The long-term use of felbamate in children with severe refractory epilepsy

Felbamate as a therapeutic alternative to drug-resistant genetic generalized epilepsy: a systematic review and meta-analysis

INTRODUCTION

The effect of felbamate (FBM) on genetic generalized epilepsy (GGE) remains largely unknown. The utilization of FBM has been limited due to its potential risk of aplastic anemia and hepatic failure. This study aimed to comprehensively evaluate the efficacy and safety of FBM in the treatment of drug-resistant GGE.

METHODS

We searched the databases, including PubMed, Web of Science, Embase, and Google Scholar, to identify cases of GGE treated with FBM. Data on outcomes and adverse events were extracted from these studies.

RESULTS

The literature search yielded 9 studies with 166 cases in which FBM was used as an adjunct therapy to treat drug-resistant GGE. The pooled responder rate to FBM was 65% (95% confidence interval CI, 51-80). 17% (95% CI, 3-31) achieved seizure freedom. 81% (95% CI, 60-100) of patients with Epilepsy with myoclonic atonic seizures were responders. Adverse events were reported in 40% (95% CI, 26-54) of patients.

CONCLUSIONS

Patients with drug-resistant GGE achieved good responses to FBM. The high heterogeneity between studies calls for further research with large-scale, randomized controlled trials. Given the rare reports of idiosyncratic reactions of aplastic anemia and hepatic failure, intense laboratory monitoring and a slower titration schedule are recommended.

Impact of Antiseizure Medications on Appetite and Weight in Children

There are numerous potential factors that may affect growth in children with epilepsy, and these must be evaluated in any child with appetite and weight concerns. Antiseizure medications (ASMs) have potential adverse effects, and many may affect appetite, thus impacting normal growth and weight gain. The aim of this review is to focus on the impact of both epilepsy and ASMs on appetite and weight in children. We systematically reviewed studies using Medline assessing the impact of ASMs on appetite and weight in children. Eligible studies included randomized controlled trials and open-label studies (open-label extension and interventional) that targeted or included the pediatric population (0-18 years of age). Each study was classified using the American Academy of Neurology (AAN) Classification of Evidence for Therapeutic Studies, and the level of evidence for impact on appetite and weight in children was graded. ASMs associated with decreased appetite and/or weight loss include fenfluramine, topiramate, zonisamide, felbamate, rufinamide, stiripentol, cannabidiol, brivaracetam and ethosuximide; ASMs with minimal impact on weight and appetite in children include oxcarbazepine, eslicarbazepine, lamotrigine, levetiracetam, lacosamide, carbamazepine, vigabatrin and clobazam. The ASM most robustly associated with increased appetite and/or weight gain is valproic acid; however, both pregabalin and perampanel may also lead to modest weight gain or increased appetite in children. Certain ASMs may impact both appetite and weight, which may lead to increased morbidity of the underlying disease and impaired adherence to the treatment regimen.

Medical Comorbidities in MECP2 Duplication Syndrome: Results from the International MECP2 Duplication Database

Since the discovery of MECP2 duplication syndrome (MDS) in 1999, efforts to characterise this disorder have been limited by a lack of large datasets, with small case series often favouring the reporting of certain conditions over others. This study is the largest to date, featuring 134 males and 20 females, ascertained from the international MECP2 Duplication Database (MDBase). We report a higher frequency of pneumonia, bronchitis, bronchiolitis, gastroesophageal reflux and slow gut motility in males compared to females. We further examine the prevalence of other medical comorbidities such as epilepsy, gastrointestinal problems, feeding difficulties, scoliosis, bone fractures, sleep apnoea, autonomic disturbance and decreased pain sensitivity. A novel feature of urinary retention is reported and requires further investigation. Further research is required to understand the developmental trajectory of this disorder and to examine the context of these medical comorbidities in a quality of life framework.

Use of a physiologically based pharmacokinetic-pharmacodynamic model for initial dose prediction and escalation during a paediatric clinical trial

AIMS

To build and verify a physiologically based pharmacokinetic (PBPK) model for radiprodil in adults and link this to a pharmacodynamic (PD) receptor occupancy (RO) model derived from in vitro data. Adapt this model to the paediatric population and predict starting and escalating doses in infants based on RO. Use the model to guide individualized dosing in a clinical trial in 2- to 14-month-old children with infantile spasms.

