Randomised comparative monotherapy trial of phenobarbitone, phenytoin, carbamazepine, or sodium valproate for newly diagnosed childhood epilepsy

Treatment strategies

There has been important progress in the identification of antiepileptic compounds and their indications in children over the past 15 years: their number has doubled and specific pediatric trials are being performed to document their effect according to seizures and syndromes as well as their tolerability in pediatrics. The improved understanding of pharmacokinetics and drug-drug interactions has helped to optimize treatment. Specific issues specific of infants have also been studied although new antiepileptic drugs are still dramatically lacking for this age group. Before reaching a syndromic diagnosis, the choice of a first- line agent goes to compounds with the largest range of efficacy and least identified risks. Subsequent choices are mainly based on the epilepsy syndrome and seizure type in addition to good clinical practice to determine dose, adverse effect profile, risk of aggravating seizures and drug interactions, clinician's experience, cultural habits, and availability of drugs. If there are several options, preference is given to the compound that exhibits the best risk/benefit ratio, or the most rapid titration when seizure frequency is the major issue. For new antiepileptic compounds, price is often a limiting factor in countries with poor insurance coverage. Third generation anti-epileptic drugs are emerging which also seem to be promising.

Anticonvulsant and anxiolytic activity of the peptide fraction isolated from the venom of the social wasp Polybia paulista

BACKGROUND

Arthropod venoms have attracted interest because they represent a source of neuroactive compounds that can be useful tools in neuroscience and pharmacological investigations.

OBJECTIVE

The purpose of the present work was to evaluate the anticonvulsant, anxiolytic, and behavioral effects of the peptide fraction separated from venom of the social wasp.

MATERIALS AND METHODS

The low- molecular-weight compounds of the venom were separated by ultrafiltration and the bioassays were performed to test anticonvulsant and anxiolytic effects, as well as alterations in the spontaneous behavior of the animals.

RESULTS

Intracerebroventricular injections of the compounds induced dose-dependent anticonvulsant effects and a potent anxiolytic activity. Regarding behavioral effects, no significant differences were observed in relation to the saline control group.

CONCLUSION

The low-molecular-weight compounds of the venom of Polybia paulista include neuroactive peptides that can be used as pharmacological resources for anticonvulsant and anxiolytic drug research.

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.

Behavioral problems in children with epilepsy in rural Kenya

The aims of this study were to record behavioral problems in children with epilepsy (CWE), compare the prevalence with that reported among healthy children without epilepsy, and investigate the risk factors. A child behavioral questionnaire for parents comprising 15 items was administered to the main caregiver of 108 CWE and 108 controls matched for age in Kilifi, Kenya. CWE had a higher mean score for reported behavioral problems than controls (6.9 vs 4.9, t=4.7, P<0.001). CWE with active epilepsy also recorded more behavioral problems than those with inactive epilepsy (8.2 vs 6.2, t=-2.9, P=0.005). A significantly greater proportion of CWE (49% vs 26% of controls) were reported to have behavioral problems. Active epilepsy, cognitive impairment, and focal seizures were the most significant independent covariates of behavioral problems. Behavioral problems in African CWE are common and need to be taken into consideration in planning comprehensive clinical services in this region.

Behavioural comorbidity in Tanzanian children with epilepsy: a community-based case-control study

AIM

The aim of this study was to define the prevalence of and risk factors for behavioural disorders in children with epilepsy from a rural district of Tanzania by conducting a community-based case-control study.

METHOD

One hundred and twelve children aged 6 to 14 years (55 males, 57 females; median age 12 y) with active epilepsy (at least two unprovoked seizures in the last 5 y) were identified in a cross-sectional survey and included in this study. Children who were younger than 6 years were excluded in order to eliminate febrile seizures. Behaviour was assessed using the Rutter scale; children who scored 13 or more were considered to have disordered behaviour. A comparison group was made up of age- and sex-matched children without epilepsy (n = 113; 57 males, 56 females; median age 12 y).

RESULTS

Behavioural disorders were diagnosed in 68 of 103 (66%) children with epilepsy and in 19 of 99 (19%) controls. Disordered behaviour was significantly more common in children with epilepsy than in the comparison group (univariate odds ratio 8.2; 95% confidence interval [CI] 4.3-15.6; p < 0.001) and frequent seizures and poor scholastic attainment were associated in children with epilepsy. Behavioural disorders were not associated with antiepileptic drug usage. Attention problems were present in 48 of 91 (53%) children with epilepsy and 16 of 97 (17%) controls (univariate odds ratio 5.7; 95% CI 2.9-11.1; p < 0.001). In children with epilepsy, attention problems were significantly more common in males and were associated with frequent seizures.

INTERPRETATION

Children with epilepsy in a rural area of sub-Saharan Africa have a high prevalence of behavioural disorders and attention problems, both of which are associated with frequent seizures. Providing behaviour assessment and appropriate intervention programmes for children with epilepsy may reduce the burden of behaviour disorders in this setting.

Pharmacologic treatment of intractable epilepsy in children: a syndrome-based approach

The successful pharmacologic treatment of intractable childhood epilepsy is predicated upon an accurate classification of the epilepsy syndrome. The selection of an antiepileptic drug is facilitated by the knowledge of syndrome-specific efficacy, the anticipation of potential side effects, and a careful risk-benefit assessment tailored to each patient. As such, the identification of comorbidities and careful monitoring for treatment-emergent adverse events, especially cognitive and behavioral effects, is of utmost importance. Especially in refractory cases, polypharmacy may increase the likelihood of side effects, but carefully chosen combinations can result in synergistic benefit. For most epilepsy syndromes, newer antiepileptic drugs typically yield equivalent efficacy and superior tolerability. Nevertheless, continued research is needed to further contrast the syndrome-specific efficacy and tolerability of available drugs and to foster the development of new agents with superior efficacy and side effect profiles.

Treatment of benign focal epilepsies in children: when and how should be treated?

