Valproic Acid and the Liver Injury in Patients with Epilepsy: An Update

Combination of metformin and sub-therapeutic dose of valproic acid prevent valproic acid-induced toxicity in animal model of epilepsy

Valproic acid (VPA) is one of the most prescribed drugs for epilepsy. Extended use of VPA not only induces hepatotoxicity but also impairs the cognitive functions. Metformin has been reported to prevent epileptogenesis and enhance memory. To counter the VPA-induced adverse events, it is hypothesized that combination of sub-therapeutic dose of VPA with metformin may attenuate the toxicity stemming from the therapeutic dose of VPA. Pentylenetetrazole (PTZ)-induced kindling model of epilepsy in mice was used to assess the combined effects of sub-therapeutic dose of VPA (100 mg/kg) and metformin (200 mg/kg). The memory performance was analyzed by passive avoidance test, while alkaline comet assay was used to determine genotoxicity. Histopathological examination and serum biochemical analysis was performed to determine hepatotoxicity. Results showed that combination dose of VPA with metformin reduced seizure scores. VPA (300 mg/kg) administered as a single agent did not enhance memory impairment caused by PTZ, however, combination of sub-therapeutic dose of VPA with metformin enhanced memory function. Furthermore, in alkaline comet assay, combination therapy demonstrated reduced genotoxicity compared to the VPA 300 mg/kg. Histopathological examination of liver and analysis of serum hepatic enzymes revealed that combination therapy (VPA + metformin) reversed the toxicity as seen in case of PTZ or VPA (300 mg/kg) treated animals with no other treatment given. Based on the study data, it is concluded that the combination of sub-therapeutic dose of VPA with metformin might be used for epileptic seizures. This will prevent the hepatotoxicity and enhanced memory functions as compared to the VPA given as a single agent therapy.

Pre-treatment risk predictors of valproic acid-induced dyslipidemia in pediatric patients with epilepsy

Background: Valproic acid (VPA) stands as one of the most frequently prescribed medications in children with newly diagnosed epilepsy. Despite its infrequent adverse effects within therapeutic range, prolonged VPA usage may result in metabolic disturbances including insulin resistance and dyslipidemia. These metabolic dysregulations in childhood are notably linked to heightened cardiovascular risk in adulthood. Therefore, identification and effective management of dyslipidemia in children hold paramount significance. Methods: In this retrospective cohort study, we explored the potential associations between physiological factors, medication situation, biochemical parameters before the first dose of VPA (baseline) and VPA-induced dyslipidemia (VID) in pediatric patients. Binary logistic regression was utilized to construct a predictive model for blood lipid disorders, aiming to identify independent pre-treatment risk factors. Additionally, The Receiver Operating Characteristic (ROC) curve was used to evaluate the performance of the model. Results: Through binary logistic regression analysis, we identified for the first time that direct bilirubin (DBIL) (odds ratios (OR) = 0.511, p = 0.01), duration of medication (OR = 0.357, p = 0.009), serum albumin (ALB) (OR = 0.913, p = 0.043), BMI (OR = 1.140, p = 0.045), and aspartate aminotransferase (AST) (OR = 1.038, p = 0.026) at baseline were independent risk factors for VID in pediatric patients with epilepsy. Notably, the predictive ability of DBIL (AUC = 0.690, p < 0.0001) surpassed that of other individual factors. Furthermore, when combined into a predictive model, incorporating all five risk factors, the predictive capacity significantly increased (AUC = 0.777, p < 0.0001), enabling the forecast of 77.7% of dyslipidemia events. Conclusion: DBIL emerges as the most potent predictor, and in conjunction with the other four factors, can effectively forecast VID in pediatric patients with epilepsy. This insight can guide the formulation of individualized strategies for the clinical administration of VPA in children.

Associations between one-carbon metabolism and valproic acid-induced liver dysfunction in epileptic patients

Valproic acid (VPA) has been widely used as an antiepileptic drug for decades. Although VPA is effective and well-tolerated, long-term VPA treatment is usually associated with hepatotoxicity. However, the underlying mechanisms of VPA-caused hepatotoxicity remain unclear. In this study, a total of 157 pediatric patients with epilepsy were recruited and divided into normal liver function (NLF, 112 subjects) group and abnormal liver function (ABLF, 45 subjects) group. We observed that MTHFR A1298C and MTHFR C677T variants may be linked to VPA-induced liver dysfunction (p = 0.001; p = 0.023, respectively). We also found that the MTHFR A1298C polymorphism was associated with a higher serum Hcy level (p = 0.001) and a lower FA level (p = 0.001). Moreover, the serum Hcy levels was strongly correlated with the GSH and TBARS concentrations (r = -0.6065, P < 0.001; r = 0.6564, P < 0.001, respectively). Furthermore, logistic analysis indicated that MTHFR A1298C/C677T polymorphisms and increased Hcy concentrations may be risk factors for VPA-induced liver dysfunction. These results suggested that individual susceptibility to VPA-induced liver dysfunction may result from MTHFR A1298C/C677T polymorphisms and increased Hcy levels. This study may be helpful for the prevention and guidance of VPA-induced liver dysfunction.

Sex differences in the susceptibility to valproic acid-associated liver injury in epileptic patients

BACKGROUND

Valproic acid has been widely used as an antiepileptic drug for several decades. Long-term valproic acid treatment is usually accompanied by liver injury. Although both men and women are susceptible to valproic acid-associated liver injury, hepatotoxicity differs between the sexes. However, the mechanisms underlying sex differences in valproic acid-associated liver injury remain unclear.

METHODS

To explore potential risk factors for the susceptibility to valproic acid-associated liver injury, 231 pediatric patients with epilepsy (119 males, 112 females) were enrolled for laboratory and genetic analysis.

RESULTS

Heterozygous genotype of catalase C-262T (P = 0.045) and the concentrations of glutathione (P = 0.002) and thiobarbituric acid-reactive substances (P = 0.011) were associated with the sex-specific susceptibility to valproic acid-associated liver injury. Meanwhile, logistic regression analysis revealed that carriers of heterozygous genotype of catalase C-262T (P = 0.010, odds ratio: 4.163; 95 percent confidence interval 1.400 - 7.378), glutathione concentration (P = 0.001, odds ratio: 2.421; 95 percent confidence interval 2.262 - 2.591) and male patients (P = 0.005, odds ratio: 1.344; 95% confidence interval 0.782 - 2.309) had a higher risk for valproic acid-associated liver injury.

