Aplicación de un modelo farmacocinético poblacional para el seguimiento de pacientes en tratamiento con dolutegravir: estudio piloto

Introducción: a pesar de los avances en tratamiento antirretroviral, existe la posibilidad de que personas que viven con el virus de la inmunodeficiencia humana (VIH) experimenten falla terapéutica vinculada a múltiples factores que impactan en la respuesta al fármaco. Objetivos: evaluar la utilidad de aplicar un modelo farmacocinético en pacientes con diagnóstico de VIH en tratamiento con dolutegravir para el análisis de las concentraciones plasmáticas experimentales. Adicionalmente, se pretende identificar potenciales interacciones farmacológicas, evaluar adherencia y fallo terapéutico. Material y método: se realizó un estudio piloto transversal y observacional en pacientes VIH tratados con dolutegravir que incluyó la dosificación de la concentración plasmática, evaluación de adherencia mediante el cuestionario simplificado de adherencia a la medicación (SMAQ) y retiro de medicación. Se utilizó un modelo poblacional referenciado en la bibliografía para la predicción de concentraciones de dolutegravir en cada paciente y se compararon con las concentraciones experimentales. Resultados: fueron incluidos en el estudio 21 pacientes. Al cotejar las concentraciones plasmáticas experimentales con la simulación farmacocinética se encontraron diferencias para 12 pacientes, las cuales se explican por posibles interacciones farmacológicas, mala adherencia u otros factores que afectan la farmacocinética. Se detectó 38% de no adherencia de acuerdo con SMAQ y 23% de acuerdo con el retiro de medicación. Conclusiones: se expone el rol potencial de los modelos farmacocinéticos para la interpretación de concentraciones plasmáticas y se genera la necesidad de avanzar en este tipo de estudios para el establecimiento de rango terapéutico y aplicabilidad clínica.

Introduction: Despite advances in antiretroviral treatment, there is a possibility that people living with HIV may experience treatment failure linked to multiple factors that impact drug response. Objective: To evaluate the usefulness of applying a pharmacokinetic model in patients diagnosed with HIV undergoing treatment with dolutegravir for the analysis of experimental plasma concentrations. Additionally, the aim is to identify potential drug interactions, assess adherence, and therapeutic failure. Method: A cross-sectional, observational pilot study was conducted in HIV patients treated with dolutegravir, which included plasma concentration dosing, assessment of adherence using the Simplified Medication Adherence Questionnaire (SMAQ), and medication withdrawal. A population-based model referenced in the literature was used to predict dolutegravir concentrations in each patient and these were compared with experimental concentrations. Results: Twenty-one patients were included in the study. When comparing experimental plasma concentrations with pharmacokinetic simulation, differences were found for 12 patients, which can be explained by possible drug interactions, poor adherence, or other factors affecting pharmacokinetics. Non-adherence was detected in 38% according to the SMAQ and 23% according to medication withdrawal. Conclusions: The potential role of pharmacokinetic models in the interpretation of plasma concentrations is highlighted, emphasizing the need to advance in this type of studies to establish therapeutic ranges and clinical applicability.

Introdução: Apesar dos avanços no tratamento antirretroviral, existe a possibilidade de que pessoas que vivem com HIV experimentem falha terapêutica ligada a múltiplos fatores que impactam na resposta ao medicamento. Objetivos: Avaliar a utilidade da aplicação de um modelo farmacocinético em pacientes com diagnóstico de HIV em tratamento com dolutegravir para análise de concentrações plasmáticas experimentais. Além disso, pretende-se identificar potenciais interações medicamentosas, avaliar a adesão e a falha terapêutica. Método: Um estudo piloto observacional transversal foi conduzido em pacientes HIV tratados com dolutegravir que incluiu dosagem de concentração plasmática, avaliação de adesão usando o questionário simplificado de adesão à medicação (SMAQ) e retirada da medicação. Um modelo populacional referenciado na literatura foi utilizado para prever as concentrações de dolutegravir em cada paciente e compará-las com as concentrações experimentais. Resultados: 21 pacientes foram incluídos no estudo. Ao comparar as concentrações plasmáticas experimentais com a simulação farmacocinética, foram encontradas diferenças em 12 pacientes, que são explicadas por possíveis interações medicamentosas, má adesão ou outros fatores que afetam a farmacocinética. Foram detectadas 38% de não adesão segundo o SMAQ e 23% segundo retirada da medicação. Conclusões: Fica exposto o papel potencial dos modelos farmacocinéticos para a interpretação das concentrações plasmáticas e gera-se a necessidade de avançar neste tipo de estudos para estabelecer a faixa terapêutica e a aplicabilidade clínica.

