Therapeutic Drug Monitoring of Antiepileptic Drugs in Women with Epilepsy Before, During, and After Pregnancy.

During pregnancy, the pharmacokinetics of an antiepileptic drug is altered because of changes in the clearance capacity and volume of distribution. These changes may have consequences for the frequency of seizures during pregnancy and fetal exposure to antiepileptic drugs. In 2009, a review was published providing guidance for the dosing and therapeutic drug monitoring of antiepileptic drugs during pregnancy. Since that review, new drugs have been licensed and new information about existing drugs has been published. With this review, we aim to provide an updated narrative overview of changes in the pharmacokinetics of antiepileptic drugs in women during pregnancy. In addition, we aim to formulate advice for dose modification and therapeutic drug monitoring of antiepileptic drugs. We searched PubMed and the available literature on the pharmacokinetic changes of antiepileptic drugs and seizure frequency during pregnancy published between January 2007 and September 2018. During pregnancy, an increase in clearance and a decrease in the concentrations of lamotrigine, levetiracetam, oxcarbazepine's active metabolite licarbazepine, topiramate, and zonisamide were observed. Carbamazepine clearance remains unchanged during pregnancy. There is inadequate or no evidence for changes in the clearance or concentrations of clobazam and its active metabolite N-desmethylclobazam, gabapentin, lacosamide, perampanel, and valproate. Postpartum elimination rates of lamotrigine, levetiracetam, and licarbazepine resumed to pre-pregnancy values within the first few weeks after pregnancy. We advise monitoring of antiepileptic drug trough concentrations twice before pregnancy. This is the reference concentration. We also advise to consider dose adjustments guided by therapeutic drug monitoring during pregnancy if the antiepileptic drug concentration decreases 15-25% from the pre-pregnancy reference concentration, in the presence of risk factors for convulsions. If the antiepileptic drug concentration changes more than 25% compared with the reference concentration, dose adjustment is advised. Monitoring of levetiracetam, licarbazepine, lamotrigine, and topiramate is recommended during and after pregnancy. Monitoring of clobazam, N-desmethylclobazam, gabapentin, lacosamide, perampanel, and zonisamide during and after pregnancy should be considered. Because of the risk of teratogenic effects, valproate should be avoided during pregnancy. If that is impossible, monitoring of both total and unbound valproate is recommended. More research is needed on the large number of unclear pregnancy-related effects on the pharmacokinetics of antiepileptic drugs.

Failure of ketogenic diet therapy in GLUT1 deficiency syndrome.

PURPOSE: Epilepsy in GLUT1 deficiency syndrome is generally drug-resistant; ketogenic diet (KD) therapy is the mainstay of therapy, as production of ketones provides the brain with an alternative energy source, bypassing the defect in GLUT1. Failure of KD therapy and risk factors for failure have been sparsely published. METHODS: We performed a retrospective study of GLUT1DS patients with refractory epilepsy failing on KD therapy, to identify their clinical characteristics. RESULTS: Failure of the ketogenic diet was due to KD inefficacy (poor effect despite adequate ketosis), as well as intolerance and an inability to attain ketosis. Our cohort of seven patients in whom KD therapy failed stood out for their advanced age at seizure onset, i.e. almost 4 years vs 8 months in large series, female sex, as well as their advanced age at diagnosis and initiation of KD therapy. EEG recordings during KD therapy can aid in the assessment of effectiveness of the KD therapy. CONCLUSIONS: GLUT1DS is generally described as a treatable disorder and existing case series do not provide details of treatment failure. In select patients with GLUT1DS, KD therapy fails, rendering GLUT1DS an essentially untreatable disorder. Failure of the ketogenic diet was due to KD inefficacy (poor effect despite adequate ketosis), as well as intolerance and an inability to attain ketosis. Failure to reduce seizure frequency with deterioration of the EEG findings should lead to consideration of cessation of KD therapy.

Optimal clinical management of children receiving dietary therapies for epilepsy: Updated recommendations of the International Ketogenic Diet Study Group.