DISCUSSION

The mechanism underlying valproic acid-induced hepatotoxicity remains unclear. Additionally, factors that may contribute to the observed differences in the incidence of hepatotoxicity between males and females have yet to be defined. This study identifies several genetic factors that may predispose patients to valproic acid-associated hepatotoxicity.

LIMITATIONS

This relatively small sample size of children with one ethnicity some of whom were taking other antiepileptics that are potentially hepatotoxic.

CONCLUSION

Catalase C-262T genotype, glutathione concentration and gender (male) are potential risk factors for the susceptibility to valproic acid-associated liver injury.

Successful LC-MS/MS assay development and validation for determination of valproic acid and its metabolites supporting proactive pharmacovigilance

Valproic acid (VPA) is a well-documented contributor to liver injury, which is likely caused by the formation of its toxic metabolites. Monitoring VPA and its metabolites is very meaningful for the pharmacovigilance, but the availability of a powerful assay is a prerequisite. In this study, for the first time, a sensitive and specific LC-MS/MS method was developed and validated to simultaneously quantify the concentrations of VPA and its six pestering isomer metabolites (3-OH-VPA, 4-OH-VPA, 5-OH-VPA, 2-PGA, VPA-G, and 2-ene-VPA) in human plasma, using 5-OH-VPA-d7 and VPA-d6 as the internal standards (ISs). We also figured out another tricky problem that the concentrations of the parent drug and the metabolites vary widely. Of note, after protein precipitation and dilution with acetonitrile (ACN) and 50% ACN successively, the analytes and the ISs were successfully separated on a Kinetex C18 column. Intriguingly, sacrificing its signal intensity by elevated collision energy of VPA finally achieved the simultaneous determination. As expected, the method showed great linearity (r > 0.998) over the concentration ranges for all analytes. The inter-day and intra-day accuracy and precision were both acceptable. The method was successfully applied in 127 children with epilepsy. This novel assay will support the VPA-associated pharmacovigilance in the future.

Liver Involvement in Patients with Rare MBOAT7 Variants and Intellectual Disability: A Case Report and Literature Review

The membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) protein is an acyltransferase catalyzing arachidonic acid incorporation into lysophosphatidylinositol. Patients with rare, biallelic loss-of-function variants of the MBOAT7 gene display intellectual disability with neurodevelopmental defects. The rs641738 inherited variant associated with reduced hepatic MBOAT7 expression has been linked to steatotic liver disease susceptibility. However, the impact of biallelic loss-of-function MBOAT7 variants on liver disease is not known. We report on a 2-year-old girl with MBOAT7-related intellectual disability and steatotic liver disease, confirming that MBOAT7 loss-of-function predisposes to liver disease.

Valproate-Induced Metabolic Syndrome

Valproic acid (VPA) and its salts (sodium calcium magnesium and orotic) are psychotropic drugs that are widely used in neurology and psychiatry. The long-term use of VPA increases the risk of developing adverse drug reactions (ADRs), among which metabolic syndrome (MetS) plays a special role. MetS belongs to a cluster of metabolic conditions such as abdominal obesity, high blood pressure, high blood glucose, high serum triglycerides, and low serum high-density lipoprotein. Valproate-induced MetS (VPA-MetS) is a common ADR that needs an updated multidisciplinary approach to its prevention and diagnosis. In this review, we consider the results of studies of blood (serum and plasma) and the urinary biomarkers of VPA-MetS. These metabolic biomarkers may provide the key to the development of a new multidisciplinary personalized strategy for the prevention and diagnosis of VPA-MetS in patients with neurological diseases, psychiatric disorders, and addiction diseases.

Endoplasmic Reticulum Stress and Mitochondrial Stress in Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a widespread and harmful disease closely linked to mitochondrial and endoplasmic reticulum stress (ERS). Globally, severe drug-induced hepatitis, cirrhosis, and liver cancer are the primary causes of liver-related morbidity and mortality. A hallmark of DILI is ERS and changes in mitochondrial morphology and function, which increase the production of reactive oxygen species (ROS) in a vicious cycle of mutually reinforcing stress responses. Several pathways are maladapted to maintain homeostasis during DILI. Here, we discuss the processes of liver injury caused by several types of drugs that induce hepatocyte stress, focusing primarily on DILI by ERS and mitochondrial stress. Importantly, both ERS and mitochondrial stress are mediated by the overproduction of ROS, destruction of Ca2+ homeostasis, and unfolded protein response (UPR). Additionally, we review new pathways and potential pharmacological targets for DILI to highlight new possibilities for DILI treatment and mitigation.

Effect of ANKK1 Polymorphisms on Serum Valproic Acid Concentration in Chinese Han Adult Patients in the Early Postoperative Period

INTRODUCTION

This study aimed to investigate the relationship between gene polymorphisms and clinical factors with the concentrations of valproic acid (VPA) in adult patients who underwent neurosurgery in China.

METHODS

A total of 531 serum concentration samples at steady state were collected from 313 patients to develop a population pharmacokinetic (PPK) model. Data analysis was performed using nonlinear mixed effects modeling. Covariates included demographic parameters, biological characteristics, and genetic polymorphism. Bootstrap evaluation showed that the final model was stable. Sensitive analysis was performed to verify the relationship between gene polymorphisms and concentrations of VPA. Linear regression was used to analyze the relationship between VPA concentration, ANKK1, and daily dosage.

RESULTS

In the recruited patients, 17 of 25 single-nucleotide polymorphism distributions were consistent with the Hardy-Weinberg equilibrium. A one-compartment model with first-order absorption and elimination was developed for VPA injections. VPA clearance was significantly influenced by three variables: sex (17.41% higher in male than female patients), body weight, and the ANKK1 gene. Typical values for the elimination clearance and the volume of central compartment were 0.614 L/min and 23.5 L, respectively. The model evaluation indicated the stable and precise performance of the final model. After sensitive analysis using Kruskal-Wallis and Mann-Whitney U tests, we found that patients with AA alleles had higher VPA concentrations than those with GG and AG alleles. Linear regression models showed that gene polymorphisms of ANKK1 had little effects on VPA concentration.

CONCLUSION

A PPK model of VPA in Chinese Han patients was successfully established; this can be helpful for model-informed precision-dosing approaches in clinical patient care, and for exploring the mechanism of VPA-induced weight gain.