Human Data on Pharmacokinetic Interactions of Cannabinoids: A Narrative Review.

Concomitant use of cannabinoids with other drugs may result in pharmacokinetic drug-drug interactions, mainly due to the mechanism involving Phase I and Phase II enzymes and/or efflux transporters. Cannabinoids are not only substrates but also inhibitors or inducers of some of these enzymes and/or transporters. This narrative review aims to provide the available information reported in the literature regarding human data on the pharmacokinetic interactions of cannabinoids with other medications. A search on Pubmed/Medline, Google Scholar, and Cochrane Library was performed. Some studies were identified with Google search. Additional articles of interest were obtained through cross-referencing of published literature. All original research papers discussing interactions between cannabinoids, used for medical or recreational/adult-use purposes, and other medications in humans were included. Thirty-two studies with medicinal or recreational/adult-use cannabis were identified (seventeen case reports/series, thirteen clinical trials, and two retrospective analyses). In three of these studies, a bidirectional pharmacokinetic drug-drug interaction was reported. In the rest of the studies, cannabinoids were the perpetrators, as in most of them, concentrations of cannabinoids were not measured. In light of the widespread use of prescribed and non-prescribed cannabinoids with other medications, pharmacokinetic interactions are likely to occur. Physicians should be aware of these potential interactions and closely monitor drug levels and/or responses. The existing literature regarding pharmacokinetic interactions is limited, and for some drugs, studies have relatively small cohorts or are only case reports. Therefore, there is a need for high-quality pharmacological studies on cannabinoid-drug interactions.

Drug-Drug Interaction Between Cannabidiol, Cyclosporine, and Mycophenolate Mofetil: A Case Report.

Kidney transplantation remains the optimal therapy for many patients with end-stage kidney disease (ESKD). Chronic pain is one of the most common and distressing symptoms among patients with ESKD, and its treatment is a complex and challenging task to accomplish. The benefits of cannabidiol (CBD) in chronic pain treatment have been reported recently. Cannabidiol is metabolized by cytochrome P450, mainly CYP3A4 and CYP2C19, and can also undergo direct conjugation via UDP-glucuronosyltransferase enzymes, with a growing body of evidence suggesting it is also a potent inhibitor or inducer of these pathways. Cannabidiol was also found to be a potent inhibitor of carboxylesterases in vitro. Because cytochrome P450 enzymes and carboxylesterases are also responsible for the clearance and activation of immunosuppressants, respectively, drug-drug interactions are likely to occur. Here, we report a pharmacokinetic drug interaction between CBD and cyclosporine and mycophenolate mofetil in a patient with ESKD with a kidney transplantation. It is thus crucial to take into account these interactions and monitor drug levels to avoid drug toxicity or a lack of efficacy. This study is in accordance with the guidelines of the Declaration of Helsinki and the Declaration of Istanbul.

Quantitative systems pharmacology Model to characterize valproic acid-induced hyperammonemia and the effect of L-carnitine supplementation.

