Comparative study of ethosuximide and sodium valproate in the treatment of typical absence seizures (petit mal)

Ethosuximide, sodium valproate or lamotrigine for absence seizures in children and adolescents

BACKGROUND

This is an updated version of the Cochrane Review previously published in 2019. Absence seizures (AS) are brief epileptic seizures which present in childhood and adolescence. Depending on clinical features and electroencephalogram (EEG) findings they are divided into typical, atypical absences, and absences with special features. Typical absences are characterised by sudden loss of awareness and an EEG typically shows generalised spike wave discharges at three cycles per second. Ethosuximide, valproate and lamotrigine are currently used to treat absence seizures. This review aims to determine the best choice of antiepileptic drug for children and adolescents with AS.

OBJECTIVES

To review the evidence for the effects of ethosuximide, valproate and lamotrigine as treatments for children and adolescents with absence seizures (AS), when compared with placebo or each other.

SEARCH METHODS

For the latest update we searched the Cochrane Register of Studies (CRS Web, 22 September 2020) and MEDLINE (Ovid, 1946 to September 21, 2020). CRS Web includes randomised or quasi-randomised, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), the Cochrane Central Register of Controlled Trials (CENTRAL), and the Specialized Registers of Cochrane Review Groups including Epilepsy. No language restrictions were imposed. In addition, we contacted Sanofi Winthrop, Glaxo Wellcome (now GlaxoSmithKline) and Parke Davis (now Pfizer), manufacturers of sodium valproate, lamotrigine and ethosuximide respectively.

SELECTION CRITERIA

Randomised parallel group monotherapy or add-on trials which include a comparison of any of the following in children or adolescents with AS: ethosuximide, sodium valproate, lamotrigine, or placebo.

DATA COLLECTION AND ANALYSIS

Outcome measures were: 1. proportion of individuals seizure free at one, three, six, 12 and 18 months post randomisation; 2. individuals with a 50% or greater reduction in seizure frequency; 3. normalisation of EEG and/or negative hyperventilation test; and 4. adverse effects. Data were independently extracted by two review authors. Results are presented as risk ratios (RR) with 95% confidence intervals (95% CIs). We used GRADE quality assessment criteria to evaluate the certainty of evidence for the outcomes derived from all included studies.

MAIN RESULTS

On the basis of our selection criteria, we included no new studies in the present review. Eight small trials (total number of participants: 691) were included from the earlier review. Six of them were of poor methodological quality (unclear or high risk of bias) and seven recruited less than 50 participants. There are no placebo-controlled trials for ethosuximide or valproate, and hence, no evidence from randomised controlled trials (RCTs) to support a specific effect on AS for either of these two drugs. Due to the differing methodologies used in the trials comparing ethosuximide, lamotrigine and valproate, we thought it inappropriate to undertake a meta-analysis. One large randomised, parallel double-blind controlled trial comparing ethosuximide, lamotrigine and sodium valproate in 453 children with newly diagnosed childhood absence epilepsy found that at 12 months, seizure freedom was higher in patients taking ethosuximide (70/154, 45%) than in patients taking lamotrigine (31/146, 21%; P < 0.001), with no difference between valproate (64/146, 44%) and ethosuximide (70/154, 45%; P > 0.05). In this study, the frequency of treatment failures due to intolerable adverse events was significantly different among the treatment groups, with the largest proportion of adverse events in the valproic acid group (48/146, 33%) compared to the ethosuximide (38/154, 25%) and the lamotrigine (29/146, 20%) groups (P < 0.037). Overall, this large study demonstrates the superior effectiveness of ethosuximide and valproic acid compared to lamotrigine as initial monotherapy aimed to control seizures without intolerable adverse effects in children with childhood absence epilepsy. This study provided high certainty of the evidence for outcomes for which data were available. However, the certainty of the evidence provided by the other included studies was low, primarily due to risk of bias and imprecise results because of the small sample sizes. Hence, conclusions regarding the efficacy of ethosuximide, valproic acid and lamotrigine derive mostly from this single study.

AUTHORS' CONCLUSIONS

Since the last version of this review was published, we have found no new studies. Hence, the conclusions remain the same as the previous update. With regards to both efficacy and tolerability, ethosuximide represents the optimal initial empirical monotherapy for children and adolescents with AS. However, if absence and generalised tonic-clonic seizures coexist, valproate should be preferred, as ethosuximide is probably inefficacious on tonic-clonic seizures.

Valproic Acid and Epilepsy: From Molecular Mechanisms to Clinical Evidences

After more than a century from its discovery, valproic acid (VPA) still represents one of the most efficient antiepi-leptic drugs (AEDs). Pre and post-synaptic effects of VPA depend on a very broad spectrum of actions, including the regu-lation of ionic currents and the facilitation of GABAergic over glutamatergic transmission. As a result, VPA indirectly mod-ulates neurotransmitter release and strengthens the threshold for seizure activity. However, even though participating to the anticonvulsant action, such mechanisms seem to have minor impact on epileptogenesis. Nonetheless, VPA has been reported to exert anti-epileptogenic effects. Epigenetic mechanisms, including histone deacetylases (HDACs), BDNF and GDNF modulation are pivotal to orientate neurons toward a neuroprotective status and promote dendritic spines organization. From such broad spectrum of actions comes constantly enlarging indications for VPA. It represents a drug of choice in child and adult with epilepsy, with either general or focal seizures, and is a consistent and safe IV option in generalized convulsive sta-tus epilepticus. Moreover, since VPA modulates DNA transcription through HDACs, recent evidences point to its use as an anti-nociceptive in migraine prophylaxis, and, even more interestingly, as a positive modulator of chemotherapy in cancer treatment. Furthermore, VPA-induced neuroprotection is under investigation for benefit in stroke and traumatic brain injury. Hence, VPA has still got its place in epilepsy, and yet deserves attention for its use far beyond neurological diseases. In this review, we aim to highlight, with a translational intent, the molecular basis and the clinical indications of VPA.

Ethosuximide, sodium valproate or lamotrigine for absence seizures in children and adolescents

BACKGROUND

This is an updated version of the Cochrane Review previously published in 2017.Absence seizures (AS) are brief epileptic seizures which present in childhood and adolescence. Depending on clinical features and electroencephalogram (EEG) findings they are divided into typical, atypical absences, and absences with special features. Typical absences are characterised by sudden loss of awareness and an EEG typically shows generalised spike wave discharges at three cycles per second. Ethosuximide, valproate and lamotrigine are currently used to treat absence seizures. This review aims to determine the best choice of antiepileptic drug for children and adolescents with AS.

OBJECTIVES

To review the evidence for the effects of ethosuximide, valproate and lamotrigine as treatments for children and adolescents with absence seizures (AS), when compared with placebo or each other.

SEARCH METHODS

For the latest update we searched the Cochrane Register of Studies (CRS Web, 29 May 2018), which includes the Cochrane Epilepsy Group's Specialized Register and the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (Ovid, 1946 to 29 May 2018), ClinicalTrials.gov (29 May 2018) and the WHO International Clinical Trials Registry Platform (ICTRP, 29 May 2018). Previously we searched Embase (1988 to March 2005) and SCOPUS (1823 to 31 March 2014), but this is no longer necessary because randomised controlled trials (RCTs) and quasi-RCTs in Embase and SCOPUS are now included in CENTRAL. No language restrictions were imposed. In addition, we contacted Sanofi Winthrop, Glaxo Wellcome (now GlaxoSmithKline) and Parke Davis (now Pfizer), manufacturers of sodium valproate, lamotrigine and ethosuximide respectively.

SELECTION CRITERIA

Randomised parallel group monotherapy or add-on trials which include a comparison of any of the following in children or adolescents with AS: ethosuximide, sodium valproate, lamotrigine, or placebo.

DATA COLLECTION AND ANALYSIS

Outcome measures were: (1) proportion of individuals seizure free at one, three, six, 12 and 18 months post randomisation; (2) people with a 50% or greater reduction in seizure frequency; (3) normalisation of EEG and/or negative hyperventilation test; and (4) adverse effects. Data were independently extracted by two review authors. Results are presented as risk ratios (RR) with 95% confidence intervals (95% CIs). We used GRADE quality assessment criteria to evaluate the certainty of evidence derived from all included studies.

MAIN RESULTS

On the basis of our selection criteria, we included no new studies in the present review. Eight small trials (total number of participants: 691) were included from the earlier review. Six of them were of poor methodological quality (unclear or high risk of bias) and seven recruited less than 50 participants. There are no placebo-controlled trials for ethosuximide or valproate, and hence, no evidence from RCTs to support a specific effect on AS for either of these two drugs. Due to the differing methodologies used in the trials comparing ethosuximide, lamotrigine and valproate, we thought it inappropriate to undertake a meta-analysis. One large randomised, parallel double-blind controlled trial comparing ethosuximide, lamotrigine and sodium valproate in 453 children with newly diagnosed childhood absence epilepsy found that at 12 months, the freedom-from-failure rates for ethosuximide and valproic acid were similar and were higher than the rate for lamotrigine. The frequency of treatment failures due to lack of seizure control (P < 0.001) and intolerable adverse events (P < 0.037) was significantly different among the treatment groups, with the largest proportion of lack of seizure control in the lamotrigine cohort, and the largest proportion of adverse events in the valproic acid group. Overall, this large study demonstrates the superior effectiveness of ethosuximide and valproic acid compared to lamotrigine as initial monotherapy aimed to control seizures without intolerable adverse effects in children with childhood absence epilepsy. The risk of bias for this study was low. We rated the overall certainty of the evidence available from the included studies to be moderate or high.