METHODS

A PBPK model for radiprodil was developed to investigate the systemic exposure of the drug after oral administration in fasted and fed adults; this was then linked to RO via a PD model. The model was then expanded to include developmental physiology and ontogeny to predict escalating doses in infants that would result in a specific RO of 20, 40 and 60% based on average unbound concentration following a twice daily (b.i.d.) dosing regimen. Dose progression in the clinical trial was based on observed concentration-time data against PBPK predictions.

RESULTS

For paediatric predictions, the elimination of radiprodil, based on experimental evidence, had no ontogeny. Predicted b.i.d. doses ranged from 0.04 mg/kg for 20% RO, 0.1 mg/kg for 40% RO to 0.21 mg/kg for 60% RO. For all infants recruited in the study, observed concentration-time data following the 0.04 mg/kg and subsequent doses were within the PBPK model predicted 5^th and 95^th percentiles.

CONCLUSION

To our knowledge, this is the first time a PBPK model linked to RO has been used to guide dose selection and escalation in the live phase of a paediatric clinical trial.

Felbamate for infantile spasms syndrome resistant to first-line treatments

AIM

To analyse the effects of felbamate in refractory infantile spasms/West syndrome.

METHOD

We conducted a 10-year retrospective study of infants (including all infants younger than 18mo) treated with felbamate for electroencephalography-recorded epileptic spasms persisting after first-line treatment.

RESULTS

In total, 29 infants (17 males, 12 females) were included in the study. Felbamate was initiated at a mean age of 13.8 months (range 4.5-66mo) after sequential administration or combination of vigabatrin and oral steroids; a ketogenic diet was implemented in 23 infants. Eight infants became spasm-free at a mean dose of 34.6mg/kg/day felbamate (range 26-45mg/kg/day). Mean duration of felbamate use was 19 months (range 1-67mo) for the 19 infants whose treatment was terminated. No severe side effects were observed. Reversible neutropenia led to withdrawal of felbamate in six patients. One spasm-free patient demonstrated recurrence when felbamate was withdrawn.

INTERPRETATION

N-methyl-d-aspartate receptors with felbamate controlled epileptic spasms in eight infants resistant to first-line treatment should be targeted.

Safety and tolerability profile of new antiepileptic drug treatment in children with epilepsy

INTRODUCTION

Treatment of pediatric epilepsy requires a careful evaluation of the safety and tolerability profile of antiepileptic drugs (AEDs) to avoid or minimize as much as possible adverse events (AEs) on various organs, hematological parameters, and growth, pubertal, motor, cognitive and behavioral development.

AREAS COVERED

Treatment-emergent AEs (TEAEs) reported in the literature 2000-2018 regarding second- and third-generation AEDs used in the pediatric age, with exclusion of the neonatal period that exhibits specific peculiarities, have been described on the basis of their frequency, severity/tolerability, and particular association with a given AED.

EXPERT OPINION

Somnolence/sedation and behavioral changes, like irritability and nervousness, are among the most commonly observed TEAEs associated with almost all AEDs. Lamotrigine, Gabapentin, Oxcarbazepine, and Levetiracetam appear to be the best-tolerated AEDs with a ≤2% withdrawal rate, while Tiagabine and Everolimus are discontinued in up to >20% of the patients because of intolerable TEAEs. For some AEDs, literature data are scanty to draw a high-level evidence on their safety and tolerability profile. The reasons are: insufficient population size, short duration of treatments, or lack of controlled trials. A future goal is that of identifying clearer, easier, and more homogeneous methodological strategies to facilitate AED testing in pediatric populations.

Disease Specific Aspects of Malnutrition in Neurogeriatric Patients

Malnutrition in elderly patients is a common condition. Nevertheless, there is evidence on specific risk factors and problems of malnutrition in geriatric patients with neurological diseases. In this review, we summarize recent knowledge on malnutrition in different neurological diseases with a focus on elderly patients. This overview also provides strategies for a more specific and profound assessment of neurogeriatric patients to improve identification and treatment of malnutrition. Early and consequent treatment of malnutrition can lead to a decreased progression of the neurological disease and to a better quality of life in geriatric patients.