Valproic acid (VPA) is a short-chain fatty acid widely prescribed in the treatment of seizure disorders and epilepsy syndromes, although its therapeutic value may be undermined by its toxicity. VPA serious adverse effects are reported to have a significant and dose-dependent incidence, many associated with VPA-induced hyperammonemia. This effect has been linked with reduced levels of carnitine; an endogenous compound involved in fatty acid's mitochondrial ß-oxidation by facilitation of its entrance via the carnitine shuttle. High exposure to VPA can lead to carnitine depletion causing a misbalance between the intra-mitochondrial ß-oxidation and the microsomal ω-oxidation, a pathway that produces toxic metabolites such as 4-en-VPA which inhibits ammonia elimination. Moreover, a reduction in carnitine levels might be also related to VPA-induced obesity and lipids disorder. In turn, L-carnitine supplementation (CS) has been recommended and empirically used to reduce VPA's hepatotoxicity. The aim of this work was to develop a Quantitative Systems Pharmacology (QSP) model to characterize VPA-induced hyperammonemia and evaluate the benefits of CS in preventing hyperammonemia under both chronic treatment and after VPA overdosing. The QSP model included a VPA population pharmacokinetics model that allowed the prediction of total and unbound concentrations after single and multiple oral doses considering its saturable binding to plasma proteins. Predictions of time courses for 2-en-VPA, 4-en-DPA, VPA-glucuronide, carnitine, ammonia and urea levels, and for the relative change in fatty acids, Acetyl-CoA, and glutamate reflected the VPA induced changes and the efficacy of the treatment with L-carnitine. The QSP model was implemented to give a rational basis for the L-carnitine dose selection to optimize CS depending on VPA dosage regime and to assess the currently recommended L-carnitine rescue therapy after VPA overdosing. Results show that a L-carnitine dose equal to the double of the VPA dose using the same interdose interval would maintain the ammonia levels at baseline. The QSP model may be expanded in the future to describe other adverse events linked to VPA-induced changes in endogenous compounds.

Development of a Population Pharmacokinetic Model for Cyclosporine from Therapeutic Drug Monitoring Data.

AIM: To develop a population pharmacokinetic model for Uruguayan patients under treatment with cyclosporine (CsA) that can be applied to TDM. Patients and Methods. A total of 53 patients under treatment with CsA were included. 37 patients with at least one pharmacokinetic profile described with four samples were considered for model building, while the remaining 16 were considered for the assessments of predictive performances. Pharmacokinetic parameter estimation was performed using a nonlinear mixed effect modelling implemented in the Monolix® software (version 2019R1, Lixoft, France); meanwhile, simulations were performed in R v.3.6.0 with the mlxR package. RESULTS: A two-compartment model with a first-order disposition model including lag time was used as a structural model. The final model was internally validated using prediction corrected visual predictive check (pcVPC) and other graphical diagnostics. A total of 621 CsA steady-state concentrations were analyzed for model development. Population estimates for the absorption constant (ka) and lag time were 0.523 h-1 and 0.512 h, respectively; apparent clearance (CL/F) was 30.3 L/h (relative standard error [RSE] ± 8.25%) with an interindividual variability of 39.8% and interoccasion variability of 38.0%; meanwhile, apparent clearance of distribution (Q/F) was 17.0 L/h (RSE ± 12.1%) with and interindividual variability of 53.2%. The covariate analysis identified creatinine clearance (ClCrea) as an individual factor influencing the Cl of CsA. The predictive capacity of the population model was demonstrated to be effective since predictions made for new patients were accurate for C1 and C2 (MPPEs below 50%). Bayesian forecasting improved significantly in the second and third occasions. CONCLUSION: A population pharmacokinetic model was developed to reasonably estimate the individual cyclosporine clearance for patients. Hence, it can be utilized to individualize CsA doses for prompt and adequate achievement of target blood concentrations of CsA.

Clinical Pharmacokinetics of Cannabinoids and Potential Drug-Drug Interactions.

Over the past few years, considerable attention has focused on cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), the two major constituents of Cannabis sativa, mainly due to the promising potential medical uses they have shown. However, more information on the fate of these cannabinoids in human subjects is still needed and there is limited research on the pharmacokinetic drug-drug interactions that can occur in the clinical setting and their prevalence. As the use of cannabinoids is substantially increasing for many indications and they are not the first-line therapy in any treatment, health care professionals must be aware of drug-drug interactions during their use as serious adverse events can happen related with toxic or ineffective outcomes. The present chapter overview summarizes our current knowledge on the pharmacokinetics and metabolic fate of CBD and THC in humans and discusses relevant drug-drug interactions, giving a plausible explanation to facilitate further research in the area.

Pharmacokinetics of Subcutaneous Levetiracetam in Palliative Care Patients.