AUTHORS' CONCLUSIONS

Since the last version of this review was published, we have found no new studies. Hence, the conclusions remain the same as the previous update. With regards to both efficacy and tolerability, ethosuximide represents the optimal initial empirical monotherapy for children and adolescents with AS. However, if absence and generalised tonic-clonic seizures coexist, valproate should be preferred, as ethosuximide is probably inefficacious on tonic-clonic seizures.

Comparative efficacy of antiepileptic drugs for patients with generalized epileptic seizures: systematic review and network meta-analyses

Background Valproate is a widely prescribed antiepileptic drug for generalized epilepsies, due to the extensive knowledge on its efficacy since it is on the market for many decades. However, a large number of new antiepileptic medicines was introduced into clinical practice and may be better options for treatment, considering that these medicines differ in terms of efficacy spectrum. Despite extensive research, questions regarding which medicine would constitute the first option for the monotherapy treatment of generalized epilepsy remain. Aim of the Review To compare the relative efficacy of all available antiepileptic drugs in the monotherapy treatment of generalized epileptic seizures; and also to compare all antiepoileptig drugs with valproate, which is the current first-line treatment for generalized epilepsy. Methods A systematic review for randomized controlled clinical trials was performed. Network meta-analyses used Bayesian random effects model. Sensitivity analyses determined the results´ robustness. The relative probability of two efficacy outcomes ("Seizure free" and "Therapeutic inefficacy") to happen for each medcicine was calculated using the Surface Under the Cumulative Ranking Curve. Results Seven papers (1809 patients) studied the efficacy of valproate, lamotrigine, phenytoin, carbamazepine, topiramate, levetiracetam, and phenobarbital in the treatment of generalized tonicclonic, tonic, and clonic seizures. Phenytoin demonstrated to be inferior to valproate in leaving the patient free of these seizures types [OR: 0.50 (95% CrI 0.27, 0.87)]. Lamotrigine (61%) showed the highest probability of presenting the outcome "Seizure free", followed by levetiracetam (47%), topiramate (44%), and valproate (38%) in the treatment of generalized tonic-clonic, tonic, and clonic seizures. Meanwhile, valproate exhibited greater chance of presenting the outcome "Therapeutic inefficacy" (62%). Regarding absence seizures itself, there was no difference in the efficacy of lamotrigine and ethosuximide when compared to valproate. However, the ranking indicates that ethosuximide (52%) and valproate (47%) are both more likely than lamotrigine to keep the patient free of seizures. Conclusions Lamotrigine, levetiracetam, and topiramate are as effective as valproate for treating generalized tonic-clonic, tonic, and clonic seizures. Meanwhile, valproate and ethosuximide are the best options for the treatment of absence seizures promoting better control of seizures, which is the primary goal of pharmacotherapy.

Enhanced interlaminar excitation or reduced superficial layer inhibition in neocortex generates different spike-and-wave-like electrographic events in vitro

Acute in vitro models have revealed a great deal of information about mechanisms underlying many types of epileptiform activity. However, few examples exist that shed light on spike-and-wave (SpW) patterns of pathological activity. SpW are seen in many epilepsy syndromes, both generalized and focal, and manifest across the entire age spectrum. They are heterogeneous in terms of their severity, symptom burden, and apparent anatomical origin (thalamic, neocortical, or both), but any relationship between this heterogeneity and underlying pathology remains elusive. In this study we demonstrate that physiological delta-frequency rhythms act as an effective substrate to permit modeling of SpW of cortical origin and may help to address this issue. For a starting point of delta activity, multiple subtypes of SpW could be modeled computationally and experimentally by either enhancing the magnitude of excitatory synaptic events ascending from neocortical layer 5 to layers 2/3 or selectively modifying superficial layer GABAergic inhibition. The former generated SpW containing multiple field spikes with long interspike intervals, whereas the latter generated SpW with short-interval multiple field spikes. Both types had different laminar origins and each disrupted interlaminar cortical dynamics in a different manner. A small number of examples of human recordings from patients with different diagnoses revealed SpW subtypes with the same temporal signatures, suggesting that detailed quantification of the pattern of spikes in SpW discharges may be a useful indicator of disparate underlying epileptogenic pathologies. NEW & NOTEWORTHY Spike-and-wave-type discharges (SpW) are a common feature in many epilepsies. Their electrographic manifestation is highly varied, as are available genetic clues to associated underlying pathology. Using computational and in vitro models, we demonstrate that distinct subtypes of SpW are generated by lamina-selective disinhibition or enhanced interlaminar excitation. These subtypes could be detected in at least some noninvasive patient recordings, suggesting more detailed analysis of SpW may be useful in determining clinical pathology.

Comparative efficacy of antiepileptic drugs in children and adolescents: A network meta-analysis

OBJECTIVE

To estimate the comparative efficacy among antiepileptic drugs in the pediatric population (0-18 years).

METHODS

Using the Embase and MEDLINE databases, we updated to February 2017 the search strategy of the National Institute for Health and Care Excellence guidelines for epilepsy. We only included randomized clinical trials conducted in children and mixed-age populations. According to the PRISMA network meta-analysis guideline, the study-level quality assessment was made with the Cochrane risk-of-bias tool. Three investigators independently selected articles. The efficacy outcome was considered to be seizure freedom or ≥50% seizure reduction.

RESULTS

We selected 46 randomized clinical trials. A total of 5652 individuals were randomized to 22 antiepileptic drugs and placebo. The point estimates of carbamazepine and lamotrigine efficacy showed their superiority with respect to all comparator antiepileptic drugs for the treatment of newly diagnosed focal epilepsy. In refractory focal epilepsy, levetiracetam (odds ratio [OR] = 3.3, 95% credible interval [CrI] = 1.3-7.6) and perampanel (OR = 2.5, 95% CrI = 1.1-5.8) were more effective compared to placebo. Ethosuximide and valproic acid were both superior to lamotrigine against absence seizures. The OR point estimate showed the superiority of adrenocorticotropic hormone over all comparators in infantile spasms. A wide heterogeneity in the length of follow-up was observed among the studies.

SIGNIFICANCE

This network meta-analysis suggests that the quality of studies should be improved through the use of comparative designs, relevant outcomes, appropriate follow-up length, and more reliable inclusion criteria.

Ethosuximide, sodium valproate or lamotrigine for absence seizures in children and adolescents

BACKGROUND

This is an updated version of the original Cochrane review originally published in 2003, Issue 3, and updated in 2005, Issue 4.Absence seizures are brief epileptic seizures which present in childhood and adolescence. Depending on clinical features and electroencephalogram (EEG) findings they are divided into typical, atypical absences, and absences with special features. Typical absences are characterised by sudden loss of awareness and an EEG typically shows generalised spike wave discharges at three cycles per second. Ethosuximide, valproate and lamotrigine are currently used to treat absence seizures. This review aims to determine the best choice of antiepileptic drug for children and adolescents with typical absence seizures.

OBJECTIVES

To review the evidence for the effects of ethosuximide, valproate and lamotrigine as treatments for children and adolescents with absence seizures, when compared with placebo or each other.

SEARCH METHODS

We searched the Cochrane Epilepsy Group's Specialized Register (1 September 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 1 September 2016), MEDLINE (Ovid, 1946 to 1 September 2016), ClinicalTrials.gov (1 September 2016) and the WHO International Clinical Trials Registry Platform ICTRP (1 September 2016). Previously we searched Embase (1988 to March 2005) and SCOPUS (1823 to 31 March 2014). No language restrictions were imposed. In addition, we contacted Sanofi Winthrop, Glaxo Wellcome (now GlaxoSmithKline) and Parke Davis (now Pfizer), manufacturers of sodium valproate, lamotrigine and ethosuximide respectively.

SELECTION CRITERIA

Randomised parallel group monotherapy or add-on trials which include a comparison of any of the following in children or adolescents with absence seizures: ethosuximide; sodium valproate; lamotrigine; or placebo.

DATA COLLECTION AND ANALYSIS

Outcome measures were: (1) proportion of individuals seizure free at one, three, six, 12 and 18 months post randomisation; (2) people with a 50% or greater reduction in seizure frequency; (3) normalisation of EEG and/or negative hyperventilation test; and (4) adverse effects. Data were independently extracted by two review authors. Results are presented as risk ratios (RR) with 95% confidence intervals (95% CIs).

MAIN RESULTS

Eight small trials were found (three of them not included in the previous version of the review). Six of them were of poor methodological quality and seven recruited less than 50 participants. There are no placebo-controlled trials for ethosuximide or valproate, and hence, no evidence from randomised controlled trials to support a specific effect on absence seizures for either of these two drugs. Due to the differing methodologies used in the trials comparing ethosuximide, lamotrigine and valproate, we thought it inappropriate to undertake a meta-analysis. One large randomised, parallel double-blind controlled trial comparing ethosuximide, lamotrigine and sodium valproate in children with newly diagnosed childhood absence epilepsy found that at 12 months, the freedom-from-failure rates for ethosuximide and valproic acid (VPA) were similar and were higher than the rate for lamotrigine. The frequency of treatment failures due to lack of seizure control (P < 0.001) and intolerable adverse events (P < 0.037) was significantly different among the treatment groups, with the largest proportion of lack of seizure control in the lamotrigine cohort, and the largest proportion of adverse events in the VPA group. Overall, this large study demonstrates the superior effectiveness of ethosuximide and VPA compared to lamotrigine as initial monotherapy aimed to control seizures without intolerable adverse effects in children with childhood absence epilepsy.