Benign focal epilepsies represent almost one-fourth of all childhood epilepsies and are a frequent occurrence in clinical practice. They include benign infantile seizures (BIS), Panayiotopoulos syndrome (PS), and benign childhood epilepsy with centrotemporal spikes (BCECTS) in this order of the onset age. Because the prognosis is always excellent in patients with benign focal epilepsies, we must consider the risks and benefits of chronic antiepileptic drug (AED) administration. AED treatment is usually not recommended for the patients with a first attack, but should be considered for those with a second or third attack. A choice of AED has been based on the expert opinion. Carbamazepine (CBZ) is recommended for both acute and chronic treatment of seizure clusters in patients with BIS. Valproic acid (VPA), CBZ or clobazam (CLB) appears to be a first option of AED for patients with PS. A common first choice for BCECTS is CBZ in the USA and Japan, and VPA in the EU. The treatment period should be as short as possible without waiting for EEG normalization, possibly within 2 years after the initiation of AED. We must remember that some patients with BCECTS may have an "atypical evolution". In conclusion, when and how to treat this benign condition should be determined in an individual manner based on the length and frequency of seizures, circadian rhythm of the attacks, interictal EEG findings, cognitive and behavioral functions in daily life and the attitude of the parents toward seizure recurrences and AED side effects.

Update on the Genetic Polymorphisms of Drug-Metabolizing Enzymes in Antiepileptic Drug Therapy

Genetic polymorphisms in the genes that encode drug-metabolizing enzymes are implicated in the inter-individual variability in the pharmacokinetics and pharmaco-dynamics of antiepileptic drugs (AEDs). However, the clinical impact of these polymorphisms on AED therapy still remains controversial. The defective alleles of cytochrome P450 (CYP) 2C9 and/or CYP2C19 could affect not only the pharmacokinetics, but also the pharmacodynamics of phenytoin therapy. CYP2C19 deficient genotypes were associated with the higher serum concentration of an active metabolite of clobazam, N-desmethylclobazam, and with the higher clinical efficacy of clobazam therapy than the other CYP2C19 genotypes. The defective alleles of CYP2C9 and/or CYP2C19 were also found to have clinically significant effects on the inter-individual variabilities in the population pharmacokinetics of phenobarbital, valproic acid and zonisamide. EPHX1 polymorphisms may be associated with the pharmacokinetics of carbamazepine and the risk of phenytoin-induced congenital malformations. Similarly, the UDP-glucuronosyltransferase 2B7 genotype may affect the pharmacokinetics of lamotrigine. Gluthatione S-transferase null genotypes are implicated in an increased risk of hepatotoxicity caused by carbamazepine and valproic acid. This article summarizes the state of research on the effects of mutations of drug-metabolizing enzymes on the pharmacokinetics and pharmacodynamics of AED therapies. Future directions for the dose-adjustment of AED are discussed.

The operational model of a network for managing patients with convulsive epilepsy in rural West China

OBJECTIVE

To establish an operational model of a network for managing patients with convulsive epilepsy in rural areas of West China.

METHODS

The network is under unified leadership of the public health administration departments, who liaised with medical institutions and disease control and prevention organizations to foster local communities to participate. Patients with convulsive epilepsy were treated with phenobarbital. Trained local primary health care physicians carried out screening, treatment, and follow-up. Political, financial, and technological support was incrementally provided through the network. Efficacy was assessed as the percentage reduction in seizure frequency and the retention of patients on treatment.

RESULTS

Two thousand five hundred fourteen patients with active convulsive epilepsy were enrolled. After more than 1 year of treatment, 78.4% of the patients had a 50% or greater reduction in seizure frequency and 43.3% remained seizure free. Probability of retention was 85.8% at 750 days. Nearly 20% patients withdrew from the project, and most of them migrated out of the study areas. Some regular training and educational programs were also carried out.

CONCLUSION

This pragmatic procedure suggests that the network could be suitable for managing convulsive epilepsy in resource-poor regions. Such a network could depend on existing primary health services to ensure its sustainability.

Consensus guidelines into the management of epilepsy in adults with an intellectual disability

BACKGROUND

Epilepsy has a pervasive impact on the lives of people with intellectual disability and their carers. The delivery of high-quality care is impacted on by the complexity and diversity of epilepsy in this population. This article presents the results of a consensus clinical guideline process.

RESULTS

A Delphi process identified a list of priority areas for the development of evidence-based guidelines. All guidelines were graded and consensus on scoring was achieved across the guideline group.

CONCLUSION

There is a dearth of high-quality evidence from well-constructed studies on which to base guidance. However, the development of internationally derived consensus guidelines may further support the management of epilepsy in adults with an intellectual disability.

Divalproex sodium in children with partial seizures: 12-month safety study

This phase III, open-label, multicenter, outpatient study evaluated the 12-month safety of valproate using divalproex sodium sprinkle capsules for partial seizures, with or without secondary generalization, in children aged 3-10 years (n = 169). Laboratory parameters and vital signs were assessed, and the Wechsler Scales of Intelligence, the Developmental Profile-II, movement-related items from the Udvalg for Kliniske Undersøgelser, and the Behavior Assessment System for Children were administered. Efficacy was measured by the 4-week seizure rate. The most common treatment-emergent adverse events in the 169 study patients were typical childhood illnesses: pyrexia (18%), cough (17%), and nasopharyngitis (14%). The most common adverse events not considered typical childhood illnesses were vomiting (14%), tremor (9%), somnolence (8%), and diarrhea (8%). Of the 169 patients, 11 (6.5%) were hospitalized with serious treatment-emergent adverse events. Although elevated ammonia levels were observed in 31 treated patients, and mean increases in uric acid concentrations and decreases in platelets were observed, the majority of patients were asymptomatic. Except for tremor, no increases in movement-related adverse effects were observed. Small numeric improvements were reported in the Wechsler Scales and the Behavior Assessment System for Children. The safety findings in this 12-month study are generally consistent with previous reports of valproate in adult and pediatric epilepsy patients.

