A systematic review of antiepileptic drug initiation and withdrawal

Relapse After Drug Withdrawal in Patients with Epilepsy After Two Years of Seizure-Free: A Cohort Study

BACKGROUND AND STUDY AIMS

Antiepileptic drugs are the first choice of treatment for patients with epilepsy. However, the withdrawal of antiepileptic drugs after seizure-free remains a significant focus for the majority of patients with epilepsy and their families. In this study, we evaluated the risk factors associated with relapse after drug withdrawal in patients with seizure free for 2 years. We aimed to guide patients in seizure-free to assess the risk of drug withdrawal.

PATIENTS AND METHODS

Through screening, 452 patients with epilepsy were included in the study.Patients were followed up for at least 2 years or more. Analyzed their clinical data by applying the χ2-test, Kaplan-Meier survival analysis and multivariate Cox regression analysis.

RESULTS

423 patients completed follow-up, of which 304 cases recurred (71.9%).Related recurrence factors include age of onset, type of seizure, number of AEDs, seizure-free time before withdrawal, and electroencephalogram (EEG) results before drug withdrawal (P<0.05). The results of correlation analysis showed that age of onset, seizure frequency, seizure type, number of AEDs, the period from AEDs treatment to a seizure-free status, EEG results before drug withdrawal, and pre-medication course, were all significantly related to the recurrence of seizures after drug reduction and withdrawal (P<0.05). We identified a range of independent risk factors, including onset age, seizure frequency, Multiple AEDs and the period from AEDs treatment to a seizure-free status.

CONCLUSION

The overall recurrence rate of epilepsy in our patient cohort was high, and the peak recurrence period was within one-year of drug withdrawal. Patients with partial seizures, a short seizure-free time before withdrawal, severe EEG abnormalities before drug reduction, and a long course of the disease, are prone to relapse. Patients with an older age at onset and a high frequency of attack, those taking multi-drug combination therapy, and those that take a long time to gain control, should be managed carefully to AEDs withdrawal.

The differential role of magnetic resonance imaging in predicting surgical outcomes between children versus adults with temporal lobe epilepsy

OBJECTIVE

This study aims to investigate the clinical discrepancies and the different predictors of anterior temporal lobectomy (ATL) in children (<18 years at surgery) and adults (>18 years at surgery) with temporal lobe epilepsy (TLE).

MATERIALS AND METHODS

A total of 262 patients (56 children and 206 adults) with TLE who underwent ATL were included in this study. The clinical variables, including patients' characteristics, preoperative evaluations, pathology, surgical prognosis, and surgical predictors were assessed the discrepancies between TLE children versus adults using univariate and multivariate analyses. Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom and AEDs withdrawal after ATL, and the difference between TLE children and adults was analyzed using the Log-Rank test.

RESULTS

There were significant differences including semiology, magnetic resonance imaging (MRI) examinations, numbers of preoperative AEDs, and pathologies between TLE children and adults (P < 0.05, Q < 0.05). The MRI-detected epileptic focus was the only independent predictor of seizure freedom (P = 0.002, Q = 0.036) in TLE children, and the concordance of MRI-detected focus with video-electroencephalography (video-EEG)-detected epileptic zone was the only variable associated with seizure freedom in TLE adults (OR = 2.686, 95% CI = 1.014-7.115, P = 0.047). The TLE children experienced a higher probability of AEDs withdrawal than adults after surgery (P = 0.005).

SIGNIFICANCE

There were remarkable differences in clinical manifestations, MRI examinations, number of preoperative AEDs, and pathologies between TLE children versus adults. TLE children had a higher possibility of AEDs withdrawal than adults after surgery. The favorable seizure outcome of ATL depended on the early complete resection of MRI-detected epileptogenic focus in TLE children, while the concordance of MRI-detected focus with EEG-detected epileptogenic zone was the only predictor of favorable seizure outcomes in TLE adults.

Risk of seizure relapse and long-term outcomes after discontinuation of antiseizure medication in children with epilepsy

OBJECTIVES

The aims of this study were to evaluate the demographic and clinical characteristics of children with epilepsy who discontinued their antiseizure medication (ASM), to determine potential predictors of seizure relapse, to calculate the rate of seizure relapse, and to detect long-term seizure outcomes.

METHODS

A total of 269 seizure-free children with epilepsy who were decided to discontinue their ASM and were followed up for at least 18 months after ASM withdrawal were retrospectively evaluated.

