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Background The absorption and bioavailability of oral gabapentin are associated with a high degree of interindividual variability. Gabapentin enacarbil, a prodrug of gabapentin, is well absorbed and provides sustained, dose-proportional exposure to gabapentin. The aim of this analysis was to describe the interindividual variability in the bioavailability of gabapentin following gabapentin enacarbil administration in healthy subjects. Methods Gabapentin pharmacokinetic (PK) parameters following an oral dose of gabapentin enacarbil 1200 mg (2 600-mg tablets) were compared across six phase I studies in healthy adults (n = 12 per study). The distribution of bioavailability values was assessed in all studies. Results The mean PK parameters of gabapentin were consistent across the trials: maximum concentration (Cmax) range: 6.4-7.9 µg/mL; time to Cmax range: 5.2-8.2 hours; area under the plasma-concentration curve extrapolated from time 0 to infinity (AUC0-∞) or at steady state (AUCss) range: 70.8-109.4 µg·hr/mL; and bioavailability range: 64.8-82.9%. Overall, the mean bioavailability was 74.1% (standard deviation, 14.1; coefficient of variation, 19.1%). Individual bioavailability across all studies ranged from 42% to 100%. Conclusions Gabapentin PK following gabapentin enacarbil administration was consistent across studies, with low interindividual variability in bioavailability. Gabapentin enacarbil may provide more consistent and predictable exposure to gabapentin than oral gabapentin formulations.

Highly purified cannabidiol (CBD) has demonstrated efficacy with an acceptable safety profile in patients with Lennox‐Gastaut syndrome or Dravet syndrome in randomized, double‐blind, add‐on, controlled phase 3 trials. It is important to consider the possibility of drug‐drug interactions (DDIs). Here, we review six trials of CBD (Epidiolex/Epidyolex; 100 mg/mL oral solution) in healthy volunteers or patients with epilepsy, which investigated potential interactions between CBD and enzymes involved in drug metabolism of common antiseizure drugs (ASDs). CBD did not affect CYP3A4 activity. Induction of CYP3A4 and CYP2C19 led to small reductions in exposure to CBD and its major metabolites. Inhibition of CYP3A4 activity did not affect CBD exposure and caused small increases in exposure to CBD metabolites. Inhibition of CYP2C19 activity led to a small increase in exposure to CBD and small decreases in exposure to CBD metabolites. One potentially clinically important DDI was identified: combination of CBD and clobazam (CLB) did not affect CBD or CLB exposure, but increased exposure to major metabolites of both compounds. Reduction of CLB dose may be considered if adverse reactions known to occur with CLB are experienced when it is coadministered with CBD. There was a small increase of exposure to stiripentol (STP) when coadministered with CBD. STP had no effect on CBD exposure but led to minor decreases in exposure to CBD metabolites. Combination of CBD and valproate (VPA) did not cause clinically important changes in the pharmacokinetics of either drug, or 2‐propyl‐4‐pentenoic acid. Concomitant VPA caused small increases in exposure to CBD metabolites. Dose adjustments are not likely to be necessary when CBD is combined with STP or VPA. The safety results from these trials were consistent with the known safety profile of CBD. These trials indicate an overall low potential for DDIs between CBD and other ASDs, except for CLB.

