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PubMed2005

Anticonvulsant properties of the novel nootropic agent nefiracetam in seizure models of mice and rats.

PURPOSE: Nefiracetam (NEF) is a novel pyrrolidone-type nootropic agent, and it has been reported to possess various pharmacologic effects as well as cognition-enhancing effects. The present study focused on the anticonvulsant effect of NEF and its potential for antiepileptic therapy. METHODS: The anticonvulsant properties of NEF were investigated in experimental seizure models of mice and rats, compared with levetiracetam (LEV) and other standard antiepileptic drugs [AEDs; zonisamide (ZNS), phenytoin (PHT), carbamazepine (CBZ), valproic acid (VPA), diazepam (DZP), and ethosuximide (ESM)]. With reference to standard programs for evaluating potential AEDs, the study included the traditional maximal electroshock seizure and subcutaneous chemoconvulsant (pentylenetetrazole, bicuculline, picrotoxin, strychnine, or N-methyl-D-aspartate) seizure tests and two threshold models (the increasing-current electroshock seizure test and intravenous pentylenetetrazole seizure threshold test). Neurotoxic activities were examined with the rotarod test and traction test. RESULTS: NEF inhibited electroshock-induced seizures at nontoxic doses, whereas it had no effect on seizures chemically induced by pentylenetetrazole, bicuculline, picrotoxin, strychnine, or N-methyl-D-aspartate. The anticonvulsant spectrum of NEF paralleled that of ZNS, PHT, and CBZ. The anticonvulsant efficacy of NEF was comparable with that of ZNS and less potent than that of PHT, CBZ, and DZP. However, the safety margin of NEF was superior to that of ZNS, CBZ, VPA, and DZP. LEV showed only slight anticonvulsant effects in threshold models, and it was not effective in conventional screening models. CONCLUSIONS: These results suggest that NEF has distinct anticonvulsant spectrum and mechanisms from those of LEV. NEF is an orally active and safe AED, and it possesses a potential for antiepileptic therapy.

Animals↗
PubMed2004

Side effects of antiepileptics--a review.

Older generation antiepileptic drugs like Phenobarbital (Luminal), carbamazepine (Tegretol), phenytoin (Dilantin), and valproic acid (Depakote) have several shortcomings such as suboptimal response rates, significant adverse effects, several drug interactions, and a narrow therapeutic index. New antiepileptic drugs have been developed in the last decade to overcome some of these problems. These newer generation antiepileptics like felbamate (Felbatol), gabapentin (Neurontin), lamotrigine (Lamictal), levetiracetam (Keppra), oxcarbazepine (Trileptal), tiagabine (Gabitril), topiramate (Topamax), and zonisamide (Zonegran) have better tolerability profiles, low interaction potential, and significantly less enzyme inducing or inhibiting properties. As the use of antiepileptic drugs has expanded to include treatment of neuropathic pain, newer side effects have been reported. In addition to the common side effects of antiepileptic drugs, like dizziness, drowsiness, and mental slowing; other side effects like weight gain, metabolic acidosis, nephrolithiasis, angle closure glaucoma, skin rash, hepatotoxicity, colitis, and movement and behavioral disorders, to name a few, have been brought to our attention. This review is an attempt to highlight the features and incidences of some of these side effects.

Journal Article↗
PubMed2006

Comparison of the efficacy and tolerability of new antiepileptic drugs: what can we learn from long-term studies?

