-point CBD calibration curves were prepared using 60 µL of plasma from healthy volunteers. Samples were analyzed in a Shimadzu Nexera X2 UHPLC system, which was coupled to a Sciex QTRAP 6500 mass spectrometer. Chromatography was optimized in acetonitrile (ACN)/water with a 70%-90% gradient of ACN in 2 minutes. Multiple reaction monitoring transitions of major CBD and THC metabolites were optimized in patient plasma. RESULTS: The optimized UHPLC-MS/MS method was validated for the linear range (1-300 ng/mL) of CBD (r2 = 0.996). The limit of quantification and limit of detection were 0.26 and 0.86 ng/mL, respectively. Accuracy and precision met the acceptable validation limits. CBD recovery and matrix effects were 83.9 ± 13.9% and 117.4 ± 4.5%, respectively. The method was successfully applied to quantify CBD and detect the major CBD and THC metabolites in clinical samples. 7-COOH-CBD was the most intensely detected metabolite followed by glucuronide conjugates. CONCLUSIONS: A simple and sensitive method for rapidly monitoring CBD and identifying relevant metabolites was developed. Its applicability in samples from children treated for epilepsy was demonstrated, making it an excellent alternative for performing pharmacokinetic studies.

Medicina Integrativa en Pediatría y Neonatología en Argentina / Integrative Medicine in Pediatrics and Neonatology in Argentina

Transcurrimos un tiempo en el que están cambiando muchos paradigmas, con lo que se abre la perspectiva de un universo holístico e interconectado. Estos paradigmas están transformando también la medicina, proporcionando la comprensión y el respeto entre diferentes filosofías y sus correspondientes prácticas. Los niños son el futuro y la esperanza para el mundo; la Pediatría es la disciplina más importante para el cuidado de su salud, desde la concepción hasta el final de la adolescencia. La Pediatría debe ocuparse no solo de los individuos y sus organismos, sino también de influencias ambientales, culturales y sociales, que tienen impacto considerable sobre la salud física, emocional y mental de los niños y sus familias.

Principios de estadística Bayesiana y su relación con la farmacocinética aplicada / Principles of Bayesian statistics and its relationship with applied pharmacokinetics

La metodología estadística Bayesiana permite, si se conoce la probabilidad poblacional de que un suceso ocurra, modificar su valor cuando se dispone de nueva información individual. Aunque las metodologías Bayesiana y frecuentista (clásica) tienen idénticos campos de aplicación, la primera se aplica cada vez más en investigación científica y análisis de big data. En la farmacoterapia moderna, la farmacocinética clínica ha sido responsable de la expansión de la monitorización, facilitada por desarrollos técnico-analíticos y matemático-estadísticos. La farmacocinética poblacional ha permitido identificar y cuantificar las características fisiopatológicas y de tratamiento en una población de pacientes determinada, en particular en pediatría y neonatología, y otros grupos vulnerables, explicando la variabilidad farmacocinética interindividual. Asimismo, la estimación Bayesiana resulta importante como herramienta estadística aplicada en programas informáticos de optimización farmacoterapéutica cuando la monitorización farmacológica se basa en la interpretación farmacocinética clínica. Aunque con ventajas y limitaciones, la optimización farmacoterapéutica basada en la estimación Bayesiana es cada vez más usada en la actualidad, siendo el método de referencia. Esto es particularmente conveniente para la práctica clínica de rutina debido al limitado número de muestras requeridas por parte del paciente, y a la flexibilidad en cuanto a los tiempos de muestreo de sangre para cuantificación de fármacos. Así, la aplicación de los principios Bayesianos a la práctica de la farmacocinética clínica resulta en la mejora de la atención farmacoterapéutica.