AUTHORS' CONCLUSIONS

With regards to both efficacy and tolerability, ethosuximide represents the optimal initial empirical monotherapy for children and adolescents with absence seizures. However, if absence and generalised tonic-clonic seizures coexist, valproate should be preferred, as ethosuximide is probably inefficacious on tonic-clonic seizures.

The Cognitive Profile of Ethosuximide in Children

INTRODUCTION

Although ethosuximide is one of the oldest antiepileptic drugs (AEDs), little information is available about the cognitive side effects of ethosuximide.

OBJECTIVE

The aim of this study was to investigate the cognitive profile of ethosuximide.

METHODS

In this cross-sectional study, we used an extensive neuropsychological test battery in patients with epilepsy aged 6-16 years who were treated with monotherapy ethosuximide. We evaluated the efficacy of the drug by seizure frequency (seizure free or not).

RESULTS

We included 61 patients with a mean age of 9.4 years [standard deviation (SD) 2.7] who used on average 686 mg/day (SD 245) ESM as monotherapy. ESM was effective in the majority of the patients (70 % were seizure free for at least 6 months at moment of inclusion). The total study population showed impairments of intelligence, visuomotor, and attentional function including activation/alertness. Comparisons between the well-controlled patients and patients who were not in remission showed significantly lower intelligence values and lower performance on the visual-perceptual and attentional tasks for the group with ongoing seizures. Our results suggested that the higher order cognitive dysfunctions (such as intelligence and visual-perceptual functions) may be regarded as seizure or aetiology effects and that the impaired fluid cognitive functions, such as activation/alertness, sustained auditory attention and attentional control or switching, were due to ESM.

CONCLUSION

This study suggests the attentional dysfunction resulting in psychomotor slowing and alertness deficits may be regarded as effects of ethosuximide. Although no untreated baseline assessment was available, these effects are comparable to those of other AEDs, and ethosuximide may therefore be considered an AED with only mild effects on cognition. As ethosuximide is a first-line therapy for absence seizures in childhood, and drug-induced cognitive impairment may interfere with development, learning, and academic achievement, these findings are of interest to clinicians who prescribe this drug, especially when informing parents.

Ethosuximide Induces Hippocampal Neurogenesis and Reverses Cognitive Deficits in an Amyloid-β Toxin-induced Alzheimer Rat Model via the Phosphatidylinositol 3-Kinase (PI3K)/Akt/Wnt/β-Catenin Pathway

Neurogenesis involves generation of new neurons through finely tuned multistep processes, such as neural stem cell (NSC) proliferation, migration, differentiation, and integration into existing neuronal circuitry in the dentate gyrus of the hippocampus and subventricular zone. Adult hippocampal neurogenesis is involved in cognitive functions and altered in various neurodegenerative disorders, including Alzheimer disease (AD). Ethosuximide (ETH), an anticonvulsant drug is used for the treatment of epileptic seizures. However, the effects of ETH on adult hippocampal neurogenesis and the underlying cellular and molecular mechanism(s) are yet unexplored. Herein, we studied the effects of ETH on rat multipotent NSC proliferation and neuronal differentiation and adult hippocampal neurogenesis in an amyloid β (Aβ) toxin-induced rat model of AD-like phenotypes. ETH potently induced NSC proliferation and neuronal differentiation in the hippocampus-derived NSC in vitro. ETH enhanced NSC proliferation and neuronal differentiation and reduced Aβ toxin-mediated toxicity and neurodegeneration, leading to behavioral recovery in the rat AD model. ETH inhibited Aβ-mediated suppression of neurogenic and Akt/Wnt/β-catenin pathway gene expression in the hippocampus. ETH activated the PI3K·Akt and Wnt·β-catenin transduction pathways that are known to be involved in the regulation of neurogenesis. Inhibition of the PI3K·Akt and Wnt·β-catenin pathways effectively blocked the mitogenic and neurogenic effects of ETH. In silico molecular target prediction docking studies suggest that ETH interacts with Akt, Dkk-1, and GSK-3β. Our findings suggest that ETH stimulates NSC proliferation and differentiation in vitro and adult hippocampal neurogenesis via the PI3K·Akt and Wnt·β-catenin signaling.

Antiepileptic Drug Treatment in Children with Epilepsy

Most children with new-onset epilepsy achieve seizure freedom with appropriate antiepileptic drugs (AEDs). However, nearly 20 % will continue to have seizures despite AEDs, as either monotherapy or in combination. Despite the growing market of new molecules over the last 20 years, the proportion of drug-resistant epilepsies has not changed. In this review, we report the evidence of efficacy and safety based on phase III randomized controlled clinical trials (RCTs) of AEDs currently used in the paediatric population. We conducted a literature search using the PubMed database and the Cochrane Database of Systematic Reviews. We also analysed the RCTs of newer AEDs whose efficacy in adolescents and adults might suggest possible use in children. Most of the phase III trials on AEDs in children have major methodological limitations that considerably limit meaningful conclusions about comparative efficacy between old and new molecules. Since the efficacy of new drugs has only been reported versus placebo, the commonly held opinion that new and newer AEDs have a better safety profile than old ones does not appear to be supported by evidence. Despite limited solid evidence, pharmacological management has improved over the years as a consequence of increased awareness of some degree of specificity of treatment in relation to different epilepsy syndromes and attention to adverse events. Future research should be directed taking these factors, as well as the diversity of epilepsy, into consideration.

Current advances in childhood absence epilepsy

BACKGROUND

Childhood absence epilepsy is an age-dependent, idiopathic, generalized epilepsy with a characteristic seizure appearance. The disorder is likely to be multifactorial, resulting from interactions between genetic and acquired factors, but the debate is still open. We review recent studies on different aspects of childhood absence epilepsy and also to describe new concepts.

METHODS

Data for this review were identified using Medline and PubMed survey to locate studies dealing with childhood absence epilepsy. Searches included articles published between 1924 and 2013.

RESULTS

The diagnosis comprises predominant and associated seizure types associated with other clinical and electroencephalographic characteristics. Many studies have challenged the prevailing concepts, particularly with respect to the pathophysiological mechanisms underlying the electroencephalographic seizure discharges. Childhood absence epilepsy fits the definition of system epilepsy as a condition resulting from the persisting susceptibility of the thalamocortical system as a whole to generate seizures. This syndrome, if properly defined using strict diagnostic criteria, has a good prognosis. In some cases, it may affect multiple cognitive functions determining risk for academic and functional difficulties; the detection of children at risk allows tailored interventions. Childhood absence epilepsy is usually treated with ethosuximide, valproate, lamotrigine, or levetiracetam, but the most efficacious and tolerable initial empirical treatment has not been well defined.

CONCLUSIONS

We review recent studies and new concepts on the electroclinical features and pathophysiological findings of childhood absence epilepsy in order to highlight areas of consensus as well as areas of uncertainty that indicate directions for future research.

Pretreatment EEG in childhood absence epilepsy: associations with attention and treatment outcome

OBJECTIVE

In children with newly diagnosed childhood absence epilepsy (CAE), determine pretreatment EEG features and their associations with baseline neuropsychological function and short-term treatment outcome.

METHODS

In a multicenter, randomized clinical trial, patients with CAE underwent a pretreatment, 1-hour video-EEG and neuropsychological testing with freedom-from-failure and seizure-freedom (SF) outcome assessed at the 16- to 20-week visit.

RESULTS

Detailed evaluation of the pretreatment EEG was possible for 99.8% of participants (445/446). Median time to first seizure was 6.0 minutes (range 0-59 minutes), median number of seizures was 5 (range 1-60), and median seizure duration was 10.8 seconds (range 3.3-77.6 seconds). Median duration of shortest seizure per EEG was 7.5 seconds (range 3.0-77.6 seconds). Seizure frequency was not associated with baseline measures of attention, executive function, or treatment outcome. Presence of a seizure lasting ≥20 seconds was noted in 29% of subjects (129/440); these children had higher median omissions T score on the Conners Continuous Performance Test (56.3 vs 51.6, p = 0.01). Patients with a shortest seizure of longer duration were more likely to demonstrate treatment success by both freedom-from-failure (p = 0.02) and SF (p = 0.005) criteria, even after controlling for age, treatment group, and number of seizures, with good predictive value (area under the curve 78% for SF).

CONCLUSIONS

CAE is reliably and quickly confirmed by EEG. Occurrence of a seizure ≥20 seconds, but not overall seizure frequency, was associated with differential baseline measures of attention. Patients whose shortest pretreatment EEG seizure was longer in duration were more likely to achieve SF, regardless of treatment.

Selecting anti-epileptic drugs: a pediatric epileptologist's view, a computer's view

OBJECTIVE

To identify which clinical characteristics are important to include in clinical decision support systems developed for Antiepileptic Drug (AEDs) selection.

METHODS

Twenty-three epileptologists from the Childhood Absence Epilepsy network completed a survey related to AED selection. Using cluster analysis their responses where classified into subject matter groups and weighted for importance.

RESULTS

Five distinct subject matter groups were identified and their relative weighting for importance were determined: disease characteristics (weight 4.8 ± 0.049), drug toxicities (3.82 ± 0.098), medical history (3.12 ± 0.102), systemic characteristics (2.57 ± 0.048) and genetic characteristics (1.08 ± 0.046).

CONCLUSION

Research about prescribing patterns exists but research on how such data can be used to train advanced technology is novel. As machine learning algorithms becomes more and more prevalent in clinical decisions support systems, developing methods for determining which data should be part of those algorithms is equally important.

