The role of carnitine supplementation during valproic acid therapy

Embryonic exposure to acetyl-L-carnitine protects against valproic acid-induced cardiac malformation in zebrafish model

Worldwide, estimated counts of about 7.9 million children are born with serious birth defects. In addition to genetic factors, prenatal exposure to drugs and environmental toxicants represents a major contributing factor to congenital malformations. In earlier investigation, we explored cardiac malformation caused by valproic acid (VPA) during early developing stages of zebrafish. Since heart depends on mitochondrial fatty acid oxidative metabolism for energy demands in which carnitine shuttle has a major role, the present study aimed to investigate the effect of acetyl-L-carnitine (AC) against VPA-induced cardiac malformation in developing zebrafish. Initially, AC was subjected to toxicological evaluation, and two micromolar concentrations (25 µM and 50 µM) were selected for evaluation. A sub-lethal concentration of VPA (50 µM) was selected to induce cardiac malformation. The embryos were grouped and the drug exposures were made at 2.5 h post-fertilization (hpf). The cardiac development and functioning was monitored. A progressive decline in cardiac functioning was noted in group exposed to VPA 50 µM. At 96 hpf and 120 hpf, the morphology of heart was severely affected with the chambers which became elongated and string-like accompanied by histological changes. Acridine orange staining showed accumulation of apoptotic cells. Group exposed to VPA 50 µM with AC 50 µM showed a significant reduction in pericardial sac edema with morphological, functional and histological recovery in developing heart. Moreover, reduced number of apoptotic cells was noted. The improvement with AC might be due to restoration of carnitine homeostasis for cardiac energy metabolism in developing heart.

The serum acylcarnitines profile in epileptic children treated with valproic acid and the protective roles of peroxisome proliferator-activated receptor a activation in valproic acid-induced liver injury

Valproic acid (VPA) is widely used as a major drug in the treatment of epilepsy. Despite the undisputed pharmacological importance and effectiveness of VPA, its potential hepatotoxicity is still a major concern. Being a simple fatty acid, the hepatotoxicity induced by VPA has long been considered to be due primarily to its interference with fatty acid β-oxidation (β-FAO). The aim of this study was to investigate the biomarkers for VPA-induced abnormal liver function in epileptic children and to determine potential mechanisms of its liver injury. Targeted metabolomics analysis of acylcarnitines (ACs) was performed in children's serum. Metabolomic analysis revealed that VPA -induced abnormal liver function resulted in the accumulation of serum long-chain acylcarnitines (LCACs), and the reduced expression of β-FAO relevant genes (Carnitine palmitoyltrans-ferase (CPT)1, CPT2 and Long-chain acyl-CoA dehydrogenase (LCAD)), indicating the disruption of β-FAO. As direct peroxisome proliferator-activated receptor a (PPARα)- regulated genes, CPT1A, CPT2 and LCAD were up-regulated after treatment with PPARα agonist, fenofibrate (Feno), indicating the improvement of β-FAO. Feno significantly ameliorated the accumulation of various lipids in the plasma of VPA-induced hepatotoxic mice by activating PPARα, significantly reduced the plasma ACs concentration, and attenuated VPA-induced hepatic steatosis. Enhanced oxidative stress and induced by VPA exposure were significantly recovered using Feno treatment. In conclusion, this study indicates VPA-induced β-FAO disruption might lead to liver injury, and a significant Feno protective effect against VPA -induced hepatotoxicity through reversing fatty acid metabolism.

Expanded newborn screening for inherited metabolic disorders by tandem mass spectrometry in a northern Chinese population

Tandem mass spectrometry (MS/MS) has been developed as one of the most important diagnostic platforms for the early detection and screening of inherited metabolic disorders (IMDs). To determine the disease spectrum and genetic characteristics of IMDs in Suqian city of Jiangsu province in the northern Chinese population, dried blood spots from 2,04,604 newborns, were assessed for IMDs by MS/MS from January 2016 to November 2020. Suspected positive patients were diagnosed through next-generation sequencing (NGS) and validated by Sanger sequencing. One hundred patients with IMDs were diagnosed, resulting in an overall incidence of 1/2,046, of which 56 (1/3,653), 22 (1/9,300), and 22 (1/9,300) were confirmed amino acids disorders (AAs), organic acids disorders (OAs), fatty acid oxidation disorders (FAODs) positive cases, respectively. The highest incidence of IMDs is phenylalanine hydroxylase deficiency (PAHD) (45 cases), with a total incidence of 1:4,546. Hot spot mutations in phenylalanine hydroxylase (PAH)-related genes are c.158G > A (24.44%), c.728G > A (16.67%), c.611A > G (7.78%), and c.331C>T (7.78%). The related hot spot mutation of the MMACHC gene is c.609G > A (45.45%). Short-chain acyl-CoA dehydrogenase deficiency (SCAD)-related ACADS gene hotspot mutations are c.164C > T (33.33%) and c.1031A > G (33.33%). Our work indicated that the overall incidence of IMDs is high, and the mutations in PAH, ACADS, and MMACHC genes are the leading causes of IMDs in Suqian city. The incidence of AAs in Suqian city is higher than in other Chinese areas. The disease spectrum and genetic backgrounds were elucidated, contributing to the treatment and prenatal genetic counseling of these disorders in this region.

