Valproic Acid—Induced Hyperammonemia and Thrombocytopenia in an Elderly Woman

Valproic Acid-Associated Hyperammonemia: A Systematic Review

BACKGROUND

Hyperammonemia is an adverse effect that poses clinical uncertainty around valproic acid (VPA) use. The prevalence of symptomatic and asymptomatic hyperammonemia and its relationship to VPA concentration is not well established. There is also no clear guidance regarding its management. This results in variability in the monitoring and treatment of VPA-induced hyperammonemia. To inform clinical practice, this systematic review aims to summarize evidence available around VPA-associated hyperammonemia and its prevalence, clinical outcomes, and management.

METHODS

An electronic search was performed through Ovid MEDLINE, Ovid Embase, Web of Science, and PsycINFO using search terms that identified hyperammonemia in patients receiving VPA. Two reviewers independently performed primary title and abstract screening with a third reviewer resolving conflicting screening results. This process was repeated during the full-text review process.

RESULTS

A total of 240 articles were included. Prevalence of asymptomatic hyperammonemia (5%-73%) was higher than symptomatic hyperammonemia (0.7%-22.2%) and occurred within the therapeutic range of VPA serum concentration. Various risk factors were identified, including concomitant medications, liver injury, and defects in carnitine metabolism. With VPA discontinued, most symptomatic patients returned to baseline mental status with normalized ammonia level. There was insufficient data to support routine monitoring of ammonia level for VPA-associated hyperammonemia.

CONCLUSIONS

Valproic acid-associated hyperammonemia is a common adverse effect that may occur within therapeutic range of VPA. Further studies are required to determine the benefit of routine ammonia level monitoring and to guide the management of VPA-associated hyperammonemia.

Case of significantly delayed divalproex-induced thrombocytopaenia

We describe a 48-year-old male patient on long-term divalproex treatment for bipolar disorder who developed grade II thrombocytopaenia after approximately 18 years of therapy. Abrupt cessation of divalproex led to immediate platelet level reconstitution.

Assessment of oral health status of children with epilepsy: A retrospective cohort study

BACKGROUND

Epileptic children are liable to experience oral health problems either due to the disease itself or medications administered to control the condition.

AIM

We aimed to investigate caries experience, gingival health and oro-facial traumatic injuries in a sample of epileptic Egyptian children.

DESIGN

A retrospective cohort study was conducted from September 2016 to April 2017 using data from medical records in Children Hospital at Ain Shams University. Dental examination was performed for 100 epileptic children and 80 healthy subjects who matched in age, gender, and socio-economic status. Caries experience was measured using the decayed, missing and filled teeth (DMFT or dmft) index and gingival index (GI) of Loe and Sillness was used to determine gingival health status. Oro-facial injuries were assessed using the WHO classification of trauma. Quantitative data were presented as mean, SD, and 95% CI values. Qualitative data were presented as frequencies and percentages and the significance level was set at P ≤ 0.05.

RESULTS

The mean ± SD GI for epileptic children was significantly higher (1.16 ± 0.42) than that of healthy children. (1.01 ± 0.11) Healthy subjects had significantly lower mean dmf index scores 2.2 ± 2.6 compared to epileptic subjects where mean dmf scores were 4.1 ± 2.1. No significant difference, however, was detected between the two groups regarding caries experience in permanent dentition or incidence of oro-facial injuries.

CONCLUSIONS

Epileptic children are highly burdened with gingival problems and liable to develop dental caries especially in primary dentition. Oral traumatic injuries, however, are not common complications if seizure attacks are well controlled.

Reversible Thrombocytopenia after Gabapentin in an HIV-Positive Patient

Gabapentin has become increasingly used in psychiatric practice specifically for anxiety disorders. Even though gabapentin is not approved by the US Food and Drug Administration to treat anxiety, physicians sometimes use it as an alternative to benzodiazepines in patients with a history of substance abuse. Gabapentin is also prescribed when individuals are at risk of thrombocytopenia which is not considered a side effect. Among patients at risk of thrombocytopenia are those positive for human immunodeficiency virus (HIV). Here we present a case of an HIV-positive man who presented for inpatient psychiatric care with severe anxiety and a history of alcohol and benzodiazepine abuse. In this patient, gabapentin worsened thrombocytopenia after repeated exposure to this medication. We suggest caution when considering gabapentin for patients with preexisting low platelet counts, as there seems to be a risk for worsening thrombocytopenia with this antiepileptic in the presence of HIV infection.

Dental care in patients with epilepsy: a survey of 82 patients and their attending dentists and neurologists in southern Germany

INTRODUCTION

The current study assessed the knowledge and attitudes of dentists and neurologists, and of their patients with epilepsy, in the catchment area of an outpatient clinic for epilepsy in southern Germany.

METHODS

One-hundred patients with epilepsy were asked to complete questionnaires about their dental treatment. Attitudes of their attending dentists and neurologists were also assessed.