Evaluating the safety and efficacy of felbamate in the context of a black box warning: A single center experience

INTRODUCTION

Felbamate was approved in 1993 to treat partial seizures with and without secondary generalization in adults and in Lennox-Gastaut Syndrome in children. Its use was later restricted when rare but fatal cases of aplastic anemia and hepatic failure were identified.

METHODS

This single center analysis retrospectively evaluated the safety and efficacy of felbamate in a cohort of children, adolescents, and adults with epilepsy.

RESULTS

A chart review identified 103 patients taking felbamate. The range of felbamate dose was 300-4500 mg (mean: 1800 ± 900 mg). The duration of therapy ranged from 1 month to 20 years (mean duration: 35 ± 45 months). Eighteen (17.5%) subjects experienced adverse events including insomnia, nausea, vomiting, decreased appetite, weight loss, gastric discomfort, diarrhea, mood and behavioral problems, high blood pressure, headache, and elevated liver enzymes. Out of these, 6 (5.9%) patients discontinued the therapy. No hepatic failure or agranulocytosis was observed. Fifty-nine (57.72%) patients achieved ≥ 50% reduction in seizure frequency, and 30 (29.12%) patients achieved seizure freedom.

CONCLUSIONS

These findings suggest that felbamate is safe, well tolerated, and effective in treatment of various types of epilepsy syndromes.

Weight change, genetics and antiepileptic drugs

Weight gain caused by antiepileptic drugs (AEDs) constitutes a serious problem in the management of people with epilepsy. AEDs associated with weight gain include sodium valproate, pregabalin and vigabatrin. Excessive weight gain can lead to non-compliance with treatment and to an exacerbation of obesity-related conditions. The mechanisms by which AEDs cause weight gain are not fully understood. It is likely that weight change induced by some AEDs has a genetic underpinning, and recent developments in DNA sequencing technology should speed the understanding, prediction and thus prevention of serious weight change associated with AEDs. This review focuses on the biology of obesity in the context of AEDs. Future directions in the investigations of the mechanism of weight change associated with these drugs and the use of such knowledge in tailoring the treatment of specific patient groups are explored.

Newer anticonvulsant medications in pediatric neurology

OPINION STATEMENT

Antiepileptic drugs (AEDs) are the mainstay of treatment for recurrent seizures. Uncontrolled seizures may cause medical, developmental, and psychological disturbances. The medical practitioner should thus strive to eliminate or minimize seizures. Treatment advances in epilepsy include 1) identification of the basic mechanisms of epilepsy and action of AEDs, 2) the introduction of new AEDs, and 3) the use of neurostimulation, including vagus nerve stimulation. Treatment with AEDs involves balancing each AED's efficacy against its side effects. In some patients, effective AEDs must be discontinued because of intolerable side effects. Although all AEDs have a proven efficacy, the choice of AEDs should be based on better efficacy for individual seizure types or epilepsy syndromes. Side effects also differ from drug to drug and must be taken into account. This article focuses on studies and expert opinion consensus to guide the choice of AEDs.

Update on the newer antiepileptic drugs in child neurology: advances in treatment of pediatric epilepsy

The goal of epilepsy treatment is the prevention of recurrent seizures, and antiepileptic drugs (AEDs) are the mainstay. Uncontrolled seizures may cause medical, developmental, and psychologic disturbances. Treatment advances include 1) identification of the basic mechanisms of epilepsy and action of AEDs, 2) the introduction of many new AEDs, and 3) the use of neurostimulation, starting with vagus nerve stimulation. We must balance the efficacy of an AED versus its side effects, which if persistent, lead to patient discontinuation of the AED. Although all AEDs have a proven efficacy, they are differentiated by their efficacy for a given seizure type or epilepsy syndrome versus the side effects or tolerability. The many new AEDs give us a larger armamentarium for epilepsy treatment. We refer to studies and expert opinion consensus.

Pharmacotherapy for children and adolescents with epilepsy

INTRODUCTION

Childhood epilepsies are the most frequent neurological problems that occur in children. Despite the introduction of new antiepileptic drugs (AEDs) 25-30% of children with epilepsy remain refractory to medical therapy.