Valproic Acid Serum Concentration and Incidence of Toxicity in Pediatric Patients

In certain pediatric patients on valproic acid, therapeutic range (50-100 μg/mL) is maximized or exceeded to achieve better seizure control. This study compared incidence of common valproic acid adverse effects (thrombocytopenia, hepatotoxicity, and hyperammonemia) across maintenance concentration and age group. One hundred twenty-four children on maintenance valproic acid between January 2013 and January 2021 were eligible for inclusion. Fifty-six patients were maintained in concentration range 50 to 80 μg/mL, an additional 44 between 80 and 100 μg/mL and 24 between 100 and 120 μg/mL. Forty-one patients were prepubescent, 57 pubescent, and 26 postpubescent. There were no statistically significant differences observed in the primary endpoint of thrombocytopenia across serum concentration range (P = .093) or age group (P = .628). No significant differences in hepatic dysfunction (P = .099) or hyperammonemia (P = .548) were observed in serum concentration groups. Similarly, age group analysis observed no difference in hepatic dysfunction (P = .615) or hyperammonemia (P = .369). Serum valproic acid levels >100 μg/mL can be considered in select pediatric patients based on this study.

L-Carnitine and Acylcarnitines: Mitochondrial Biomarkers for Precision Medicine

Biomarker discovery and implementation are at the forefront of the precision medicine movement. Modern advances in the field of metabolomics afford the opportunity to readily identify new metabolite biomarkers across a wide array of disciplines. Many of the metabolites are derived from or directly reflective of mitochondrial metabolism. L-carnitine and acylcarnitines are established mitochondrial biomarkers used to screen neonates for a series of genetic disorders affecting fatty acid oxidation, known as the inborn errors of metabolism. However, L-carnitine and acylcarnitines are not routinely measured beyond this screening, despite the growing evidence that shows their clinical utility outside of these disorders. Measurements of the carnitine pool have been used to identify the disease and prognosticate mortality among disorders such as diabetes, sepsis, cancer, and heart failure, as well as identify subjects experiencing adverse drug reactions from various medications like valproic acid, clofazimine, zidovudine, cisplatin, propofol, and cyclosporine. The aim of this review is to collect and interpret the literature evidence supporting the clinical biomarker application of L-carnitine and acylcarnitines. Further study of these metabolites could ultimately provide mechanistic insights that guide therapeutic decisions and elucidate new pharmacologic targets.

Mitochondrial Dysfunction in Kidney Disease and Uremic Sarcopenia

Recently, there has been an increased focus on the influences of mitochondrial dysfunction on various pathologies. Mitochondria are major intracellular organelles with a variety of critical roles, such as adenosine triphosphate production, metabolic modulation, generation of reactive oxygen species, maintenance of intracellular calcium homeostasis, and the regulation of apoptosis. Moreover, mitochondria are attracting attention as a therapeutic target in several diseases. Additionally, a lot of existing agents have been found to have pharmacological effects on mitochondria. This review provides an overview of the mitochondrial change in the kidney and skeletal muscle, which is often complicated with sarcopenia and chronic kidney disease (CKD). Furthermore, the pharmacological effects of therapeutics for CKD on mitochondria are explored.

Valproate inhibits mitochondrial bioenergetics and increases glycolysis in Saccharomyces cerevisiae

The widely used mood stabilizer valproate (VPA) causes perturbation of energy metabolism, which is implicated in both the therapeutic mechanism of action of the drug as well as drug toxicity. To gain insight into these mechanisms, we determined the effects of VPA on energy metabolism in yeast. VPA treatment increased levels of glycolytic intermediates, increased expression of glycolysis genes, and increased ethanol production. Increased glycolysis was likely a response to perturbation of mitochondrial function, as reflected in decreased membrane potential and oxygen consumption. Interestingly, yeast, mouse liver, and isolated bovine cytochrome c oxidase were directly inhibited by the drug, while activities of other oxidative phosphorylation complexes (III and V) were not affected. These findings have implications for mechanisms of therapeutic action and toxicity.

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

BACKGROUND

Valproic acid (VPA) as a widely used primary medication in the treatment of epilepsy is associated with reversible or irreversible hepatotoxicity. Long-term VPA therapy is also related to increased risk for the development of non-alcoholic fatty liver disease (NAFLD). In this review, metabolic elimination pathways of VPA in the liver and underlying mechanisms of VPA-induced hepatotoxicity are discussed.

METHODS

We searched in PubMed for manuscripts published in English, combining terms such as "Valproic acid", "hepatotoxicity", "liver injury", and "mechanisms". The data of screened papers were analyzed and summarized.

RESULTS

The formation of VPA reactive metabolites, inhibition of fatty acid β-oxidation, excessive oxidative stress and genetic variants of some enzymes, such as CPS1, POLG, GSTs, SOD2, UGTs and CYPs genes, have been reported to be associated with VPA hepatotoxicity. Furthermore, carnitine supplementation and antioxidants administration proved to be positive treatment strategies for VPA-induced hepatotoxicity.

CONCLUSION

Therapeutic drug monitoring (TDM) and routine liver biochemistry monitoring during VPA-therapy, as well as genotype screening for certain patients before VPA administration, could improve the safety profile of this antiepileptic drug.

The neural stem cell/carnitine malnutrition hypothesis: new prospects for effective reduction of autism risk?