Ketogenic dietary therapies (KDTs) are established, effective nonpharmacologic treatments for intractable childhood epilepsy. For many years KDTs were implemented differently throughout the world due to lack of consistent protocols. In 2009, an expert consensus guideline for the management of children on KDT was published, focusing on topics of patient selection, pre-KDT counseling and evaluation, diet choice and attributes, implementation, supplementation, follow-up, side events, and KDT discontinuation. It has been helpful in outlining a state-of-the-art protocol, standardizing KDT for multicenter clinical trials, and identifying areas of controversy and uncertainty for future research. Now one decade later, the organizers and authors of this guideline present a revised version with additional authors, in order to include recent research, especially regarding other dietary treatments, clarifying indications for use, side effects during initiation and ongoing use, value of supplements, and methods of KDT discontinuation. In addition, authors completed a survey of their institution's practices, which was compared to responses from the original consensus survey, to show trends in management over the last 10 years.

Long-term clinical outcomes and economic evaluation of the ketogenic diet versus care as usual in children and adolescents with intractable epilepsy.

OBJECTIVE: To examine long-term retention rate, clinical outcomes, cost-utility and cost-effectiveness of the Ketogenic Diet (KD) compared with care as usual (CAU) in children and adolescents with intractable epilepsy from a societal perspective. METHODS: Participants were randomized into a KD or CAU group. Seizure frequency, quality adjusted life years (QALYs), side-effects, seizure severity, health care costs, production losses, patient and family costs were assessed at baseline and during 16-months of follow-up. Incremental cost-effectiveness ratios (ICERs) (i.e. cost per QALY and cost per responder) and cost-effectiveness acceptability curves are presented. RESULTS: 48 children were included in the analyses of this study (26 from KD group). In total, 58% of the KD group completed the follow-up of 16 months; 11 dropped-out for various reasons. At 16 months, 35% of the KD participants had a seizure reduction≥50% from baseline, compared with 18% of the CAU participants. Mean costs per patient in the CAU group were €53,367 (extrapolated) compared to €61,019 per patient in the KD group, resulting in an ICER of €46,564 per responder. Cost per QALY rose well above any acceptable ceiling ratio. At 4-months' follow-up, the KD group showed significantly more gastro-intestinal problems compared to the CAU group. At 16 months, the KD group reported fewer problems compared to CAU. Furthermore, 46.2% of the KD group reported a decrease in severity of their worst seizure compared to 32% of the CAU group. CONCLUSION: The KD group resulted in more responders and showed greater improvement on seizure severity. Furthermore, the KD did not lead to worsening of side-effects other than gastro-intestinal problems (only at 4 months' follow-up). However, as only a minimal difference in QALYs was found between the KD group and the CAU group, the resulting cost per QALY ratios were inconclusive.

A systematic review of economic evaluations of treatments for patients with epilepsy.

The increasing number of treatment options and the high costs associated with epilepsy have fostered the development of economic evaluations in epilepsy. It is important to examine the availability and quality of these economic evaluations and to identify potential research gaps. As well as looking at both pharmacologic (antiepileptic drugs [AEDs]) and nonpharmacologic (e.g., epilepsy surgery, ketogenic diet, vagus nerve stimulation) therapies, this review examines the methodologic quality of the full economic evaluations included. Literature search was performed in MEDLINE, EMBASE, NHS Economic Evaluation Database (NHS EED), Econlit, Web of Science, and CEA Registry. In addition, Cochrane Reviews, Cochrane DARE and Cochrane Health Technology Assessment Databases were used. To identify relevant studies, predefined clinical search strategies were combined with a search filter designed to identify health economic studies. Specific search strategies were devised for the following topics: (1) AEDs, (2) patients with cognitive deficits, (3) elderly patients, (4) epilepsy surgery, (5) ketogenic diet, (6) vagus nerve stimulation, and (7) treatment of (non)convulsive status epilepticus. A total of 40 publications were included in this review, 29 (73%) of which were articles about pharmacologic interventions. Mean quality score of all articles on the Consensus Health Economic Criteria (CHEC)-extended was 81.8%, the lowest quality score being 21.05%, whereas five studies had a score of 100%. Looking at the Consolidated Health Economic Evaluation Reporting Standards (CHEERS), the average quality score was 77.0%, the lowest being 22.7%, and four studies rated as 100%. There was a substantial difference in methodology in all included articles, which hampered the attempt to combine information meaningfully. Overall, the methodologic quality was acceptable; however, some studies performed significantly worse than others. The heterogeneity between the studies stresses the need to define a reference case (e.g., how should an economic evaluation within epilepsy be performed) and to derive consensus on what constitutes "standard optimal care."