Background: Seizure control is challenging in the palliative care setting. Subcutaneous (SC) levetiracetam (LEV) is currently an off-label route of administration and effectiveness, tolerability, and pharmacokinetics studies for this route are scarce. Objectives: This prospective study aimed at evaluating effectiveness and tolerability of SC LEV as well as characterizing its pharmacokinetics. Subjects: Patients (n = 7) who attended the palliative care clinic between September 2018 and January 2019 with diagnosis of seizures, ≥18 years, and in need of SC route of administration were included in the study. Measurements: LEV plasma levels were determined using high-performance liquid chromatography and pharmacokinetic analysis were performed using Monolix 2018R2 (France). pH and osmolality of the three SC infusion solutions were also determined. Results: Seven patients took part in the study. Seizures were controlled in six out of seven patients with doses of 1000 and 3000 mg/day. Adverse effects were mild. pH and osmolality of the SC infusion solutions were within the accepted values reported in the literature. Mean plasma LEV concentrations were 14.4 mg/L (1000 mg/day) and 27.7 mg/L (2000 mg/day). The population clearance (2.5 L/h) and the elimination half-life (10.4 hours) were successfully estimated. Conclusions: Based on this data, SC LEV was effective and well tolerated. Pharmacokinetic parameters for the SC route were successfully determined.

Potential Pharmacokinetic Drug-Drug Interactions between Cannabinoids and Drugs Used for Chronic Pain.

Choosing an appropriate treatment for chronic pain remains problematic, and despite the available medication for its treatment, still, many patients complain about pain and appeal to the use of cannabis derivatives for pain control. However, few data have been provided to clinicians about the pharmacokinetic drug-drug interactions of cannabinoids with other concomitant administered medications. Therefore, the aim of this brief review is to assess the interactions between cannabinoids and pain medication through drug transporters (ATP-binding cassette superfamily members) and/or metabolizing enzymes (cytochromes P450 and glucuronyl transferases).

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.

Programme for Harmonization to the International Scale in Latin America for BCR-ABL1 quantification in CML patients: findings and recommendations.

Objectives The quantitation of BCR-ABL1 mRNA is mandatory for chronic myeloid leukemia (CML) patients, and RT-qPCR is the most extensively used method in testing laboratories worldwide. Nevertheless, substantial variation in RT-qPCR results makes inter-laboratory comparability hard. To facilitate inter-laboratory comparative assessment, an international scale (IS) for BCR-ABL1 was proposed. Methods The laboratory-specific conversion factor (CF) to the IS can be derived from the World Health Organization (WHO) genetic reference panel; however, this material is limited to the manufacturers to produce and calibrate secondary reference reagents. Therefore, we developed secondary reference calibrators, as lyophilized cellular material, aligned to the IS. Our purpose was both to re-evaluate the CF in 18 previously harmonized laboratories and to propagate the IS to new laboratories. Results Our field trial including 30 laboratories across Latin America showed that, after correction of raw BCR-ABL1/ABL1 ratios using CF, the relative mean bias was significantly reduced. We also performed a follow-up of participating laboratories by annually revalidating the process; our results support the need for continuous revalidation of CFs. All participating laboratories also received a calibrator to determine the limit of quantification (LOQ); 90% of them could reproducibly detect BCR-ABL1, indicating that these laboratories can report a consistent deep molecular response. In addition, aiming to investigate the variability of BCR-ABL1 measurements across different RNA inputs, we calculated PCR efficiency for each individual assay by using different amounts of RNA. Conclusions In conclusion, for the first time in Latin America, we have successfully organized a harmonization platform for BCR-ABL1 measurement that could be of immediate clinical benefit for monitoring the molecular response of patients in low-resource regions.

Potential Therapeutic Role of Carnitine and Acetylcarnitine in Neurological Disorders.