Therapeutic and Toxic Effects of Valproic Acid Metabolites

Valproic acid (VPA) and its salts are psychotropic drugs that are widely used in neurological diseases (epilepsy, neuropathic pain, migraine, etc.) and psychiatric disorders (schizophrenia, bipolar affective disorder, addiction diseases, etc.). In addition, the indications for the appointment of valproate have been expanding in recent years in connection with the study of new mechanisms of action of therapeutic and toxic metabolites of VPA in the human body. Thus, VPA is considered a component of disease-modifying therapy for multiple tumors, neurodegenerative diseases (Huntington's disease, Parkinson's disease, Duchenne progressive dystrophy, etc.), and human immunodeficiency syndrome. The metabolism of VPA is complex and continues to be studied. Known pathways of VPA metabolism include: β-oxidation in the tricarboxylic acid cycle (acetylation); oxidation with the participation of cytochrome P-450 isoenzymes (P-oxidation); and glucuronidation. The complex metabolism of VPA explains the diversity of its active and inactive metabolites, which have therapeutic, neutral, or toxic effects. It is known that some active metabolites of VPA may have a stronger clinical effect than VPA itself. These reasons explain the relevance of this narrative review, which summarizes the results of studies of blood (serum, plasma) and urinary metabolites of VPA from the standpoint of the pharmacogenomics and pharmacometabolomics. In addition, a new personalized approach to assessing the cumulative risk of developing VPA-induced adverse reactions is presented and ways for their correction are proposed depending on the patient's pharmacogenetic profile and the level of therapeutic and toxic VPA metabolites in the human body fluids (blood, urine).

[Status epilepticus in a pregnant patient with a previously unrecognized POLG-associated disease]

POLG-associated diseases are rare causes of pharmacoresistant epilepsy and status epilepticus, especially in adult patients. Phenotypic and genotypic variability in these conditions causes the complexity of their diagnosis. In the study, we report a case of a 33-year-old female patient who developed recurrent convulsive status epilepticus with focal clonic onset at the week 22/23 of pregnancy. Intensive anti-seizure therapy was administered, including the use of valproic acid, as well as the treatment of somatic complications. Given the acute onset, the semiology of seizures, the presence of psychopathological symptoms, autoimmune etiology of the disease was initially suspected. A month after the withdrawal of valproic acid, the patient began to show signs of toxic hepatitis, which eventually led to death. According to the results of whole-exome sequencing obtained later, the patient was a carrier of a pathogenic homozygous variant c.2243G>C (p.W748S) in the POLG gene. The presented case highlights the importance of molecular genetic testing and the risk associated with valproic acid hepatotoxicity in patients with cryptogenic epileptic status.

HDACi Delivery Systems Based on Cellulose Valproate Nanoparticles

The ability of histone deacetylase inhibitors (HDACi) like valproic acid (VPA) as a therapeutic for inflammatory diseases or cancer has increased the interest in HDACi and their targeted transport to diseased tissues. Administration of VPA immobilized on polymeric carriers was found to be a suitable approach to circumvent drawbacks such as rapid metabolization, short serum half-life, or side effects. Polysaccharides are convenient biopolymeric carriers due to their biocompatibility and biodegradability. Furthermore, the hydroxy-, amino-, or carboxylic groups are predestinated for functionalization. The esterification of three hydroxy groups of cellulose with VPA leads to products having a high amount of VPA loading. Subsequent shaping yielded uniform nanoparticles (NPs) of around 150 nm in size capable of releasing VPA in a controlled way under physiological conditions.

Potential risk of liver injury in epileptic patients during COVID-19 pandemic

Most of the antiseizure medications (ASMs) are metabolized in liver and many of them particularly first-generation ASMs have the potential to increase liver enzymes or induce liver injury. Hence, treatment of new onset seizures or epilepsy by ASMs during the course of coronavirus disease 2019 (COVID-19), which could potentially be complicated by hepatic dysfunction, is a challenging clinical issue. Intravenous form of levetiracetam which has no significant hepatic metabolism or drug-drug interaction is often a favorable option to control seizures in acute phase of COVID-19. Administration of enzyme inducer ASMs and valproate with the well-known hepatotoxicity and common drug interactions is not generally recommended. In patients with epilepsy who are under control with potentially hepatotoxic ASMs, close observation and cautious dose reduction or drug switch should be considered if any evidence of hepatic impairment exists. However, risks of possible breakthrough seizures should be weighed against benefits of lowering the hazard of liver injury. In patients with epilepsy who receive polytherapy with ASMs, transient dose modification with the tendency to increase the dose of ASMs with more favorable safety profile and less drug interaction and decrease the dose of drugs with main hepatic metabolism, high protein binding, potential to cause liver injury and known drug-drug reaction should be considered. Finally, decision making should be individualized based on patients’ conditions and course of illness.

Valproic acid induced liver injury: An insight into molecular toxicological mechanism

Valproic acid (VPA) is an anti-seizure drug that causes idiosyncratic liver injury. 2-propyl-4-pentenoic acid (Δ⁴VPA), a metabolite of VPA, has been implicated in VPA-induced hepatotoxicity. This review summarizes the pathogenesis involved in VPA-induced liver injury. The VPA induce liver injury mainly by i) liberation of Δ⁴VPA metabolites; ii) decrease in glutathione stores and antioxidants, resulting in oxidative stress; iii) inhibition of fatty acid β-oxidation, inducing mitochondrial DNA depletion and hypermethylation; a decrease in proton leak; oxidative phosphorylation impairment and ATP synthesis decrease; iv) induction of fatty liver via inhibition of carnitine palmitoyltransferase I, enhancing nuclear receptor peroxisome proliferator-activated receptor-gamma and acyl-CoA thioesterase 1, and inducing long-chain fatty acid uptake and triglyceride synthesis. VPA administration aggravates liver injury in individuals with metabolic syndromes. Therapeutic drug monitoring, routine serum levels of transaminases, ammonia, and lipid parameters during VPA therapy may thus be beneficial in improving the safety profile or preventing the progression of DILI.