RESULTS

The enrolled children had been followed up for a median of 46 months (range 18-126 months; IQR: 29-61) after ASM withdrawal and 90 (33.5%) of their seizures relapsed. The median time to seizure relapse was 8 months (range 0.23-117 months; IQR: 2-25). Seizure relapse occurred in 16.7% of the 90 children at 1 month, 45.6% at 6 months, 62.2% at 1 year, 74.4% at 2 years, and 94.4% at 5 years. Univariate logistic regression analyses revealed six predictors significantly related to relapse: age at first seizure, age at diagnosis of epilepsy, intellectual disability, EEG findings after ASM withdrawal, ASM tapering time, and number of seizures on ASM. In multivariate logistic regression analyses, age at first seizure, intellectual disability, and ASM tapering time were not significantly associated anymore. The other three remained independently predictive. Pharmacological control of seizures with monotherapy was restored in 93.3% of the children with seizure relapse.

CONCLUSION

This study evaluated potential predictors of seizure relapse, some of which have rarely been evaluated in previous studies. Adolescent age at diagnosis, abnormal EEG findings after ASM withdrawal, and high number of seizures on ASM were associated with a higher risk of seizure relapse. Abnormal MRI findings such as malformations of cortical development and hydrocephalus may be potential biomarkers for the risk of seizure relapse.

Rapid versus slow withdrawal of antiepileptic drugs

BACKGROUND

The ideal objective of treating a person with epilepsy is to induce remission (free of seizures for some time) using antiepileptic drugs (AEDs) and withdraw the AEDs without causing seizure recurrence. Prolonged usage of AEDs may have long-term adverse effects. Hence, when a person with epilepsy is in remission, it is logical to attempt to discontinue the medication. The timing of withdrawal and the mode of withdrawal arise while contemplating withdrawal of AEDs. This review examines the evidence for the rate of withdrawal of AEDs (whether rapid or slow tapering) and its effect on seizure recurrence. This is an updated version of the Cochrane Review previously published in 2020.

OBJECTIVES

To quantify risk of seizure recurrence after rapid (tapering period of three months or less) or slow (tapering period of more than three months) discontinuation of antiepileptic drugs in adults and children with epilepsy who are in remission, and to assess which variables modify the risk of seizure recurrence.

SEARCH METHODS

For the latest update, on 8 November 2021, we searched: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid), and SCOPUS. There were no language restrictions. CRS Web includes randomized or quasi-randomized, controlled trials from PubMed, Embase, ClinicalTrials.gov, the World Health Organization International Clinical Trials Registry Platform (ICTRP), CENTRAL, and the Specialized Registers of Cochrane Review Groups including Epilepsy.

SELECTION CRITERIA

Randomized controlled trials that evaluated withdrawal of AEDs in a rapid or slow tapering after varying periods of seizure control in people with epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the trials for inclusion and extracted the data. The outcomes assessed included seizure freedom after one, two, or five years of AED withdrawal; time to recurrence of seizure following withdrawal; occurrence of status epilepticus; mortality; morbidity due to seizure, such as injuries, fractures, and aspiration pneumonia; and quality of life (assessed by validated scale).

MAIN RESULTS

There are two included studies in this review. One study randomized 57 children with epilepsy with seizure freedom for at least two years to taper down the AED over one or six months. The study was not blinded and there were no details of randomization. Over the period of 54 months of follow-up, 20/30 participants in the one-month group remained seizure-free compared to 15/27 participants in the six-month group (no evidence of a difference). There was no information on time of seizure recurrence for each group to allow a comparison. The other study involved 149 children. There was a non-significant trend towards a lower risk of seizure recurrence after one year of AED withdrawal in participants allocated to slow tapering (risk ratio (RR) 0.76, 95% confidence interval (CI) 0.58 to 1.01; P = 0.06; very low-certainty evidence). At the end of two years, 30 participants were seizure free in the rapid-tapering group and 29 participants in the slow-tapering group (RR 0.87, 95% CI 0.58 to 1.29; P = 0.48; very low-certainty evidence). At the end of five years, 10 participants were seizure free in the rapid-tapering group and six participants in the slow-tapering group (RR 1.40, 95% CI 0.54 to 3.65; P = 0.49; very low-certainty evidence). There were no data for the other outcomes. Due to the methodological heterogeneity and the difference in the duration of tapering, we did not perform a quantitative synthesis of these studies. Currently, one Italian trial is ongoing that is investigating if a slow or a rapid withdrawal schedule of AEDs influences return of seizures (relapse) in adults with focal or generalized epilepsy who have been seizure free for at least two years (no preliminary results available).