BACKGROUND: Current therapy of neurological disorders has several limitations. Although a high number of drugs are clinically available, several subjects do not achieve full symptomatic remission. In recent years, there has been an increasing interest in the therapeutic potential of L-carnitine (LCAR) and acetyl-L-carnitine (ALCAR) because of the multiplicity of actions they exert in energy metabolism, as antioxidants, neuromodulators and neuroprotectors. They also show excellent safety and tolerability profile. OBJECTIVE: To assess the role of LCAR and ALCAR in neurological disorders. METHODS: A meticulous review of the literature was conducted in order to establish the linkage between LCAR and ALCAR and neurological diseases. RESULTS: LCAR and ALCAR mechanisms and effects were studied for Alzheimer's disease, depression, neuropathic pain, bipolar disorder, Parkinson's disease and epilepsy in the elderly. Both substances exert their actions mainly on primary metabolism, enhancing energy production, through ß-oxidation, and the ammonia elimination via urea cycle promotion. These systemic actions impact positively on the Central Nervous System state, as Ammonia and energy depletion seem to underlie most of the neurotoxic events, such as inflammation, oxidative stress, membrane degeneration, and neurotransmitters disbalances, present in neurological disorders, mainly in the elderly. The impact on bipolar disorder is controversial. LCAR absorption seems to be impaired in the elderly due to the decrease of active transportation; therefore, ALCAR seems to be the more effective option to administer. CONCLUSION: ALCAR emerges as a simple, economical and safe adjuvant option in order to impair the progression of most neurological disorders.

Sentidos del cuidado en centros de privación de libertad para adolescentes en Uruguay / Meanings of care in adolescent detention centers in Uruguay / Significado dos cuidados em centros de detenção juvenil no Uruguay

Resumen (analítico) El artículo explora sentidos y significados asociados al cuidado por parte de agentes responsables de la custodia de adolescentes en centros de privación de libertad en Uruguay. La investigación cualitativa es un estudio de caso de tipo único, descriptivo y en profundidad que presenta un corpus compuesto por entrevistas, documentos, observaciones y registro en diario de campo. Se describen tres categorías de análisis en las que se reflexiona sobre el cuidado: acerca de la medida socioeducativa, la seguridad como criterio de funcionamiento y el acceso a los derechos a través de la política punitiva. Se concluye que existen visiones plurales asociadas al cuidado y que el tratamiento de los y las adolescentes se basa en el castigo por la vía del encierro disciplinante que legitima el uso de prácticas violentas.

Abstract (analytical) This article analyzes the meanings and ideas associated with care among the adults who operate adolescent detention centers in Uruguay. This qualitative research involves a unique, descriptive and in-depth case study that presents a corpus consisting of interviews, documents, observations and field notes. Three categories of analysis are described in relation to the concept of care: care as a socio-educational measure, safety as an operating standard and access to rights through punitive politics. The article argues that there are pluralist visions associated with care and the treatment of adolescents that are based on punishment through disciplinary confinement, which legitimizes the use of violent practices.

Resumo (analítico) O artigo explora significados e ideias associadas ao cuidado dos agentes responsáveis pela custódia dos adolescentes nos centros de privação de liberdade no Uruguai. A pesquisa qualitativa é um estudo de caso único, descritivo e aprofundado, que apresenta um escopo composto por entrevistas, documentos, observações e anotações de diário de campo. Três categorias de análise são descritas nas quais se consideram o cuidado: a medida socioeducativa, a segurança como critério de funcionamento e o acesso aos direitos por meio de políticas punitivas. Conclui-se que existem visões plurais associadas ao cuidado e que o tratamento dos adolescentes é baseado na punição por meio do confinamento disciplinar que legitima o uso de práticas violentas.

Agentes del sistema de protección en Uruguay: sentidos del cuidado / Agentes do sistema de proteção no Uruguai: sentidos de cuidado / Agents of the protection system in Uruguay: meanings of care

El artículo analiza los sentidos que los/as agentes del sistema de protección social a la infancia y adolescencia en Uruguay atribuyen al cuidado. El diseño es cualitativo y se realiza un estudio de caso de tipo descriptivo, en profundidad, con enfoque etnográfico y el corpus se compone de entrevistas, documentos, observaciones y registro en diario de campo. Los resultados muestran seis categorías; estructura y recursos, necesidades, derechos, construcción de cotidiano, familia, y egreso del sistema que agrupan las reflexiones acerca del cuidado en este contexto institucional. Dentro de las conclusiones se visualiza la heterogeneidad de sentidos influidos por los roles y posiciones que se ocupan, formaciones y centros donde se desempeñan. Y la importancia de una redefinición de la ética del cuidado en el sistema de protección, la dotación de recursos para una efectiva materialidad del cuidado y la urgencia de implementar un proyecto de desinstitucionalización.