Autism spectrum disorders (ASDs) are developmental neuropsychiatric disorders with heterogeneous etiologies. As the incidence of these disorders is rising, such disorders represent a major human health problem with escalating social cost. Although recent years witnessed advances in our understanding of the genetic basis of some dysmorphic ASDs, little progress has been made in translating the improved understanding into effective strategies for ASD management or minimization of general ASD risk. Here we explore the idea, described in terms of the neural stem cell (NSC)/carnitine malnutrition hypothesis, that an unappreciated risk factor for ASD is diminished capacity for carnitine-dependent long-chain fatty acid β-oxidation in neural stem cells of the developing mammalian brain. The basic premise is that fetal carnitine status is a significant metabolic component in determining NSC vulnerability to derangements in their self-renewal program and, therefore, to fetal ASD risk. As fetal carnitine status exhibits a genetic component that relates to de novo carnitine biosynthesis and is sensitive to environmental and behavioral factors that affect maternal circulating carnitine levels, to which the fetus is exposed, we propose that reduced carnitine availability during gestation is a common risk factor that lurks beneath the genetically complex ASD horizon. One major prediction of the NSC/carnitine malnutrition hypothesis is that a significant component of ASD risk might be effectively managed from a public policy perspective by implementing a carnitine surveillance and dietary supplementation strategy for women planning pregnancies and for women in their first trimester of pregnancy. We argue that this prediction deserves serious clinical interrogation.

Valproic acid induced acute liver injury resulting in hepatic encephalopathy- a case report and literature review

Valproic acid (VPA) is a commonly used agent in the management of seizures and psychiatric disorders. Hyperammonemia is a common complication of VPA with 27.8% of patients having elevated levels – that is unrelated to hepatotoxicity and normal transaminases. Common side effects include obesity, insulin resistance, metabolic disorder and severe forms of hepatotoxicity. Other rare and idiosyncratic reactions have been reported, one of which is presented in our case. A 27-year old patient presented with hyperammonemia and encephalopathy as a consequence of idiosyncratic VPA reaction causing drug-induced liver injury (DILI) with severely elevated transaminases. DILI is commonly overlooked when investigating encephalopathy in the setting of VPA. Physicians should consider DILI in the context of hyperammonemia and transaminitis.

Mitochondrial dysfunction as a mechanism of drug-induced hepatotoxicity: current understanding and future perspectives

Mitochondria are critical cellular organelles for energy generation and are now also recognized as playing important roles in cellular signaling. Their central role in energy metabolism, as well as their high abundance in hepatocytes, make them important targets for drug-induced hepatotoxicity. This review summarizes the current mechanistic understanding of the role of mitochondria in drug-induced hepatotoxicity caused by acetaminophen, diclofenac, anti-tuberculosis drugs such as rifampin and isoniazid, anti-epileptic drugs such as valproic acid and constituents of herbal supplements such as pyrrolizidine alkaloids. The utilization of circulating mitochondrial-specific biomarkers in understanding mechanisms of toxicity in humans will also be examined. In summary, it is well-established that mitochondria are central to acetaminophen-induced cell death. However, the most promising areas for clinically useful therapeutic interventions after acetaminophen toxicity may involve the promotion of adaptive responses and repair processes including mitophagy and mitochondrial biogenesis, In contrast, the limited understanding of the role of mitochondria in various aspects of hepatotoxicity by most other drugs and herbs requires more detailed mechanistic investigations in both animals and humans. Development of clinically relevant animal models and more translational studies using mechanistic biomarkers are critical for progress in this area.

Relevance for patients:This review focuses on the role of mitochondrial dysfunction in liver injury mechanisms of clinically important drugs like acetaminophen, diclofenac, rifampicin, isoniazid, amiodarone and others. A better understanding ofthe mechanisms in animal models and their translation to patients will be critical for the identification of new therapeutic targets.

Levocarnitine for valproate-induced hyperammonemia in the psychiatric setting: A case series and literature review

Introduction

Hyperammonemia is a potential adverse effect of valproic acid (VPA) therapy, which is often asymptomatic but can lead to severe, life-threatening encephalopathy. Carnitine deficiency due to VPA is the proposed mechanism for hyperammonemia and the development of VPA-induced hyperammonemic encephalopathy (VHE). Levocarnitine, the active form of carnitine, has been suggested for treatment and prevention of VHE.

Methods

Data was collected by chart review of 3 patients who received oral levocarnitine supplementation in the psychiatric setting for VPA-induced hyperammonemia. Review of the literature was performed through June 2017 using the following PubMed search terms: valproate, valproic acid, hyperammonemia, altered mental status, encephalopathy, and levocarnitine. Articles were included if they described use of levocarnitine in VPA-treated patients with psychiatric disorders.

Results

One patient developed encephalopathy with resolution of symptoms after VPA discontinuation. Valproic acid was restarted with the addition of levocarnitine to prevent VHE reoccurrence. In the other 2 cases, levocarnitine was started prophylactically in patients who developed hyperammonemia without emergence of any clinical symptoms. Ammonia levels were reduced to normal in all cases, and no symptoms consistent with encephalopathy were reported. The literature search identified 6 additional cases with 5 of 6 reports supporting use of levocarnitine for decreased ammonia levels as well as an observational trial.

Discussion

This literature review and case series illustrates successful use of levocarnitine supplementation for reduction of ammonia levels in the setting of VPA-induced hyperammonemia among patients with psychiatric disorders. However, clinical significance of ammonia reduction in asymptomatic patients is difficult to determine.

Valproate semisodium-induced encephalopathy: diet and polypharmacy interactions

Despite extensive use of valproate in neurology and psychiatry, valproate-induced encephalopathy is a rarely reported complication. Although initially reported in the paediatric population, case reports are growing in the adult population.

