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.

Rufinamide in children with refractory epilepsy: pharmacokinetics, efficacy, and safety.

We examined the influence of age and type of concomitant antiepileptic drugs (AEDs) on the pharmacokinetics of rufinamide (RUF) as well as its efficacy and safety in 51 children with refractory epilepsy. In a retrospective noninterventional survey, dose-to-concentration ratios of RUF and concomitant AEDs were calculated: the weight-normalized dose (mg/kg/d) divided by the steady-state trough plasma drug level, which was used as a measure of clearance. During treatment with RUF concomitantly with valproic acid (VPA) young children, aged 0 to 4.9 years, had a low clearance of RUF, which did not differ from older children. If not on VPA but on enzyme inducers, young children had a threefold higher clearance of RUF than the older ones. In young children not on VPA, those on enzyme inducers had 1.7-fold higher clearance than those on nonenzyme inducers. In children neither on VPA nor on enzyme inducers, RUF clearance was age-dependent with higher clearance in younger children. Adding RUF did not change the pharmacokinetics of concomitantly used AEDs. Seizure response after 2 to 3 months on RUF treatment was found in 12 of 51 children (23.5%), at mean plasma level of 36.9 ± 22.0 µmol/L. Adverse events were reported in 41% of the patients of which fatigue was most frequent (24%).

Age and comedications influence levetiracetam pharmacokinetics in children.

The pharmacokinetics of many antiepileptic drugs differs between adults and children. The influence of age and concomitant medications on the dose/concentration ratio of levetiracetam was examined in 103 children with epilepsy. Dosing and plasma levels of levetiracetam and concomitant antiepileptic drugs were reviewed retrospectively. The dose/concentration ratio was calculated as the weight-normalized dose (mg/kg/day) divided by the steady-state trough plasma drug level, which was used as a measure of apparent oral clearance of levetiracetam. Children were classified into age groups and treatment groups: levetiracetam given with enzyme inducers (n = 24) or nonenzyme inducers (n = 69), or as monotherapy (n = 10). Levetiracetam clearance differed significantly between age groups (0-4, 5-11, and 12-17 years), i.e., the younger the child, the higher the clearance. The increase was 1.7-fold between the youngest and oldest age groups. Children on enzyme inducers exhibited significantly higher clearance (1.3-fold), compared with those on nonenzyme inducers and monotherapy. Levetiracetam did not influence the clearance of lamotrigine, valproate, topiramate, or clonazepam. In conclusion, younger age and comedication with an enzyme inducer increased levetiracetam clearance. This finding should be taken into account when treating individual patients.

Optimal clinical management of children receiving the ketogenic diet: recommendations of the International Ketogenic Diet Study Group.

The ketogenic diet (KD) is an established, effective nonpharmacologic treatment for intractable childhood epilepsy. The KD is provided differently throughout the world, with occasionally significant variations in its administration. There exists a need for more standardized protocols and management recommendations for clinical and research use. In December 2006, The Charlie Foundation commissioned a panel comprised of 26 pediatric epileptologists and dietitians from nine countries with particular expertise using the KD. This group was created in order to create a consensus statement regarding the clinical management of the KD. Subsequently endorsed by the Practice Committee of the Child Neurology Society, this resultant manuscript addresses issues such as patient selection, pre-KD counseling and evaluation, specific dietary therapy selection, implementation, supplementation, follow-up management, adverse event monitoring, and eventual KD discontinuation. This paper highlights recommendations based on best evidence, including areas of agreement and controversy, unanswered questions, and future research.

Influence of the ketogenic diet on 24-hour electroencephalogram in children with epilepsy.

The ketogenic diet is a therapeutic diet used to treat medically refractory epilepsy in children. It was found to be effective and safe. Apart from a reduced number of seizures, positive cognitive effects were described. The mechanisms of action are not fully understood, but both antiseizure and antiepileptogenic effects were proposed. Among other changes ascribed to the introduction of the diet, changes in electroencephalogram patterns might contribute to an understanding of the effects of the ketogenic diet. In this study, 23 children (mean age, 6.5 years) with pharmacoresistant epilepsy were started on the diet. They were examined via 24-hour ambulatory electroencephalogram directly before starting the diet, and after 3 months of treatment. The changing electroencephalogram pattern was evaluated qualitatively and semiquantitatively. Background activity, interictal epileptiform activity, ictal activity, and seizure reduction were evaluated. Quality of life was estimated on a visual analog scale. In 15 of 23 patients, the electroencephalogram indicated improvement in terms of more normal background activity or decreased interictal epileptiform activity. This improvement was seen in both seizure-reduction responders and nonresponders, and was not predictive of response to treatment.