Valproate and Short-Chain Fatty Acids Activate Transcription of the Human Vitamin D Receptor Gene through a Proximal GC-Rich DNA Region Containing Two Putative Sp1 Binding Sites

The vitamin D receptor (VDR) mediates 1,25-dihydroxyvitamin D3 pleiotropic biological actions through transcription regulation of target genes. The expression levels of this ligand-activated nuclear receptor are regulated by multiple mechanisms both at transcriptional and post-transcriptional levels. Vitamin D3 is the natural VDR activator, but other molecules and signaling pathways have also been reported to regulate VDR expression and activity. In this study, we identify valproic acid (VPA) and natural short-chain fatty acids (SCFAs) as novel transcriptional activators of the human VDR (hVDR) gene. We further report a comprehensive characterization of VPA/SCFA-responsive elements in the 5' regulatory region of the hVDR gene. Two alternative promoter DNA regions (of 2.4 and 3.8 kb), as well as subsequent deletion fragments, were cloned in pGL4-LUC reporter vector. Transfection of these constructs in HepG2 and human Upcyte hepatocytes followed by reporter assays demonstrated that a region of 107 bp (from -107 to -1) upstream of the transcription start site in exon 1a is responsible for most of the increase in transcriptional activity in response to VPA/SCFAs. This short DNA region is GC-rich, does not contain an apparent TATA box, and includes two bona fide binding sites for the transcription factor Sp1. Our results substantiate the hypothesis that VPA and SCFAs facilitate the activity of Sp1 on novel Sp1 responsive elements in the hVDR gene, thus promoting VDR upregulation and signaling. Elevated hepatic VDR levels have been associated with liver steatosis and, therefore, our results may have clinical relevance in epileptic pediatric patients on VPA therapy. Our results could also be suggestive of VDR upregulation by SCFAs produced by gut microbiota.

The Role of l-Carnitine in Mitochondria, Prevention of Metabolic Inflexibility and Disease Initiation

Mitochondria control cellular fate by various mechanisms and are key drivers of cellular metabolism. Although the main function of mitochondria is energy production, they are also involved in cellular detoxification, cellular stabilization, as well as control of ketogenesis and glucogenesis. Conditions like neurodegenerative disease, insulin resistance, endocrine imbalances, liver and kidney disease are intimately linked to metabolic disorders or inflexibility and to mitochondrial dysfunction. Mitochondrial dysfunction due to a relative lack of micronutrients and substrates is implicated in the development of many chronic diseases. l-carnitine is one of the key nutrients for proper mitochondrial function and is notable for its role in fatty acid oxidation. l-carnitine also plays a major part in protecting cellular membranes, preventing fatty acid accumulation, modulating ketogenesis and glucogenesis and in the elimination of toxic metabolites. l-carnitine deficiency has been observed in many diseases including organic acidurias, inborn errors of metabolism, endocrine imbalances, liver and kidney disease. The protective effects of micronutrients targeting mitochondria hold considerable promise for the management of age and metabolic related diseases. Preventing nutrient deficiencies like l-carnitine can be beneficial in maintaining metabolic flexibility via the optimization of mitochondrial function. This paper reviews the critical role of l-carnitine in mitochondrial function, metabolic flexibility and in other pathophysiological cellular mechanisms.

Detailed Molecular Mechanisms Involved in Drug-Induced Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis: An Update

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are some of the biggest public health challenges due to their spread and increasing incidence around the world. NAFLD is characterized by intrahepatic lipid deposition, accompanied by dyslipidemia, hypertension, and insulin resistance, leading to more serious complications. Among the various causes, drug administration for the treatment of numerous kinds of diseases, such as antiarrhythmic and antihypertensive drugs, promotes the onset and progression of steatosis, causing drug-induced hepatic steatosis (DIHS). Here, we reviewed in detail the major classes of drugs that cause DIHS and the specific molecular mechanisms involved in these processes. Eight classes of drugs, among the most used for the treatment of common pathologies, were considered. The most diffused mechanism whereby drugs can induce NAFLD/NASH is interfering with mitochondrial activity, inhibiting fatty acid oxidation, but other pathways involved in lipid homeostasis are also affected. PubMed research was performed to obtain significant papers published up to November 2021. The key words included the class of drugs, or the specific compound, combined with steatosis, nonalcoholic steatohepatitis, fibrosis, fatty liver and hepatic lipid deposition. Additional information was found in the citations listed in other papers, when they were not displayed in the original search.

Switching Between LC-ESI-MS/MS and EMIT Methods for Routine TDM of Valproic Acid in Pediatric Patients With Epilepsy: What Clinicians and Researchers Need to Know

Background: Valproic acid (VPA) is a widely used antiseizure medication and its dosing needs to be tailored individually through therapeutic drug monitoring (TDM) to avoid or prevent toxicity. Currently, immune-enzymatic assays such as Enzyme Multiplied Immunoassay Technique (EMIT), and Liquid Chromatography (LC)-based techniques, particularly coupled to Electrospray Ionization Tandem Mass Spectrometry (LC-ESI-MS/MS), resulting a potential lack of concordance between laboratories. Methods: In this study, plasma VPA concentrations were determined for 711 pediatric patients with epilepsy by a routine EMIT assay and by a validated in-house LC-ESI-MS/MS method on the same group of samples, aimed to address the aforementioned concern. Consistency between two assays was evaluated using linear regression and Bland-Altman analysis. Results: The calibration curve was linear in the range of 5.00-300 μg/ml for LC-ESI-MS/MS method and 1.00-150 μg/ml for EMIT assay, respectively. The two methods were proven to be accurate with quality control samples. As a result, a significant correlation between two methods was obtained with a regression equation described as [ EMIT ] = 1.214 × [ LC - ESI - MS / MS ] + 3.054 (r ² = 0.9281). Bland-Altman plot showed a mean bias of 14.5 μg/ml (95% confidence interval (CI) (-0.2, 29.2) and a mean increase of 27.8% (95% CI (3.3, 52.4) measured by EMIT assay more than that measured by LC-ESI-MS/MS method. Conclusion: In conclusion, two methods were closely correlated, but EMIT assay overestimate VPA levels in human plasma compared with LC-ESI-MS/MS method. Due to the observed significant discordance between the tested methods, switching from immunoassays to LC-based techniques for TDM of VPA deserves close attention and therapeutic range of 35.0-75.0 μg/ml may be feasible. However, further studies are needed to evaluate the eligibility of this alternative range in the clinical practice. Clinicians should be informed when switching the VPA quantitation methods during the clinical practice.

Factors Influencing Sodium Valproate Serum Concentrations in Patients with Epilepsy Based on Logistic Regression Analysis

Background

We aimed to explore the risk factors that affect the serum concentration of sodium valproate (VPA-Na) in patients with epilepsy and to provide references for the rationale of the use of VPA-Na.