Drug treatment of epilepsy in the century of the ILAE: the second 50 years, 1959-2009

The drug therapy of epilepsy evolved enormously in this 50 year period. Advances in therapeutics included the incorporation of pharmacokinetics into clinical practice, enormous advances in neurochemistry, a trend to antiepileptic drug monotherapy, better drug assessment, better understanding of therapeutic outcomes, and the recognition of the large epilepsy treatment gap in many countries. An unprecedented range of new drugs was introduced in this period. Before 1989, these included carbamazepine, valproate, ethosuximide, and the benzodiazepines. Since 1989, 13 more new drugs have been licensed and marketed and there are others in the pipeline. The International League Against Epilepsy and its leading figures have played an important role in these developments. In this period, too, there has been a rapid expansion in research and development within the pharmaceutical industry and a rise in the value of the antiepileptic drug market. In parallel, governmental regulation of pharmaceuticals has greatly increased. To what extent the overall prognosis of epilepsy has improved as a result of these activities is an interesting and perplexing question.

Thyroid hormones in children with epilepsy during long-term administration of carbamazepine and valproate

OBJECTIVE

This study evaluates the effects of long-term carbamazepine (CBZ) and valproate acid (VPA) therapy on thyroid function in epileptic children.

DESIGN

A prospective study performed in 32 newly diagnosed pediatric patients, subdivided into two groups: 18 patients treated with CBZ and 14 patients treated with VPA. Thirty-two sex- and age- matched subjects served as controls.

METHODS

Serum TSH, thyroxine (T(4)), triiodothyronine (T(3)), free thyroxine (fT(4)), free triiodothyronine (fT(3)), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) were evaluated at baseline and at the 3rd, 6th, and 12th month in all patients and in the control group. A TRH stimulation test was performed in all epileptic patients at baseline and at the 3rd, 6th, and 12th month evaluations while in controls only baseline assessment was carried out.

RESULTS

At baseline evaluation, thyroid function was normal in all epileptic children. After 3 months, CBZ-treated patients showed serum T(4) and fT(4) levels significantly lower than baseline evaluation and control subjects. Serum T(4) and fT(4) concentrations were unaffected by VPA monotherapy. Serum T(3) and fT(3) were normal in both CBZ-treated and VPA-treated patients. TRH test was normal in all patients. At 6th and 12th month evaluations, the same alterations were present in CBZ-treated patients while thyroid function remained normal in VPA-treated patients. TRH test responses were normal in all epileptic patients. TPO-Ab and TG-Ab were always absent in all patients.

CONCLUSIONS

Our data suggest that VPA monotherapy does not alter thyroid hormones. On the contrary, alterations of thyroid hormones occur in CBZ-treated children. However, the patients are euthyroid and thyroid hormone alterations are not associated with clinical or subclinical hypothyroidism.

Safety in paediatric clinical trials--a 7-year review

AIM

The safety of clinical trials in children has not been previously studied. We aimed to identify how safety is monitored and the extent of adverse drug reactions (ADRs).

METHODS

A literature review of the Medline Database for therapeutic clinical trials involving oral and intravenous medicines in children from 1996 to 2002. Papers were read to determine the safety monitoring and the presence of adverse events (AEs) or ADRs.

RESULTS

Seven hundred thirty-nine trials were identified. Thirteen (2%) had safety monitoring committees (SMCs). Five hundred twenty-three (71%) trials reported AEs and 151 (20%) of these trials reported a serious AE. ADRs were present in 270 (36.5%) trials, with 80 (11%) of trials having a moderate or severe ADR. Six clinical trials were terminated early because of significant drug toxicity. All of these had SMCs. There were deaths in 83 (11%) trials. In the majority of trials, mortality was thought to be unrelated to the investigational drug; however, in two trials mortality was higher in the treatment group.

CONCLUSIONS

About 11% of trials have a moderate or severe ADR. All paediatric clinical trials should have a SMC.

An observational study of first-line valproate monotherapy in focal epilepsy

The objective of this multinational open-label, prospective study was to collect, under naturalistic conditions, data on the effectiveness and tolerability of first-line monotherapy with valproate in subjects newly or recently diagnosed with focal onset epilepsy. Patients were treated with sustained release sodium valproate. Seizure control and occurrence of adverse events were assessed after 6 months. Around 1192 adults and 792 children were included. The mean daily valproate dose was 683 mg in children and 987 mg in adults. The retention rate at 6 months was 90.0%. At this time, 77% of subjects were seizure free (83.7% of children and 72.7% of adults). Adverse events possibly related to treatment were observed in 10.2% of subjects, leading to treatment modification for 1.7%. The most common adverse events were weight gain, gastro-intestinal, neurological and skin disorders. Sustained release sodium valproate is effective and shows acceptable tolerability as first-line monotherapy in focal onset epilepsy.

Multiple treatment comparisons in epilepsy monotherapy trials

BACKGROUND

The choice of antiepileptic drug for an individual should be based upon the highest quality evidence regarding potential benefits and harms of the available treatments. Systematic reviews and meta-analysis of randomised controlled trials should be a major source of evidence supporting this decision making process. We summarise all available individual patient data evidence from randomised controlled trials that compared at least two out of eight antiepileptic drugs given as monotherapy.

METHODS

Multiple treatment comparisons from epilepsy monotherapy trials were synthesized in a single stratified Cox regression model adjusted for treatment by epilepsy type interactions and making use of direct and indirect evidence. Primary outcomes were time to treatment failure and time to 12 month remission from seizures. A secondary outcome was time to first seizure.

RESULTS

Individual patient data for 6418 patients from 20 randomised trials comparing eight antiepileptic drugs were synthesized. For partial onset seizures (4628 (72%) patients), lamotrigine, carbamazepine and oxcarbazepine provide the best combination of seizure control and treatment failure. Lamotrigine is clinically superior to all other drugs for treatment failure but estimates suggest a disadvantage compared to carbamazepine for time to 12 month remission [Hazard Ratio (95% Confidence Interval) = 0.87(0.73 to 1.04)] and time to first seizure [1.29(1.13 to 1.48)]. Phenobarbitone may delay time to first seizure [0.77(0.61 to 0.96)] but at the expense of increased treatment failure [1.60(1.22 to 2.10)]. For generalized onset tonic clonic seizures (1790 (28%) patients) estimates suggest valproate or phenytoin may provide the best combination of seizure control and treatment failure but some uncertainty remains about the relative effectiveness of other drugs.