AUTHORS' CONCLUSIONS

In view of methodological deficiencies, and small sample size of the two included studies, we cannot draw any reliable conclusions regarding the optimal rate of tapering of AEDs. Using GRADE, we assessed the certainty of the evidence as very low for outcomes for which data were available. We judged both studies to be at an overall high risk of bias. Further studies are needed in adults and children to investigate the optimal rate of withdrawal of AEDs and to study the effects of variables such as seizure types, aetiology, intellectual disability, electroencephalography abnormalities, presence of neurological deficits, and other comorbidities on the rate of tapering.

When should we obtain a routine EEG while managing people with epilepsy?

More than eight decades after its discovery, routine electroencephalogram (EEG) remains a safe, noninvasive, inexpensive, bedside test of neurological function. Knowing when a routine EEG should be obtained while managing people with epilepsy is a critical aspect of optimal care. Despite advances in neuroimaging techniques that aid diagnosis of structural lesions in the central nervous system, EEG continues to provide critical diagnostic evidence with implications on treatment. A routine EEG performed after a first unprovoked seizure can support a clinical diagnosis of epilepsy and differentiate those without epilepsy, classify an epilepsy syndrome to impart prognosis, and characterize seizures for antiseizure management. Despite a current viral pandemic, EEG services continue, and the value of routine EEG is unchanged.

Risk of seizure recurrence from antiepileptic drug withdrawal among seizure-free patients for more than two years

OBJECTIVE

The aim of this study was to determine the outcome of antiepileptic drug (AED) withdrawal in patients who were seizure-free for more than two years.

METHODS

Patients with epilepsy who were seizure-free for at least two years and decided to stop AED therapy gradually were followed up every two months for seizure relapse. The inclusion criteria were as follows: (1) diagnosis of epilepsy, defined as the following conditions: ① at least two unprovoked (or reflex) seizures occurring >24 h apart; ② one unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years; ③ diagnosis of an epilepsy syndrome; (2) patients remained seizure-free for at least 24 consecutive months during AED therapy; and (3) patients expressed a desire to discontinue AED therapy gradually and agreed to return for regular follow-ups. The time to a seizure relapse and predictive factors were analyzed by survival methods, including sex; age at seizure onset; number of episodes; seizure-free period before AED withdrawal; duration of follow-up after AED withdrawal; AED tapering off period (taper period); results from brain magnetic resonance (MRI); electroencephalogram (EEG) after drug withdrawal; EEG before drug withdrawal; seizure type (classified as generalized, partial, or multiple types based on history); and the number of AEDs administered for long-term seizure control. A log-rank test was used for univariate analysis, and a Cox proportional hazard model was used for multivariate analysis.

RESULTS

We selected 94 patients (58 men, 36 women). The relapse ratio was 29.8%. Univariate analysis and multivariate Cox regression analysis indicated that withdrawal times and multiple AEDs, as well as the seizure-free period before withdrawal and abnormal EEG after drug withdrawal were significantly correlated with seizure recurrence and were significant independent predictive factors, with a hazard ratio of 0.839 and 3.971, 0.957, and 3.684, respectively.

SIGNIFICANCE

The relapse rate in our study was similar to commonly reported overall rates for epilepsy. Distinguishing variables, such as withdrawal times, multiple AEDs, seizure-free period before withdrawal, and abnormal EEG after drug withdrawal, need to be considered when choosing to withdraw from AEDs. Therefore, our recommendation is that after two years of seizure-free survival, patients could consider withdrawal unless they have hippocampal sclerosis (HS).

Prediction of the recurrence risk in patients with epilepsy after the withdrawal of antiepileptic drugs

Many seizure-free patients who consider withdrawing from antiepileptic drugs (AEDs) hope to discontinue treatment to avoid adverse effects. However, withdrawal has certain risks that are difficult to predict. In this study, we performed a literature review, summarized the causes of significant variability in the risk of postwithdrawal recurrent seizures, and reviewed study data on the age at onset, cause, types of seizures, epilepsy syndrome, magnetic resonance imaging (MRI) abnormalities, epilepsy surgery, and withdrawal outcomes of patients with epilepsy. Many factors are associated with recurrent seizures after AED withdrawal. For patients who are seizure-free after treatment, the role of an electroencephalogram (EEG) alone in ensuring safe withdrawal is limited. A series of prediction models for the postwithdrawal recurrence risk have incorporated various potentially important factors in a comprehensive analysis. We focused on the populations of studies investigating five risk prediction models and analyzed the predictive variables and recommended applications of each model, aiming to provide a reference for personalized withdrawal for patients with epilepsy in clinical practice.