If one knows the probability of an event occurring in a population, Bayesian statistics allows mo difying its value when there is new individual information available. Although the Bayesian and frequentist (classical) methodologies have identical fields of application, the first one is increasin gly applied in scientific research and big data analysis. In modern pharmacotherapy, clinical phar macokinetics has been used for the expansion of monitoring, facilitated by technical-analytical and mathematical-statistical developments. Population pharmacokinetics has allowed the identification and quantification of pathophysiological and treatment characteristics in a specific patient popu lation, especially in the pediatric and neonatal population and other vulnerable groups, explaining interindividual variability. Likewise, Bayesian estimation is important as a statistical tool applied in pharmacotherapy optimization software when pharmacological monitoring is based on clinical phar macokinetic interpretation. With its advantages and despite its limitations, pharmacotherapeutic op timization based on Bayesian estimation is increasingly used, becoming the reference method today. This characteristic is particularly convenient for routine clinical practice due to the limited number of samples required from the patient and the flexibility it shows regarding blood sampling times for drug quantification. Therefore, the application of Bayesian principles to the practice of clinical phar macokinetics has led to the improvement of pharmacotherapeutic care.

Farmacología clínica de cannabidiol en epilepsias refractarias / Clinical pharmacology of cannabidiol in refractory epilepsy

OBJETIVO: El objetivo del presente trabajo es brindar una revisión sistemática y actualizada acerca de la farmacología de cannabidiol, con especial énfasis en la farmacocinética, eventos adversos e interacciones, vinculada al uso de este fármaco en epilepsias refractarias. MÉTODO: Se realizó una revisión de los trabajos publicados y relaciona-dos con la farmacocinética y los eventos adversos e interacciones farmacológicas de cannabidiol utilizado para el tratamiento de las epilepsias refractarias mediante una búsqueda en PubMed y LILACS. RESULTADOS: Los estudios originales que describen la farmacocinética de cannabidiol de manera exhaustiva son limitados aunque informativos. La absorción de cannabidiol es rápida y se incrementa la biodisponibilidad por la ingesta conjunta de comidas ricas en grasas. El cannabidiol presenta farmacocinética lineal hasta dosis de 3.000 mg/día y se acumula por la administración continua. La semivida de eliminación se referencia entre 14 y 60 horas dependiendo de los tiempos de toma de muestra del estudio farmacocinético y no se descartan modificaciones en la eliminación por la administración en dosis múltiples. De las interacciones farmacológicas entre cannabidiol con otros fármacos antiepilépticos referenciadas hasta el momento, aquella con clobazam es la que presenta mayor evidencia científica. Los eventos adversos más frecuentes asociados al uso de cannabidiol fueron de gravedad leve o moderada e incluyeron somnolencia, principalmente por el uso conjunto de clobazam, y alteraciones gastrointestinales. Se evidenciaron asimismo anormalidades en la función hepática concomitantes con el uso de ácido valproico. CONCLUSIONES: Ante la creciente demanda de la utilización de cannabidiol en epilepsias refractarias, es fundamental el conocimiento de su farmacología por parte del equipo de salud. En especial, el farmacéutico clínico juega un papel primordial en la monitorización de su seguridad y eficacia. Esto permite la optimización del tratamiento clínico del cannabidiol administrado conjuntamente con otros fármacos antiepilépticos de mayor uso, lo que conduce a maximizar la actividad farmacológica y minimizar la aparición de eventos adversos al igual que de interacciones farmacológicas. El seguimiento clínico del paciente resulta fundamental para evitar la discontinuación del tratamiento o exacerbación de eventos adversos que afecten la calidad de vida del paciente