Clinicians need to be aware of this potentially life-threatening complication. We report a case in a 37-year-old woman with bipolar I disorder with previously uncomplicated valproate use, who developed encephalopathy when valproate was restarted a few years later. The patient has provided consent for publication.

Sudden valproate-induced hyperammonemia managed with L-carnitine in a medically healthy bipolar patient: Essential review of the literature and case report

RATIONALE

Valproic Acid is a commonly used psychiatric drug primarily used as a mood stabilizer. Mild hyperammonemia is a Valproic Acid common adverse effect. This report presents an example of treated hyperammonemia on Valproic acid therapy managed with L-carnitine administration in BD patients characterized by sudden vulnerability.

PATIENT CONCERNS

We report the case of a 29-year-old man suffering from bipolar disorder (BD) and substance use disorder who exhibited sudden altered mental status upon admittance to the inpatient unit. The patient was started on Valproic acid with no improvement.

DIAGNOSES

The patient had remarkably high ammonia levels (594 μg/dL) without hepatic insufficiency, likely due to his valproate treatment.

INTERVENTIONS

The patient was administered lactulose, intravenous hydration, and i.v. levocarnitine supplementation 4.5 g/day.

OUTCOMES

The administration leads to reduction of ammonia levels to 99 μg/dL within 12 hours upon initiation of carnitine therapy and progressive restore of his mental status within 24 hours.

LESSONS

Resolution of hyperammonemia caused by Valproic acid therapy may be enhanced with the administration of L-carnitine. An interesting aspect of this case was how rapidly the patient responded to the carnitine therapy.

Brain carnitine deficiency causes nonsyndromic autism with an extreme male bias: A hypothesis

Could 10-20% of autism be prevented? We hypothesize that nonsyndromic or "essential" autism involves extreme male bias in infants who are genetically normal, but they develop deficiency of carnitine and perhaps other nutrients in the brain causing autism that may be amenable to early reversal and prevention. That brain carnitine deficiency might cause autism is suggested by reports of severe carnitine deficiency in autism and by evidence that TMLHE deficiency - a defect in carnitine biosynthesis - is a risk factor for autism. A gene on the X chromosome (SLC6A14) likely escapes random X-inactivation (a mixed epigenetic and genetic regulation) and could limit carnitine transport across the blood-brain barrier in boys compared to girls. A mixed, common gene variant-environment hypothesis is proposed with diet, minor illnesses, microbiome, and drugs as possible risk modifiers. The hypothesis can be tested using animal models and by a trial of carnitine supplementation in siblings of probands. Perhaps the lack of any Recommended Dietary Allowance for carnitine in infants should be reviewed. Also see the video abstract here: https://youtu.be/BuRH_jSjX5Y.

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.

Medicinal-Induced Behavior Disorders

Commonly used medications can have neuropsychiatric and behavioral effects that may be idiosyncratic or metabolic in nature, or a function of interactions with other drugs, toxicity, or withdrawal. This article explores an approach to the patient with central nervous system toxicity, depending on presentation of sedation versus agitation and accompanying physical signs and symptoms. The effects of antihypertensives, opioids, antibiotics, antiepileptic agents, steroids, Parkinson's disease medications, antipsychotics, medications for human immunodeficiency virus infection, cancer chemotherapeutics, and immunotherapies are discussed. A look at the prevalence of adverse reactions to medications and the errors underlying such occurrences is included.

A Review of Valproic Acid–Induced Carnitine Deficiency and Replacement

Objective:

To review valproic acid–induced carnitine deficiency and subsequent carnitine replacement.

Data Sources:

Articles indexed in MEDLINE from 1966 to May 2000, as well as other published works and standard references.

Data Extraction:

Studies investigating clinical epidemiologic and pathologic evidence of the role of valproic acid–induced carnitine deficiency and double-blind clinical trials evaluating the effectiveness of carnitine replacement with anticonvulsant therapy are presented.

Data Synthesis:

Clinical epidemiologic and pathologic studies provide evidence of valproic acid–induced carnitine deficiency. There is no clear consensus for providing carnitine supplementation to all patients taking valproic acid — It is only indicated for children with valproic acid–induced hepatotoxicity and those with valproic acid overdose.

Conclusions:

There is evidence that implicates valproic acid in inducing carnitine deficiency. Patients should be evaluated clinically for signs and symptoms of carnitine deficiency before beginning supplementation. Currently, carnitine supplementation should be reserved for children with valproic acid–induced hepatotoxicity and valproic acid overdose until the results of further clinical studies are available.

Encephalopathy and Hyperammonemia Associated with Valproic Acid

Objective:

To discuss the case of a patient who experienced an altered level of consciousness secondary to hyperammonemia associated with valproic acid who had normal drug concentrations and liver function tests.

Case Summary:

A 48-year-old man with a history of seizure disorder treated with valproic acid presented with an altered level of consciousness. An extensive workup revealed only an increased ammonia level. His medications were withheld. Within 24 hours, the ammonia level returned to normal and he was able to be aroused. His antiseizure medication was changed to gabapentin. All of his chronic medications, other than valproic acid, were restarted. The patient has had no further increases in ammonia levels or episodes of altered mental status.

Discussion:

Encephalopathy due to hyperammonemia is generally due to severe liver dysfunction. In our case, however, hyperammonemia occurred in a patient with normal liver function who was also taking valproic acid. An objective causality assessment revealed that the adverse drug event was probably related to valproic acid. A review of the literature indicates that the increased ammonia levels were probably secondary to the effect of valproic acid on the kidneys or the liver. Withdrawal of the offending agent resulted in normalization of ammonia levels and resolution of encephalopathy.