Updated ILAE evidence review of antiepileptic drug efficacy and effectiveness as initial monotherapy for epileptic seizures and syndromes

The purpose of this report was to update the 2006 International League Against Epilepsy (ILAE) report and identify the level of evidence for long-term efficacy or effectiveness for antiepileptic drugs (AEDs) as initial monotherapy for patients with newly diagnosed or untreated epilepsy. All applicable articles from July 2005 until March 2012 were identified, evaluated, and combined with the previous analysis (Glauser et al., 2006) to provide a comprehensive update. The prior analysis methodology was utilized with three modifications: (1) the detectable noninferiority boundary approach was dropped and both failed superiority studies and prespecified noninferiority studies were analyzed using a noninferiority approach, (2) the definition of an adequate comparator was clarified and now includes an absolute minimum point estimate for efficacy/effectiveness, and (3) the relationship table between clinical trial ratings, level of evidence, and conclusions no longer includes a recommendation column to reinforce that this review of efficacy/evidence for specific seizure types does not imply treatment recommendations. This evidence review contains one clarification: The commission has determined that class I superiority studies can be designed to detect up to a 20% absolute (rather than relative) difference in the point estimate of efficacy/effectiveness between study treatment and comparator using an intent-to-treat analysis. Since July, 2005, three class I randomized controlled trials (RCT) and 11 class III RCTs have been published. The combined analysis (1940-2012) now includes a total of 64 RCTs (7 with class I evidence, 2 with class II evidence) and 11 meta-analyses. New efficacy/effectiveness findings include the following: levetiracetam and zonisamide have level A evidence in adults with partial onset seizures and both ethosuximide and valproic acid have level A evidence in children with childhood absence epilepsy. There are no major changes in the level of evidence for any other subgroup. Levetiracetam and zonisamide join carbamazepine and phenytoin with level A efficacy/effectiveness evidence as initial monotherapy for adults with partial onset seizures. Although ethosuximide and valproic acid now have level A efficacy/effectiveness evidence as initial monotherapy for children with absence seizures, there continues to be an alarming lack of well designed, properly conducted epilepsy RCTs for patients with generalized seizures/epilepsies and in children in general. These findings reinforce the need for multicenter, multinational efforts to design, conduct, and analyze future clinically relevant adequately designed RCTs. When selecting a patient's AED, all relevant variables and not just efficacy and effectiveness should be considered.

Specific safety and tolerability considerations in the use of anticonvulsant medications in children

Epilepsy is one of the most common neurological disorders in the pediatric age range, and the majority of affected children can be safely and effectively treated with antiepileptic medication. While there are many antiepileptic agents on the market, specific drugs may be more efficacious for certain seizure types or electroclinical syndromes. Furthermore, certain adverse effects are more common with specific classes of medication. Additionally patient-specific factors, such as age, race, other medical conditions, or concurrent medication use may result in higher rates of side effects or altered efficacy. Significant developmental changes in gastric absorption, protein binding, hepatic metabolism, and renal clearance are seen over the pediatric age range, which impact pharmacokinetics. Such changes must be considered to determine optimal dosing and dosing intervals for children at specific ages. Furthermore, approximately one third of children require polytherapy for seizure control, and many more take concurrent medications for other conditions. In such children, drug–drug interactions must be considered to minimize adverse effects and improve efficacy. This review will address issues of antiepileptic drug efficacy, tolerability and ease of use, pharmacokinetics, and drug–drug interactions in the pediatric age range.

Long-term effectiveness of ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy

PURPOSE

We performed this study to evaluate the long-term efficacy and tolerability of ethosuximide (ESX), valproic acid (VPA), and lamotrigine (LTG) as initial monotherapies for patients with newly diagnosed childhood absence epilepsy.

METHODS

We retrospectively reviewed the medical records of 128 patients (45 boys and 83 girls) diagnosed with childhood absence epilepsy at the Seoul National University Hospital. The diagnosis was based on the criteria proposed by Panayiotopoulos in 2005. We measured the seizure-free rate and the retention rate observed during 2 years of treatment. Follow-up electroencephalography (EEG), any reported adverse events, and reasons for antiepileptic drug (AED) discontinuation were reviewed.

RESULTS

The seizure-free rate of ESX (84%) was significantly higher than that of VPA (62%) and LTG (53%) at 3 months. The seizure-free rate of ESX (90%) was significantly higher than that of LTG (63%) at 6 months. After 9 months, there was no significant difference in seizure-free rate among the three groups. There were no significant differences among the three groups in terms of normalization of EEG at 12 months (ESX, 77%; VPA, 83%; and LTG, 64%), retention rate throughout the whole treatment period, and adverse-event rates (ESX, 25%; VPA, 29%; and LTG, 14%).

CONCLUSION

This study suggests that ESX, VPA, and LTG are equally effective in the long-term treatment of newly diagnosed CAE patients. However, the onset of efficacy was faster for ESX compared with VPA or LTG. Efficacy, tolerability, and adverse event profiles should be carefully considered when selecting AEDs to treat individual patients with CAE.

Characteristics of successful recruitment in prospective pediatric pharmacogenetic studies

BACKGROUND

There is a need to explore feasible means of accruing an appropriate study cohort to help fill the knowledge gap between pharmacogenetic contributions to drug response and clinical application in the pediatric population.

OBJECTIVES

The aim of this study was to identify factors affecting recruitment of eligible subjects in pharmacogenetic studies at a large Midwestern pediatric academic medical center. The objectives were to evaluate recruitment success of ongoing trials and ascertain contributors to differential recruitment rates. We hypothesized that studies with good recruitment of eligible subjects would share characteristics not present in studies with lower than anticipated recruitment. The goal was to better understand barriers to good recruitment in pharmacogenetic studies to help inform future trial and infrastructure design.

METHODS

Investigators designed a survey with proposed elements of success, which was then completed by lead and/or site investigators of all pharmacogenetics studies at the institution. Results were evaluated using an investigator-developed likelihood of success scoring system.

RESULTS

Two studies recruited >95% of the approached eligible patients; 4 studies were consistent with investigator-anticipated recruitment (>50%), and 1 study did not meet expected recruitment. A study's total score on the investigator-devised scoring tool correlated well with the proportion of approached patients recruited (Pearson's correlation, r = 0.82; P < 0.001). Multiple factors impacted successful recruitment into these pharmacogenetic studies. Features of studies with successful recruitment included standardized clinical care, an ongoing team-patient relationship, severe and/or life-threatening outcome measures, study coordinator with experience in clinical research, a study medication with few or no alternative treatment options, and active involvement of the research team in clinical care.

CONCLUSIONS

A scoring system for study characteristics may be useful to calculate the risk of failure for successful recruitment, allow discrimination among characteristics contributing to the risk, and permit study design alterations to improve likelihood of successful recruitment in pediatric pharmacogenetic studies.

Ethosuximide, valproic acid, and lamotrigine in childhood absence epilepsy

BACKGROUND

Childhood absence epilepsy, the most common pediatric epilepsy syndrome, is usually treated with ethosuximide, valproic acid, or lamotrigine. The most efficacious and tolerable initial empirical treatment has not been defined.

METHODS

In a double-blind, randomized, controlled clinical trial, we compared the efficacy, tolerability, and neuropsychological effects of ethosuximide, valproic acid, and lamotrigine in children with newly diagnosed childhood absence epilepsy. Drug doses were incrementally increased until the child was free of seizures, the maximal allowable or highest tolerable dose was reached, or a criterion indicating treatment failure was met. The primary outcome was freedom from treatment failure after 16 weeks of therapy; the secondary outcome was attentional dysfunction. Differential drug effects were determined by means of pairwise comparisons.

RESULTS

The 453 children who were randomly assigned to treatment with ethosuximide (156), lamotrigine (149), or valproic acid (148) were similar with respect to their demographic characteristics. After 16 weeks of therapy, the freedom-from-failure rates for ethosuximide and valproic acid were similar (53% and 58%, respectively; odds ratio with valproic acid vs. ethosuximide, 1.26; 95% confidence interval [CI], 0.80 to 1.98; P=0.35) and were higher than the rate for lamotrigine (29%; odds ratio with ethosuximide vs. lamotrigine, 2.66; 95% CI, 1.65 to 4.28; odds ratio with valproic acid vs. lamotrigine, 3.34; 95% CI, 2.06 to 5.42; P<0.001 for both comparisons). There were no significant differences among the three drugs with regard to discontinuation because of adverse events. Attentional dysfunction was more common with valproic acid than with ethosuximide (in 49% of the children vs. 33%; odds ratio, 1.95; 95% CI, 1.12 to 3.41; P=0.03).

CONCLUSIONS

Ethosuximide and valproic acid are more effective than lamotrigine in the treatment of childhood absence epilepsy. Ethosuximide is associated with fewer adverse attentional effects. (ClinicalTrials.gov number, NCT00088452.)

Antiepileptic drug treatment in children

Epilepsy is one of the most common neurological disorders of childhood, and antiepileptic drugs represent the main component of its treatment. The current emphasis in epilepsy treatment is to improve quality of life, not only by suppressing seizure, but also by minimizing the side effects of medications. The last 15 years have been characterized by significant advances in the development of new agents that have helped us to get closer to this goal. Knowledge of the essential properties, key indications and interactions of each antiepileptic drug will help to optimize efficacy and reduce adverse reactions. Age is also a determining factor of the epilepsy phenotype and its treatment. This review addresses the principles of pediatric epilepsy treatment, summarizes the profile of each of the commonly used antiepileptic drugs, and provides a treatment paradigm for particular seizures and epilepsy syndromes of childhood.