OBJECTIVE: A review of long-term open-label studies was performed with the aim of detecting differences in efficacy and/or tolerability of new antiepileptic drugs (AEDs). METHODS: From more than 500 open studies conducted to evaluate the efficacy and tolerability of gabapentin (GBP), lamotrigine (LTG), levetiracetam (LEV), oxcarbazepine (OXC), pregabalin (PGB), tiagabine (TGB), topiramate (TPM) or zonisamide (ZNS), we selected all studies that reported or allowed us to calculate the number of patients who achieved seizure freedom for 6 months and/or the number of patients withdrawing for adverse effects and/or the number or percentage of patients continuing treatment after 1 year. RESULTS: No studies were found in which this information was available for OXC, PGB, TGB or ZNS. The number of patients who achieved seizure freedom for 6 months was reported in four studies each for GBP and TPM, five studies for LTG, and eight studies for LEV. The best efficacy profile using this end point was found for LEV, followed by TPM, LTG, and GBP. Twenty-two studies reported the number of patients withdrawing due to adverse effects. LEV was the best-tolerated AED, a little ahead of LTG, and significantly better than GBP or TPM . TPM was by far the least well-tolerated drug. Information concerning patients continuing treatment after 1 year was reported in two GBP studies, two TPM studies, six LEV studies and five LTG studies. GBP had a very low retention rate (between 20% and 25% of patients continued the drug), while TPM and LTG had a retention rate of 40-60% and LEV had a retention rate of 60-75%. CONCLUSION: One limitation of these rankings is that their statistical value is limited because of the indirect nature of the comparisons. Anyhow, this review covers the main studies published thus far on this subject and provides full updated information on the current literature about these drugs.

Anticonvulsants↗
PubMed2004

New medication treatment options for bipolar disorders.

OBJECTIVE: To assess new treatment options for bipolar disorders. METHOD: Controlled studies of new treatments for bipolar disorders were identified by computerized searches and reviews of scientific meeting proceedings, and were compiled by drug category. RESULTS: Two main categories of medications, newer anticonvulsants and newer antipsychotics, are yielding emerging new treatment options for bipolar disorders. Newer anticonvulsants have diverse psychotropic profiles, and although not generally effective for acute mania, may have utility for other aspects of bipolar disorders (e.g. lamotrigine for maintenance or acute bipolar depression), or for comorbid conditions (e.g. gabapentin for anxiety or pain, topiramate for obesity, bulimia, alcohol dependence, or migraine, and zonisamide for obesity). In contrast, newer antipsychotics generally appear effective for acute mania, and some may ultimately prove effective in acute depression (e.g. olanzapine combined with fluoxetine, quetiapine) and maintenance (e.g. olanzapine). CONCLUSION: Emerging research is yielding new treatment options for bipolar disorders and comorbid conditions.

Anticonvulsants↗
PubMed2006

Rapid identification of P-glycoprotein substrates and inhibitors.

Identifying molecules that interact with P-glycoprotein (P-gp) is important for drug discovery but is also generally reliant on time-consuming in vitro and in vivo studies. As an alternative approach, the current study applied pharmacophore models and database screening to rapidly retrieve molecules that bind as substrates or inhibitors for P-gp from commercial databases and then confirmed their affinity as inhibitors in vitro. Seven molecules (acitretin, cholecalciferol, misoprostol, nafcillin, repaglinide, salmeterol, and telmisartan) with no published details for P-gp affinity, one positive control inhibitor (miconazole), and two negative control molecules (phenelzine and zonisamide) were selected for testing. The MDCK-MDR1 in vitro cell model was used to confirm their inhibitory effect on [3H]digoxin transport, and the ATPase assay was used as an additional in vitro tool to indicate P-gp activation. All seven test drugs were confirmed to have P-gp affinity. Additionally, our experimental results provided plausible explanations for the published pharmacokinetic profiles of the tested drugs and their classification according to the biopharmaceutics and drug disposition classification system. In this study, we showed the successful application of pharmacophore models to accurately predict P-gp binding, which holds promise to anticipate drug-drug interactions from screening drug databases and a priori prediction of novel P-gp inhibitors or substrates.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Unknown people believed to be known: the 'assoziierende Erinnerungs- fälschungen' by Kraepelin.