O artigo analisa os significados que os agentes do sistema de proteção social para crianças e adolescentes no Uruguai atribuem ao cuidado. O delineamento é qualitativo a partir de um estudo de caso do tipo descritivo e em profundidade com um corpus de entrevistas, documentos, observações e registros em diário de campo. Os resultados mostram seis categorias; estrutura e recursos, necessidades, direitos, construção da vida cotidiana, família e desligamento do sistema que agrupam as reflexões sobre o cuidado nesse contexto institucional. Dentro das conclusões é visualizada a heterogeneidade de sentidos influenciados pelas posições ocupadas, treinamento e centros onde eles trabalham. O artigo conclui com a importância de uma redefinição da ética do cuidado no sistema de proteção, a alocação de recursos para uma materialidade efetiva do cuidado e a urgência de implementar um projeto de desinstitucionalização.

The article analyzes the meanings that the agents of the social protection system for children and adolescents in Uruguay attribute to care. The research design is qualitative and a descriptive, indepth, case study with ethnographic approach is carried out along a corpus of interviews, documents, observations, and a field-notes journal. The results show six categories; structure and resources, needs, rights, construction of daily life, family, and discharge of the system that envolve the reflections about care in this institutional context. Within the conclusions is visualized the heterogeneity of meanings influenced by the roles and positions that are occupied, trainment and centers where they perform. And the importance of a redefinition of the ethics of care in the protection system, the allocation of resources for an effective materiality of care and the urgency of implementing a deinstitutionalization project.

Population Pharmacokinetics of Clozapine and Norclozapine and Switchability Assessment between Brands in Uruguayan Patients with Schizophrenia.

Clozapine (CZP) is an atypical antipsychotic agent commonly used in the treatment of schizophrenia. It is metabolized primarily by CYP1A2 enzyme, yielding a pharmacologically active metabolite, norclozapine (NCZP). Significant intra- and interindividual pharmacokinetic (PK) variability for CZP and NCZP has been observed in routine therapeutic drug monitoring. So the goal of this study was to evaluate the magnitude and variability of concentration exposure to CZP and its active metabolite NCZP on pharmacokinetic parameters in Uruguayan patients with schizophrenia with a focus on covariates such as cigarette smoking, age, sex, caffeine consumption, brands available of CZP, and comedication using population PK (PPK) modeling methodologies. Patients with a diagnosis of schizophrenia treated with brand-name CZP (Leponex®) for more than a year were included in the study. Then these patients were switched to the similar brand of CZP (Luverina®). Morning predose blood samples for determination of CZP and NCZP using a HPLC system equipped with a UV detector were withdrawn on both occasions at steady state and under the same comedication. Ninety-eight patients, 22 women and 76 men, took part in the study. Mean ± standard deviation for CZP and NCZP concentration was 421 ± 262 ng/mL and 275 ± 180 ng/mL, respectively. After covariate evaluation, only smoking status remained significant in CZP apparent clearance, inducing a mean increment of 32% but with no clinical impact. The results obtained with the two brands of CZP should ensure comparable efficacy and tolerability with the clinical use of either product. Smoking was significantly associated with a lower exposure to CZP due to higher clearance. The results obtained with the two brands commercialized in our country hint a bioequivalence scenario in the clinical setting.

Lamotrigine-Valproic Acid Interaction Leading to Stevens-Johnson Syndrome.