A prospective study on changes in blood levels of cholecystokinin-8 and leptin in patients with refractory epilepsy treated with the ketogenic diet.

OBJECTIVE: To evaluate the changes in serum CCK-8 and leptin levels in patients with refractory epilepsy treated with the ketogenic diet (KD). METHODS: In this prospective study, patients aged between one and 40 years with refractory epilepsy were included. CCK-8 and leptin were measured in serum at baseline and after three and 12 months of treatment with the KD using an enzyme-linked Immunoabsorbant Assay. Seizure frequency and responsiveness were calculated. RESULTS: Fifty-four patients were included; 26 patients (48%) were still on the KD at 12 months. After three and 12 months, respectively, 39% and 26% were responders. CCK-8 values were statistically significantly increased at three months (p=0.005) and 12 months (p=0.012). In responders, at three months follow-up, this increase of CCK-8 was significant (p=0.020), whereas in the non-responders it was not (p=0.34). Leptin values were decreased at three and 12 months, the decrease at three months being statistically significant in post-pubertal men (p=0.028) and post-pubertal women (p=0.007). SIGNIFICANCE: In responders to the KD, serum CCK-8 increased statistically significantly during treatment at three months. Serum leptin decreased statistically significantly at three months in men and in post-pubertal women. It is plausible that the increase of CCK-8 and the decrease of leptin contribute to the anti-convulsive effect of the KD.

Cognitive and behavioral impact of the ketogenic diet in children and adolescents with refractory epilepsy: A randomized controlled trial.

PURPOSE: The ketogenic diet (KD) is increasingly used for the treatment of refractory epilepsy in childhood because of the beneficial effect on seizure reduction. The aim of the current study was to objectively assess cognition and aspects of behavior during the first 4months of a randomized controlled study in children and adolescents. METHODS: Participants from a tertiary epilepsy center were randomized to a KD group (intervention) or a care-as-usual (CAU) group (control). Follow-up assessments on cognition and behavior were performed approximately 4months after initiation of the KD with a combination of parent report questionnaires and individually administered psychological tests for the children. RESULTS: A total of 50 patients were enrolled in this study, 28 patients from the KD group and 22 patients from the CAU group. The KD group showed lower levels of anxious and mood-disturbed behavior and was rated as more productive. Cognitive test results showed an improvement of activation in the KD group. CONCLUSIONS: This study showed a positive impact of the KD on behavioral and cognitive functioning in children and adolescents with refractory epilepsy. More specifically, an activated mood and cognitive activation were observed in patients treated with the KD.

An economic evaluation of the ketogenic diet versus care as usual in children and adolescents with intractable epilepsy: An interim analysis.

OBJECTIVES: To gain insight into the cost-effectiveness of the ketogenic (KD) diet compared with care as usual (CAU) in children and adolescents with intractable epilepsy, we conducted an economic evaluation from a societal perspective, alongside a randomized controlled trial. METHODS: Participants from a tertiary epilepsy center were randomized into KD (intervention) group or CAU (control) group. Seizure frequency, quality adjusted life years (QALYs), health care costs, production losses of parents and patient, and family costs were assessed at baseline and during a 4-month study period and compared between the intervention and control groups. The incremental cost-effectiveness ratios (ICERs) (i.e., cost per QALY and cost per responder), and cost-effectiveness acceptability curves (CEACs) were calculated and presented. RESULTS: In total, 48 children were included in the analyses of this study (26 KD group). At 4 months, 50% of the participants in the KD group had a seizure reduction ≥50% from baseline, compared with 18.2 of the participants in the CAU group. The mean costs per patient in the CAU group were €15,245 compared to €20,986 per patient in the KD group, resulting in an ICER of €18,044 per responder. We failed, however, to measure any benefits in terms of QALYs and therefore, the cost per QALY rise high above any acceptable ceiling ratio. It might be that the quality of life instruments used in this study were not sufficiently sensitive to detect changes, or it might be that being a clinical responder is not sufficient to improve a patient's quality of life. Univariate and multivariate sensitivity analyses and nonparametric bootstrapping were performed and demonstrated the robustness of our results. SIGNIFICANCE: The results show that the KD reduces seizure frequency. The study did not find any improvements in quality of life and, therefore, unfavorable cost per QALY ratio's resulted.