A male patient with epilepsy, who developed a unique form of paramnesia after an episode of zonisamide-induced psychosis is reported. The patient consistently mistook people who were quite new to him, such as staff of the hospital, for persons whom he had met long ago. However, he did not misidentify their names or other attributes, such as their occupations. This extraordinary form of misidentification does not fall into any known subcategory of misidentification syndromes. Rather, this paramnesia falls into the classical description of 'assoziierende Erinnerungsfälschungen' by Kraepelin. The neuropsychological interpretation of the reported patient is difficult. However, loss of familiarity with environmental objects due to his long sustained epileptic history is supposed to be a possible mechanism of paramnesia.

Adult↗
PubMed1997

Effects of various antiepileptic drugs on plasma levels of lamotrigine, a novel antiepileptic, in rats.

The pharmacokinetics of lamotrigine (LTG) and effects of carbamazepine (CBZ), valproic acid (VPA) and zonisamide (ZNS) on LTG kinetics were investigated in rats. LTG plasma levels were measured by high-performance liquid chromatography (HPLC). A single oral administration of LTG at 2.5-10 mg/kg showed linear disposition kinetics. In the pharmacokinetic parameters of LTG when combined with CBZ, the maximal plasma concentration (Cmax) and the area under the plasma concentration curve (AUC0-36) values were significantly lower and the time to maximal plasma concentration (Tmax) value was significantly higher than those in LTG alone. Furthermore, the Cmax and AUC0-36 values of LTG when pretreated with CBZ for 7 days were significantly lower than those from simultaneous treatment with CBZ. The Cmax and AUC0-36 values of LTG when combined with VPA were significantly lower than those for LTG alone. There was no significant difference in the Tmax or time of elimination half-life (t1/2) values of LTG between simultaneous and pretreatment with VPA. Of the pharmacokinetic parameters of LTG with ZNS combination, the Cmax value of LTG after long-term dosings of ZNS decreased significantly, whereas no significant change in Cmax was observed after the combined single administration of LTG and ZNS. Single and chronic ZNS treatment did not significantly affect the Tmax, t1/2 and AUC0-36 values of LTG. The LTG trough level was significantly reduced by CBZ administration, reached the bottom level at 6 days after starting CBZ administration, and recovered gradually after withdrawal of CBZ. These results suggest that CBZ, VPA and ZNS causes changes in the plasma LTG level. They also suggest that in therapy combining LTG with one of these antiepileptics, especially CBZ, the LTG concentration in plasma should be monitored carefully.

Administration, Oral↗
PubMed2002

Clinical pharmacology: drugs as a benefit and/or risk in sudden unexpected death in epilepsy?

Death may be the consequence of natural or unnatural causes, such as accidents, homicide, and suicide, which have no relationship to the disease of epilepsy. Direct causes of death include status epilepticus, and indirect causes may be head trauma or drowning subsequent to a seizure. When death occurs suddenly and without explanation, the term sudden unexpected unexplained death is used. Unexplained is a term that clinicians and research scientists are working to clarify. Numerous preclinical animal studies have been conducted as models for sudden death and have led to clinical studies in persons with epilepsy. These studies show that sympathetic nerve stimulation, ouabain, or coronary occlusion increased temporal dispersion of recovery of ventricular excitability and led to an underlying electrical instability that predisposed the ventricularmyocardium to arrhythmia. Cardiac arrhythmias in an animal model for ouabain-induced toxicity were associated with neural autonomic dysfunction. Neural discharges were characterized by increases, decreases, or no change in the discharge of postganglionic cardiac sympathetic nerves monitored simultaneously, predisposing to cardiac arrhythmia. Stimulation of the sympathetic ventrolateral cardiac nerve produced a shift in the origin of the pacemaker and tachyarrhythmias because the nerve is not uniformly distributed to the various regions of the heart but is localized to the atrioventricular junctional and ventricular regions. Such nonuniform distribution of sympathetic nerves would also contribute to initiation of arrhythmia as a nonuniform neural discharge occurred. Studies examining the physiology and pharmacology of this finding in multiple animal models found that subconvulsant, interictal discharge was associated with autonomic cardiac neural non-uniform discharge and cardiac arrhythmias. As a result of further investigations, Lathers and Schraeder edited a book in 1990 that summarized the clinical problem of sudden unexpected death and epilepsy (SUDEP). The contributors concluded that there was a paucity of clinical data addressing the mechanism of death. Regulatory response resulting from the consequent increased awareness of SUDEP occurred in 1993, when the FDA focused attention of practitioners and pharmaceutical manufacturers on the question of whether use of anticonvulsant drugs contributes to or prevents sudden unexpected death in epileptic persons. The FDA-convened panel of scientists considered the prevalence of sudden unexpected death in patients involved in studies associated with developing new anticonvulsant drugs and reviewed data on the risk of sudden unexpected death in patients taking lamotrigine. The risk of SUDEP was no different from thatfound in the young epilepsy population in general. Estimated SUDEP rates in patients receiving the new anticonvulsant drugs lamotrigine, gabapentin, topiramate, tigabine, and zonisamide were found to be similar to those in patients receiving standard anticonvulsant drugs, suggesting that SUDEP rates reflect population rates and not a specific drug effect. The FDA required warning labels on the risk of SUDEP in association with the use of each of the above-mentioned drugs. Another effect of bringing SUDEP to the attention of epilepsy researchers has been the expansion of basic science and the development of epidemiological and clinical studies directed at this phenomenon. Results from some of these studies are discussed in this article.