Valproic acid-induced pancreatitis: 16 new cases and a review of the literature

BACKGROUND

Acute pancreatitis is rarely seen in children, and, in contrast to cases in adults, it is often drug induced. One possible medication is the antiepileptic drug valproic acid (VPA), which is commonly prescribed for generalized and focal epilepsy, migraine, neuropathic pain, and bipolar disorder. The common side effects associated with VPA are typically benign, but less common but more serious adverse effects may occur. These include hepatotoxicity, hyperammonemic encephalopathy, coagulation disorders, and pancreatitis. Since 1979, a few cases of pancreatitis induced by VPA have been published in the medical literature.

METHODS

We mailed a questionnaire to all members of the "German Section of the International League against Epilepsy," asking about VPA-induced side effects. We also reviewed the medical literature for VPA-induced pancreatitis.

RESULTS

Fifty-three publications (90 patients) published from 1979 to 2005 were found. Our survey in Germany, however, yielded 16 cases of pancreatitis from 1994 to 2003 whose original files we could study in detail. None of these patients had been published previously.

CONCLUSIONS

The difference between 90 patients reported worldwide from 1979 to 2005 and the 16 new documented cases from only Germany over 10 years corroborates that the occurrence of this severe side effect is under reported.

Valproate as a mainstay of therapy for pediatric epilepsy

This article reviews relevant pharmacologic and clinical information gathered for valproate since it was introduced into clinical practice 37 years ago and the application of this information for the treatment of childhood epilepsy. Valproate is available for oral and parenteral use. Oral forms are almost completely bioavailable but the rate of absorption varies between formulations. The Chrono tablet formulation has not been adapted for children aged <6 years, in whom the oral solution or syrup, requiring two or three daily administrations, has been used until recently. A new formulation specifically adapted for children, Chronosphere, administrated once or twice daily, is a modified-release formulation of valproate that minimizes fluctuations in serum drug concentrations during a dosage interval. Plasma protein binding is 80-94% and tends to decrease with increasing drug concentration. Valproate elimination is markedly decreased in newborns compared with older children and adults. Elimination by glucuronidation only becomes fully effective by the age of 3-4 years. In children aged 2-10 years receiving valproate, plasma clearances are 50% higher than those in adults. Over the age of 10 years, pharmacokinetic parameters approximate those of adults. Valproate can increase plasma concentrations of concomitant drugs, such as phenobarbital and lamotrigine, by inhibiting their metabolism. As a result of its broad spectrum of efficacy in a wide range of seizure types and epilepsy syndromes, valproate is a drug of choice for children with newly diagnosed epilepsy (focal or generalized), idiopathic generalized epilepsy, epilepsies with prominent myoclonic seizures or with multiple seizure types, and photosensitive epilepsies. In the group of cognitive epilepsies, in which severe spike and wave discharges are accompanied by cognitive deterioration, valproate, ethosuximide, or both should be tested before using corticosteroids. In comparative trials with carbamazepine, phenytoin, and phenobarbital in focal epilepsy and with ethosuximide in absence epilepsy, valproate was as effective and showed a favorable tolerability profile, with minimal adverse cognitive and CNS effects. The low potential for paradoxical seizure aggravation and the long-term efficacy of the drug are additional important factors that contribute to its excellent profile. Intravenous valproate may be effective for the treatment of convulsive and non-convulsive status epilepticus that is refractory to conventional drugs. In infants, potential benefits should be carefully weighed against the risk of liver toxicity. Gastrointestinal intolerance is a relatively frequent, dose-related adverse effect of the drug in children. Bodyweight increase and tremor may be observed in older children and adolescents. Despite the challenge of newer drugs, valproate remains a gold standard antiepileptic drug for the treatment of children.

Role of valproate across the ages. Treatment of epilepsy in children

In June 2005 a team of experts participated in a workshop with the objective of reaching agreement on the place of valproate use in the treatment of paediatric epilepsy patients. A general "consensus of the meeting" was that the initiation of antiepileptic drug (AED) treatment should be based on a seizure-syndromic approach in children. Participants of the meeting also agreed that valproate is currently the AED with the broadest spectrum across all types of seizures and syndromes. Its superiority has been shown over almost 40 years of clinical experience. The best results are seen in idiopathic generalized epilepsy with or without photosensitivity, idiopathic focal and symptomatic generalized tonic-clonic seizures (GTCS). Evidence supports the use of valproate, ethosuximide and lamotrigine in absence epilepsies and the use of carbamazepine, lamotrigine, oxcarbazepine, phenytoin, topiramate, valproate and phenobarbital for primary GTCS. For new AEDs trials have been undertaken to define their therapeutic role but studies comparing their role to 'old' broad-spectrum drugs in specific syndromes are missing. Experts concluded that intravenous (i.v.) valproate is a useful agent in the treatment of non-convulsive status epilepticus (SE). There is an easy transition to oral treatment following i.v. valproate use. The discussion also concluded that, despite the lack of studies, valproate is an interesting, underutilized alternative in convulsive SE but more controlled studies are needed. The side effects of valproate use are well documented. Its effect on cognition and behaviour is more favourable than many of the other AEDs which is an important consideration in children. Overall, the clinical consensus of the meeting was that valproate's well established therapeutic properties far outweigh the negative side effects. Contraindication or withdrawal should be assessed individually.

ILAE treatment guidelines: evidence-based analysis of antiepileptic drug efficacy and effectiveness as initial monotherapy for epileptic seizures and syndromes

PURPOSE

To assess which antiepileptic medications (AEDs) have the best evidence for long-term efficacy or effectiveness as initial monotherapy for patients with newly diagnosed or untreated epilepsy.

METHODS

A 10-member subcommission of the Commission on Therapeutic Strategies of The International League Against Epilepsy (ILAE), including adult and pediatric epileptologists, clinical pharmacologists, clinical trialists, and a statistician evaluated available evidence found through a structured literature review including MEDLINE, Current Contents and the Cochrane Library for all applicable articles from 1940 until July 2005. Articles dealing with different seizure types (for different age groups) and two epilepsy syndromes were assessed for quality of evidence (four classes) based on predefined criteria. Criteria for class I classification were a double-blind randomized controlled trial (RCT) design, >or=48-week treatment duration without forced exit criteria, information on >or=24-week seizure freedom data (efficacy) or >or=48-week retention data (effectiveness), demonstration of superiority or 80% power to detect a <or=20% relative difference in efficacy/effectiveness versus an adequate comparator, and appropriate statistical analysis. Class II studies met all class I criteria except for having either treatment duration of 24 to 47 weeks or, for noninferiority analysis, a power to only exclude a 21-30% relative difference. Class III studies included other randomized double-blind and open-label trials, and class IV included other forms of evidence (e.g., expert opinion, case reports). Quality of clinical trial evidence was used to determine the strength of the level of recommendation.

RESULTS

A total of 50 RCTs and seven meta-analyses contributed to the analysis. Only four RCTs had class I evidence, whereas two had class II evidence; the remainder were evaluated as class III evidence. Three seizure types had AEDs with level A or level B efficacy and effectiveness evidence as initial monotherapy: adults with partial-onset seizures (level A, carbamazepine and phenytoin; level B, valproic acid), children with partial-onset seizures (level A, oxcarbazepine; level B, None), and elderly adults with partial-onset seizures (level A, gabapentin and lamotrigine; level B, None). One adult seizure type [adults with generalized-onset tonic-clonic (GTC) seizures], two pediatric seizure types (GTC seizures and absence seizures), and two epilepsy syndromes (benign epilepsy with centrotemporal spikes and juvenile myoclonic epilepsy) had no AEDs with level A or level B efficacy and effectiveness evidence as initial monotherapy.

CONCLUSIONS

This evidence-based guideline focused on AED efficacy or effectiveness as initial monotherapy for patients with newly diagnosed or untreated epilepsy. The absence of rigorous comprehensive adverse effects data makes it impossible to develop an evidence-based guideline aimed at identifying the overall optimal recommended initial-monotherapy AED. There is an especially alarming lack of well-designed, properly conducted RCTs for patients with generalized seizures/epilepsies and for children in general. The majority of relevant existing RCTs have significant methodologic problems that limit their applicability to this guideline's clinically relevant main question. Multicenter, multinational efforts are needed to design, conduct and analyze future clinically relevant RCTs that can answer the many outstanding questions identified in this guideline. The ultimate choice of an AED for any individual patient with newly diagnosed or untreated epilepsy should include consideration of the strength of the efficacy and effectiveness evidence for each AED along with other variables such as the AED safety and tolerability profile, pharmacokinetic properties, formulations, and expense. When selecting a patient's AED, physicians and patients should consider all relevant variables and not just efficacy and effectiveness.

Pharmacological treatment of childhood absence epilepsy

This review discusses current pharmacological treatment of childhood absence epilepsy (CAE). The key to successful treatment is the correct diagnosis of the epileptic syndrome, hence the initial part of the paper discusses the definition, diagnostic criteria and epidemiology. This is followed by a detailed analysis of pharmacological agents used in the treatment of CAE. The characteristics of old and new anticonvulsants used in the treatment of CAE are also reviewed. For each of the drugs, the mechanism of action, usual dose, common side effects and recommendations for treatment are also discussed. A separate section focuses on instances when anticonvulsants may exacerbate seizures. Particular emphasis is given to the evidence currently available, on which clinical practice needs to be based.

Idiopathic generalized epilepsies: clinical and electroencephalogram diagnosis and treatment

This review concentrates on the principles of the clinical and electroencephalogram diagnosis of idiopathic generalized epilepsies and their treatment. The electroclinical variability of the main seizure types is detailed and particular emphasis is placed on the differential diagnosis from other seizures and nonepileptic conditions that is essential for the optimal management of these patients. The authors review the various idiopathic generalized epilepsy subsyndromes and conditions that are included in both the 1989 International League Against Epilepsy classification system and the recently proposed International League Against Epilepsy scheme, but also syndromes and forms that have not been formally recognized. Finally, the authors describe the principles of antiepileptic drug treatment with the old and newer drugs, and their specific indications and contraindications in the various syndromes and seizure types.