Conclusions:

With a widening of its clinical indications, the use of valproic acid has been increasing. Even though valproic acid concentrations may be therapeutic/nontoxic and liver function tests normal, practitioners are encouraged to check the ammonia level. Hyperammonemia, once recognized, is easily treated.

Two cases of valproic acid poisoning treated with l-carnitine

Two cases of acute valproic acid poisoning with central nervous system depression and raised ammonia level without hepatotoxicity were reported. They were treated successfully with the use of the antidotes: l-carnitine and other supportive measures. Clinical manifestation and progress was described, and discussion is focused on the use of l-carnitine in valproic acid–induced hyperammonemia, from its mechanism to the clinical experiences in the literature. Based on the favorable response of our two cases and the literature review, we recommend the administration of intravenous l-carnitine in patients of valproic acid overdose with hyperammonemia or valproic acid–induced hyperammonemic encephalopathy and hepatotoxicity at a dose of 50 mg/kg every 8 h for the first initial 24 h with further individual assessment.

Valproic Acid—Induced Hyperammonemia in a Patient With Schizoaffective Disorder

Valproic acid is used in psychiatry as a mood stabilizer and can be very effective in reducing symptoms of agitation. Valproic acid may cause hyperammonemia through carnitine deficiency created by its inhibition of mitochondrial enzymes in the urea cycle. Clinical presentation of hyperammonemia usually involves lethargy and somnolence, which may also be noted with therapeutic serum concentration during valproic acid therapy. The diagnosis of hyperammonemia is often overlooked due to a clinical presentation that may include normal liver enzyme tests and serum valproate levels that are within the therapeutic range. Treatment modalities may include discontinuation of valproic acid therapy, lactulose, naloxone, and hemodialysis. Carnitine supplementation, for both prevention and acute treatment of hyperammonemia, has been anecdotally reported and may be considered. This article illustrates a case of an adult male with schizoaffective disorder who was treated with valproic acid and subsequently developed hyperammonemia, despite therapeutic valproic acid serum levels and normal liver enzyme tests. Possible causes of hyperammonemia and current treatment options will be described, as well as suggestions for monitoring for this adverse event in the clinical setting.

Levocarnitine induced seizures in patients on valproic acid: A negative systematic review

OBJECTIVE

Warnings of L-carnitine induced seizures are recorded on product monographs and pharmacy databases, without any referenced literature. This medication can potentially improve the hospital course in those patients with valproic acid (VPA) induced hyperammonemic encephalopathy, but may be withheld because of this warning. The goal was to perform an extensive systematic review of the literature to document the incidence of levocarnitine (L-carnitine) induced seizures in those patients on VPA therapy.

METHODS

Articles from MEDLINE, BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library, the International Clinical Trials Registry Platform, clinicaltrials.gov (inception to June 2015), and reference lists of relevant articles were searched. The strength of evidence was to be adjudicated using both the Oxford and GRADE methodology by two independent reviewers.

RESULTS

We failed to identify a single study implicating L-carnitine supplementation leading to seizures in any patient on VPA therapy. This contradicts all quoted, but unsubstantiated, concerns on product monographs and pharmacy databases related to seizure induction/propagation with L-carnitine supplementation.

CONCLUSION

There is no literature available to support claims of L-carnitine induced seizures during supplementation in patients on VPA therapy for seizures. This contradicts quoted, but not referenced, concerns on the product monograph. In patients suffering from hypocarnitinemia or hyperammonemic encephalopathy while on VPA, L-carnitine supplementation can be considered knowing there is no data to support seizure propagation or induction with administration of this supplement.

Valproate Induced Hyperammonemic Delirium

Sodium valproate induced hyperammonaemic delirium with normal liver function tests is a relatively uncommon adverse effect. It may be mistaken for psychosis or worsening of mania leading to wrong diagnosis and improper management. Plasma ammonia levels should be monitored in all patients developing altered mental status after receiving valproate therapy. This is a case series of hyperammonaemic delirium due to valproate reported to the Department of Pharmacology from Department of Psychiatry over a period of one year.

Placebo-controlled trial of valproic Acid versus risperidone in children 3-7 years of age with bipolar I disorder

OBJECTIVE

The objective of this study was to determine the efficacy and safety of valproic acid versus risperidone in children, 3-7 years of age, with bipolar I disorder (BPD), during a mixed or manic episode.

METHODS

Forty-six children with Diagnostic and Statistical Manual of Mental Disorders. 4th ed., Text Revision (DSM-IV-TR) diagnosis of bipolar disorder, manic, hypomanic, or mixed episode, were recruited over a 6 year period from two academic outpatient programs for a double-blinded, placebo-controlled trial in which subjects were randomized in a 2:2:1 ratio to risperidone solution, valproic acid, or placebo.

RESULTS

After 6 weeks of treatment, the least-mean Young Mania Rating Scale (YMRS) total scores change, adjusted for baseline YMRS scores, from baseline by treatment group was: Valproic acid 10.0±2.46 (p=0.50); risperidone 18.82±1.55 (p=0.008); and placebo 4.29±3.56 (F=3.93, p=0.02). The mixed models for repeated measure (MMRM) analysis found a significant difference for risperidone-treated subjects versus placebo treated subjects (p=0.008) but not for valproic acid-treated subjects versus placebo-treated subjects (p=0.50). Treatment with risperidone over 6 weeks led to increased prolactin levels, liver functions, metabolic measures, and weight/body mass index (BMI). Treatment with valproic acid led to increases in weight/BMI and decreases in total red blood cells (RBC), hemoglobin, and hematocrit.