Animals↗
PubMed2002

Pediatric partial and generalized seizures.

Eight new anticonvulsant medications have been approved in the United States since 1993, offering physicians a greater range of options for treating children with partial and generalized seizures. However, pediatric neurologists have been faced with limited pediatric pharmacokinetic and pharmacodynamic information. This article reviews the newer antiepilepsy drugs-gabapentin, felbamate, lamotrigine, topiramate, oxcarbazepine, levetiracetam, and zonisamide-and summarizes what is currently known about the safety and efficacy of these drugs in treating partial and generalized seizures in the pediatric population. Further studies are needed, however, to thoroughly evaluate their efficacy and safety in children.

Anticonvulsants↗
PubMed2004

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

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

Anticonvulsants↗
PubMed2005

Treatment of pediatric epilepsy: expert opinion, 2005.

BACKGROUND: Childhood epilepsies are a heterogeneous group of conditions that differ in diagnostic criteria and management and have dramatically different outcomes. Despite increasing data on treatment of epilepsy, research findings on childhood epilepsy are more limited and many clinical questions remain unanswered, so that clinicians must often rely on clinical judgment. In such clinical situations, expert opinion can be especially helpful. METHODS: A survey on pediatric epilepsy and seizures (33 questions and 645 treatment options) was sent to 41 U.S. physicians specializing in pediatric epilepsy, 39 (95%) of whom completed it. In some questions, the experts were asked to recommend overall treatment approaches for specific syndromes (the order in which they would use certain strategies). Most of the questions asked the experts to rate options using a modified version of the RAND 9-point scale for medical appropriateness. Consensus was defined as a non-random distribution of scores by chi-square test, with ratings used to assign a categorical rank (first line/usually appropriate, second line/equivocal, and third line/usually not appropriate) to each option. RESULTS: Valproate was treatment of choice for symptomatic myoclonic and generalized tonic-clonic seizures except in the very young, with lamotrigine and topiramate also first line (usually appropriate). Zonisamide was first line only if the child also has myoclonic seizures. For initial monotherapy for complex partial seizures, oxcarbazepine and carbamazepine were treatments of choice, with lamotrigine and levetiracetam also first line. As initial therapy for infantile spasms caused by tuberous sclerosis, viagabatrin was treatment of choice, with adrenocorticotropic hormone (ACTH) also first line. As initial therapy for infantile spasms that are symptomatic in etiology, ACTH was treatment of choice, with topiramate also first line. As initial therapy for Lennox-Gastaut syndrome, valproate was treatment of choice, with topiramate and lamotrigine also first line. For acute treatment of a prolonged febrile seizure or cluster of seizures, rectal diazepam was treatment of choice. For benign childhood epilepsy with centro-temporal spikes, oxcarbazepine and carbamazepine were treatments of choice, with gabapentin, lamotrigine, and levetiracetam also first line. For childhood absence epilepsy, ethosuximide was treatment of choice, with valproate and lamotrigine also first line. For juvenile absence epilepsy, valproate and lamotrigine were treatments of choice. For juvenile myoclonic epilepsy in adolescent males, valproate and lamotrigine were treatments of choice, with topiramate also first line; for juvenile myoclonic epilepsy in adolescent females, lamotrigine was treatment of choice, with topiramate and valproate other first-line options. As initial therapy for neonatal status epilepticus, intravenous phenobarbital was treatment of choice, with intravenous lorazepam or fosphenytoin also first line. As initial therapy for all types of pediatric status epilepticus, lorazepam was treatment of choice, with intravenous diazepam also first line. For generalized tonic-clonic status epilepticus, rectal diazepam and fosphenytoin were also first line; for complex partial status epilepticus, fosphenytoin was also first line; and for absence status epilepticus, intravenous valproate was also first line. CONCLUSION: The expert panel reached consensus on many treatment options. Within the limits of expert opinion and with the understanding that new research data may take precedence, the experts' recommendations provide helpful guidance in situations where the medical literature is scant or lacking. The information in this report should be evaluated in conjunction with evidence-based findings.