OBJECTIVE: The aim of this article is to provide a systematic and updated review on the pharmacology of cannabidiol in the context of refractory epilepsy, with special emphasis on its pharmacokinetics, adverse drug reactions and drug-drug interactions. METHOD: A review of the literature related to cannabidiol pharmacokinetics, adverse drug reactions and drug-drug interactions was carried out in the context of refractory epilepsy, through a search in PubMed and LILACS. RESULTS: Original studies that exhaustively describe the pharmacokinetics of cannabidiol are limited but informative. Cannabidiol is rapidly absorbed and its bioavailability increases when administered with high fat meals. Cannabidiol exhibits a linear pharmacokinetic profile for doses up to 3,000 mg/day and accumulates after multiple administrations. Elimination half-life has been reported between 14 h and 60 h depending on the sampling times of each study; changes in cannabidiol elimination due to continuous administration cannot be discarded. Of all reported drug-drug interactions with anticonvulsants or other co-administered drugs in patients with epilepsy, the strongest evidence is provided with clobazam. The most frequent cannabidiol-related adverse drug reactions were low to moderate and included somnolence, mainly related to concomitant administration of clobazam, and gastrointestinal alterations. Also, liver function abnormalities were reported during the use of cannabidiol and valproic acid. CONCLUSIONS: Given the increased use of cannabidiol in refractory epilepsy, a comprehensive understanding of its pharmacological profile is essential for the clinical team. Specifically, clinical pharmacists play an important role in monitoring cannabidiol's safety and efficacy. This approach leads to treatment optimization, allowing to maximizing the pharmacological activity and minimizing the occurrence of adverse events as well as drug-to-drug interactions. Clinical follow-up is essential to avoid discontinuation of treatment or exacerbation of adverse events, which may impair the patients' quality of life

Clinical pharmacology of cannabidiol in refractory epilepsy.

OBJECTIVE: The aim of this article is to provide a systematic and updated review  on the pharmacology of cannabidiol in the context of refractory epilepsy, with  special emphasis on its pharmacokinetics, adverse drug reactions and drug-drug interactions. METHOD: A review of the literature related to cannabidiol pharmacokinetics, adverse drug reactions and drug-drug interactions was  carried out in the context of refractory epilepsy, through a search in PubMed and LILACS. RESULTS: Original studies that exhaustively describe the pharmacokinetics of  cannabidiol are limited but informative. Cannabidiol is rapidly absorbed and its  bioavailability increases when administered with high fat meals. Cannabidiol  exhibits a linear pharmacokinetic profile for doses up to 3,000 mg/day and  accumulates after multiple administrations. Elimination half-life has been  reported between 14 h and 60 h depending on the sampling times of each  study; changes in cannabidiol elimination due to continuous administration  cannot be discarded. Of all reported drugdrug interactions with anticonvulsants  or other co-administered drugs in patients with epilepsy, the strongest evidence  is provided with clobazam. The most frequent cannabidiol-related adverse drug  reactions were low to moderate and included somnolence, mainly related to  concomitant administration of clobazam, and gastrointestinal alterations. Also,  liver function abnormalities were reported during the use of cannabidiol and valproic acid. CONCLUSIONS: Given the increased use of cannabidiol in refractory epilepsy, a  comprehensive understanding of its pharmacological profile is essential for the  clinical team. Specifically, clinical pharmacists play an important role in  monitoring cannabidiol's safety and efficacy. This approach leads to treatment  optimization, allowing to maximizing the pharmacological activity and minimizing the occurrence of adverse events as well as drug-to-drug interactions. Clinical  follow-up is essential to avoid discontinuation of treatment or exacerbation of  adverse events, which may impair the patients' quality of life.