AREAS COVERED

This review aims to highlight the main published data on the treatment of childhood epilepsy. The electronic database, PubMed, and abstract proceedings were used to identify studies. The aim of antiepileptic therapy should be to provide complete seizure control, if possible without the burden of any side effect. Since 1993, new agents have been approved for use as an antiepileptic. Although there are few published data (especially in pediatric populations) to establish that the second-generation AEDs are more efficacious than the older AEDs, they appear to have better tolerability.

EXPERT OPINION

Old AEDs are efficacious agents that continue to play a major role in the current treatment of epilepsy. These agents actually remain the first-line treatment for many specific seizure types or epileptic syndromes. The new AEDs were initially approved as adjunct agents and--subsequently--as monotherapy for various seizure types in the adult and children. Despite these improvements, few AEDs are now considered to be a first-choice for the treatment of epilepsy in children.

The safety and tolerability of newer antiepileptic drugs in children and adolescents

The newer antiepileptic drugs (AEDs) provide more therapeutic options and overall improved safety and tolerability for patients. To provide the best care, physicians must be familiar with the latest tolerability and safety data. This is particularly true in children, given there are relatively fewer studies examining the effects of AEDs in children compared with adults. Since we now have significant paediatric literature on each of these agents, we provide a comprehensive and current literature review of the newer AEDs, focusing on safety and tolerability data in children and adolescents. Because the safety profiles in children differ from those in adults, familiarity with this literature is important for child neurologists and other paediatric caregivers. We have organized the data by organ system for each AED for easier reference.

Treatment of Lennox-Gastaut Syndrome (LGS)

Lennox-Gastaut Syndrome (LGS) is a severe form of epilepsy that usually starts in early to mid childhood and is characterized by multiple seizure types, abnormal electroencephalogram with slow spike-and-wave discharges and cognitive problems. Numerous approaches are currently used to treat LGS, including use of conventional antiepileptic drugs (most commonly sodium valproate, lamotrigine and topiramate), other drug interventions (corticosteroids and intravenous immunoglobulin) and nonpharmacologic treatments (ketogenic diet, corpus callosotomy and vagus nerve stimulation). Rufinamide is the most recent antiepileptic drug to have shown efficacy in the treatment of LGS. Despite the variety of therapeutic options, there have been only five double-blind, placebo-controlled clinical trials of antiepileptic drugs in LGS and none of these were head-to-head comparison trials. The evidence supporting the use of available treatments for LGS is, therefore, not robust. Here, we review the evidence supporting the use of specific therapies in LGS and provide recommendations on how to set appropriate treatment goals, select treatments and minimize polypharmacy. A suggested treatment algorithm is presented and discussed. Sodium valproate is recommended for first-line therapy; if seizures persist, alternative interventions should be trialed on an individually tailored basis.

Pentoxifylline ameliorates lithium-pilocarpine induced status epilepticus in young rats

The neuroprotective effects of pentoxifylline (PTX) against lithium-pilocarpine (Li-Pc)-induced status epilepticus (SE) in young rats are described. Animals treated with PTX (0, 20, 40, and 60 mg/kg) before induction of SE were examined for latency to and frequency of SE, behavioral changes, oxidative stress, neurochemical alterations in the hippocampus and striatum, and histological abnormalities in the hippocampus. Treatment with PTX significantly ameliorated the frequency and severity of epileptic seizures in a dose-dependent manner. Our behavioral studies using the elevated plus-maze, rotarod, and water maze tests suggested a significant reduction in anxiety, enhanced motor performance, and improved learning and memory in PTX-treated rats. Li-Pc-induced neuronal cell loss and sprouting of mossy fibers in the hippocampus were also attenuated by PTX. The neuroprotective activity of PTX was accompanied by reduction in oxidative stress and reversal of SE-induced depletion of dopamine and 5-hydroxytryptamine in hippocampus and striatum. The results of this study provide a good rationale to explore the prophylactic/therapeutic potential of PTX in SE.

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.