Material/Methods

The enzyme-multiplied immunoassay technique was used to determine the serum VPA-NA concentrations of 109 patients, and the results were retrospectively analyzed and summarized. A multivariate logistic regression model was used to analyze substandard serum VPA-Na concentrations.

Results

Fifty-six patients (51.38%) treated with VPA-Na tablets were within the effective treatment range of 50–100 μg/mL, while 53 patients (48.62%) were out of the treatment range. The results indicated that the standard-reaching rate of serum drug concentration in the juvenile group was higher than that in the adult and elderly groups; the standard-reaching rates of serum drug concentrations in the low-dose group and the intermediate-dose group were lower than that in the high-dose group; and the standard-reaching rate of serum drug concentration in the group receiving carbapenems in combination was lower than that in the non-combination group; all differences were statistically significant. The combination with carbapenems and enzyme inducers was an independent risk factor for VPA-Na serum concentration below the target level in hospitalized patients.

Conclusions

To improve clinical efficacy and reduce the occurrence of adverse reactions, there is a need for therapeutic drug monitoring of VPA-Na. Moreover, individual administration should be implemented when VPA-Na tablets are used in the treatment of epilepsy because of the significant fluctuation in VPA-Na blood concentration.

Valproic Acid After Neurosurgery Induces Elevated Risk of Liver Injury: A Prospective Nested Case-Control Study

BACKGROUND

Valproic acid (VPA) has been widely used to prevent epileptic seizures after neurosurgery in China. We have found that the incidence of liver injury (LI) in patients using VPA after neurosurgery is higher than that in other patients.

OBJECTIVE

The objective of this study was to investigate the risk factors of LI in patients using VPA after neurosurgery.

METHODS

A nested case-control study was conducted in patients using VPA after neurosurgery between September 2019 and March 2021. Cases of LI were matched to controls by age and body mass index (BMI). Conditional logistic regression was used to estimate matched odds ratios representing the odds of LI. A receiver operating characteristic curve was used to analyze the optimal cutoff condition.

RESULTS

A total of 248 people (62 LI and 186 control) were enrolled. Among patients with vs without LI, the matched odds ratio for trough concentration of VPA was significant (matched odds ratio [OR], 1.09; 95% confidence interval [CI]: 1.01-1.19). The course of treatment (OR: 1.17, 95% CI: 1.02-1.33), Glasgow score (OR: 0.26, 95% CI: 0.10-0.67), gene polymorphisms of CYP2C19 (OR: 2.09, 95% CI: 1.03-146.93), and UGT1A6 (OR: 34.61, 95% CI: 1.19-1003.23) were all related to the outcome. The optimal cutoff of the course of treatment was 10 days, while the trough concentration of VPA was determined to be 66.16 mg/L.

CONCLUSION

Length of treatment, VPA trough concentration, and Glasgow score were associated with LI in patients after neurosurgery. A gene test may be necessary for people who are prescribed VPA for a long time.

Evaluating risk detection methods to uncover ontogenic-mediated adverse drug effect mechanisms in children

BACKGROUND

Identifying adverse drugs effects (ADEs) in children, overall and within pediatric age groups, is essential for preventing disability and death from marketed drugs. At the same time, however, detection is challenging due to dynamic biological processes during growth and maturation, called ontogeny, that alter pharmacokinetics and pharmacodynamics. As a result, methodologies in pediatric drug safety have been limited to event surveillance and have not focused on investigating adverse event mechanisms. There is an opportunity to identify drug event patterns within observational databases for evaluating ontogenic-mediated adverse event mechanisms. The first step of which is to establish statistical models that can identify temporal trends of adverse effects across childhood.

RESULTS

Using simulation, we evaluated a population stratification method (the proportional reporting ratio or PRR) and a population modeling method (the generalized additive model or GAM) to identify and quantify ADE risk at varying reporting rates and dynamics. We found that GAMs showed improved performance over the PRR in detecting dynamic drug event reporting across child development stages. Moreover, GAMs exhibited normally distributed and robust ADE risk estimation at all development stages by sharing information across child development stages.

CONCLUSIONS

Our study underscores the opportunity for using population modeling techniques, which leverage drug event reporting across development stages, as biologically-inspired detection methods for evaluating ontogenic mechanisms.

Effects of Sodium Valproate Monotherapy on Blood Liver Enzyme Levels in Patients with Epilepsy: A Meta-Analysis

We conducted this meta-analysis to assess the effects of sodium valproate (VPA) monotherapy on blood liver enzymes in patients with epilepsy. PubMed, Web of Science, EBSCO, Cochrane Library, Wanfang, China national knowledge infrastructure databases were searched. Nine studies were included. Results showed: (1) The overall SMD for blood AST, ALT, and GGT levels of VPA monotherapy group versus control group were 0.70 (95% CI=0.31 to 1.09, Z=3.52, p=0.0004), 0.47 (95% CI=- 0.01 to 0.95, Z=1.91, p=0.06), 0.44 (95% CI=0.29 to 0.60, Z=5.55, p<0.00001), respectively. (2) In subgroup meta-analysis, increased blood AST and GGT levels were observed in epileptic minors (AST: total SMD=0.85, 95% CI=0.40 to 1.30, Z=3.69, p=0.0002; GGT: total SMD=0.46, 95% CI=0.29 to 0.63, Z=5.25, p<0.00001). Elevated blood ALT level was observed in Asian patients receiving VPA monotherapy (total SMD=0.70, 95% CI=0.51 to 0.90, Z=7.01, p<0.00001), and the early stage of VPA monotherapy (total SMD=0.93, 95% CI=0.57 to 1.29, Z=5.09, p<0.00001). Overall, our results indicated that blood AST and GGT were significantly increased in epileptic minors receiving VPA monotherapy. The elevation of blood ALT was observed in Asian patients and the early stage of VPA monotherapy. However, due to the small number of included studies, our results should be considered with caution.

Acute liver failure with thrombotic microangiopathy due to sodium valproate toxicity: A case report

BACKGROUND

Sodium valproate is widely used in the treatment of epilepsy in clinical practice. Most adverse reactions to sodium valproate are mild and reversible, while serious idiosyncratic side effects are becoming apparent, particularly hepatotoxicity. Herein, we report a case of fatal acute liver failure (ALF) with thrombotic microangiopathy (TMA) caused by treatment with sodium valproate in a patient following surgery for meningioma.