RESULTS

Patients with epilepsy: The questionnaires were returned by 82% of patients. Of these, 84% regularly (once or twice a year) sought out a dentist, 79% reported their epilepsy to the dentist, 6% were refused treatment by a dentist because of their epilepsy, 10% had already experienced a seizure while at a dental office and 52% wished for more detailed information pretreatment. Dentists: Although 97% treated patients with epilepsy, 21% believed that their equipment was inappropriate for treating a patient experiencing seizures. The majority were not familiar with interactions between antibiotics/analgetics and anti-epileptic drugs. Short-term general anaesthesia was preferred for critical patients by 70% of dentists, 70% recommended dental ceramic for prosthetic reconstruction of anterior teeth and 64% would not recommend use of a removable denture. Neurologists: Sixty-two per cent were asked for advice by their patients, 71% knew about particular risks and interactions between antibiotics/analgetics and anti-epileptic drugs, 8% would stop valproic acid before extensive dental intervention and 92% recommended general anaesthesia in critical patients (uncooperative patients, patients with learning difficulties, and patients with frequent generalised tonic-clonic or complex partial seizures).

DISCUSSION

In general, patients were satisfied with their dental treatment. Regarding the clinician's role, however, dentists need to know more with respect to treating patients with seizures. Beyond that, it would be desirable for neurologists to take more time to answer their patients' questions regarding dental care.

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 hyperammonaemia superimposed upon severe neuropsychiatric lupus: a case report and review of the literature

This paper presents a case of systemic lupus erythematosus (SLE) with neuropsychiatric features, where the outcome was influenced by the development of hyperammonaemia, probably induced by sodium valproate. A case of severe SLE occurring in a 20-year-old Maori girl is described. Her disease had been characterised by neuropsychiatric features for several years, culminating in persistent seizure activity at the time of her final presentation. Her management with anticonvulsants was complicated by the development of intractable hyperammonaemia which contributed to irreversible clinical deterioration. We have reviewed the English literature for reports of valproate-related hyperammonaemia which has often been described in the setting of seizure and mood disorders. This is the first case where it has been reported, superimposed upon severe neuropsychiatric SLE (NP-SLE). The mechanism by which valproate induces hyperammonaemia remains incompletely understood but is likely to relate to the urea cycle. Under normal metabolic conditions, acyl-CoA is transported into the mitochondria via a carnitine transport system. It is then converted to acetyl-CoA via β-oxidation and eventually to N-acetyl glutamate. This pathway can be interrupted by the introduction of sodium valproate, leading to a reduction of free coenzyme A, acetyl-CoA and carnitine, and resulting in the decreased availability of cofactors necessary for the function of the urea cycle. As this is the primary means of ammonia metabolism, serious elevation in serum ammonia levels may occur in patients on this anticonvulsant medication. In this patient with active NP-SLE, the combined autoimmune and metabolic brain insult contributed to a fatal outcome.

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.

Interaction between valproic acid and carbapenem antibiotics

The serum concentration of valproic acid (VPA) in epilepsy patients decreased by the administration of carbapenem antibiotics, such as meropenem, panipenem or imipenem, to a sub-therapeutic level. This review summarized several case reports of this interaction between VPA (1-4 g dose) and carbapenem antibiotics to elucidate the possible mechanisms decreasing VPA concentration by carbapenem antibiotics. Studies to explain the decrease were carried out using rats by the following sites: absorption of VPA in the intestine, glucuronidation in the liver, disposition in blood and renal excretion. In the intestinal absorption site, there are two possible mechanisms: inhibition of the intestinal transporter for VPA absorption by carbapenem antibiotics, and the decrease of beta-glucuronidase supplied from enteric bacteria, which were killed by antibiotics. This is consistent with a view that the decrease of VPA originated from VPA-Glu, relating to entero-hepatic circulation. The second key site is in the liver, because of no decreased in VPA level by carbapenem antibiotics in hepatectomized rats. There are three possible mechanisms in the liver to explain the decreased phenomenon: first, decrease of the UDPGA level by carbapenem antibiotics. UDPGA is a co-factor for UDP-glucuronosyltransferase (UGT)-mediated glucuronidation of VPA. Second, the direct activation of UGT by carbapenem antibiotics. This activation was observed after pre-incubation of human liver microsomes with carbapenem antibiotics. Third, the inhibition of beta-glucuronidase in liver by carbapenem antibiotics and the decreased VPA amount liberated from VPA-Glu. The third site is the distribution of VPA in blood (erythrocytes and plasma). Plasma VPA distributed to erythrocytes by the inhibition of transporters (Mrp4), which efflux VPA from erythrocytes to plasma, by carbapenem antibiotics. The increase of renal excretion of VPA as VPA-Glu depends on the increase of VPA-Glu level by UGT. One or a combination of some factors in these mechanisms might relate to the carbapenem-mediated decrease of the plasma VPA level.