CONCLUSION

For patients with partial onset seizures, results favour carbamazepine, oxcarbazepine and lamotrigine. For generalized onset tonic clonic seizures, results favour valproate and phenytoin.

Multiple Molecular pathways explain the anti-proliferative effect of valproic acid on prostate cancer cells in vitro and in vivo

BACKGROUND

Valproic acid (VPA), is a drug approved by the FDA for epilepsy and bipolar disorders. It is a known Histone Deacetylase Inhibitor (HDACI). We tested VPA, for its anti-proliferative activity in prostate cancer (PCa) cell lines in vitro and in vivo.

METHODS

DU-145 and PC-3 PCa cell lines were cultured with different doses of VPA. Cells were examined for their viability, cell cycle status and expression of cell cycle arrest, and proliferation markers. Nude mice bearing xenografts of human PCa cell lines, DU-145, and PC-3, were administered VPA in their drinking water.

RESULTS

VPA displayed a dose- and time-dependent anti-proliferative effect on DU-145 and PC-3 PCa cell lines in vitro. A sustained effect of the drug was seen on cell cycle arrest even at 24 hr after removal of the drug, after which the effects returned to the basal state. Administration of 0.4% w/v VPA in drinking water (resulting in 0.4 mM VPA, in plasma) was effective in inducing growth arrest, cell death, and senescence in vivo and was also anti-angiogenic. The activation of all or some of these anti-proliferative pathways may be contingent on acetylation status of histones, confirmed by detection of increased acetyl-H3K9 in VPA-treated samples when compared with untreated controls. Pharmacodynamic studies showed an increase in expression of p21 and decrease in PCNA in xenografts of VPA-treated mice compared with protein expression in untreated controls.

CONCLUSIONS

VPA may be functioning as an HDACI to inhibit growth of PCa cells in vitro and in vivo by modulating multiple pathways including cell cycle arrest, apoptosis, angiogenesis, and senescence.

Side effects of phenobarbital and carbamazepine in childhood epilepsy: randomised controlled trial

OBJECTIVE

To compare the behavioural side effects associated with two commonly used antiepilepsy drugs-phenobarbital and carbamazepine-in children in Bangladesh.

DESIGN

Prospective randomised controlled single centre trial.

SETTING

Specialist children's hospital in Dhaka, Bangladesh.

PARTICIPANTS

108 children aged 2-15 with generalised tonic-clonic (n=51) or partial and secondary generalised seizures (n=57).

MAIN OUTCOME MEASURES

Seizure control and behavioural side effects.

RESULTS

91 children were followed up for 12 months. Six required a change of antiepilepsy drug. Side effects were compared in 85 children. In the last quarter of the 12 month follow-up, 71 children were seizure free after one year's treatment. Thirty two in the phenobarbital group and 39 in the carbamazepine group had no seizures in 74 and 102 days after randomisation, respectively. Ten children had increased behavioural problems, which were unacceptable in four (one in the phenobarbital group and three in the carbamazepine group). Independent t tests, however, showed no difference between the two trial drugs.

CONCLUSION

There was no excess in behavioural side effects with phenobarbital in children with epilepsy in a country with limited resources. Trial registration NCT00381537.

New statistical method for analyzing time to first seizure: example using data comparing carbamazepine and valproate monotherapy

INTRODUCTION

Time to first seizure is a common outcome in antiepileptic drug (AED) studies. Previous studies have typically failed to find statistically significant differences between carbamazepine (CBZ) and valproate (VPS). We re-analyzed a meta-analysis comparing CBZ and VPS monotherapy with new powerful statistical methods that incorporate baseline seizure rate information.

METHODS

Individual patient data were available on 1,265 patients from a meta-analysis of five trials. The outcome measure was time to first seizure after randomization, adjusted for background variables and baseline seizure rate.

RESULTS

We found strong evidence of an interaction between treatment and epilepsy type, and between treatment and age. For generalized onset seizures, VPS was statistically significantly better than CBZ: VPS delayed the first seizure after treatment 58%, 52%, 44%, and 36% longer than CBZ for individuals aged 10, 20, 30, or 40, respectively. For partial onset seizures in individuals older than 30, CBZ was significantly better then VPS; CBZ delayed the time to first seizure by 9%, 25%, 44%, and 66% longer than VPS for individuals aged 20, 30, 40, or 50, respectively.

CONCLUSION

The results show clear age-varying differences between the effectiveness of CBZ and VPS for generalized onset and partial onset seizures, which have not been identified in previous studies using standard statistical methods. In future trials of AED monotherapy or add-on where time to first or Nth seizure is an outcome, methodology that can incorporate baseline seizure rate information would allow more powerful comparisons between treatments or between treatment and placebo.

Neurotoxins from invertebrates as anticonvulsants: From basic research to therapeutic application

Invertebrate venoms have attracted considerable interest as a potential source of bioactive substances, especially neurotoxins. These molecules have proved to be extremely useful tools for the understanding of synaptic transmission events, and they have contributed to the design of novel drugs for the treatment of neurological disorders and pain. In this context, as epilepsy involves neuronal substrates, which are sites of action of many neurotoxins; venoms may be particularly useful for antiepileptic drug (AED) research. Epilepsy is a chronic disease whose treatment consists of controlling seizures with antiepileptics that very often induce strong undesirable side effects that may limit treatment. Here, we review the vast, but yet unexplored, world of neurotoxins from invertebrates used as probes in pharmacological screening for novel and less toxic antiepileptics. We briefly review (1) the molecular basis of epilepsy, as well as the sites of action of commonly used anticonvulsants (we bring a comprehensive review of the elements from invertebrate venoms which are mostly studied in neuroscience research and may be useful for drug development); (2) peptides from conus snails; (3) peptides and polyamine toxins from spiders and wasps; and (4) peptides from scorpions.