CONCLUSIONS

In this small sample of preschool children with BPD, risperidone demonstrated clear efficacy versus placebo, whereas valproic acid did not. The laboratory and weight findings suggest that younger children with BPD are more sensitive to the effects of both of these psychotropics, and that, therefore, frequent laboratory and weight monitoring are warranted.

Hyperammonemic Encephalopathy due to Valproic Acid and Topiramate Interaction

Valproic acid-induced hyperammonemic encephalopathy is a rare yet serious adverse drug reaction. Medication interactions such a valproic acid and topiramate can precipitate an event. We present the case of a 52-year-old female that presented with acute mental status change and hypersomnolence due to hyperammonemia caused by a valproic acid derivative. The patient improved after withdrawal of the offending medications and treatment with lactulose. Clinicians should remain hypervigilant in monitoring for valproic acid-induced hyperammonemic encephalopathy and risk factors such as polypharmacy.

Valproate-induced hyperammonemia in juvenile ceroid lipofuscinosis (Batten disease)

PURPOSE

Valproate-induced hyperammonemia (VHA) and hyperammonemic encephalopathy (VHE) are well-known complications of valproate (VPA) treatment. Currently recognised risk factors for VHE include a high VPA dosage, the need for polytherapy and long duration of treatment. Despite the severe nature of the epilepsy, presence of concomitant psychiatric manifestations, and frequent need for poly-pharmacy associated with juvenile ceroid lipofuscinosis (JNCL, Batten disease) neither this disorder nor other subtypes of neuronal ceroid lipofuscinosis have previously been identified as risk factors for VHA/VHE. The aim of the present publication is to describe four cases with VHE in a well-defined Danish population of JNCL.

METHOD

An examination of medical records of all 35 patients with JNCL in Denmark was conducted and revealed fourteen patients treated with VPA.

RESULTS

Four patients treated with VPA developed VHE. All patients were prescribed VPA in standard dosages, had normal plasma concentrations of VPA and received antiepileptic drug (AED) polytherapy. Symptoms occurred shortly after commencement or increase in dose of VPA, and were quickly reversible upon discontinuation of VPA. Carnitine supplement was administrated in two patients, which resulted in resolution of symptoms and normalized ammonium levels.

CONCLUSION

Patients with JNCL are in great risk of developing VHA and VHE due to a high rate of polytherapy. Furthermore, studies have shown that carnitine level can be depressed in JNCL, which may increase the risk of VHA and VHE. We recommend that increased attention should be given to these patients.

Nutrition as medical therapy

Recent data support the use of nutritional agents for use as targeted medical therapy. This article reviews some of the pharmacologic roles that parenteral nutritional ingredients (selenium, lipid emulsion, insulin, and levocarnitine) can play in the setting of critical illness.

Lacosamide-induced valproic acid toxicity

Valproic acid is commonly used in the treatment of both focal and generalized epilepsies and is often well tolerated. There are many reported cases of hyperammonemic encephalopathy and other well-known side effects reported during use of valproic acid either alone or in combination with other antiepileptics. This case report demonstrates valproic acid toxicity in the presence of lacosamide, which has not previously been reported. Full recovery occurred after withdrawal of both valproic acid and lacosamide.

Valproate-induced hyperammonemic encephalopathy: a brief review

BACKGROUND

This brief review presents a comprehensive evaluation of valproate-induced encephalopathy (VHE) and also discusses potential mechanisms of the condition.

SCOPE

Sodium valproate (VPA) is an effective antiepileptic drug used in neurology as well as in psychiatry, in adults and children. VHE requires early diagnosis and management. Focused research efforts in understanding the condition will help decrease its incidence. Delay in recognition of VHE can result in the development of potentially life-threatening complications.

FINDINGS

Management options are described. Since VPA frequently causes a modest rise in plasma ammonia levels which is asymptomatic, it is important to recognize the symptoms of VHE promptly and to correlate them with the plasma ammonia levels.

CONCLUSIONS

Although there are several case reports on VHE, this review is a comprehensive evaluation of its causes and potential mechanisms. Rapid diagnosis and management will help in reducing VHE-related morbidity.

Valproate-induced hyperammonemic encephalopathy: an update on risk factors, clinical correlates and management

INTRODUCTION

Valproate (VPA)-induced hyperammonemic encephalopathy (VHE) is a serious drug-related adverse effect characterized by lethargy, vomiting, cognitive slowing, focal neurological deficits and decreased levels of consciousness ranging from drowsiness to coma.

METHODS

We present a case series (n=5) and also review previous cases of VHE (n=30) in psychiatric patients to provide an update on risk factors, clinical correlates and management of VHE.

RESULTS

To our knowledge, there are 30 (16 female, 14 male) previously reported VHE cases in psychiatric patients. Risk factors for VHE include VPA-drug interactions, mental retardation, carnitine deficiency and presence of urea cycle disorders. Length of VPA treatment, VPA dosage, serum VPA levels and serum ammonia levels do not appear to correlate with onset or severity of VHE.VPA discontinuation is the primary treatment of VHE, although, l-carnitine, lactulose and neomycin have been used adjunctively in some patients.

CONCLUSION

Clinicians should consider VHE in patients taking VPA who present with lethargy, gastrointestinal symptoms, confusion and decreased levels of drowsiness. VPA discontinuation is currently the mainstay of treatment for VHE, although more research is warranted to delineate the underlying risk factors for VHE and consolidate treatment modalities for this potentially life-threatening drug adverse effect.