The MCT-ketogenic diet as a treatment option in refractory childhood epilepsy: A prospective study with 2-year follow-up.

The present study assessed the long-term (i.e., 24months) efficacy of the ketogenic diet (KD) as an add-on therapy in children with refractory epilepsy, with focus on seizure frequency, seizure severity, and tolerability. Most patients were treated with the MCT-diet. At one and two years, 33% and 23%, respectively, of the 48 included patients were still on the KD. After three months, one year, and two years of treatment, 16.7% of the patients were responders. The highest responder rate (i.e., 22.9%) was seen at six and nine months of treatment. Of the fifteen patients with seizure clusters during baseline, 60% were responders after three months when looking at cluster reduction and most of them were not responders for the total seizure frequency. From three months of treatment onwards, most of the patients had a relevant decrease in seizure severity which was mainly related to the most severe seizure type. Gastrointestinal dysfunction was often reported, especially in the first six weeks of treatment. Growth deceleration was present in 30% of the patients, and weight reduction in 15%. Improved arousal was mentioned in 30% of patients. No patients developed ECG abnormalities or kidney stones. Increase in lipid profile was rare. The KD is an effective therapy for children with therapy-resistant epilepsy. Effectiveness is reflected in the reduction of seizure frequency as well as in the reduction of seizure severity. After 6months of treatment, it is obvious which patients are responders and tolerate the treatment well. Most of these patients will continue to benefit from the KD for a longer time. Long-term use of the diet was well tolerated.

Cost-effectiveness of the ketogenic diet and vagus nerve stimulation for the treatment of children with intractable epilepsy.

PURPOSE: The objective of this study was to estimate the expected cost-utility and cost-effectiveness of the ketogenic diet (KD), vague nerve stimulation (VNS) and care as usual (CAU), using a decision analytic model with a 5-year time horizon. METHODS: A Markov decision analytical model was constructed to estimate the incremental costs, quality-adjusted life years (QALYs) and successfully treated patient (i.e. 50% or more seizure reduction) of the treatment strategies KD, VNS and CAU, from a health care perspective. The base case considered children with intractable epilepsy (i.e. two or more antiepileptic drugs had failed) aged between 1 and 18 years. Data were derived from literature and expert meetings. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: Our results suggest that KD is more effective and less costly, and thus cost-effective compared with VNS, after 12 months. However, compared to CAU, neither KD nor VNS are cost-effective options, they are both more effective but also more expensive (€346,899 and €641,068 per QALY, respectively). At 5 years, VNS is cost-effective compared with KD and CAU (€11,378 and €68,489 per QALY, respectively) and has a 51% probability of being cost-effective at a ceiling ratio of €80,000 per QALY. CONCLUSIONS: Our results suggest that on average the benefits of KD and VNS fail to outweigh the costs of the therapies. However, these treatment options should not be ignored in the treatment for intractable epilepsy in individual or specific groups of patients. There is a great need for high quality comparative studies with large patient samples which allow for subgroup analyses, long-term follow-up periods and outcome measures that measure effects beyond seizure frequency (e.g. quality of life). When this new evidence becomes available, reassessment of the cost-effectiveness of KD and VNS in children with intractable epilepsy should be carried out.

Can an early 24-hour EEG predict the response to the ketogenic diet? A prospective study in 34 children and adults with refractory epilepsy treated with the ketogenic diet.