Plasma levels of antiepileptic drugs in children on the ketogenic diet.

Influence of the ketogenic diet on plasma concentrations of antiepileptic drugs was investigated in an open clinical study of 51 children (mean age 6.6 years) with medically refractory epilepsy. The plasma levels of concomitantly used antiepileptic drugs were determined immediately before and 3 months after initiating the ketogenic diet. To compensate for adjustments in dosing, the plasma concentration in relation to the dose per kilogram of body weight per day, i.e. the level-to-dose ratio, was used for comparison; it was calculated as the plasma concentration (micromol/L) divided by the corresponding weight-normalized dose (mg/kg body weight/day) for each drug and child. The level-to-dose ratios of each drug before and during the diet were compared. No significant changes in these ratios could be found for valproic acid, lamotrigine, topiramate, clonazepam, or phenobarbital. In 16 children, the ratio of the free unbound concentration of valproic acid to its total plasma concentration was compared before and during the diet, but it did not change significantly. Thus, the ketogenic diet did not change the plasma concentrations of commonly used antiepileptic drugs in children in any significant way. Therefore, when initiating the diet, it does not seem necessary to adjust drug doses due to pharmacokinetic interactions.

Age and antiepileptic drugs influence topiramate plasma levels in children.

The influence of age and comedication on the dose-to-level ratio of topiramate was examined in 91 children with epilepsy treated with topiramate. The topiramate dosing and plasma concentrations, as well as those of their concomitant antiepileptic drugs were examined retrospectively. The dose-to-level ratio was used as a measure of clearance and was calculated as the weight-normalized topiramate dose (mg/kg/day) divided by the steady-state trough plasma drug level in the child. The children were classified in age groups and treatment groups; topiramate was administered with an enzyme inducer (n = 32), with a nonenzyme inducer (n = 49), or as monotherapy (n = 10). The topiramate clearance in children aged 0-8 years compared with those aged 9-17 years was more than twofold higher if treated with an enzyme-inducing antiepileptic drug and 1.5-fold higher if treated with a nonenzyme inducer. Children receiving enzyme inducers had a more than twofold higher clearance compared with those who did not. Within all age groups, significant differences in topiramate clearance were observed between those receiving enzyme inducers and those receiving nonenzyme inducers or monotherapy. Thus younger age and concomitant enzyme inducers, both acting independently, significantly increased the clearance of topiramate in children. This effect has to be considered to optimize treatment in the individual patient.

Reduction of seizures with low-dose clonazepam in children with epilepsy.

The acute effects of low-dose clonazepam on seizure frequency in children with epilepsy was evaluated. In an open study, 19 children with epilepsy (15 generalized and four partial) were examined during hospitalization with recordings of seizures by trained personnel. Seizures were counted during two 24-hour periods: before and after a single intramuscular injection of clonazepam 0.01-0.04 mg/kg body weight. Plasma concentrations of clonazepam were determined. The median number of seizures in all children on control days was 22 (range = 1-180) and, on days after low-dose clonazepam, the median was 6 (range = 0-73). The relative changes demonstrated a median of -70% (range from -100% to + 43%). A significant reduction of seizures (P = 0.0031) at median maximal plasma levels of clonazepam of 23 nmol/L (range = 11-41 nmol/L) was found. Thus in this study of the acute effects of a low-dose level of clonazepam on seizure frequency a significant reduction was found at plasma levels below those usually recommended. Inhibition of seizure activity seems to be achieved already at low plasma levels of clonazepam. These results suggest to start treatment at low doses of clonazepam and evaluate the individual effect carefully during dose escalation aiming at lowest possible dose with therapeutic effect.