Correlation between EEG during AED withdrawal and epilepsy recurrence: a meta-analysis

To assess the risk of epilepsy recurrence after withdrawal from antiepileptic drugs (AEDs), researchers extensively studied recurrence-related risk factors, including electroencephalogram (EEG) during AED withdrawal. The relationship between EEG and epilepsy recurrence is controversial. We used meta-analysis to determine the correlation between EEG during AED withdrawal and epilepsy recurrence. A total of seven studies met the criteria for inclusion. The Newcastle-Ottawa Scale was used to conduct the research quality evaluation. Seven hundred three patients were included in meta-analysis. Patients with abnormal EEGs during withdrawal had a higher recurrence rate than patients with normal EEGs. Abnormal EEGs during withdrawal were a risk factor for recurrence.

Early withdrawal of non-anesthetic antiepileptic drugs after successful termination of nonconvulsive seizures and nonconvulsive status epilepticus

PURPOSE

Multiple antiepileptic drugs (AEDs) are often necessary to treat nonconvulsive seizures (NCS) and nonconvulsive status epilepticus (NCSE). AED polypharmacy places patients at risk for adverse side effects and drug-drug interactions. Identifying the likelihood of seizure relapse when weaning non-anesthetic AEDs may provide guidance in the critical care unit.

METHOD

Ninety-nine adult patients with successful treatment of electrographic-proven NCS or NCSE on continuous critical care EEG (CCEEG) monitoring were identified retrospectively. Patients were determined to undergo an AED wean if the number of non-anesthetic AEDs was reduced at the time of discharge compared to the number of non-anesthetic AEDs at primary seizure cessation. Primary outcome was recurrent seizures either clinically or by CCEEG during hospitalization. Secondary outcome measures included hospital length of stay and discharge disposition.

RESULTS

The rate of recurrent seizures in the wean group was not statistically different when compared to the group that did not undergo an AED wean (17% vs. 13%, respectively; p = 0.77). The wean group had a median value of 4 (IQR: 3-4) non-anesthetic AEDs at the time of primary seizure cessation compared with 3 (IQR: 2-3) in the non-wean group (p < 0.0001). However, both groups had similar values of AEDs at discharge (median of 2 (IQR: 2-3) vs. 3 (IQR: 2-3) for wean and non-wean groups respectively; p = 0.40). Discharge disposition (favorable, acceptable, or unfavorable) was similar between groups (p = 0.32).

CONCLUSIONS

Early weaning of non-anesthetic AEDs does not increase the risk of recurrent seizures in patients treated for NCS or NCSE during their hospitalization.

Epilepsy, Antiepileptic Drugs, and Aggression: An Evidence-Based Review

Antiepileptic drugs (AEDs) have many benefits but also many side effects, including aggression, agitation, and irritability, in some patients with epilepsy. This article offers a comprehensive summary of current understanding of aggressive behaviors in patients with epilepsy, including an evidence-based review of aggression during AED treatment. Aggression is seen in a minority of people with epilepsy. It is rarely seizure related but is interictal, sometimes occurring as part of complex psychiatric and behavioral comorbidities, and it is sometimes associated with AED treatment. We review the common neurotransmitter systems and brain regions implicated in both epilepsy and aggression, including the GABA, glutamate, serotonin, dopamine, and noradrenaline systems and the hippocampus, amygdala, prefrontal cortex, anterior cingulate cortex, and temporal lobes. Few controlled clinical studies have used behavioral measures to specifically examine aggression with AEDs, and most evidence comes from adverse event reporting from clinical and observational studies. A systematic approach was used to identify relevant publications, and we present a comprehensive, evidence-based summary of available data surrounding aggression-related behaviors with each of the currently available AEDs in both adults and in children/adolescents with epilepsy. A psychiatric history and history of a propensity toward aggression/anger should routinely be sought from patients, family members, and carers; its presence does not preclude the use of any specific AEDs, but those most likely to be implicated in these behaviors should be used with caution in such cases.