Epilepsy in children

10.5 million children worldwide are estimated to have active epilepsy. Over the past 15 years, syndrome-oriented clinical and EEG diagnosis, and better aetiological diagnosis, especially supported by neuroimaging, has helped to clarify the diversity of epilepsy in children, and has improved management. Perinatal and postinfective encephalopathy, cortical dysplasia, and hippocampal sclerosis account for the most severe symptomatic epilepsies. Ion channel defects can underlie both benign age-related disorders and severe epileptic encephalopathies with a progressive disturbance in cerebral function. However, the reasons for age-related expression in children are not understood. Neither are the mechanisms whereby an epileptic encephalopathy originates. Several new drugs have been recently introduced but have provided limited therapeutic benefits. However, treatment and quality of life have improved because the syndrome-specific efficacy profile of drugs is better known, and there is heightened awareness that compounds with severe cognitive side-effects and heavy polytherapies should be avoided. Epilepsy surgery is an important option for a few well-selected individuals, but should be considered with great caution when there is no apparent underlying brain lesion.

Challenges and opportunities in the application of pharmacogenetics to antiepileptic drug therapy

The recent surge of interest in pharmacogenetics has provoked considerable thought regarding its relevance to antiepileptic drug (AED) therapy. Initial studies have focused on genes whose products play a putatively important role in AED pharmacology, particularly drug transporter proteins, drug metabolizing enzymes and ion channel subunits. However, there is a lack of good correspondence between results from different laboratories, and more recent findings are awaiting attempts at confirmation. Thus, there are currently no AED treatment guidelines that are informed by pharmacogenetic data. In order to begin to have clinical impact, standards specific to the conduct of future AED studies must be established. Of particular importance are the need for accurate epilepsy classification, appropriate AED selection and clear and objective assessment outcome measures. In addition, general standards for analysis and interpretation of genetic association data must be better codified and applied consistently across studies. Finally, extensive clinical research networks must be formulated and large numbers of well characterized patients must be recruited. Further development of these critical factors will optimize chances for overcoming current challenges posed by AED pharmacogenetic research and ultimately allow the realization of improved, more rational therapeutic strategies.

Management Guidelines for Children with Idiopathic Generalized Epilepsy

Most idiopathic generalized epilepsy (IGE) begins in childhood. Clinicians face many important management decisions for these children; however the existing literature provides little scientific guidance.

TIME OF DIAGNOSIS

At the time of presentation, it is unclear how accurately IGE seizures and syndromes are diagnosed and how consistent are the EEG correlates. Investigations beyond EEG are of uncertain value but probably are not needed. Selection of an initial antiepileptic drug (AED) is not based on any adequately powered, blinded, randomized comparative trials; however, reasonable evidence supports the use of valproic acid (VPA), lamotrigine and ethosuccimide as initial treatment for childhood absence epilepsy (CAE). Many large case series suggest the value of VPA for juvenile myoclonic epilepsy (JME) but the relative value of other, newer AEDs has not been established.

FIRST YEARS OF TREATMENT

Once AED treatment is started, it is difficult to establish that absence seizures are completely controlled and the importance of interictal spike-wave discharge remains uncertain. The value of restrictions on the child's activities has not been well studied; however serious accidents appear to be a justifiable concern in children with uncontrolled absence. Assessing the risk from photosensitivity in JME is challenging.

LENGTH OF TREATMENT

The optimal length of treatment for IGE is unclear. There is a high rate of remission in CAE when AEDs are discontinued after 1-2 years of seizure freedom; however, long-term remission in CAE occurs in only 65%. It is usually assumed that treatment for JME is life long, although about 10% appear to have permanent remission in adolescence. Discontinuing AED treatment in JME requires a very individual risk assessment.

PREPARATION FOR ADULT LIFE

Long-term social outcome for children with CAE is often unsatisfactory even if the epilepsy remits. The reasons are unclear and successful interventions have not been described. Long-term social outcome for JME has not been adequately described.

CONCLUSIONS

Further research is needed to justify the direction of many of the necessary management decisions in the diagnosis and treatment of IGE syndromes.

Evidence-based Treatment of Idiopathic Generalized Epilepsies with Older Antiepileptic Drugs

Older antiepileptic drugs continue to play a major role in the treatment of the idiopathic generalized epilepsies. Comparative studies of ethosuximide and valproate have demonstrated equivalence in the treatment of childhood absence epilepsy. Valproate can be regarded as the recommended first-line treatment for juvenile myoclonic epilepsy based on case series reports. Studies in patients with generalized tonic-clonic seizures have not separated out idiopathic from secondary generalized events. Treatment for the other idiopathic generalized epilepsy syndromes lacks evidence other than a few case reports and diverse expert opinion. Further randomized controlled trials of older antiepileptic drugs are recommended to solidify the evidence-based treatment of the idiopathic generalized epilepsies.

Lamotrigine versus valproic acid as first-line monotherapy in newly diagnosed typical absence seizures: an open-label, randomized, parallel-group study

PURPOSE

To compare the efficacy of lamotrigine (LTG) and valproic acid (VPA) in newly diagnosed children and adolescents with typical absence seizures.

METHODS

A randomized, open-label parallel-group design was used. After undergoing an awake video-EEG recording, which included one to two trials of 3 min of hyperventilation and intermittent photic stimulation, eligible patients were randomized to receive LTG or VPA. LTG was initiated at a daily dose of 0.5 mg/kg for 2 weeks in two divided doses, followed by 1.0 mg/kg/day for an additional 2 weeks. Thereafter, doses were increased in 1-mg/kg/day increments every 5 days until seizures were controlled, intolerable adverse effects occurred, or a maximum dose of 12 mg/kg/day had been reached. VPA was equally uptitrated according to clinical response, starting at 10 mg/kg and increasing by 5 mg/kg/24 h every 3 days, if required, to a maximum of 30 mg/kg/day in three divided doses. Patients were seen in the clinic every month for < or = 12 months. The primary efficacy end point at each visit was seizure freedom, defined as lack of clinically observed seizures since the previous visit and lack of electroclinical seizures during ambulatory 24-h EEG testing and a video-EEG session with hyperventilation.

RESULTS

Thirty-eight children (17 boys, 21 girls), aged from 3 to 13 years (mean, 7.5 years), all newly diagnosed with childhood or juvenile typical absence seizures, were enrolled. After 1 month of treatment, 10 (52.6%) of 19 children taking VPA and one (5.3%) of 19 taking LTG were seizure free (p = 0.004). By the 3-month follow-up, 12 (63.1%) children taking VPA and seven (36.8%) taking LTG were controlled (p = 0.19). After 12 months, 13 children taking VPA (dose range, 20-30 mg/kg/day; mean serum level, 76.8 mg/L; range, 51.4-91 mg/L) and 10 taking LTG (dose range, 2-11 mg/kg/day; mean serum level, 8.1 mg/L; range, 1.1-18 mg/L) were seizure free (p = 0.51). Side effects were mostly mild and transient and were recorded in two (10.6%) children treated with VPA and in six (31.8%) treated with LTG.

CONCLUSIONS

Both VPA and LTG can be efficacious against absence seizures, although VPA shows a much faster onset of action, at least in part because of its shorter titration schedule.

Effects of antiepileptic medications on psychiatric and behavioral comorbidities in children and adolescents with epilepsy

The three goals of this article are (1) to delineate the limitations in determining the actual incidence of antiepileptic drug (AED) psychiatric and behavioral side effects; (2) to summarize existing data on the direct effects of AEDs on psychiatric and behavioral comorbidities and examine the relationship between these direct effects and specific AED mechanisms of action; and (3) to recognize the indirect effects of AEDs on psychiatric and behavioral medications that can result in aggravation of these comorbidities through drug-drug interactions. All of these data are then combined and formatted into a practical algorithm useful in many clinical situations.

Idiopathic generalized epilepsy

Successful treatment of idiopathic generalized epilepsy begins with accurate seizure classification. Seizure types, such as absence, myoclonic, and primary generalized tonic-clonic seizures (PGTCS), often can be classified based on a detailed history and inter-ictal electroencephalogram (EEG). Ideally, patients can be classified into specific epilepsy syndromes, such as childhood absence epilepsy, juvenile myoclonic epilepsy (JME), or generalized tonic-clonic seizures on awakening. Idiopathic generalized epilepsy should be distinguished from focal epilepsy with rapid secondary generalization. If this distinction is not clear after history, physical examination, and routine inter-ictal EEG, then ambulatory EEG, video EEG monitoring, or neuroimaging studies may be needed. Ethosuximide, valproate, or lamotrigine are all appropriate first-line choices in the treatment of childhood absence epilepsy. The specific medication should be chosen based on the side effect profiles, dosing formulations, and titration schedules of the medications. The available evidence best supports valproate as the first-line choice in the treatment of JME, although lamotrigine and topiramate may be appropriate choices in this setting. More data specific to JME are needed to clarify the role of medications such as levetiracetam and zonisamide in the treatment of JME. The available evidence to guide the treatment of PGTCS is limited, because most trials did not rigorously exclude patients with focal epilepsy with rapid secondary generalization. Available evidence suggests that valproate is an appropriate first-line choice for PGTCE. Lamotrigine or topiramate also may be appropriate choices. More data are needed to clarify the role of levetiracetam and zonisamide in the treatment of PGCTS. If it is unclear whether a patient has idiopathic generalized epilepsy or focal epilepsy with secondary generalization, then a broad-spectrum anticonvulsant, including valproate, lamotrigine, or topiramate, should be considered. More data are needed to support the broad-spectrum efficacy of levetiracetam and zonisamide.