Risk factors for hyperammonemia associated with valproic acid therapy in adult epilepsy patients

Hyperammonemia is one of the side effects of treatment with valproic acid (VPA), but the risk factors and mechanisms involved remain obscure. This study analyzed the risk factors for hyperammonemia associated with VPA therapy in adult epilepsy patients. A retrospective analysis of 2724 Japanese patients (1217 males and 1507 females aged from 16 to 76years) treated with VPA between January 2006 and December 2010 were analyzed. The ammonia level increased markedly in a VPA dose-dependent manner, and was significantly elevated in patients who also used hepatic enzyme inducers such as phenytoin (PHT), phenobarbital (PB), carbamazepine (CBZ), and combinations of these drugs. When a blood ammonia level exceeding 200μg/dl was defined as hyperammonemia, the risk factors for hyperammonemia according to multiple regression analysis were a VPA dose >20mg/kg/day (odds ratio (OR): 4.1; 95% confidence interval (CI): 1.6-10.8) and concomitant use of PHT (OR: 11.0; 95% CI: 3.1-38.7), concomitant PB (OR: 4.3; 95% CI: 1.0-17.9), concomitant CBZ (OR: 2.8; 95% CI: 0.6-11.9), and concomitant topiramate (OR: 2.8; 95% CI: 1.2-6.5). Regimens containing multiple inducers were associated with an increased risk of hyperammonemia. Identification of risk factors for hyperammonemia associated with VPA therapy can help to minimize side effects during its clinical use.

Hyperammonemia in review: pathophysiology, diagnosis, and treatment

Ammonia is an important source of nitrogen and is required for amino acid synthesis. It is also necessary for normal acid-base balance. When present in high concentrations, ammonia is toxic. Endogenous ammonia intoxication can occur when there is impaired capacity of the body to excrete nitrogenous waste, as seen with congenital enzymatic deficiencies. A variety of environmental causes and medications may also lead to ammonia toxicity. Hyperammonemia refers to a clinical condition associated with elevated ammonia levels manifested by a variety of symptoms and signs, including significant central nervous system (CNS) abnormalities. Appropriate and timely management requires a solid understanding of the fundamental pathophysiology, differential diagnosis, and treatment approaches available. The following review discusses the etiology, pathogenesis, differential diagnosis, and treatment of hyperammonemia.

Valproic acid-associated acute liver failure in children: case report and analysis of liver transplantation outcomes in the United States

OBJECTIVE

To determine whether valproic acid (VPA)-associated acute liver failure (ALF; VPA-ALF) explains the poor outcomes after liver transplantation (LT) in children.

STUDY DESIGN

Organ Procurement and Transplantation Network data of pediatric patients who underwent LT for VPA-ALF and ALF caused by other drugs (non-VPA-drug-induced acute liver failure [DIALF]) were analyzed. Pre- and post-transplant variables and post-LT survival were compared between VPA-ALF and non-VPA-DIALF.

RESULTS

Seventeen children were transplanted for VPA-ALF. Of the 17 children, 82% died within 1 year of LT. Pre- and post-transplant parameters of VPA versus non-VPA-DIALF were comparable with two exceptions. The median alanine aminotransferase level at transplant was remarkably lower in VPA-ALF compared with non-VPA-DIALF (45 versus 1179 IU/L, P = .004). One-year survival probability was worse in VPA-ALF than non-VPA-DIALF (20% versus 69%, P < .0001). Median post-LT survival time for VPA-ALF was 2.8 months.

CONCLUSION

Children who underwent LT for VPA-ALF had a significantly lower survival probability than children with non-VPA-DIALF. Current data suggest that VPA-ALF in children represents an "unmasking" of mitochondrial disease. VPA-ALF should be a contraindication for LT, even in the absence of a documented mitochondrial disease.

[Relationship between plasma concentrations of valproic acid and hepatotoxicity in patients receiving high doses]

INTRODUCTION

Valproic acid (VPA) is an anticonvulsivant drug widely prescribed in the treatment of many forms of generalized epilepsy. In literature, the incidence of liver damage induced by AVP is 0.01%. It is potentialized by the combination therapy (phenobarbital, carbamazepine). Severe hepatotoxicity is rare and appears to be independent of dose and to cause a high mortality.

METHODS

The aim of our study was to evaluate the relationship between plasma concentrations of AVP and the occurrence of side effects especially hepatotoxicity in patients receiving high doses of AVP.

RESULTS

In this period, 425 plasmatic AVP monitoring were carried out in our laboratory. From 128 patients treated by high doses of AVP, only 73 were included in this study. Our work showed that adverse effects in epileptics under high doses of AVP was related to the association of the AVP with other antiepileptic in particular carbamazépine, phenobarbital and benzodiazepines rather than supra-therapeutic plasmatic concentrations of AVP. The association of AVP to major antiepileptics (carbamazépine and or phenobarbital) does not seem to generate an increase in the plasmatic concentration of AVP, which was not associated with a greater risque of adverse effects.

CONCLUSION

Consequently, clinical signs of liver toxicity may be present in AVP concentrations generally considered in the therapeutic range especially when used in high doses and or combined with antiepileptic drugs like phenobarbital or carbamazepine.