The withdrawal of antiepileptic drugs in patients with low-grade and anaplastic glioma

INTRODUCTION

The withdrawal of antiepileptic drugs (AEDs) in World Health Organization (WHO) grade II-III glioma patients with epilepsy is controversial, as the presence of a symptomatic lesion is often related to an increased risk of seizure relapse. However, some glioma patients may achieve long-term seizure freedom after antitumor treatment, raising questions about the necessity to continue AEDs, particularly when patients experience serious drug side effects. Areas covered: In this review, we show the evidence in the literature from 1990-2016 for AED withdrawal in glioma patients. We put this issue into the context of risk factors for developing seizures in glioma, adverse effects of AEDs, seizure outcome after antitumor treatment, and outcome after AED withdrawal in patients with non-brain tumor related epilepsy. Expert commentary: There is currently scarce evidence of the feasibility of AED withdrawal in glioma patients. AED withdrawal could be considered in patients with grade II-III glioma with a favorable prognosis, who have achieved stable disease and long-term seizure freedom. The potential benefits of AED withdrawal need to be carefully weighed against the presumed risk of seizure recurrence in a shared decision-making process by both the clinical physician and the patient.

International Veterinary Epilepsy Task Force consensus proposal: medical treatment of canine epilepsy in Europe

In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authors' experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible.

Prognostic Tests and Antiepileptic Drug Withdrawal After Epilepsy Surgery

Approximately one in three patients with a successful epilepsy surgery will have seizure recurrence following antiepileptic drugs (AED) withdrawal. The value of postoperative testing for predicting seizure relapse after AED tapering is not clear. The purpose of this study was to review the literature for evidence on the use of postoperative investigations before AED discontinuation after successful epilepsy surgery. We were unable to identify studies on the prognostic value of postoperative magnetic resonance imaging and AED blood levels. The literature review yielded seven studies on the predictive value of electroencephalography. Four studies found no association between interictal discharges (IED) and seizure relapse. These studies suffered from various limitations due to their retrospective design and generally small cohorts. Two of the three studies reporting a positive association were prospective and provided strong evidence of an increased risk of seizure recurrence with presence of postoperative IED in successfully operated patients undergoing AED withdrawal.

Prospective study on the withdrawal and reinstitution of antiepileptic drugs among seizure-free patients in west China

This study explored the relapse rates and risk factors for seizure recurrence after discontinuing antiepileptic drug (AED) therapy among seizure-free patients in west China, and explored whether to reinstitute AED immediately after a single seizure after AED withdrawal. Patients with epilepsy who were seizure-free for at least 2 years and decided to gradually stop AED therapy were followed up every 3 months for seizure relapse. Patients who experienced their first seizure after drug withdrawal were divided into two groups according to their willingness to reinstitute AED therapy, and were followed up until their second seizure. In the mean 29.35 months of follow-up, 37 patients (37/162, 22.8%) suffered at least one seizure after withdrawal. The cumulative probability of seizure recurrence was 16% at 12 months and 20.2% at 24 months. AED response time >1 year and multiple types of seizure were identified as risk factors for seizure recurrence. Eight patients (8/32, 25%) suffered a second seizure within 1 year after the first whether or not they reinstituted AED immediately. There were no significant demographic or clinical differences between patients who reinstituted AED therapy and those who did not. The epilepsy recurrence rate after AED withdrawal is relatively low, with a relatively slow tapering process. Patients with long AED response times and/or multiple types of seizures have a higher risk of seizure recurrence. The first seizure after drug withdrawal is not an indication for immediate AED reinstitution, but may be recommended after a second seizure.

Antiepileptic drug withdrawal in childhood epilepsy: what are the risk factors associated with seizure relapse?

BACKGROUND

In recent years, several studies have been conducted to determine the risk of relapse after antiepileptic drug (AED) withdrawal: there is no general agreement on criteria that can predict safe discontinuation or seizure recurrence.

AIMS

To evaluate prospectively the relapse rate of epilepsy associated to AED withdrawal in epileptic children and to determine the risk factors of seizure recurrence.

METHODS

One hundred-sixty-eight children with epilepsy who were seizure-free for at least 2 years were enrolled and all children were proposed to stop AED treatment and were followed. In all children electroencephalograms (EEGs) were performed before the withdrawal of AEDs and after discontinuation of the treatment.