CASE SUMMARY

A 42-year-old man who received antiepileptic treatment with sodium valproate after surgery for meningioma exhibited extreme fatigue, severe jaundice accompanied by oliguria, soy sauce-colored urine, and ecchymosis. His postoperative laboratory values indicated a rapid decreased platelet count and hemoglobin level, severe liver and kidney dysfunction, and disturbance of the coagulation system. He was diagnosed with drug-induced liver failure combined with TMA. After plasma exchange combined with hemoperfusion, pulse therapy with high-dose methylprednisolone, and blood transfusion, his liver function deteriorated, and finally, he died.

CONCLUSION

ALF with TMA is a rare and fatal adverse reaction of sodium valproate which needs to be highly valued.

Valproic Acid Suppresses Autoimmune Recurrence and Allograft Rejection in Islet Transplantation through Induction of the Differentiation of Regulatory T Cells and Can Be Used in Cell Therapy for Type 1 Diabetes

Type 1 diabetes mellitus (T1D) results from the destruction of insulin-producing β cells in the islet of the pancreas by lymphocytes. Non-obese diabetic (NOD) mouse is an animal model frequently used for this disease. It has been considered that T1D is a T cell-mediated autoimmune disease. Both CD4+ and CD8+ T cells are highly responsible for the destruction of β cells within the pancreatic islets of Langerhans. Previous studies have revealed that regulatory T (Treg) cells play a critical role in the homeostasis of the immune system as well as immune tolerance to autoantigens, thereby preventing autoimmunity. Valproic acid (VPA), a branched short-chain fatty acid, is widely used as an antiepileptic drug and a mood stabilizer. Previous reports have demonstrated that VPA treatment decreases the incidence and severity of collagen-induced arthritis and experimental autoimmune neuritis by increasing the population of Treg cells in these mouse disease models. Given the effect of VPA in the induction of Treg cells’ population, we evaluated the therapeutic potential and the protective mechanism of VPA treatment in the suppression of graft autoimmune rejection and immune recurrence in syngeneic or allogenic islet transplantation mouse models. In our study, we found that the treatment of VPA increased the expression of forkhead box P3 (FOXP3), which is a critical transcription factor that controls Treg cells’ development and function. Our data revealed that 400 mg/kg VPA treatment in recipients effectively prolonged the survival of syngeneic and allogenic islet grafts. The percentage of Treg cells in splenocytes increased in VPA-treated recipients. We also proved that adoptive transfer of VPA-induced Tregs to the transplanted recipients effectively prolonged the survival of islet grafts. The results of this study provide evidence of the therapeutic potential and the underlying mechanism of VPA treatment in syngeneic islet transplantation for T1D. It also provides experimental evidence for cell therapy by adoptive transferring of in vitro VPA-induced Tregs for the suppression of autoimmune recurrence.

PXR-mediated expression of FABP4 promotes valproate-induced lipid accumulation in HepG2 cells

Valproate (valproic acid, VPA) is widely used in the therapy of epilepsy. However, adverse effect like hepatic steatosis has been reported in patients receiving VPA treatment. But whether nuclear receptor pregnane X receptor (PXR) and fatty acid binding protein 4 (FABP4) are involved in the regulation of VPA-induced steatosis or not is still unknown. In this study, the roles of PXR and FABP4 in VPA-induced lipid accumulation in HepG2 cells were investigated. We found that the expression of PXR and FABP4 were increased by VPA in a dose-dependent manner. Knockdown of PXR not only reduced lipid accumulation but also impaired the induction of FABP4 by VPA. While overexpression of PXR enhanced both lipid accumulation and FABP4 expression. Moreover, exogenous expression of FABP4 increased triglyceride levels and enhanced lipid accumulation caused by VPA. Taken together, these results suggest that PXR-mediated expression of FABP4 is responsible for lipid accumulation caused by VPA.

Biocompatible valproic acid-coupled nanoparticles attenuate lipopolysaccharide-induced inflammation

Inflammatory diseases like sepsis are associated with dysregulated gene expression, often caused by an imbalance of epigenetic regulators, such as histone acetyltransferases (HATs) and histone deacetylases (HDACs), and consequently, altered epigenetic chromatin signatures or aberrant posttranslational modifications of signalling proteins and transcription factors. Thus, HDAC inhibitors (HDACi) are a promising class of anti-inflammatory drugs. Recently, an efficient drug delivery system carrying the class I/IIa selective HDACi valproic acid (VPA) was developed to circumvent common disadvantages of free drug administration, e.g. short half-life and side effects. The cellulose-based sulphated VPA-coupled (CV-S) nanoparticles (NPs) are rapidly taken up by cells, do not cause any toxic effects and are fully biocompatible. Importantly, VPA is intracellularly cleaved from the NPs and HDACi activity could be proven. Here, we demonstrate that CV-S NPs exhibit overall anti-inflammatory effects in primary human macrophages and are able to attenuate the lipopolysaccharide-induced inflammatory response. CV-S NPs show superior potential to free VPA to suppress the TLR-MyD88-NF-κB signalling axis, leading to decreased TNF-α expression and secretion.

Valproic Acid-Induced Liver Injury: A Case-Control Study from a Prospective Pharmacovigilance Program in a Tertiary Hospital

Introduction: Valproic acid (VPA) is an antiepileptic drug extensively used for treating partial and generalised seizures, acute mania and as prophylaxis for bipolar disorder. Drug-induced liver injury (DILI) persists as a significant issue related to fatal outcomes by VPA. The aim of this study was to increase our knowledge about this condition and to better identify patients affected. Methods: We conducted an observational retrospective case-control study that identified cases of DILI by VPA from the Pharmacovigilance Programme from our Laboratory Signals at La Paz University Hospital from January 2007 to December 2019. From the Therapeutic VPA Monitoring program, two control groups were assigned, VPA-tolerant patients and the other with patients who developed mild VPA-related liver injury but who did not meet the DILI criteria, matched for date, age and sex. Results: A total of 60 patients were included in the study: 15 cases of DILI, 30 VPA-tolerant controls and 15 controls with mild liver injury. Mean age for the cases was 45.7 years, 4 (26.7%) were women and 5 (33.34%) were children under 18 years, of them 3 (20%) were fatal. Polytherapy with other antiepileptic drugs (p = 0.047) and alcohol consumption (p < 0.001) were associated with a greater risk of developing DILI by VPA. A diagnosis of epileptic seizure was more frequently related to DILI when compared with the VPA-tolerant controls (p < 0.001). The cases developed hepatocellular liver injury (p < 0.001), while the mild hepatic damage controls had a higher rate of cholestatic liver injury (p < 0.001). The laboratory lactate dehydrogenase values were statistically higher (even at baseline) in patients with DILI than in both control groups (p = 0.033 and p = 0.039). Conclusions: VPA hepatotoxicity remains a considerable problem. This study offers interesting findings for characterising VPA-induced liver injury and at-risk patients.