Lamotrigine (LTG) is currently indicated as adjunctive therapy for focal and generalized tonic-clonic seizures and for treatment of bipolar disorder and neuropathic pain. A common concern with LTG in children is the frequency of appearance of skin rash. The intensity of this adverse effect can vary from transient mild rash to Stevens-Johnson syndrome (SJS), which can be fatal mainly when LTG is coadministered with valproic acid (VPA). Hereby, we present the case of an 8-year-old boy who suffered from SJS and other complications two weeks after LTG was added to his VPA treatment in order to control his seizures. VPA is known to decrease LTG clearance via reduced glucuronidation. In this case, the minor elimination pathway of LTG would play a more important role, and the formation of an arene oxide metabolite would be enhanced. As this reactive metabolite is detoxified mainly by enzymatic reactions, involving microsomal epoxide hydrolase and/or GSH-S-transferases and these enzymes are polymorphically expressed in humans, arene oxide toxicity is increased when epoxide hydrolase or GSH-S-transferases is either defective or inhibited or a depletion of intracellular glutathione levels is taking place. VPA can cause inhibition of epoxide hydrolase enzymes and/or depletion of glutathione levels leading to adverse cutaneous reactions.

Gestión de las sexualidades en los sistemas penales: las adolescentes mujeres / Managing sexualities in criminal systems: female adolescents / Gestão das sexualidades nos sistemas penais: as adolescentes mulheres

Resumen (descriptivo): En el artículo reflexionamos sobre la gestión de las sexualidades de las adolescentes mujeres tomando como punto de partida el Sistema Penal Juvenil Uruguayo. Trabajamos con una perspectiva de investigación cualitativa que apuesta a la producción de sentidos por parte de los y las agentes claves, a lo que sumamos los aportes de las epistemologías y las criminologías feministas. Presentamos dos tensiones analíticas, una referida a la sexualización del cuerpo y avasallamiento de la sexualidad. Y otra acerca del tratamiento de la maternidad de las adolescentes vinculado al pecado y el ejercicio de la sexualidad. Finalmente mostramos cómo muchas de las intervenciones se apuntalan en el cuerpo, al configurarse prácticas de control sociopenal destinadas a las sexualidades de las adolescentes mujeres.

Abstract (descriptive): This paper discusses the management of female adolescents' sexualities in the Juvenile Criminal System in Uruguay. The study uses a qualitative research perspective that identifies the production of meanings by key agents, supported by the contributions of feminist epistemologies and criminologies. The authors discuss two analytical tensions, one related to the sexualization of the body and its overlapping with sexuality, and another based on the treatment of adolescent motherhood linked to sin and the exercising of sexuality. Finally, we show how many of these interventions target the body through the establishment of socio criminal control practices aimed at the female adolescents' sexualities.

Resumo (descritivo): O artigo reflexiona sobre a gestão das sexualidades das mulheres adolescentes tomando como ponto de partida o Sistema Penal Juvenil Uruguaio. Trabalhamos com uma perspectiva de pesquisa qualitativa que se concentra na produção de significados pelos principais agentes, aos quais adicionamos as contribuições de epistemologias e criminologias feministas. Apresentamos duas tensões analíticas, uma relacionada à sexualização do corpo e à subjugação da sexualidade. E outro sobre o tratamento da maternidade adolescente ligada ao pecado e ao exercício da sexualidade. Finalmente, mostramos quantas intervenções são sustentadas no corpo, ao configurar práticas de controle sócio-criminal voltadas para a sexualidade das mulheres adolescentes.

Role of CYP2C9, CYP2C19 and EPHX Polymorphism in the Pharmacokinetic of Phenytoin: A Study on Uruguayan Caucasian Subjects.

Phenytoin (PHT) oxidative route leads to its main metabolite p-hydroxyphenytoin (p-HPPH), by means of CYP2C9 and CYP2C19. Formation of p-HPPH proceeds via a reactive arene-oxide intermediate. This intermediate can also be converted into PHT dihydrodiol by microsomal epoxide hydrolase (EPHX). The three enzymes are polymorphically expressed and the genetic variants are responsible for changes in the enzyme activity. In order to evaluate the effect that these polymorphisms have on PHT metabolism, PHT and p-HPPH plasma concentrations were measured and the genotype for the three enzymes was assessed in 50 Uruguayan epileptic patients. 30% of the patients were intermediate and 2% were poor metabolizers for CYP2C9, while 20% were intermediate metabolizers for CYP2C19. 44%, 10%, and 46% of subjects had intermediate, increased and decreased activities of EPHX respectively. CYP2C9 was confirmed to be the main responsible enzyme for PHT biotransformation. CYP2C19 seemed to be preponderant in p-HPPH oxidative metabolism. Apart from being responsible for the production of the dihydrodiol metabolite, EPHX also seemed to contribute to pHPPH formation when its activity is low. PHT might be recovered with a decreased activity of EPHX regardless the activity of CYP2C9.