Acute seizure-related hospitalizations in children with newly diagnosed epilepsy

Hospitalizations due to breakthrough seizures were studied in children with newly diagnosed epilepsy to evaluate (1) risk factors associated with such admissions, in particular the withholding of medication and subtherapeutic dose of anticonvulsants, and (2) the impact of the unscheduled hospitalization on subsequent seizure outcome. We recruited patients aged less than 18 years with newly diagnosed epilepsy who presented to the pediatric department in Tuen Mun Hospital between January 2002 and December 2003. Patients with acute seizure-related hospitalization within 1 year after diagnosis were included as cases (n = 36); patients with no such hospitalization were included as controls (n = 86). Treatment effect was analyzed at the last follow-up visit before January 2005. Significant univariate association was observed between seizure-related hospitalization and age at seizure onset (OR = 0.91, 95% CI 0.84, 1), idiopathic epilepsy (OR = 0.35, 95% CI 0.15, 0.81), no antiepileptic drug (OR = 3.67, 95% CI 1.51, 8.18), and subtherapeutic doses of antiepileptic drug (OR = 9.9, 95% CI 2.2, 43.8). Independent risk factors of such hospitalizations were etiology of epilepsy, no antiepileptic drug, subtherapeutic dose of antiepileptic drug, and history of febrile convulsion. Sixty-four percent of the cohort was seizure-free. Acute seizure-related hospitalization was associated with less favorable outcome (OR = 3.79, 95% CI 1.48, 9.26).

Prognosis of chronic and newly diagnosed epilepsy: revisiting temporal aspects

PURPOSE OF REVIEW

The purpose is to review recent papers on the prognosis of epilepsy, with an emphasis on the importance of considering the temporal aspects of epilepsy.

RECENT FINDINGS

The review considers five specific points: What is the chance of spontaneous remission without treatment (i.e. what is the natural history of untreated epilepsy)? What is the prognosis of epilepsy in newly diagnosed patients and how effective is therapy in previously drug-naïve patients? Does delaying treatment make long-term prognosis worse? Is the prognosis of chronic established epilepsy inevitably bad? Refractory epilepsy, pharmaco-resistance and the influence of time.

SUMMARY

This paper reviews the recent evidence that has provided data about temporal aspects of prognosis in epilepsy and confirms the importance of taking a synoptical view of prognosis, incorporating temporal aspects, in making clinical prognostic predictions.

Importance of competing risks in the analysis of anti-epileptic drug failure

BACKGROUND

Retention time (time to treatment failure) is a commonly used outcome in antiepileptic drug (AED) studies.

METHODS

Two datasets are used to demonstrate the issues in a competing risks analysis of AEDs. First, data collection and follow-up considerations are discussed with reference to information from 15 monotherapy trials. Recommendations for improved data collection and cumulative incidence analysis are then illustrated using the SANAD trial dataset. The results are compared to the more common approach using standard survival analysis methods.

RESULTS

A non-significant difference in overall treatment failure time between gabapentin and topiramate (logrank test statistic = 0.01, 1 degree of freedom, p-value = 0.91) masked highly significant differences in opposite directions with gabapentin resulting in fewer withdrawals due to side effects (Gray's test statistic = 11.60, 1 degree of freedom, p = 0.0007) but more due to poor seizure control (Gray's test statistic = 14.47, 1 degree of freedom, p-value = 0.0001). The significant difference in overall treatment failure time between lamotrigine and carbamazepine (logrank test statistic = 5.6, 1 degree of freedom, p-value = 0.018) was due entirely to a significant benefit of lamotrigine in terms of side effects (Gray's test statistic = 10.27, 1 degree of freedom, p = 0.001).

CONCLUSION

Treatment failure time can be measured reliably but care is needed to collect sufficient information on reasons for drug withdrawal to allow a competing risks analysis. Important differences between the profiles of AEDs may be missed unless appropriate statistical methods are used to fully investigate treatment failure time. Cumulative incidence analysis allows comparison of the probability of failure between two AEDs and is likely to be a more powerful approach than logrank analysis for most comparisons of standard and new anti-epileptic drugs.

First, do no harm: the risks of overtreating children with epilepsy

BACKGROUND: Although overtreatment with antiepileptic drugs contributes to the morbidity associated with epilepsy, many children still are overtreated. OBJECTIVE: To evaluate if the withdrawal of at least one antiepileptic drug (AED) in children with refractory epilepsy using polytherapy enable a better seizure control. METHOD: This was a prospective study. Children with refractory epilepsy using at least two AEDs were included. Once the patient, or guardian, agreed to participate in the study, one or more AED were slowly tapered off. The remaining AEDs dosages could be adjusted as needed, but a new AED could not be introduced. RESULTS: Fifteen patients were evaluated, three girls; ages ranging from 3 to 18 (mean=8.7 years). After at least one AED withdrawal, two (13.5%) patients became seizure free, seizures improved >50% in 5 (33.5%) patients, did not change in 5 (33.5%), and seizure frequency became worse in 3 (20%). Adverse events improved in 12 patients (80%). CONCLUSION: The withdrawal of at least one AED is a valuable option in the treatment of selected children with refractory epilepsy.

The Evaluation of Thyroid Functions, Thyroid Antibodies, and Thyroid Volumes in Children with Epilepsy during Short-Term Administration of Oxcarbazepine and Valproate

PURPOSE

The aim of this study was to evaluate the effects of short-term oxcarbazepine (OXC) and valproate (VPA) monotherapy on thyroid functions in children.

METHODS

Fifty-five newly diagnosed epileptic children with normal thyroid functions (confirmed with the thyrotropin releasing hormone stimulation test) participated in this study. VPA treatment was started in 30 patients and OXC in 25 patients. Serum thyroxine (T(4)), free thyroxine (fT(4)), triiodothyronine (T(3)), free triiodothyronine (fT(3)), reverse T3 (rT(3)), thyroid peroxidase antibodies (TPO-ab), and urine iodine levels were evaluated at baseline and at the third and sixth months of therapy.