Research Progress on the Effect of Epilepsy and Antiseizure Medications on PCOS Through HPO Axis

Epilepsy is a common chronic neurological disease that manifests as recurrent seizures. The incidence and prevalence of epilepsy in women are slightly lower than those in men. Polycystic ovary syndrome (PCOS), a reproductive endocrine system disease, is a complication that women with epilepsy are susceptible to, and its total prevalence is 8%-13% in the female population and sometimes as high as 26% in female epilepsy patients. The rate of PCOS increased markedly in female patients who chose valproate (VPA), to 1.95 times higher than that of other drugs. In addition, patients receiving other anti-seizure medications (ASMs), such as lamotrigine (LTG), oxcarbazepine (OXC), and carbamazepine (CBZ), also have reproductive endocrine abnormalities. Some scholars believe that the increase in incidence is related not only to epilepsy itself but also to ASMs. Epileptiform discharges can affect the activity of the pulse generator and then interfere with the reproductive endocrine system by breaking the balance of the hypothalamic-pituitary-ovarian (HPO) axis. ASMs may also cause PCOS-like disorders of the reproductive endocrine system through the HPO axis. Moreover, other factors such as hormone metabolism and related signalling pathways also play a role in it.

Effects of valproic acid on skeletal metabolism in children with epilepsy: a systematic evaluation and meta-analysis based on 14 studies

Background

Previous studies have reported that long-term use of valproic acid can cause changes in bone metabolism in children. We conducted this meta-analysis to determine the effects of valproic acid on bone metabolism and bone mineral density (BMD) in children with epilepsy.

Methods

Studies were searched from the databases of PubMed, Embase, Ovid, Cochrance Library, Springer Link and Web of Science. The effects of valproic acid on bone metabolism indicators and BMD were assessed through calculating the standardized mean difference (SMD) with 95% confidence interval (CI).

Results

Fourteen studies with 987 individuals were included in this analysis. The long-term use of valproic acid did not affect the levels of serum calcium (p = 0.99), phosphorus (p = 0.28), ALP (p = 0.76), PTH (p = 0.36) and osteocalcin (p = 0.72), but it led to a decrease in 25-OH-VitD (p = 0.01) and BMD (p = 0.002 for the vertebra; p = 0.004 for the femur) in treating children with epilepsy.

Conclusion

Long-term use of valproic acid in treating children with epilepsy can lead to a reduction in 25-OH-VitD and BMD. Measurements of 25-OH-VitD and BMD should be performed regularly in children taking the drug to detect early osteopenia caused by the drug.

Valproic acid therapy decreases serum 25-hydroxyvitamin D level in female infants and toddlers with epilepsy- a pilot longitudinal study

To evaluate if valproic acid (VPA) therapy is associated with vitamin D deficiency among infants and toddlers with epilepsy, a cross-sectional clinical study was conducted in 25 children with epilepsy taking VPA. Blood levels of calcium, phosphorus, alkaline phosphatase, and 25-hydroxy vitamin D [25(OH)D] and plasma VPA level were measured at 1- to 3-month intervals. At the initial and final measurements, vitamin D deficiency or insufficiency was recognized in 8 (32%) and 12 (42%), respectively. In girls, a decreasing trend in serum 25(OH)D levels (P<0.05) was observed. Polytherapy had a significant negative effect on the longitudinal change of 25(OH)D (P<0.05) in girls. In conclusion, our study indicates that a high proportion of girls after VPA therapy had hypovitaminosis D.

Biocompatible sulfated valproic acid-coupled polysaccharide-based nanocarriers with HDAC inhibitory activity

The development of bio-based nanoparticles (NPs) as drug containers is of increasing interest to circumvent several obstacles in drug therapy such as rapid drug metabolization, short serum half-life, and unspecific side effects. The histone deacetylase inhibitor valproic acid (VPA) is known for its anti-inflammatory as well as for its anti-cancer activity. Here, recently developed VPA-loaded NPs based on cellulose- and dextran VPA esters were modified with sulfuric acid half ester moieties to improve intracellular drug release. The NPs show rapid cellular uptake, are non-toxic in vitro and in vivo, and able to induce histone H3 hyperacetylation. Thus, they represent a potent drug delivery system for the application in a variety of treatment settings, such as inflammation, sepsis and defined cancer types. In addition, the flexible NP-system offers a broad range of further options for modification, e.g. for targeting strategies and multi-drug approaches.

Involvement of CYP2E1-ROS-CD36/DGAT2 axis in the pathogenesis of VPA-induced hepatic steatosis in vivo and in vitro

Valproic acid (VPA) is a widely prescribed antiepileptic drug, which may cause steatosis in the liver. Oxidative stress is associated with the progression of VPA-induced hepatic steatosis. However, the potential mechanisms are not fully understood. In this study, we demonstrated the involvement of CYP2E1-ROS-CD36/DGAT2 axis in the pathogenesis of VPA-induced hepatic steatosis in vitro and in vivo. First, VPA treatment (500 mg/kg in mice, 5 mM in LO₂ cells) induced hepatic steatosis and enhanced reactive oxidative stress (ROS) level, and ROS scavenger, N-acetyl-L-cysteine (NAC, 200 mg/kg in mice, 1 mM in LO₂ cells) reversed the changes. Next, we observed the enhanced expression and enzymatic activity of cytochrome P450 2E1 (CYP2E1) in VPA-treated mice and LO₂ cells. Importantly, VPA-induced ROS accumulation and hepatic steatosis were attenuated when CYP2E1 was inhibited using CYP2E1 inhibitor, diallyl sulfide (DAS, 100 mg/kg in mice, 1 mM in LO₂ cells) or in CYP2E1-knockdown cell line, suggesting that CYP2E1 plays a potential role in ROS production following hepatic steatosis. Furthermore, gene expression analysis showed that the mRNA levels of cluster of differentiation 36 (CD36), a fatty acid translocase protein and distinct diacylglycerol acyltransferase 2 (DGAT2) were significantly upregulated in mice and LO₂ cells after VPA treatment, while the change was alleviated by NAC and DAS. Meanwhile, time course experiments demonstrated that the increase of CYP2E1 level occurred earlier than that of ROS, CD36 and DGAT2, and ROS generation preceded the onset of hepatic steatosis. Taken together, VPA treatment enhances the expression and enzymatic activity of CYP2E1, which promotes ROS production and then causes CD36 and DGAT2 overproduction and hepatic steatosis in mice and LO₂ cells, which provides a novel insight into VPA-induced hepatic steatosis.