Objetivo: El objetivo del presente trabajo es brindar una revisión sistemática y  actualizada acerca de la farmacología de cannabidiol, con especial énfasis en la  farmacocinética, eventos adversos e interacciones, vinculada al uso de este  fármaco en epilepsias refractarias.Método: Se realizó una revisión de los trabajos publicados y relacionados con la farmacocinética y los eventos adversos e interacciones farmacológicas de  cannabidiol utilizado para el tratamiento de las epilepsias refractarias mediante  una búsqueda en PubMed y LILACS.Resultados: Los estudios originales que describen la farmacocinética de cannabidiol de manera exhaustiva son limitados aunque informativos. La absorción de cannabidiol es rápida y se incrementa la biodisponibilidad por la  ingesta conjunta de comidas ricas en grasas. El cannabidiol presenta farmacocinética lineal hasta dosis de 3.000 mg/día y se acumula por la  administración continua. La semivida de eliminación se referencia entre 14 y 60  horas dependiendo de los tiempos de toma de muestra del estudio farmacocinético y no se descartan modificaciones en la eliminación por la administración en dosis múltiples. De las interacciones farmacológicas entre  cannabidiol con otros fármacos antiepilépticos referenciadas hasta el momento,  aquella con clobazam es la que presenta mayor evidencia científica. Los eventos  adversos más frecuentes asociados al uso de cannabidiol fueron de gravedad  leve o moderada e incluyeron somnolencia, principalmente por el uso conjunto  de clobazam, y alteraciones gastrointestinales. Se evidenciaron asimismo  anormalidades en la función hepática concomitantes con el uso de ácido  valproico.Conclusiones: Ante la creciente demanda de la utilización de cannabidiol en  epilepsias refractarias, es fundamental el conocimiento de su farmacología por  parte del equipo de salud. En especial, el farmacéutico clínico juega un papel  primordial en la monitorización de su seguridad y eficacia. Esto permite la  optimización del tratamiento clínico del cannabidiol administrado conjuntamente  con otros fármacos antiepilépticos de mayor uso, lo que conduce a maximizar la  actividad farmacológica y minimizar la aparición de eventos adversos al igual  que de interacciones farmacológicas. El seguimiento clínico del paciente resulta  fundamental para evitar la discontinuación del tratamiento o exacerbación de  eventos adversos que afecten la calidad de vida del paciente.

Medicinal cannabis in Latin America: History, current state of regulation, and the role of the pharmacist in a new clinical experience with cannabidiol oil.

OBJECTIVE: Cannabis sativa was introduced in Latin America in the 16th century. Nevertheless, many years have elapsed, and scientific progress and the medicinal use of C sativa have been restricted by the national laws of the countries in the region. SUMMARY: In Argentina, the first law on medical cannabis, approved in 2017 (#17,350), establishes a regulatory framework for the medical use and scientific research of this plant and its derivatives. In 2018, the first clinical research protocol in Latin America was approved at Hospital de Pediatria Garrahan (Buenos Aires, Argentina) to evaluate the efficacy and safety of cannabidiol (CBD) oil for the treatment of pediatric patients with refractory epilepsy. In this context, the role of pharmacists in the health care system related to the study protocol and the medicinal use of CBD has evolved from dispensing to active participation in clinical follow-up and research protocols. CONCLUSION: Considering this experience, here we discuss the active role of the clinical pharmacist in the use of medicinal cannabis. Medicinal cannabis should be controlled in a legal framework based on clinical evidence, and the participation of the pharmacist in research and clinical protocols, as well as the dispensing and provision of information on the medicinal products should be emphasized in the clinical setting.

[Principles of Bayesian statistics and its relationship with applied pharmacokinetics]. / Principios de estadística Bayesiana y su relación con la farmacocinética aplicada.

If one knows the probability of an event occurring in a population, Bayesian statistics allows mo difying its value when there is new individual information available. Although the Bayesian and frequentist (classical) methodologies have identical fields of application, the first one is increasin gly applied in scientific research and big data analysis. In modern pharmacotherapy, clinical phar macokinetics has been used for the expansion of monitoring, facilitated by technical-analytical and mathematical-statistical developments. Population pharmacokinetics has allowed the identification and quantification of pathophysiological and treatment characteristics in a specific patient popu lation, especially in the pediatric and neonatal population and other vulnerable groups, explaining interindividual variability. Likewise, Bayesian estimation is important as a statistical tool applied in pharmacotherapy optimization software when pharmacological monitoring is based on clinical phar macokinetic interpretation. With its advantages and despite its limitations, pharmacotherapeutic op timization based on Bayesian estimation is increasingly used, becoming the reference method today. This characteristic is particularly convenient for routine clinical practice due to the limited number of samples required from the patient and the flexibility it shows regarding blood sampling times for drug quantification. Therefore, the application of Bayesian principles to the practice of clinical phar macokinetics has led to the improvement of pharmacotherapeutic care.