Adolescent↗
PubMed2001

Second generation anticonvulsant medications: their use in children.

The pharmacotherapy of seizure disorders has long relied on a few standard medications such as phenobarbital, phenytoin (Dilantin), valproate (Depakote), and others that represent the "first generation" of anticonvulsants. This article reviews the newer, "second-generation" anticonvulsants that were developed in the last decade. The addition of these second-generation agents has doubled the number of therapies available for the treatment of seizure disorders. They include felbamate (Felbatol), gabapentin (Neurontin), lamotrigine (Lamictal), levetiracetam (Keppra), oxcarbazepine (Trileptal), tiagabine (Gabitril), topiramate (Topamax), and zonisamide (Zonegran). This article describes the known side effects of the second-generation agents and reviews the adverse reactions of the first generation of anticonvulsants as a guide to potential toxicities. Reference tables are included that note usual dosages, available dosage forms, and tablet imprint. In addition, this article describes monitoring parameters and gives specific information regarding the use of these agents.

Adolescent↗
PubMed1996

Distinct functions of T- and L-type calcium channels during activation of bovine adrenal glomerulosa cells.

Calcium influx into adrenal glomerulosa cells is a key event during the stimulation of aldosterone secretion by physiological increases in extracellular potassium concentrations. Two types of voltage-operated calcium channels, T- and L-types, are present on bovine glomerulosa cells, but their respective functions are not yet clearly defined. Using the patch-clamp method in the perforated patch configuration combined with microfluorimetry of cytosolic calcium, we demonstrate that L-type channels are exclusively responsible for the sustained elevation of cytosolic calcium observed upon stimulation with extracellular potassium, even at low, physiological concentrations of this agonist. In contrast, aldosterone secretion appears closely related to T-type channel activity. Moreover, when the activity of each channel type is selectively modulated by pharmacological agents, such as dihydropyridines or zonisamide, the cytosolic calcium response can be clearly dissociated from the steroidogenic response. Similarly, modulation of T channel activation by protein kinase C results in a parallel inhibition of aldosterone secretion, without any effect on the levels of cytosolic free calcium. This direct functional link between T-type calcium channel activity and steroidogenesis suggests a model in which calcium entering the cell through these channels bypasses the cytosol to activate intramitochondrial steps of aldosterone biosynthesis.