Mitochondrial Diseases: A Diagnostic Revolution

Mitochondrial disorders have emerged as a common cause of inherited disease, but are traditionally viewed as being difficult to diagnose clinically, and even more difficult to comprehensively characterize at the molecular level. However, new sequencing approaches, particularly whole-genome sequencing (WGS), have dramatically changed the landscape. The combined analysis of nuclear and mitochondrial DNA (mtDNA) allows rapid diagnosis for the vast majority of patients, but new challenges have emerged. We review recent discoveries that will benefit patients and families, and highlight emerging questions that remain to be resolved.

Lessons learned from the discovery of sodium valproate and what has this meant to future drug discovery efforts?

INTRODUCTION

The discovery of the anticonvulsant properties of valproic acid and the development of valproic acid/valproate to market authorization for specific epilepsy types and syndromes, as well as their repurposing for other indications, are illustrative examples of both the strengths and weaknesses of drug development strategies.

AREAS COVERED

This review summarizes and interprets the development and repurposing history of valproic acid/valproate. The article is based on articles, including original studies and systematic reviews obtained from PubMed, Scopus, EBSCO, SCIndeks and Google Scholar databases.

EXPERT OPINION

Random screening and careful observation of the experimental effects of tested substances were crucial for discovering the anticonvulsant effects of valproic acid, while rational drug design and clinical observation strategies led to repurposing valproic acid and valproate for bipolar disorder maintenance treatmentand prevention of migraine attacks. Early planning and feasibility studies of future clinical trials are essential for obtaining marketing authorization of new substances or new indications of old anticonvulsants. Significant progress has been made recently toward understanding, treatment and prevention of hepatotoxicity caused by valproic acid/valproate, making its long-term administration safer. There are ongoing efforts to repurpose valproic acid/valproate for augmentation with antipsychotic drugs for the treatment of schizophrenia.

Is cannabidiol hepatotoxic or hepatoprotective: A review

Questions have been raised regarding the potential hepatotoxicity of cannabidiol (CBD). Conversely, several animal studies have demonstrated the hepatoprotective effects of CBD against bile duct ligation, cocaine, thioacetamide, alcohol, and several other chemicals. This review summarizes the current literature concerning the hepatic effects of CBD in humans and animals. Based on the available data, it may be concluded that there is a low probability of serious hepatotoxicity at the high therapeutic doses that are used and a much lower risk of adverse hepatic effects and a potential for hepatoprotection effects at the lower doses commonly used in dietary supplements and food products. However, a detailed safety study in rats using highly purified CBD rather than enriched Cannabis extracts is needed, enabling the determination of hepatic as well as other tissue effects and potential margin of safety.

Non-Dose-Dependent Changes in Liver Enzyme Levels of Children With Epilepsy on Treatment With Sodium Valproate

Background:

Sodium valproate (VPA) is considered as the drug of choice for the treatment of generalized epilepsy in children. Sodium Valproate may be hepatotoxic.

Aim:

To assess the level of derangement of liver enzymes in children with epilepsy on treatment with sodium valproate.

Methods:

A cohort study. One hundred fifty-three children, comprising 51 with epilepsy on treatment with VPA (group I), 51 with epilepsy on treatment with other antiepileptic drugs (AEDs) but not VPA (group II), and 51 with nonconvulsive disorders (group III) had liver function tests performed for them. Data were analyzed by SPSS version 23.0.

Results:

There were 85 males and 68 females, aged 6 months to 14 years (median = 7.0 years). There was no significant difference in the mean plasma levels of alanine transaminase (ALT), alkaline phosphatase, and gamma glutamyl transferase across the three groups of children. The mean aspartate transaminase level was significantly higher in children in group III. There was a statistically significant negative correlation between the duration of AED therapy and the mean serum level of AST (r = −0.266, P = 0.016). The serum ALT level showed a statistically significant positive correlation with the duration of AED therapy (r = 0.268, P = 0.015).

Conclusion:

Sodium valproate monotherapy does not appear to be associated with significant hepatotoxicity in children in our cohort.

Genetic and Non-genetic Factors Contributing to the Significant Variation in the Plasma Trough Concentration-to-Dose Ratio of Valproic Acid in Children With Epilepsy

Objective: This study was conducted to evaluate the potential genetic and non-genetic factors contributing to plasma trough concentration-to-dose (C ₀/D) ratio of valproic acid (VPA) in pediatric patients with epilepsy. Study Design: A single-center, retrospective cohort study was performed by collecting data from 194 children aged 1-14 years between May 2018 and November 2018. The oral solution (n = 135) group and the sustained-release (SR) tablet group (n = 59) were defined, and the plasma VPA C ₀ was measured. Twenty-six single-nucleotide polymorphisms (SNPs) were chosen for genotyping with the MassARRAY system. A multiple logistic regression model was used for data analysis. Results: Body weight (BW) and age were positively correlated with the C ₀/D ratio in 194 patients, but the positive correlation disappeared after the patients were divided into oral solution and SR tablet subgroups. The average C ₀/D ratio was significantly increased by 2.11-fold (P = 0.000) in children who took VPA SR tablets compared with children who were administered VPA oral solutions. No significant association between genetic variants and the C ₀/D ratio was found, even for the five well-studied SNPs, namely UGT2B7 G211T, C802T, C161T, T125C, and CYP2C9 ^* 3 A1075C. However, a significant association between the C ₀/D ratio and UGT1A6/9 Del>A (rs144486213) was observed in the VPA oral solution group, but not in the VPA SR tablet group. Conclusions: The dosage forms of sodium valproate, rather than BW, age, or genetic polymorphisms, significantly affected the VPA C ₀/D ratios in pediatric patients with epilepsy. Based on our findings, switching the dosage form between solution and SR tablet should be performed cautiously. Total daily dose adjustment should be considered, and the plasma concentration, seizure-control effect, and adverse drug reaction should also be monitored very closely.