Topiramate monotherapy in infantile spasm

Infantile spasm is an age-related refractory epilepsy. Topiramate is a new anticonvulsant with multiple mechanisms of action, and it may be effective for treating pediatric epilepsies. To evaluate the efficacy and tolerability of first-line topiramate treatment for infantile spasm, 20 patients received topiramate monotherapy during this study. They were treated with an initial dose of 1mg/kg/day, with a progressive titration of 1 mg/kg a week until their spasms were controlled and a maximum dose of 12 mg/kg/day was achieved. The evaluation of the treatment efficacy was based on the spasm frequency data that was obtained by the scalp and video-EEG, and by the parental count of spasm. Thirty percent of the subjects became spasm-free during the study. Six of 20 subjects (30%) had cessation of spasm and disappearance of hypsarrhythmia as seen via the video EEG; four (50%) of eight idiopathic patients had a response, whereas two (17%) of 12 patients with symptomatic infantile spasm responded. Seventy of the patients, including the spasm-free patients, had a reduction in their seizure frequency of more than 50%, and 10% of the patients had a reduction in their seizure frequency of less than 50%. The clusters of spasm frequency decreased from 10.6 +/- 8.5 to 3.5 +/- 1.4 clusters/day. Topiramate is effective and tolerated in those patients suffering from infantile spasm. Our results suggest that this drug should be considered as a new first-line drug for treating infantile spasm.

Childhood epilepsy syndromes with both focal and generalized seizures

Childhood is a time of considerable importance for the onset of epilepsy syndromes. Selection of an appropriate antiepileptic drug (AED) is central to its successful management. Different AEDs have various effects depending on whether seizures are focal or generalized and this is often used as a rational basis for drug selection. Syndromes, in which features of both focal and generalized seizures are associated in a single patient, present particular problems for pediatric prescribing and epilepsy management since an AED suitable for one seizure type may be ineffective for, or even aggravate, another seizure type. This review discusses the syndromes with different seizures types, focal and generalized, examines the treatment options that may be useful in each case and highlights the potential of some of the newer AEDs in managing these difficult syndromes.

Treatment of partial seizures in childhood : an overview

The treatment of partial seizures in children is based on the use of first generation and recently introduced antiepileptic drugs as well as nonpharmacological treatments such as the ketogenic diet, vagus nerve stimulation and surgical therapy. The present review discusses the efficacy and tolerability of different treatment options for partial seizures in childhood. Few adjunctive or monotherapy, placebo-controlled or comparative trials of the first-generation antiepileptic drugs and some of the more recently introduced antiepileptic drugs have been performed in children. This can be explained by the fact that it is only relatively recently (1989) that the International League against Epilepsy proposed that randomised, controlled trials be included among the required criteria for assessing the efficacy and tolerability of an antiepileptic agent. This led to controlled, comparative trials among older antiepileptic drugs (phenobarbital, phenytoin, carbamazepine and valproic acid), both in adults and in paediatric patients, being performed relatively 'late', based on when these drugs were first introduced. Carbamazepine and valproic acid may still be considered as first-line antiepileptic therapies for children with partial seizures. Phenobarbital and phenytoin are mostly considered as last choice drugs because of their adverse event profiles. The new generation of antiepileptic agents has added to the first- and second-line treatment options for paediatric partial seizures. To date, there are sufficient data to support the clinical use of some of the recently introduced antiepileptic drugs (e.g. oxcarbazepine, topiramate, gabapentin and lamotrigine) as adjunctive or first-line monotherapy. Because of the risk of visual field constriction with vigabatrin, the use of this drug is currently limited to patients refractory to other medications. Tiagabine, felbamate, levetiracetam and zonisamide have been shown to be effective in adults with partial seizures; however, at present there are not yet enough data on the efficacy of these drugs in children to support consideration of their use as either first-line or add-on therapy in this patient population, although controlled studies are expected shortly. Furthermore, the use of felbamate is considerably limited by rare, but severe, hepatic and haematological toxicity. Controlled trials for paediatric partial seizures are still lacking for the ketogenic diet and vagus nerve stimulation, though they may represent, in given patients, useful adjunctive alternative treatments for refractory partial seizures. In conclusion, further trials are needed to determine an optimal sequence of first- and second-line therapies and to establish whether other newer antiepileptic drugs merit consideration as initial therapy in children with partial seizures.