Aldosterone↗
PubMed2004

Efficacy and tolerability of the new antiepileptic drugs I: treatment of new onset epilepsy [RETIRED]: report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society.

OBJECTIVE: To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide-reviewed in the order in which these agents received approval by the US Food and Drug Administration) in the treatment of children and adults with newly diagnosed partial and generalized epilepsies. METHODS: A 23-member committee, including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy, evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until September 2002, with selected manual searches up until 2003. RESULTS: There is evidence either from comparative or dose-controlled trials that gabapentin, lamotrigine, topiramate, and oxcarbazepine have efficacy as monotherapy in newly diagnosed adolescents and adults with either partial or mixed seizure disorders. There is also evidence that lamotrigine is effective for newly diagnosed absence seizures in children. Evidence for effectiveness of the new AEDs in newly diagnosed patients with other generalized epilepsy syndromes is lacking. CONCLUSIONS: The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with newly diagnosed epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Acetates↗
PubMed2002

Antiepileptic drug use during the first 12 months of vagus nerve stimulation therapy: a registry study.

Understanding interrelationships between antiepileptic drugs (AEDs) and vagus nerve stimulation (VNS) therapy can guide research into epilepsy treatment. A constant cohort of patients with data available at baseline and 12 months were drawn from the VNS patient outcome registry and analyzed for changes in AEDs and seizure rates. Of the 1,407 patients, group 1 (n = 896) took fewer (n = 228) or the same (n = 668) AEDs at 12 months compared to baseline. Group 2 (n = 511) took additional (n = 251) or different (n = 260) AEDs. Median seizure rate reductions after 12 months of VNS therapy were 58% in group 1 and 55% in group 2. The number of and specific AEDs remained unchanged for 668 patients and dosages remained the same for 269 (40%) of these patients. The most commonly discontinued drugs were topiramate (n = 115), tiagabine (n = 78), carbamazepine (n = 62), lamotrigine (n = 56), and gabapentin (n = 52). Changes in seizure rates were not significantly different among patients who added levetiracetam (n = 151), zonisamide (n = 71), or oxcarbazepine (n = 46) to VNS. Changes in seizure rates were not significantly different among patients whose baseline AEDs were carbamazepine (n = 273), lamotrigine (n = 238), valproate (n = 201), topiramate (n = 190), or phenytoin (n = 151). Our results suggest the following: (a) patients commonly stay on the same AEDs during 12 months of treatment with VNS; (b) the registry cohort who had reduced AEDs by month 12 did not appear to experience any seizure exacerbation; and (c) no specific AED shows promise of unique additive antiepileptic effects in combination with VNS.

Adult↗
PubMed2003

Antiepileptic drug pharmacokinetics during pregnancy and lactation.

The ideal management of women with epilepsy during pregnancy and the postpartum period involves achieving an optimal balance between minimizing fetal and neonatal exposure to the deleterious influences both of antiepileptic drugs (AEDs) and of seizures. Women with increased seizures during pregnancy tend to have subtherapeutic AED concentrations. Multiple physiologic changes during pregnancy influence drug disposition, including increased volume of distribution, increased renal elimination, altered hepatic enzyme activity, and a decline in plasma protein concentrations. Noncompliance can also be a major factor. The majority of AEDs are characterized by significant increases in clearance during pregnancy. Lamotrigine (LTG) clearance markedly increases throughout pregnancy, to an extent greater than with the older AEDs. Studies during and after birth in mothers taking the older AEDs indicate extensive transplacental transfer and low to moderate excretion into breast milk. Limited studies of the newer AEDs indicate similar extensive transplacental transfer [LTG, oxcarbazepine, topiramate (TPM), zonisamide (ZNS)], and breast milk/maternal plasma concentration ratios less than 1 (LTG, TPM, ZNS). Especially high excretion of levetiracetam into breast milk may occur. Current published guidelines recommend that the ideal AED concentration should be established for each patient before conception and that monitoring of AED concentrations should be performed during each trimester and in the last month of pregnancy. Free concentrations should be measured for phenobarbital, phenytoin, carbamazepine, valproic acid, and primidone. Some authors recommend at least monthly monitoring of AED concentrations, especially for LTG. Future studies of formal pharmacokinetic modeling of AEDs during pregnancy and the postpartum period could provide an important step toward achieving effective drug dosing to maintain therapeutic objectives for the mother but, at the same time, to minimize fetal drug exposure.