L-Carnitine supplementation to reverse hyperammonemia in a patient undergoing chronic valproic acid treatment: A case report.

Valproic acid is a broad-spectrum anticonvulsant that has also gained attention in the psychiatric setting. With respect to safety, valproic acid may induce a seemingly rare condition, hyperammonemia, which can induce a wide variety of symptoms ranging from irritability to coma. The proposed mechanism of hyperammonemia involves depletion of carnitine and overproduction of a toxic metabolite, 4-en-valproic acid, both of which impair the urea cycle and thus ammonia elimination. Carnitine is a commonly used antidote for acute intoxication of valproic acid, but is not a therapeutic option for management of chronic adults with adverse effects related to valproic acid. We herein report a case involving a woman with epilepsy who developed hyperammonemia after a change in her anticonvulsant therapy. She reported increased seizures and gastrointestinal disturbances. Her ammonia, valproic acid, 4-en-valproic acid, and carnitine levels were monitored. Her ammonia level was elevated and her carnitine level was at the inferior limit of the population range. She was supplemented with carnitine at 1 g/day. After 1 month, her ammonia level decreased, her carnitine level increased, and her seizures were better controlled. Carnitine supplementation was useful for reversal of her hyperammonemia, allowing her to continue valproic acid for seizure control.

Carnitine and/or Acetylcarnitine Deficiency as a Cause of Higher Levels of Ammonia.

Blood carnitine and/or acetylcarnitine deficiencies are postulated in the literature as possible causes of higher ammonia levels. The aim of this study was to investigate if the use of valproic acid, the age of the patients, or certain central nervous system pathologies can cause carnitine and/or acetylcarnitine deficiency leading to increased ammonia levels. Three groups of patients were studied: (A) epileptic under phenytoin monotherapy (n = 31); (B) with bipolar disorder under valproic acid treatment (n = 28); (C) elderly (n = 41). Plasma valproic acid and blood carnitine and acyl carnitine profiles were determined using a validated HPLC and LC-MS/MS method, respectively. Blood ammonia concentration was determined using an enzymatic automated assay. Higher ammonia levels were encountered in patients under valproic acid treatment and in the elderly. This may be due to the lower carnitine and/or acetylcarnitine found in these patients. Patients with controlled seizures had normal carnitine and acetylcarnitine levels. Further studies are necessary in order to conclude if the uncontrolled bipolar disorder could be the cause of higher carnitine and/or acetylcarnitine levels.

Notas de farmacología: estudios de disolución de medicamentos del sistema nervioso central / Pharmacology notes: drug dissolution studies of the central nervous system

El propósito de los estudios in vitro es comparar las características de liberación del principio activo contenido en una forma farmacéutica sólida oral mediante la cantidad, o porcentaje de la dosis, disuelta en función del tiempo en condiciones controladas y validadas. Se realizó una comparación de disolución in vitro de flunitrazepam (Rohypnol®, Somnidual® e Inervon®) y de lamotrigina (Lamictal® y Epilepax®). Para los perfiles de disolución de flunitrazepam, una de las marcas comerciales tuvo un perfil de disolución muy diferente a las otras dos marcas. Para el caso de lamotriginano existió diferencia para aquellos pH que se consideran fundamentales para la disolución del comprimido en el tracto gastrointestinal. Los resultados obtenidos de los estudios in vitro son simplemente orientadores, permiten tan solo guiar la puesta en marcha del ensayo de bioequivalencia entre el test evaluado in vitro y la referencia utilizada en el mismo ensayo. No obstante, estos resultados pueden constituirse en un elemento de apoyo a la presunción de bioinequivalencia como causa de un evento adverso (ineficacia o toxicidad) detectado en los programas de farmacovigilancia actualmente en marcha.