Cognitive side effects of antiepileptic drugs

Antiepileptic drugs produce global changes in the excitation levels in the central nervous system and often lead to cognitive and behavioral deficits. These deficits vary and must be considered independently in every patient. A number of consistent risk factors have been established. Polypharmacy and high blood levels of an antiepileptic drug (AED) increase the risk of cognitive side effects. Different effects have been demonstrated for some AEDs, but comparative data are incomplete across all of them. Other factors such as patient age and type/frequency of seizures may also be important contributors to the patient's cognitive state. AEDs can have positive or negative effects on mood, providing another consideration in choosing the course of treatment.

Effect of antiepileptic drugs on bodyweight: overview and clinical implications for the treatment of epilepsy

The potential of specific antiepileptic drugs (AEDs) to cause clinically significant changes in bodyweight is a key consideration in the management of epilepsy; changes in weight can pose health hazards, impair body image and self-esteem, and lead to noncompliance with therapy. This article reviews the data regarding the effects of conventional and newer AEDs on weight and discusses the clinical implications of these effects for the management of patients with epilepsy. The data demonstrate that AEDs can differ substantially in their effects on weight. Some, such as valproate and carbamazepine, increase weight; others, such as topiramate and felbamate, decrease it. Still others, such as lamotrigine, levetiracetam and phenytoin, are weight neutral. Because most data regarding the effects of AEDs on weight are circumstantial, the incidence, magnitude and determinants of weight changes with AEDs remain poorly elucidated. Furthermore, little is known about the mechanisms of AED-induced changes in weight. The importance of effects on weight in selecting an AED depends largely upon the individual patient's needs and the risks and benefits of therapy for that patient. The most appropriate therapeutic choice is a weight-neutral medication unless circumstances dictate otherwise.

Levetiracetam does not alter body weight: analysis of randomized, controlled clinical trials

INTRODUCTION

Increases in body weight gain are important, and clinically significant adverse effects of several antiepileptic drugs (AED) including valproate and gabapentin. Weight gain may contribute to medication non-compliance, discontinuation, and importantly, may have secondary medical implications as well. Levetiracetam (LEV) is indicated for adjunctive treatment of partial seizures. The objective of the present evaluation was to examine the effects of LEV treatment on body weight in adult patients.

METHODS

We analyzed data derived from four prospective, placebo-controlled randomized, clinical trials conducted in both in the US and Europe. Patients included in the present analysis were both men and women, greater than 16 years old, and who had LEV exposure for at least 1 month. Body weight was measured at baseline and at the final LEV study visit. Data are analyzed for all patients, by gender, body mass index (BMI), duration of LEV exposure and by concomitant AED treatment. Wilcoxan Signed Rank, or Rank Sum test used where appropriate, with significance assigned at P<0.05. Data are presented as mean values+/-1 S.D.

RESULTS

Nine-hundred and seventy patients (age=37.5 years, 54% men/46% women) were evaluated. There were no significant differences in baseline demographics between LEV (n=631) or placebo (n=339) treated patient groups. Mean LEV dose and duration of treatment were 2053 mg/day (maximum dose of 4000 mg/day) and 125 days (maximum=181 days), respectively. Concomitant AED therapy included CBZ, PHT, VPA, PB, GBP, LTG, and VGB. For LEV-treated patients, no significant changes in body weight were noted. Mean body weight at baseline versus final study visit for LEV was 74.3+/-16.6 kg and 74.3+/-16.6 kg, respectively. For placebo-treated patients, baseline versus end of treatment weight was 72.4+/-15.4 kg and 72.7+/-15.9 kg, respectively, representing a slight, yet clinically trivial increase. Clinically significant weight change as defined as >7% change from baseline weight, occurred in 9% of LEV-treated patients (4.5% had increase in weight/4.5% decrease) versus 9.4% (5.9% had increase/3.5% decrease) in placebo-treated patients. Weight changes were not significantly different between groups. Neither baseline BMI, gender, or background AEDs, appeared to predispose to significant weight change for LEV-treated patients.

CONCLUSIONS

We conclude that treatment with LEV at clinically relevant dosages is not associated with significant weight change. LEV would, therefore, appear to be a weight neutral AED.