Abnormalities, Drug-Induced↗
PubMed2004

Initial treatment of epilepsy: special issues in treating the elderly.

The incidence of new-onset epilepsy is higher among the elderly, the most rapidly growing segment of the population, than in any other age group. New-onset seizures in elderly patients are typically cryptogenic or symptomatic partial seizures that require long-term treatment. Because seizures in the elderly are often readily controlled, considerations of tolerability and safety, including pharmacokinetics and the potential for drug interactions, may be as important as efficacy in the selection of an antiepileptic drug (AED). The newer AEDs introduced during the past decade offer advantages in this respect over older agents. Phenytoin is the most widely used AED in the United States, but its hepatic metabolism and associated enzyme induction, as well as its nonlinear pharmacokinetics, are particular disadvantages for elderly patients. Because of their potential effects on cognitive function, sedating AEDs such as phenobarbital and primidone have little place in the treatment of new-onset seizures in elderly patients. Carbamazepine also is an enzyme-inducing agent with significant potential for drug interactions. Among the newer AEDs, gabapentin and levetiracetam have good safety and cognitive effect profiles and do not interact with other drugs, and lamotrigine offers many of the same benefits. Oxcarbazepine has better tolerability than carbamazepine, and topiramate and zonisamide, although they have more cognitive side effects than the other new AEDs, can be considered for some elderly patients. Forthcoming data from the Veterans Affairs Cooperative Trial 428, as well as recent guidelines from the American Academy of Neurology and the American Epilepsy Society, are likely to provide support for the use of selected second-generation AEDs as first-line agents for the treatment of epilepsy in elderly patients.

Aged↗
PubMed2006

Optimizing therapy of seizures in women who use oral contraceptives.

There is no evidence that oral contraceptives (OCs) increase seizure activity, and OC use in the setting of antiepileptic drug (AED) treatment provides pregnancy prevention at among the highest rates of any available contraceptive method. One concern, however, is the increased risk for OC failure with the use of cytochrome P450 3A4 enzyme-inducing AEDs, such as phenobarbital, carbamazepine, phenytoin, felbamate, topiramate, and oxcarbazepine. Felbamate induces metabolism of only the progestogenic component, whereas topiramate induces metabolism of only the estrogenic component. There is preliminary evidence that lamotrigine induces the metabolism of a progestin, levonorgestrel. It is unclear whether the estrogenic or the progestogenic component is more clinically important in preventing pregnancy. To ensure maximal pregnancy prevention, it is therefore recommended that women taking enzyme-inducing AEDs should receive OCs containing at least 50 mug of ethinyl estradiol and that low-dose formulations in general should not be used. AEDs that do not induce cytochrome P450 3A4 enzymes, including valproic acid, gabapentin, levetiracetam, tiagabine, vigabatrin, zonisamide, and pregabalin, do not interact with OCs. There are no concerns regarding the treatment of seizures or increased pregnancy risk with the use of OCs and these non-enzyme-inducing AEDs. Lamotrigine levels, however, are reduced by 50% in the setting of OC use. Therefore, women with epilepsy taking lamotrigine need to be monitored carefully for seizures when OCs are started and for toxicity when OCs are discontinued. Dose adjustment to maintain clinical stability may be necessary in these settings. The placebo or pill-free week of the OC regimen may also be a period when clinical toxicity can occur. Even with the considerations discussed in this review, OCs are a reasonable contraceptive option for women with epilepsy taking AEDs.

Anticonvulsants↗