Antiepileptic drug development for "therapeutic orphans"

Epilepsy is the most common serious neurological disorder among children. Excluding the elderly, the incidence of epilepsy is highest among children. About half of children with epilepsy have epilepsy syndromes that have unique onset in childhood. Clinical drug trials of antiepileptic drugs (AEDs) among children have been primarily performed using drugs developed for the larger adult partial epilepsy market. The current AED drug development system essentially renders children with epilepsy "therapeutic orphans" who can only benefit from AED development if a drug developed for adult partial epilepsy happens to also be effective for a pediatric epilepsy syndrome. The rapid evolution of different seizure types and childhood epilepsy syndromes, and rapid changes in baseline neurological status, make distinguishing clinical changes due to study drugs in clinical trials and the natural history of the epilepsy syndrome difficult. Unique ethical issues (e.g., informed consent), practical and logistical issues (e.g., serum AED level monitoring with microassay methods), as well as major financial and regulatory disincentives for the pharmaceutical industry are additional barriers to need-based AED development for children. A government-funded pediatric epilepsy group or consortium to conduct clinical trials similar to the successful Children's Oncology Group (COG) and regulations plus financial incentives that encourage the pharmaceutical industry to develop AEDs specifically for children are needed.

Epilepsy: from consensus to daily practice

Most clinicians would accept that epilepsy treatment should begin with monotherapy, and in the majority of cases this is the preferred drug maintenance option. The clinical choice of one antiepileptic drug (AED) over another should be based on firm evidence of efficacy and tolerability as evaluated in comparative monotherapy studies and pharmacokinetics. This paper presents the findings of evidence-based reviews of AED monotherapy in patients newly diagnosed with epilepsy. The main study was conducted in the United Kingdom and investigated the clinical evidence supporting AEDs used as first-line monotherapy. In this paper the general treatment recommendations will focus on valproate, one of the mainstay drugs used in the fight against epilepsy. Finally, with these recommendations in mind, the principles behind AED drug selection in clinical practice will be discussed. Factors for consideration that impact on AED decision-making include: seizure and syndrome diagnosis, AED tolerability profiles, patient characteristics and pharmacokinetic/pharmacodynamic AED interactions.

Chronic management of seizures in the syndromes of idiopathic generalized epilepsy

As a group, idiopathic generalized epilepsies (IGEs) have the highest rates of complete seizure control with medication. However, there are little evidence-based data to guide drug choice for treatment. Examples of IGE include absence epilepsy, generalized tonic-clonic epilepsy, and juvenile myoclonic epilepsy. Generalized epilepsies seem to be particularly vulnerable to seizure aggravation, and medications that are primarily effective against partial seizures are more commonly involved in seizure aggravation than other medications. A review of current research has shown that only a few medications can control IGE without potentially causing seizure aggravation. Broad-spectrum antiepileptic drugs such as valproate (VPA), lamotrigine, and topiramate are extremely effective at controlling a variety of seizures without causing excessive seizure aggravation. Among these drugs, VPA has the longest clinical experience history and the largest body of published data.

Childhood epilepsy: what is the evidence for what we think and what we do?

This article reviews the strength of the evidence that underlies the current approach to the management of childhood epilepsy. The authors reviewed published, peer-reviewed English literature accessed through PubMed and Cochrane reviews with evidence rated as Class 1 (strongest) to Class 4 (weakest). There is considerable inaccuracy in the diagnosis of seizures and epilepsy syndromes. Sound information supports the consensus that the diagnosis of epilepsy should await two unprovoked seizures. Population-based studies indicate that remission from childhood onset epilepsy occurs in at least 50% of children. It is easier to predict a good seizure outcome than a poor one. Absence of concomitant neurologic handicap and onset before about 12 years of age are the most consistent predictors of remission. Intractability is poorly defined and difficult to predict until several antiepilepsy drugs have been used and failed to control the seizures. Most epilepsy syndrome diagnoses do not yield an accurate prognosis. Social outcome appears unsatisfactory in about 50% of cases without intellectual handicap. Death is rare in childhood epilepsy. Those without severe neurologic handicaps have the same mortality as the general population. We identified only 27 published randomized trials of antiepilepsy drugs in children that compare the efficacy of antiepilepsy drugs, offer treatment of syndromes currently without successful treatment, or have negative effects. There is a pressing need for better definitions of seizures and epilepsy syndromes. The causes of poor social outcome are unclear. Intractability needs a clear definition and randomized trials comparing treatment regimes are sadly lacking.

Acute pancreatitis in children from Valproic acid: case series and review

Valproic acid (VPA) is a commonly prescribed medication approved for use in the United States for epilepsy, migraine, and bipolar disorder. Although the common adverse effects associated with VPA are typically benign, less common but more serious adverse effects can occur. These include hepatotoxicity, teratogenicity, possible polycystic ovaries with the potential for sterility or carcinogenesis, and pancreatitis. A characteristic clinical profile has been determined for several of these adverse effects. We report four children with VPA-induced pancreatitis, one of which was fatal, and review the literature. Three of these children presented within a 4-year period (1995-1999) at the same institution. Because previous reviews have included either a small number of patients, or both pediatric and adult patients, we reviewed only pediatric cases to minimize any effect from adults with more serious co-existing medical illnesses. We attempted to determine the following: (1) if there are any characteristics that are predictive of pancreatitis and whether it will be fatal; (2) whether different clinical and laboratory characteristics exist for nonfatal vs fatal cases; and (3) if a specific pediatric patient profile, similar to that with VPA associated hepatotoxity or polycystic ovary-androgenism syndrome, could be identified.

Pharmacological and therapeutic properties of valproate: a summary after 35 years of clinical experience

Thirty-five years since its introduction into clinical use, valproate (valproic acid) has become the most widely prescribed antiepileptic drug (AED) worldwide. Its pharmacological effects involve a variety of mechanisms, including increased gamma-aminobutyric acid (GABA)-ergic transmission, reduced release and/or effects of excitatory amino acids, blockade of voltage-gated sodium channels and modulation of dopaminergic and serotoninergic transmission. Valproate is available in different dosage forms for parenteral and oral use. All available oral formulations are almost completely bioavailable, but they differ in dissolution characteristics and absorption rates. In particular, sustained-release formulations are available that minimise fluctuations in serum drug concentrations during a dosing interval and can therefore be given once or twice daily. Valproic acid is about 90% bound to plasma proteins, and the degree of binding decreases with increasing drug concentration within the clinically occurring range. Valproic acid is extensively metabolised by microsomal glucuronide conjugation, mitochondrial beta-oxidation and cytochrome P450-dependent omega-, (omega-1)- and (omega-2)-oxidation. The elimination half-life is in the order of 9 to 18 hours, but shorter values (5 to 12 hours) are observed in patients comedicated with enzyme-inducing agents such as phenytoin, carbamazepine and barbiturates. Valproate itself is devoid of enzyme-inducing properties, but it has the potential of inhibiting drug metabolism and can increase by this mechanism the plasma concentrations of certain coadministered drugs, including phenobarbital (phenobarbitone), lamotrigine and zidovudine. Valproate is a broad spectrum AED, being effective against all seizure types. In patients with newly diagnosed partial seizures (with or without secondary generalisation) and/or primarily generalised tonic-clonic seizures, the efficacy of valproate is comparable to that of phenytoin, carbamazepine and phenobarbital, although in most comparative trials the tolerability of phenobarbital was inferior to that of the other drugs. Valproate is generally regarded as a first-choice agent for most forms of idiopathic and symptomatic generalised epilepsies. Many of these syndromes are associated with multiple seizure types, including tonic-clonic, myoclonic and absence seizures, and prescription of a broad-spectrum drug such as valproate has clear advantages in this situation. A number of reports have also suggested that intravenous valproate could be of value in the treatment of convulsive and nonconvulsive status epilepticus, but further studies are required to establish in more detail the role of the drug in this indication. The most commonly reported adverse effects of valproate include gastrointestinal disturbances, tremor and bodyweight gain. Other notable adverse effects include encephalopathy symptoms (at times associated with hyperammonaemia), platelet disorders, pancreatitis, liver toxicity (with an overall incidence of 1 in 20,000, but a frequency as high as 1 in 600 or 1 in 800 in high-risk groups such as infants below 2 years of age receiving anticonvulsant polytherapy) and teratogenicity, including a 1 to 3% risk of neural tube defects. Some studies have also suggested that menstrual disorders and certain clinical, ultrasound or endocrine manifestations of reproductive system disorders, including polycystic ovary syndrome, may be more common in women treated with valproate than in those treated with other AEDs. However, the precise relevance of the latter findings remains to be evaluated in large, prospective, randomised studies.