Population pharmacokinetics of amikacin in patients with pediatric cystic fibrosis.

INTRODUCTION: Amikacin is commonly used in patients with pediatric cystic fibrosis (CF) for the treatment of pulmonary exacerbations. Amikacin efficacy is related to maximum plasma concentration/minimum inhibitory concentration (Cmax/MIC) ratio >8. Pharmacokinetic data in patients with pediatric CF are scarce. The aim of this study was to develop a population pharmacokinetic (PopPK) model describing amikacin disposition in patients with pediatric CF. METHODS: CF patients under 18 years of age with pulmonary exacerbation who received amikacin were enrolled. Patients received different amikacin regimens (30 mg-1 kg-1 day-1 every 8, 12, or 24 hours) depending on the patient's status and hospital protocols. Amikacin serum levels were obtained for therapeutic drug monitoring. PopPK model was developed using MONOLIX Suite-2018R1 (Lixoft). RESULTS: A total of 39 patients (114 amikacin concentrations) were included in this study. Population estimates for the elimination rate constant (k) and the volume of distribution (V) were 0.541 hours-1 and 0.451 L/kg, respectively. Between-subject and between-occasion variability were 53% and 16.5% for k and 31% and 22% for V, respectively. Bodyweight was a significant covariate associated with V. Based on simulations, almost 70% of the patients receiving 30 mg-1 kg-1 day-1 every 24 hours would achieve a Cmax/MIC ratio >8 which is an appropriate therapeutic goal while no patient in the other two groups (Q8 and Q12) would achieve that objective. CONCLUSIONS: The regimen of 30 mg-1 kg-1 day-1 every 24 hours more adequately fulfilled the therapeutic target for amikacin. Although all our patients had good clinical results and a good adverse-events profile, further studies are necessary to redefine the optimal treatment strategy.

Identification of Factors Affecting Tacrolimus Trough Levels in Latin American Pediatric Liver Transplant Patients.

Tacrolimus is the cornerstone in pediatric liver transplant immunosuppression. Despite close monitoring, fluctuations in tacrolimus blood levels affect safety and efficacy of immunosuppressive treatments. Identifying the factors related to the variability in tacrolimus exposure may be helpful in tailoring the dose. The aim of the present study was to characterize the clinical, pharmacological, and genetic variables associated with systemic tacrolimus exposure in pediatric liver transplant patients. De novo transplant patients with a survival of more than 1 month were considered for inclusion and were genotyped for cytochrome P450 3A5 (CYP3A5). Peritransplant clinical factors and laboratory covariates were recorded retrospectively between 1 month and 2 years after transplant, including alanine aminotransferase (ALT), aspartate aminotransferase, hematocrit, and tacrolimus predose steady-state blood concentrations collected 12 hours after tacrolimus dosing. A linear mixed effect (LME) model was used to assess the association of these factors and the log-transformed tacrolimus dose-normalized trough concentration (logC0/D) levels. Bootstrapping was used to internally validate the final model. External validation was performed in an independent group of patients who matched the original population. The developed LME model described that logC0/D increases with increases in time after transplant (ß = 0.019, 95% confidence interval [CI], 0.010-0.028) and ALT values (ß = 0.00030, 95% CI, 0.00002-0.00056), whereas logC0/D is significantly lower in graft CYP3A5 expressers compared with nonexpressers (ß = -0.349, 95% CI, -0.631 to -0.062). In conclusion, donor CYP3A5 genotype, time after transplant, and ALT values are associated with tacrolimus disposition between 1 month and 2 years after transplant. A better understanding of tacrolimus exposure is essential to minimize the occurrence of an out-of-range therapeutic window that may lead to adverse drug reactions or acute rejection.