RESULTS

In the OXC group, serum T(4), fT(4), T(3), fT(3), and rT(3) levels were found to be decreased at the third and sixth months, the differences were significant compared to the baseline values except for fT(3) levels at the third month and fT(4) and rT(3) levels at the sixth month (p < 0.05). At the sixth month, serum T(4) level dropped below the normal reference value in 8 (32%), fT(4) in 5 (20%), T(3) in 4 (16%), and fT(3) in 3 (12%) patients. In the VPA group, mean T(4), fT(4), T(3), fT(3), and rT(3) levels at 3 and 6 months remained similar compared to the baseline values (p > 0.05). Mean serum thyroid stimulating hormone levels increased significantly at the sixth month compared to the baseline values in the VPA group (p < 0.05) while it remained unchanged in the OXC group (p > 0.05). There was no effect of either drug on urinary iodine excretion and serum TPO-ab levels remained in normal ranges throughout the study.

CONCLUSIONS

In this prospective study, it is documented that children under short-term OXC or VPA therapy showed altered thyroid functions similar to the changes observed after long-term treatment. Although, the clinical significance of these results need to be evaluated with future studies, this observation of altered thyroid functions points out that thyroid functions may need to be monitored closely in children receiving antiepileptic treatment, even in the short-time interval.

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.

Experimental and clinical evidence for loss of effect (tolerance) during prolonged treatment with antiepileptic drugs

Development of tolerance (i.e., the reduction in response to a drug after repeated administration) is an adaptive response of the body to prolonged exposure to the drug, and tolerance to antiepileptic drugs (AEDs) is no exception. Tolerance develops to some drug effects much more rapidly than to others. The extent of tolerance depends on the drug and individual (genetic?) factors. Tolerance may lead to attenuation of side effects but also to loss of efficacy of AEDs and is reversible after discontinuation of drug treatment. Different experimental approaches are used to study tolerance in laboratory animals. Development of tolerance depends on the experimental model, drug, drug dosage, and duration of treatment, so that a battery of experimental protocols is needed to evaluate fully whether tolerance to effect occurs. Two major types of tolerance are known. Pharmacokinetic (metabolic) tolerance, due to induction of AED-metabolizing enzymes has been shown for most first-generation AEDs, and is easy to overcome by increasing dosage. Pharmacodynamic (functional) tolerance is due to "adaptation" of AED targets (e.g., by loss of receptor sensitivity) and has been shown experimentally for all AEDs that lose activity during prolonged treatment. Functional tolerance may lead to complete loss of AED activity and cross-tolerance to other AEDs. Convincing experimental evidence indicates that almost all first-, second-, and third-generation AEDs lose their antiepileptic activity during prolonged treatment, although to a different extent. Because of diverse confounding factors, detecting tolerance in patients with epilepsy is more difficult but can be done with careful assessment of decline during long-term individual patient response. After excluding confounding factors, tolerance to antiepileptic effect for most modern and old AEDs can be shown in small subgroups of responders by assessing individual or group response. Development of tolerance to the antiepileptic activity of an AED may be an important reason for failure of drug treatment. Knowledge of tolerance to AED effects as a mechanism of drug resistance in previous responders is important for patients, physicians, and scientists.

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.

Phenobarbital for childhood epilepsy: systematic review

INTRODUCTION: Against a background of concern about the safety of new pharmaceutical products, there has been renewed interest in one of the oldest antiepileptic drugs (AEDs), phenobarbital. Although still in widespread use in developing countries, its popularity has slipped in Western countries over the past century, partly because of controversy about its adverse effect profile. This critical review examines the evidence supporting its effectiveness and its associated behavioural adverse effects for febrile convulsions and childhood epilepsy. METHODS: Relevant randomised controlled trials (RCTs) of phenobarbital vs other antiepileptic drugs or placebo between 1970-2005 were identified through a comprehensive manual and computer database search of the world biomedical literature. Eleven RCTs of febrile convulsions and nine RCTs of childhood epilepsy were systematically reviewed against a conventional set of quality criteria. RESULTS: With a few exceptions, the overall quality of clinical trial methodology, especially in the early studies conducted in the 1970s and 1980s, was poor. There is no evidence for a difference in antiepileptic efficacy between phenobarbital and any other compared AED, yet no evidence for absolute efficacy. No convincing evidence exists for an excess of behavioural adverse effects, over other AEDs, attributable to phenobarbital. Masked studies of phenobarbital in childhood epilepsy have shown no significant differences in behavioural or cognitive adverse effects compared to other AEDs. This is in contrast to the excess of such adverse effects reported in studies open to observer bias. However, the one finding of reduction in cognitive ability associated with phenobarbital treatment for febrile convulsions remains a concern. Future areas of clinical and genetic epidemiological research are outlined.

Treatment options and paradigms in childhood temporal lobe epilepsy

Temporal lobe epilepsy in adults is a relatively homogenous syndrome with hippocampal sclerosis being its most common pathologic substrate. In the pediatric age group, low-grade neoplasms and cortical dysplasia are much more common than hippocampal sclerosis. Pediatric temporal lobe epilepsy has distinct semiologic, electrophysiologic and imaging characteristics as compared with its adult counterpart. The various treatment options for pediatric temporal lobe epilepsy include antiepileptic drugs, resective surgery, vagal nerve stimulation and the ketogenic diet. In spite of the multiple antiepileptic drugs currently available, 5-10% of all newly diagnosed cases will remain intractable to medical therapy and should be referred for presurgical evaluation. Resective surgery offers the best chance of seizure freedom in carefully selected patients. Future areas of research include new drug development, better imaging and localization techniques, and brain stimulation.

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.

Practitioner review: use of antiepileptic drugs in children

BACKGROUND

The aim in treating epilepsy is to minimise or control seizures with full respect of quality-of-life issues, especially of cognitive functions. Optimal treatment first demands a correct recognition of the major type of seizures, followed by a correct diagnosis of the type of epilepsy or of the specific syndrome.

METHODS

Review of data from literature and personal clinical experience in treating children with epilepsy.

RESULTS

After summarising the general aspects on the diagnosis and treatment of the main forms of childhood epilepsy, we review key issues about management of seizure disorders, including when to start treatment, how to proceed when the first treatment fails, and how to set the targets of treatment. A special section is devoted to the new concept of epileptic encephalopathy and to the influence of "interictal" EEG abnormalities on cognition, behaviour, and motor abilities in children, providing some suggestions on why and how to treat these conditions. A second section approaches the choice of treatment according to the specific syndromes including infantile spasms, focal epilepsies, syndromes with typical absence seizures, the myoclonic epilepsies and the Lennox-Gastaut syndrome.