Different clinical manifestations of hyperammonemic encephalopathy

Valproate is an effective anticonvulsant. Although it is usually well tolerated, it has been associated with many neurological, hematopoietic, hepatic, and digestive system side effects. Among these side effects, hyperammonemia without clinical or laboratory evidence of hepatotoxicity is rare and is an important clinical consideration. The aim of this article was to evaluate the reasons for the unexpected symptoms observed in seven patients with epilepsy patients during valproate treatment. We evaluated seven adult patients with localization-related epilepsy who presented with different acute or subacute neurological symptoms related to valproate-induced hyperammonemic encephalopathy. Four of the seven patients had acute onset of confusion, decline in cognitive abilities, and ataxia. Two had subacute clinical symptoms, and the other patient had symptoms similar to those of acute toxicity. These unusual clinical symptoms and similar cases had not been reported in the literature before. Serum ammonia levels were elevated in all seven patients. After discontinuation of valproate, complete clinical improvement was observed within 5-10 days. On the basis of our work, we suggest that the ammonia levels of a patient who has new neurological symptoms and has been taking valproate must be checked. Clinicians should be aware that these clinical symptoms may be related to valproate-induced hyperammonemic encephalopathy. The symptoms have been observed to resolve dramatically after withdrawal of the drug.

Case report: valproic Acid and risperidone treatment leading to development of hyperammonemia and mania

This case report describes two children who developed hyperammonemia together with frank manic behavior during treatment with a combination of valproic acid and risperidone. One child had been maintained on valproic acid for years and risperidone was added. In the second case, valproic acid was introduced to a child who had been treated with risperidone for years. In both cases, discontinuing the valproic acid resulted in normalization of ammonia levels and cessation of the manic behavior. This case report alerts physicians to the importance of obtaining serum ammonia levels in children treated with valproic acid and risperidone who present with manic behavior.

Safety and tolerability of mood-stabilising anticonvulsants in the elderly

The authors review current research on the safety and tolerability of anticonvulsant medications used for individuals over the age of 60 years with affective disorders, agitation and other psychiatric disorders. Three anticonvulsants currently approved in the US for treatment of bipolar affective disorder are reviewed: valproate, lamotrigine and extended-release carbamazepine. The authors discuss the pharmacokinetics, pharmacodynamics, drug-drug interactions and the impact of ageing for each drug. There are few studies of anticonvulsant medications in elderly patients with bipolar disorder or other psychiatric conditions. Therefore, the authors summarise adverse events of greatest prevalence and/or greatest severity based on data derived predominately from studies of geriatric patients with epilepsy and/or other non-psychiatric indications. Guidelines are offered for the safe use of these medications in the elderly, based on research literature.

Acute Hyperammonemic Coma with Chronic Valproic Acid Therapy

OBJECTIVE

To report a case of dose-related hyperammonemic coma without liver failure in a patient receiving chronic valproate therapy.

CASE SUMMARY

A 56-year-old woman with poorly controlled epilepsy, receiving valproate at subtherapeutic levels for 6 years, developed a life-threatening hyperammonemic coma following a moderate dosage increase.

DISCUSSION

Hyperammonemic coma without associated liver failure is an extremely rare complication of valproate therapy, described primarily in patients with inborn errors of metabolism and occurring idiosyncratically during initial stages of therapy. In our case, family history was suggestive of an X-linked disorder, raising the possibility that our patient may have been an asymptomatic carrier of a urea cycle enzyme deficiency unmasked by valproate therapy. To our knowledge, as of October 24, 2005, only one prior case of hyperammonemic coma in the context of chronic valproate monotherapy has been described. Application of the Naranjo probability scale score suggests that a causal relationship between valproic acid and hyperammonemic coma was probable.

CONCLUSIONS

The widespread use of valproic acid emphasizes the need to maintain a high degree of suspicion with respect to this rare but potentially fatal adverse effect at all times, regardless of therapy duration.

Levetiracetam for Mood Stabilization and Maintenance of Seizure Control Following Multiple Treatment Failures

OBJECTIVE

To report the case of a patient who experienced adverse events in succession to antiepileptic medications being used for both antiepileptic and mood-stabilization benefit.

CASE SUMMARY

A 46-year-old white woman developed hyponatremia with carbamazepine, hyperammonemia with divalproex, cognitive impairment with topiramate, and hyponatremia with oxcarbazepine. The patient was stabilized physically and psychiatrically on levetiracetam without any noted adverse events.

DISCUSSION

The adverse events in this report have been associated with the medications in question. The patient's presentation is unique, as she developed adverse events in succession to antiepileptic drugs being used to treat both a seizure disorder and symptoms of mood instability. The Naranjo rankings for the reported adverse events indicated the associations were probable (carbamazepine, divalproex, oxcarbazepine) and possible (topiramate). After repeated incidences of intolerability to these drugs, levetiracetam was initiated and provided both seizure control and mood-stabilizing benefits, which eventually led to hospital discharge.

CONCLUSIONS

Levetiracetam may provide mood-stabilizing qualities through a mechanism that is unique from that of other antiepileptic agents used for their mood-stabilizing properties. There are potential advantages with levetiracetam, as no specific therapeutic drug monitoring parameters need to be followed after its introduction. Additionally, this case emphasizes the importance of therapeutic drug monitoring and frequent assessments to prevent physical and psychiatric adverse reactions.

Hyperammonemia with Valproic Acid: Colonic Ischemia Associated with “Triptan” Use Visual Side Effects with Pegylated Interferon: Alopecia Areata with Infliximab: Adverse Effects Seen with Medications Used for Irritable Bowel Syndrome

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