RESULTS

A total of 48 (28.6%) children relapsed; half of these patients relapsed while reducing the AED dose and the other half after the AED was withdrawn; after 2 years without AEDs, the risk of relapse was very low. Data evaluated by multivariable analysis showed that the children receiving polytherapy before AED withdrawal, having a history of febrile seizures and suffering from multiple seizure types relapsed more frequently. The presence of abnormal post-withdrawal EEG recordings was associated with a higher risk of seizure recurrence.

CONCLUSIONS

Epileptic children, after a seizure-free period of 2 years, have a low risk of seizure recurrence. The potential risk factors of relapse, are multiple seizure types previous polytherapy, history of febrile seizures and abnormalities in post-withdrawal EEG.

Trends in the use of antiepileptic drugs among pregnant women in the US, 2001-2007: a medication exposure in pregnancy risk evaluation program study

BACKGROUND

Little is known about the extent of antiepileptic drug (AED) use in pregnancy, particularly for newer agents. Our objective was to assess whether AED use has increased among pregnant women in the US, 2001-2007.

METHODS

  We analysed data from the Medication Exposure in Pregnancy Risk Evaluation Program (MEPREP) database, 1 January 2001 to 31 December 2007. We identified liveborn deliveries among women, aged 15-45 years on delivery date, who were members of MEPREP health plans (n=585615 deliveries). Pregnancy exposure to AEDs, determined through outpatient pharmacy dispensing files. Older AEDs were available for clinical use before 1993; other agents were considered newer AEDs. Information on sociodemographic and medical/reproductive factors was obtained from linked birth certificate files. Maternal diagnoses were identified based on ICD-9 codes.

RESULTS

  Prevalence of AED use during pregnancy increased between 2001 (15.7 per 1000 deliveries) and 2007 (21.9 per 1000 deliveries), driven primarily by a fivefold increase in the use of newer AEDs. Thirteen per cent of AED-exposed deliveries involved a combination of two or more AEDs. Psychiatric disorders were the most prevalent diagnoses, followed by epileptic and pain disorders, among AED users regardless of AED type, year of conception or gestational period.

CONCLUSIONS

  AED use during pregnancy increased between 2001 and 2007, driven by a fivefold increase in the use of newer AEDs. Nearly one in eight AED-exposed deliveries involved the concomitant use of more than one AED. Additional investigations of the reproductive safety of newer AEDs may be needed.

Stress within the postseizure time window inhibits seizure recurrence

Recurrence is a key characteristic in the development of epilepsy. It remains unclear whether seizure recurrence is sensitive to postseizure stress. Here, tonic-clonic seizures were induced with a convulsive dose of pentylenetetrazole (PTZ), and acute seizure recurrence was evoked with a subconvulsive dose of the drug. We found that stress inhibited seizure recurrence when applied 30minutes or 2hours, but not 4hours, after the tonic-clonic seizure. The time-dependent anti-recurrence effect of stress was mimicked by the stress hormone corticosterone and blocked by co-administration of mineralocorticoid and glucocorticoid receptor antagonists. Furthermore, in a PTZ-induced epileptic kindling model, corticosterone administered 30minutes after each seizure decreased the extent of seizures both during the kindling establishment and in the following challenge test. These results provide novel insights into both the mechanisms of and therapeutic strategies for epilepsy.

Stopping antiepileptic drugs: when and why?

After a patient has initiated an antiepileptic drug (AED) and achieved a sustained period of seizure freedom, the bias towards continuing therapy indefinitely can be substantial. Studies show that the rate of seizure recurrence after AED withdrawal is about two to three times the rate in patients who continue AEDs, but there are many benefits to AED withdrawal that should be evaluated on an individualized basis. AED discontinuation may be considered in patients whose seizures have been completely controlled for a prolonged period, typically 1 to 2 years for children and 2 to 5 years for adults. For children, symptomatic epilepsy, adolescent onset, and a longer time to achieve seizure control are associated with a worse prognosis. In adults, factors such as a longer duration of epilepsy, an abnormal neurologic examination, an abnormal EEG, and certain epilepsy syndromes are known to increase the risk of recurrence. Even in patients with a favorable prognosis, however, the risk of relapse can be as high as 20% to 25%. Before withdrawing AEDs, patients should be counseled about their individual risk for relapse and the potential implications of a recurrent seizure, particularly for safety and driving.