CONCLUSIONS

Antiepileptic drugs (AEDs) can efficiently control seizures in most children. However, the specificity of AEDs is relatively limited, although continuing research is leading to a better understanding of the relationship between pathogenesis and the mechanism(s) and site(s) of drug action.

Efficacy assessment of phenobarbital in epilepsy: a large community-based intervention trial in rural China

BACKGROUND

Many people with epilepsy need not experience further seizures if the diagnosis and treatment are correct. Most epilepsy patients have convulsions, which are usually fairly easy to diagnose. This study tested a model for treatment of people with convulsive forms of epilepsy at primary health-care level in rural areas of China.

METHODS

Patients with convulsive epilepsy were identified at primary care level and provided with phenobarbital monotherapy. Local physicians, who were provided with special training, carried out screening, treatment, and follow-up. A local neurologist confirmed the diagnoses. Efficacy was assessed from the percentage reduction in seizure frequency from baseline and the retention of patients on treatment.

FINDINGS

The study enrolled 2455 patients. In 68% of patients who completed 12 months' treatment, seizure frequency was decreased by at least 50%, and a third of patients were seizure free. 72% of patients who completed 24 months' treatment had reduction of seizure frequency of at least 50% and a quarter of patients remained seizure free. Probability of retention was 0.84 at 1 year, and 0.76 at 2 years. Medication was well tolerated and reported adverse events were mild; only 32 patients (1%) discontinued medication because of side-effects.

INTERPRETATION

This pragmatic study confirmed that this simple protocol was suitable for the treatment of convulsive forms of epilepsy in rural areas of China. Physicians with basic training could treat epilepsy patients with phenobarbital, with beneficial effects for most patients with convulsive seizures. Few cognitive or behavioural adverse events were noted, but formal psychometric testing was not done.

An overview of methods and empirical comparison of aggregate data and individual patient data results for investigating heterogeneity in meta-analysis of time-to-event outcomes

Combining the results of individual studies using meta-analysis may be undertaken using either aggregate data (AD) or individual patient data (IPD). In any meta-analysis it is important to consider statistical heterogeneity between studies. Potential sources of heterogeneity can be explored using regression models with either AD or IPD. An overview of approaches and empirical assessment of how the results and conclusions differ from these analyses is undertaken using a meta-analysis of five randomized controlled trials comparing two antiepileptic drugs with time-to-event outcomes. Alternative meta-regression models using AD are compared to stratified Cox regression models using IPD. Age as a potential cause of heterogeneity is detected by both AD and IPD regression models. Time from first ever seizure to randomization is only identified by some AD models. A more thorough explanation of heterogeneity is obtained from the model using IPD but further empirical evidence comparing IPD and AD results are needed.

Multiple mechanisms induce transcriptional silencing of a subset of genes, including oestrogen receptor alpha, in response to deacetylase inhibition by valproic acid and trichostatin A

Valproate (VPA) and trichostatin A (TSA), inhibitors of zinc-dependent deacetylase activity, induce reduction in the levels of mRNA encoding oestrogen receptor-alpha (ERalpha), resulting in subsequent clearance of ERalpha protein from breast and ovarian cell lines. Inhibition of oestrogen signalling may account for the endocrine disorders, menstrual abnormalities, osteoporosis and weight gain that occur in a proportion of women treated with VPA for epilepsy or for bipolar mood disorder. Transcriptome profiling revealed that VPA and TSA also modulate the expression of, among others, key regulatory components of the cell cycle. Meta-analysis of genes directly responsive to oestrogen indicates that VPA and TSA have a generally antioestrogenic profile in ERalpha positive cells. Concomitant treatment with cycloheximide prevented most of these changes in gene expression, including downregulation of ERalpha mRNA, indicating that a limited number of genes signal a hyperacetylated state within cells. Three members of the NAD-dependent deacetylases, the sirtuins, are upregulated by VPA and by TSA and sirtuin activity contributes to loss of ERalpha expression. However, prolonged inhibition of the sirtuins by sirtinol also induces loss of ERalpha from cells. Mechanistically, we show that VPA invokes reversible promoter shutoff of the ERalpha, pS2 and cyclin D1 promoters, by inducing recruitment of methyl cytosine binding protein 2 (MeCP2) with concomitant exclusion of the maintenance methylase DNMT1. Furthermore, we demonstrate that, in the presence of VPA, local DNA methylation, deacetylation and demethylation of activated histones and recruitment of inhibitory complexes occurs on the pS2 promoter.

Antiepileptic drug monotherapy: pediatric concerns

Selecting the optimal antiepileptic drug (AED) begins with accurate epilepsy classification, including seizure type and epilepsy syndrome if possible. Based on the available data, children with focal epilepsy, with or without secondary generalization, can be treated with a traditional or newer narrow-spectrum or broad-spectrum AED. Children with generalized convulsive epilepsy, mixed epilepsy, or seizures of an unknown type are best treated with a broad-spectrum AED. Children with childhood absence epilepsy can be treated with ethosuximide, valproate, or lamotrigine. In all cases, the best choice among the various AED options requires consideration of factors such as seizure frequency, seizure severity, AED adverse event profile, AED titration schedule, patient comorbidities, prescription plan coverage, and cost. Most children with epilepsy achieve the goal of "no seizures and no side effects" and most children eventually become seizure free without AEDs. If accurate epilepsy classification is made, clear differences in efficacy are not evident among the multiple available AEDs. Better comparative data emphasizing adverse event profiles, comorbidities and longer-term outcome are needed between the traditional and newer AEDs.

Endocrine and metabolic changes in epileptic patients receiving valproic acid

It has been well known for many years that valproic acid (VPA) therapy can induce obesity and important endocrine dysfunctions; among these dysfunctions, the most common are hyperandrogenism, menstrual disorders, polycystic ovary syndrome, hyperinsulinism, and changes in LH, FSH, and sexual and thyroid hormones. Moreover, abnormalities in pubertal development and impaired skeletal growth have been reported. The aim of this review is to analyze the main effects of VPA on endocrinological functions in patients with epilepsy in order to understand in depth the pathophysiological mechanisms and, consequently, to improve the care of these patients.