The real mechanism of VPA-induced hyperammonemia remains unknown

Valproic acid (VPA) is a well-tolerated and effective agent for the treatment of epilepsy, bipolar disorder, and schizoaffective disorder. Several case reports have indicated that VPA may induce serious symptomatic hyperammonemia. Based on analysis of susceptible patients, several possible mechanisms and risk factors have been proposed to identify the patients at risk. Nevertheless, we report the case of a schizoaffective patient who developed severe hyperammonemia occurring after brief exposure to VPA, despite the absence of any known risk factors. Until now, early recognition of the signs and symptoms of hyperammonemia is crucial to managing this unusual adverse reaction.

Antiepileptic drugs: the old and the new

During the past decade several new antiepileptic drugs (AEDs) have become available, including new formulations of some of the older medications. Understanding the pharmacokinetics of the new AEDs is important because they are primarily used for adjunctive therapy and interactions with other medications can result in significant toxicities. The new-generation AEDs do not cause serious morbidity in overdose, and treatment is primarily supportive. Specific medications should be chosen based on the patient's history and presentation.

Drugs and pharmaceuticals: management of intoxication and antidotes

The treatment of patients poisoned with drugs and pharmaceuticals can be quite challenging. Diverse exposure circumstances, varied clinical presentations, unique patient-specific factors, and inconsistent diagnostic and therapeutic infrastructure support, coupled with relatively few definitive antidotes, may complicate evaluation and management. The historical approach to poisoned patients (patient arousal, toxin elimination, and toxin identification) has given way to rigorous attention to the fundamental aspects of basic life support--airway management, oxygenation and ventilation, circulatory competence, thermoregulation, and substrate availability. Selected patients may benefit from methods to alter toxin pharmacokinetics to minimize systemic, target organ, or tissue compartment exposure (either by decreasing absorption or increasing elimination). These may include syrup of ipecac, orogastric lavage, activated single- or multi-dose charcoal, whole bowel irrigation, endoscopy and surgery, urinary alkalinization, saline diuresis, or extracorporeal methods (hemodialysis, charcoal hemoperfusion, continuous venovenous hemofiltration, and exchange transfusion). Pharmaceutical adjuncts and antidotes may be useful in toxicant-induced hyperthermias. In the context of analgesic, anti-inflammatory, anticholinergic, anticonvulsant, antihyperglycemic, antimicrobial, antineoplastic, cardiovascular, opioid, or sedative-hypnotic agents overdose, N-acetylcysteine, physostigmine, L-carnitine, dextrose, octreotide, pyridoxine, dexrazoxane, leucovorin, glucarpidase, atropine, calcium, digoxin-specific antibody fragments, glucagon, high-dose insulin euglycemia therapy, lipid emulsion, magnesium, sodium bicarbonate, naloxone, and flumazenil are specifically reviewed. In summary, patients generally benefit from aggressive support of vital functions, careful history and physical examination, specific laboratory analyses, a thoughtful consideration of the risks and benefits of decontamination and enhanced elimination, and the use of specific antidotes where warranted. Data supporting antidotes effectiveness vary considerably. Clinicians are encouraged to utilize consultation with regional poison centers or those with toxicology training to assist with diagnosis, management, and administration of antidotes, particularly in unfamiliar cases.

Potential relationships between transaminase abnormality and valproic acid clearance or serum carnitine concentrations in Japanese epileptic patients

This study tested the hypothesis that the determinants of mild liver injury are prerequisites for more severe idiosyncratic hepatotoxicity. This study verified whether the possible risk factors for rare idiosyncratic valproic acid (VPA)-induced hepatotoxicity, VPA clearance and/or serum carnitine concentrations are common to those for a mild elevation in transaminases in VPA-treated patients. VPA clearance was calculated in 172 Japanese patients with epilepsy, using a non-linear mixed-effects regression program. Carnitine concentrations were determined in a subset of 60 patients. The relationships between VPA clearance, carnitine concentration and levels of transaminases and ammonia were evaluated by Pearson's correlation coefficients. The final model of VPA apparent clearance (CL/F) was as follows: CL/F (L h−1) = 0.012 × (BW/40)0.34 × dose0.55 × 0.90gender × 1.32PHT × 1.11CBZ × 1.12PB, where BW = total body weight (kg); gender = 1 if female, 0 if male; PHT/CBZ/PB = 1 if phenytoin, carbamazepine, or phenobarbital, respectively, is coadministrated, otherwise 0. Either a higher VPA clearance or acyl/free carnitine ratio and a lower total and/or free carnitine concentration, but not VPA concentration, were associated with the mild elevation in transaminases or ammonia. These results support the initial hypothesis, while also helping to clarify the mechanism of severe idiosyncratic hepatotoxicity with VPA.

Drug-induced nutrient deficiencies

Good clinical care extends beyond mere diagnosis and treatment of disease to appreciation that nutrient deficiencies can be the price of effective drug therapy. The major risk factors for developing drug-induced nutrient deficiencies are lack of awareness by the prescribing physician and long duration of drug therapy. The field of pharmacogenomics has potential to improve clinical care by detecting patients at risk for complications from drug therapy. Further improvements in patient safety rely on physicians voluntarily reporting serious suspected adverse drug reactions.

Valproic Acid-induced hyperammonemia in the elderly: a review of the literature

Valproic acid and its derivatives are commonly used to treat many psychiatric conditions in the elderly. Hyperammonemia is a less common but important side effect of these drugs. The elderly patient appears highly vulnerable to this side effect of this group of medications. In this paper, we systematically review the published literature for hyperammonemia induced by valproic acid and its derivatives. We describe the three reported cases and review possible treatment strategies for this condition.