PURPOSE: We examined whether early EEG changes in a 24-h EEG at 6 weeks of treatment were related to the later clinical response to the ketogenic diet (KD) in a 6-month period of treatment. METHODS: We examined 34 patients with heterogeneous epilepsy syndromes (21 children, 13 adults) and found 9 clinical responders (≥50% seizure reduction); this is a responder rate of 26%. We visually counted the interictal epileptic discharge index (IED index) in % during 2h of wakefulness and in the first hour of sleep (method 1), and also globally reviewed EEG changes (method 2), while blinded to the effect of the KD. RESULTS: At group level we saw a correlation between nocturnal reduction of IED-index at 6 weeks and seizure reduction in the follow-up period. A proportional reduction in IED index of 30% from baseline in the sleep EEG, was associated with being a responder to the diet (Pearson Chi-square p=0.04). EEG scoring method 2 observed a significantly larger proportion of patients with EEG-improvement in sleep in KD responders than in non-responders (p=0.03). At individual level, however, EEG changes did not correlate very strongly to the response to the diet, as IED reduction in sleep was also seen in 15% (method 1) to 26% (method 2) of the non-responders. CONCLUSION: Nocturnal reduction of IEDs is related to the response to the KD, however in daily clinical practice, an early EEG to predict seizure reduction should not be advised for individual patients.

The ketogenic diet as a treatment option in adults with chronic refractory epilepsy: efficacy and tolerability in clinical practice.

The ketogenic diet (KD) is a high-fat, low-protein, low-carbohydrate diet that is used as a treatment for patients with difficult-to-control epilepsy. The present study assesses the efficacy and tolerability of the KD as an add-on therapy in adults with chronic refractory epilepsy. 15 adults were treated with the classical diet or MCT diet. During a follow-up period of 1 year we assessed seizure frequency, seizure severity, tolerability, cognitive performance, mood and quality of life (QOL). We found a significant reduction in seizures among the patients who followed the diet at least 1 year (n=5). Of these 5 patients, 2 had a reduction between 50 and 90%. Analyzing the study months separately, we found a seizure reduction of ≥50% in 26.6% of the patients during at least 1 month of treatment. Common side-effects were gastrointestinal disorders, loss of weight and fatigue. There was a considerable, non-significant improvement found in mood and QOL scores. Improvements were independent of reduction in seizure frequency, indicating that the effects of the KD reach further than seizure control.

Research into the (Cost-) effectiveness of the ketogenic diet among children and adolescents with intractable epilepsy: design of a randomized controlled trial.

BACKGROUND: Epilepsy is a neurological disorder, characterized by recurrent unprovoked seizures which have a high impact on the individual as well as on society as a whole. In addition to the economic burden, epilepsy imposes a substantial burden on the patients and their surroundings. Patients with uncontrolled epilepsy depend heavily on informal care and on health care professionals. About 30% of patients suffer from drug-resistant epilepsy. The ketogenic diet can be a treatment of last resort, especially for children. The beneficial effect of the ketogenic diet has been proven, but information is lacking about its cost-effectiveness. In the current study we will evaluate the (cost-) effectiveness of the ketogenic diet in children and adolescents with intractable epilepsy. METHODS/DESIGN: In a RCT we will compare the ketogenic diet with usual care. Embedded in this RCT will be a trial-based and model-based economic evaluation, looking from a societal perspective at the cost-effectiveness and cost-utility of the ketogenic diet versus usual care. Fifty children and adolescents (aged 1-18) with intractable epilepsy will be screened for eligibility before randomization into the intervention or the usual care group. The primary outcome measure is the proportion of children with a 50% or more reduction in seizure frequency. Secondary outcomes include seizure severity, side effects/complaints, neurocognitive, socio-emotional functioning, and quality of life. Costs and productivity losses will be assessed continuously by a prospective diary and a retrospective questionnaire. Measurements will take place during consults at baseline, at 6 weeks and at 4 months after the baseline period, and 3, 6, 9 and 12 months follow-up after the 4 months consult. DISCUSSION: The proposed research project will be the first study to provide data about the cost-effectiveness of the ketogenic diet for children and adolescents with intractable epilepsy, in comparison with usual care. It is anticipated that positive results in (cost-) effectiveness of the proposed intervention will contribute to the improvement of treatment for epilepsy in children and adolescents and will lead to a smaller burden to society.