Prescribing antiepileptic drugs: should patients be switched on the basis of cost?

To assess the costs of switching from one antiepileptic drug (AED) to another, all associated direct and indirect costs, not only drug acquisition costs, must be considered. The perspective of the healthcare system evaluated in cost-effectiveness analysis is of crucial importance. Multiple clinical factors can influence clinical decisions regarding switching AEDs. The economic cost of poorly controlled epilepsy is enormous and the most cost-effective intervention is an AED that provides total seizure control. Cost-minimisation studies have evaluated costs associated with various medications. If only efficacy and adverse events were considered, then the 'older' AEDs were generally more cost effective than the 'newer' AEDs. Most studies only examine very specific clinical situations and are not suitable for establishing general clinical recommendations. The pharmacoeconomics of AED choice is highly country specific. While switching to generic formulations is, in general, cost effective, some changes may be detrimental and more costly than remaining on the trade name preparation. For example, as a result of differences in bioavailability and possible loss of seizure control, changing patients to generic phenytoin and carbamazepine can be problematic. Fosphenytoin may only be cost effective in certain clinical situations compared with intravenous phenytoin. Seizure control should not be sacrificed on the basis of costs alone, as the major endpoint in treating epilepsy with AEDs is seizure control without adverse effects. Switching AEDs in clinical practice still depends on the individual clinical situation and choosing AED therapy solely on the basis of initial acquisition costs is unlikely to be cost effective in the long-term care of patients with epilepsy.

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.

Phenobarbital for the Treatment of Epilepsy in the 21st Century: A Critical Review

SUMMARY

Phenobarbital (PB) is the most widely used antiepileptic drug (AED) in the developing world and remains a popular choice in many industrialized countries. Meta-analyses of randomized controlled trials suggest that few differences in efficacy exist between PB and other established AEDs, but its possible deleterious cognitive and behavioral side effects remain a concern in the developed world. In contrast, high degrees of efficacy and tolerability in everyday clinical use have been demonstrated consistently in observational studies in developing countries. We propose that a pragmatic, comprehensive outcomes program be carried out, perhaps under the aegis of the Global Campaign Against Epilepsy, to optimize the conditions of the use of PB, so that more people around the world can benefit from this cost-effective medication and live more fulfilling lives.

Behavioral and psychiatric adverse events associated with antiepileptic drugs commonly used in pediatric patients

Multiple factors-including the efficacy of the antiepileptic drug for the particular seizure type, availability of pediatrics-friendly formulations, the ease of dosing and titration, and tolerability issues, such as possible drug interactions and adverse events-affect the selection of the best antiepileptic drug for a child with epilepsy. Behavioral problems are common in children with epilepsy and can be aggravated or initiated by antiepileptic drug therapy. The types and frequencies of antiepileptic drug-associated behavioral events can influence a clinician's drug selection, drug management, and counseling of parents. Unfortunately, appreciating differences among antiepileptic drugs in behavioral adverse event profiles is problematic because, among other reasons, methodologies for reporting, collecting, and analyzing adverse events are not uniform across trials, and there is marked heterogeneity in study design among trials. This review summarizes incidence rates for behavioral and psychiatric adverse events taken from studies of children with epilepsy. These rates are reported for the 10 most commonly prescribed antiepileptic drugs (valproic acid, carbamazepine, phenobarbital, lamotrigine, phenytoin, levetiracetam, oxcarbazepine, topiramate, zonisamide, and gabapentin), grouped according to their predominant mechanism of action. Despite the numerous methodologic inconsistencies, some similarities in adverse event profiles among antiepileptic drugs that share mechanisms of action are apparent. Moreover, the overwhelming body of data on the behavioral effects of phenobarbital should convince clinicians that, whenever possible, it should not be used as the initial-or even the second-monotherapy in children with epilepsy.

Efficacy and tolerability of conversion to monotherapy with lamotrigine compared with valproate and carbamazepine in patients with epilepsy

OBJECTIVE

This randomized, open-label study was designed to compare the efficacy and tolerability of lamotrigine monotherapy with those of valproate and carbamazepine monotherapy in patients with epilepsy whose seizures were uncontrolled on their prestudy antiepileptic drug monotherapy.

METHODS

Patients meeting eligibility criteria were randomized 2:1 to lamotrigine:carbamazepine or lamotrigine:valproate. The treatment phase was divided into a 4-week dose-escalation phase (Weeks 1-4), during which lamotrigine, carbamazepine, or valproate was added to patient's prestudy monotherapy; an 8-week add-on phase (Weeks 5-12), during which patients were stabilized on both the study medication and their prestudy antiepileptic therapy; an 8-week withdrawal phase (Weeks 13-20), during which prestudy antiepileptic therapy could be withdrawn if clinically appropriate; and an 8-week monotherapy phase (Weeks 21-28), during which patients could be treated with study medication as monotherapy.

RESULTS

The numbers of patients randomized to the carbamazepine and valproate arms of the study were 144 (98 lamotrigine, 46 carbamazepine) and 158 (105 lamotrigine, 53 valproate), respectively. Successful monotherapy sustained for at least 7 weeks was achieved in comparable percentages of patients in the lamotrigine group (56%) and the carbamazepine group (54%) and in more patients in the lamotrigine group (49%) than the valproate group (40%). Among monotherapy completers, the percentage of patients with zero seizures during the monotherapy phase was comparable for lamotrigine (41%) and carbamazepine (30%) and significantly higher (P<0.05) with lamotrigine (32%) than with valproate (11%). No differences between treatments were observed with respect to time to treatment failure or time to first seizure. Lamotrigine was also better tolerated than carbamazepine or valproate.

CONCLUSION

Lamotrigine monotherapy was as effective as and better tolerated than carbamazepine or valproate monotherapy in patients whose seizures were uncontrolled on their prestudy antiepileptic drug monotherapy.