Is the interaction between felbamate and valproate against seizures induced by 4-aminopyridine and pentylenetetrazole in mice beneficial?

We compared the effects of adding a non-protective dose of valproate (VPA) to increasing single doses of felbamate (FBM) with those of monotherapy and vice versa in CD1 mice. Anticonvulsant effects were evaluated against seizures induced by 14 mg kg(-1) of 4-aminopyridine (4-AP) and by 110 mg kg(-1) of pentylenetetrazole (PTZ), and neurotoxicity by the rotarod test. The study also assessed changes in concentrations of anticonvulsants, gamma-aminobutyric acid (GABA) and glutamate in the whole brain. VPA increased the potency ratio of FBM against 4-AP (1.94, P<0.05) but not against PTZ. VPA increased the neurotoxicity of FBM (3.30, P<0.05) and the protective index of FBM was, therefore, reduced from 12.0 to 7.0 for the 4-AP model and from 11.8 to 5.2 for the PTZ model; VPA reduced brain FBM, and increased brain GABA in relation to FBM monotherapy. On the other hand, FBM increased the potency ratio of VPA against 4-AP (1.60, P<0.05) but not against the PTZ, and had no effect on the rotarod model. Therefore, the protective index increased from 1.1 to 1.6 for the 4-AP model and decreased from 1.9 to 1.7 for the PTZ model. FBM did not change brain VPA, and changes in brain GABA and glutamate were not clearly related to anticonvulsant effects. In conclusion, although the addition of a low dose of FBM to VPA was beneficial in the 4-AP model, the addition of a low dose of VPA to FBM was not; both combinations were disadvantageous in the PTZ model. This interaction appears to be pharmacodynamic because a pharmacokinetic mechanism was discarded.

Synergistic interaction between felbamate and lamotrigine against seizures induced by 4-aminopyridine and pentylenetetrazole in mice

We compared the effects of adding a nonprotective dose of felbamate to increasing single doses of lamotrigine with those of monotherapy and vice versa in CD1 mice. Anticonvulsant effects were evaluated against seizures induced by both 14 mg/kg of 4-aminopyridine and 110 mg/kg of pentylenetetrazole, and neurotoxic effects were evaluated by the rotarod test. Changes in anticonvulsants, gamma-aminobutyric acid (GABA) and glutamate concentrations in the whole brain were also assessed. Lamotrigine increased the potency ratio of felbamate against 4-aminopyridine (1.80, 95% confidence interval (CI) 1.23-2.65, P<0.05) but not against pentylenetetrazole nor on rotarod, the protective index being increased from 12.0 to 17.1 for 4-aminopyridine, with a reduction in brain felbamate, and with an increase in brain GABA. Felbamate increased the potency ratio of lamotrigine against 4-aminopyridine (4.35, 95% CI 2.05-9.25, P<0.05) but not on rotarod, the protective index being increased from 4.4 to 15.7; there were no changes in brain lamotrigine, and changes in brain GABA and/or glutamate were unrelated to the pharmacodynamic effects. In conclusion, a nonprotective dose of lamotrigine increased the therapeutic index of felbamate and vice versa, and these effects appeared to be pharmacodynamic.

The clinical impact of new antiepileptic drugs after a decade of use in epilepsy

The introduction of numerous effective, well tolerated and safe new antiepileptic drugs (AEDs) in the last decade of the 20th century has widened the choice of treatment options in epilepsy and improved the tolerability and the ease of use of treating patients with epilepsy. Nevertheless, significant safety and efficacy deficits continue to exist. Severe idiosyncratic reactions and organ toxicity have hampered the wide use of some of the newer AEDs. As a decade before, about one third of patients with chronic epilepsy is resistant to current pharmacotherapy. Even in patients in whom pharmacotherapy is efficacious, current AED do not seem to affect the progression or the underlying natural history of epilepsy. In addition, there is currently no drug available which prevents the development of epilepsy, e.g. after head trauma. Thus, there is an unmet need for safer and more effective drugs, especially for chronic, drug-resistant epilepsy. To stimulate the development of even better compounds, the demonstrated benefits and risks of current new AEDs are reviewed.