Treatment of typical absence seizures and related epileptic syndromes

Typical absences are brief (seconds) generalised seizures of sudden onset and termination. They have 2 essential components: clinically, the impairment of consciousness (absence) and, generalised 3 to 4Hz spike/polyspike and slow wave discharges on electroencephalogram (EEG). They differ fundamentally from other seizures and are pharmacologically unique. Their clinical and EEG manifestations are syndrome-related. Impairment of consciousness may be severe, moderate, mild or inconspicuous. This is often associated with motor manifestations, automatisms and autonomic disturbances. Clonic, tonic and atonic components alone or in combination are motor symptoms; myoclonia, mainly of facial muscles, is the most common. The ictal EEG discharge may be consistently brief (2 to 5 seconds) or long (15 to 30 seconds), continuous or fragmented, with single or multiple spikes associated with the slow wave. The intradischarge frequency may be constant or may vary (2.5 to 5Hz). Typical absences are easily precipitated by hyperventilation in about 90% of untreated patients. They are usually spontaneous, but can be triggered by photic, pattern, video games stimuli, and mental or emotional factors. Typical absences usually start in childhood or adolescence. They occur in around 10 to 15% of adults with epilepsies, often combined with other generalised seizures. They may remit with age or be lifelong. Syndromic diagnosis is important for treatment strategies and prognosis. Absences may be severe and the only seizure type, as in childhood absence epilepsy. They may predominate in other syndromes or be mild and nonpredominant in syndromes such as juvenile myoclonic epilepsy where myoclonic jerks and generalised tonic clonic seizures are the main concern. Typical absence status epilepticus occurs in about 30% of patients and is more common in certain syndromes, e.g. idiopathic generalised epilepsy with perioral myoclonia or phantom absences. Typical absence seizures are often easy to diagnose and treat. Valproic acid, ethosuximide and lamotrigine, alone or in combination, are first-line therapy. Valproic acid controls absences in 75% of patients and also GTCS (70%) and myoclonic jerks (75%); however, it may be undesirable for some women. Similarly, lamotrigine may control absences and GTCS in possibly 50 to 60% of patients, but may worsen myoclonic jerks; skin rashes are common. Ethosuximide controls 70% of absences, but it is unsuitable as monotherapy if other generalised seizures coexist. A combination of any of these 3 drugs may be needed for resistant cases. Low dosages of lamotrigine added to valproic acid may have a dramatic beneficial effect. Clonazepam, particularly in absences with myoclonic components, and acetazolamide may be useful adjunctive drugs.

The management of refractory idiopathic epilepsies

Idiopathic epilepsies comprise a wide variety of partial and generalized syndromes that have in common a known or presumed genetic etiology and the lack of overt abnormalities other than the epilepsy itself. Most of these epilepsies have a benign natural history and/or show a favorable response to antiepileptic drug (AED) therapy, but pharmacoresistance does occur in some patients. In general, therapeutic algorithms in idiopathic partial epilepsies (IPEs) are similar to those used for symptomatic partial epilepsies, but aggressive pharmacologic therapy is rarely indicated in these patients. In self-limited conditions such as benign epilepsy of childhood with centrotemporal spikes or some forms of benign epilepsy with occipital paroxysms, AED treatment may not even be indicated unless seizures interfere significantly with quality of life. Valproate (VPA) is usually regarded as the drug of choice in idiopathic generalized epilepsies (IGEs). Most patients become rapidly seizure free, and poor compliance or prescription of an inappropriate AED because of misdiagnosis are the most common causes of treatment failure in IGEs. In those patients who did not respond well to VPA (or in whom VPA is considered contraindicated), the choice of alternative AEDs is guided by syndromic diagnosis and associated possible coexistence of multiple seizure types. Lamotrigine is establishing itself as a useful agent for many refractory IGEs, and might be considered for first-line use in selected patients. Topiramate (TPM) is another promising new agent in the management of refractory tonic-clonic seizures of nonfocal onset, but its potential efficacy against other primarily generalized seizure types has not been clearly established. Some of the older drugs, particularly ethosuximide (ESM), barbiturates, and benzodiazepines (BZDs), still have an important role in the management of refractory IGEs, especially in combination with VPA. Because carbamazepine (CBZ), phenytoin (PHT), tiagabine (TGB), vigabatrin (VGB), and gabapentin (GBP) may precipitate or aggravate absence and/or myoclonic jerks, their role in IGE syndromes associated with multiple seizure types is limited mostly to adjunctive use in patients unresponsive to first-line therapy.

Assessing risk to benefit ratio in antiepileptic drug therapy

Assessment of risk to benefit ratio in patients with epilepsy is crucial in determining the need for treatment, the choice of drugs and the use of monitoring tools such as laboratory tests and other investigations. Active epilepsy per se carries significant risks in terms of increased mortality, susceptibility to psychopathology and physical injury, and reduced quality of life as a result of restricted lifestyle, stigma and prejudice. By preventing the occurrence of seizures, antiepileptic drugs (AEDs) attenuate or eliminate altogether seizure-related risks, but other risks may arise due to the side effects of the drugs, all of which have a relatively narrow therapeutic index. While there are no major differences in the degree of efficacy between AEDs which are effective in any given seizure type, side effect profiles differ considerably from one agent to another and represent a major factor in determining choice of treatment. Assessment of risk to benefit ratio should also take into consideration patient-specific factors such as type and severity of the epilepsy, age, sex, childbearing potential, medical and drug history, associated disease, use of concomitant medication (including the contraceptive pill) and the prospected patient's compliance. In some benign epilepsy syndromes, such as idiopathic partial epilepsy with centro-temporal spikes, the risk of side effects from AEDs may outweigh potential benefits in terms of seizure control, and treatment is generally not indicated. At the opposite end of the spectrum, the serious morbidity and mortality associated with severe epileptic encephalopathies, such as the Lennox-Gastaut syndrome, justifies aggressive treatment even with drugs associated with a relatively high risk of life threatening side effects such as felbamate. The present article will provide an overview of specific risks associated with epilepsy and with the various drugs used for its treatment, and will attempt to evaluate the complex balance between these risks and therapeutic benefits in different categories of patients.

Significant anticonvulsant side-effects in children and adolescents

The anticonvulsant (AED) history for 216 children and adolescents with epilepsy was reviewed to determine the incidence and types of significant side effects (SSE) which warranted ceasing the drug (not due to a lack of response or a high dose). All parents of patients with epilepsy seen by the author over a 2 year period (March 1996 - March 1998) were questioned about SSE to previous AEDs, and the child's current therapy was also monitored prospectively to determine SSE. There were 107 girls and 109 boys ranging in age from 3 months - 18 years. Eighty-three patients had been exposed to a single AED while 133 had multiple AED exposures: mean 3.6 drugs; range 2-10 drugs. They were exposed to a total of 568 AEDs with SSE occurring in 15% of drug contacts: 7% due to behavioural changes such as irritability, aggression or hyperactivity; 8% were due to other factors such as a rash, headache, gastrointestinal disturbance or drowsiness. Fifty-seven children (26%) had experienced at least one SSE with 19 (9%) having SSE to more than one AED (range 2-4). Global developmental delay or an intellectual disability (ID) were present in 67 patients, and 27 (40%) of these experienced SSE compared with 30 (20%) of the group with normal cognition. This difference was principally due to the higher incidence of behavioural SSE in the ID group 28% versus 6% for the normal cognition group. Allowing for the higher number of AEDs used in the ID group (implying that their epilepsy was more difficult to control), behavioural SSE were still significantly more likely to occur in this group, i.e. 1: 9.6 drug exposures compared with 1: 31. 8 exposures for the normal cognition group (P<0.001). Monotherapy trials underestimate the true incidence of SSE in clinical practice as 26% of children had experienced at least one SSE and 9% had SSE to more than one AED. Those with ID were three times more likely to have behavioural SSE than children with normal cognition.

Lamictal (lamotrigine) monotherapy for typical absence seizures in children

PURPOSE

To investigate whether lamotrigine (LTG) monotherapy is effective and safe for newly diagnosed typical absence seizures in children and adolescents (aged 3-15 years, n = 45).

METHODS

A "responder-enriched" study design was used: open-label dose escalation was followed by placebo-controlled, double-blind testing of LTG. Conventional hyperventilation testing with EEG recording was used to confirm diagnoses and assess treatment success defined as complete freedom from seizures. Ambulatory 24-h EEG recordings provided supporting evidence of effectiveness. Safety was assessed by evaluation of adverse events, vital signs, and physical, neurologic, and laboratory examinations. Plasma samples were taken to evaluate the pharmacokinetics of LTG.

RESULTS

During initial open-label dose escalation, 71.4% of patients (intent-to-treat) or 82% (per protocol analysis) became seizure free; individual patients responded at doses ranging from 2 to 15 mg/kg/day (median, 5.0). In the placebo-controlled, double-blind phase of the study, statistically significantly more patients remained seizure free when treated with LTG (62%) than with placebo (21%; p < 0.02; for the intent-to-treat analysis). Mean plasma concentrations of LTG, were linearly related to dose, although there was substantial interindividual variation. No patients were withdrawn from the study for any safety-related reason.

CONCLUSIONS

LTG monotherapy is effective for typical absence seizures in children and is generally well tolerated.

Evaluation of the antiinflammatory activity of sodium valproate in rats and mice

1. Treatment of rats with sodium valproate (100, 200 and 400 mg/kg i.p.) reduced the paw oedema induced by carrageenan by 36, 15 and 48%, respectively, within 3 h . 2. The effect produced by the higher dose (400 mg/kg) was equivalent to that produced by indomethacin (100 mg/kg). At 100 and 400 mg/kg, sodium valproate decreased the granuloma formation by a significant level. Similar doses of sodium valproate did not affect the rectal temperature in yeast-fevered mice, except with a dose of 200 mg/kg, which showed a significant decrease at 180 and 240 min posttreatment. 3. In comparison, sodium salicylate reduced the hyperthermia very significantly throughout the study period. 4. In normothermic mice, the rectal temperature changed only with a 400 mg/kg dose, but did not respond to lower SV doses. 5. The results indicate that sodium valproate, useful clinically as an epileptic drug, may have a potential therapeutic use as a mild antiinflammatory agent.