Purpose: Super-refractory status epilepticus (SRSE) presents management challenges due to the absence of randomized controlled trials and a plethora of potential medical therapies. The literature on treatment options for SRSE reports variable success and quality of evidence. This review is a sequel to the 2020 American Epilepsy Society (AES) comprehensive review of the treatment of convulsive refractory status epilepticus (RSE). Methods: We sought to determine the effectiveness of treatment options for SRSE. We performed a structured literature search (MEDLINE, Embase, CENTRAL, CINAHL) for studies on reported treatments of SRSE. We excluded antiseizure medications (ASMs) covered in the 2016 AES guideline on the treatment of established SE and the convulsive RSE comprehensive review of the 2020 AES. Literature was reviewed on the effectiveness of vagus nerve stimulation, ketogenic diet (KD), lidocaine, inhalation anesthetics, brain surgery, therapeutic hypothermia, perampanel, pregabalin (PGB), and topiramate in the treatment of SRSE. Two authors reviewed each therapeutic intervention. We graded the level of the evidence according to the 2017 classification scheme of the American Academy of Neurology. Results: For SRSE (level U; 39 class IV studies total), insufficient evidence exists to support that perampanel, PGB, lidocaine, or acute vagus nerve stimulation (VNS) is effective. For children and adults with SRSE, insufficient evidence exists to support that the KD is effective (level U; 5 class IV studies). For adults with SRSE, insufficient evidence exists that brain surgery is effective (level U, 7 class IV studies). For adults with SRSE insufficient, evidence exists that therapeutic hypothermia is effective (level C, 1 class II and 4 class IV studies). For neonates with hypoxic-ischemic encephalopathy, insufficient evidence exists that therapeutic hypothermia reduces seizure burden (level U; 1 class IV study). For adults with SRSE, insufficient evidence exists that inhalation anesthetics are effective (level U, 1 class IV study) and that there is a potential risk of neurotoxicity. Conclusion: For patients with SRSE insufficient, evidence exists that any of the ASMs reviewed, inhalational anesthetics, ketogenic diet, acute VNS, brain surgery, and therapeutic hypothermia are effective treatments. Data supporting the use of these treatments for SRSE are scarce and limited mainly to small case series and case reports and are confounded by differences in patients’ population, and comedications, among other factors.

Highlights • Behavioral adverse effects can limit use of levetiracetam, particularly in Veteran populations. • Vitamin B6 supplementation has been suggested to reduce irritability. • 22 Veterans were supplemented with vitamin B6 for levetiracetam-associated irritability. • 20 (91%) of Veterans had data regarding irritability. • 9 (45%) Veterans noted improvement in irritability with supplementation. • 11 (55%) Veterans noted no improvement., Objectives Levetiracetam, a commonly prescribed antiseizure medication (ASM), may cause irritability, depression, and anger. The mechanisms underlying these behavioral effects and individual risk factors remain unknown. Mitigation strategies are limited, including discontinuation, supplementation with vitamin B6, or switching to an alternative ASM. Several retrospective studies and anecdotal reports, primarily in pediatric populations, suggest vitamin B6 supplementation may be helpful in reducing levetiracetam-associated irritability. Although data in adult patients is limited, and no data is available for Veterans. The objective of this project was to describe our preliminarily experience with vitamin B6 supplementation for alleviating levetiracetam-associated irritability in male Veterans with epilepsy. Methods Retrospective chart reviews were completed for patients who had an active prescription for levetiracetam from the William S. Middleton Memorial Veterans Hospital from January 1, 2015 to June 1, 2020. A total of 26 charts were screened. Patients were excluded if not using vitamin B6 supplementation or if deceased at end of data collection. Baseline characteristics were compared, including age, sex, comorbidities, and concomitant medications. Charts were then reviewed to identify any clinical description of irritability, including subjective assessment of change in symptoms across multiple visits, and scores from standardized instruments including the patient health questionnaire (PHQ-9), generalized anxiety disorder questionnaire (GAD-7), and/or irritability in adult patients with epilepsy (I-EPI) questionnaire. These symptoms and scores were then compared pre- and post-B6 supplementation. Results Of 22 patients, data was available for 20 (91%). For patients with data available, 9 (45%) showed improved irritability following supplementation with vitamin B6 and 11 (55%) showed no improvement. Conclusions This project suggests that vitamin B6 supplementation may have a role in mitigating levetiracetam-associated irritability in a male Veteran population. These results support future prospective controlled studies to assess further the efficacy of this approach and characteristics associated with successful treatment in veterans.

Poor adherence to anti-seizure medications (ASMs) is associated with breakthrough seizures and potentially increased toxicity in patients with epilepsy. Extended-release (ER) drugs and immediate-release (IR) drugs with a long half-life (t1/2) that permit once-daily dosing (such as, perampanel, zonisamide, lamotrigine [IR, ER] and topiramate [ER]) have a number of advantages over short t1/2 ASMs that require multiple daily dosing. These advantages include simplification of dosing regimens, reduction in pill burden, and a decrease in the peak-to-trough fluctuations in serum drug concentration that may be associated with a decreased risk of adverse effects and seizures. Such properties have wider implications in improving patient adherence to treatment. This article is intended as a practical guide for clinicians that provides an overview of the features of ER ASMs and long t1/2 IR ASMs that are advantageous in the context of patient adherence and pharmacokinetic "forgiveness" (after missing a dose). In addition, we note that efforts to improve adherence should not depend solely on drug dosing regimens and drug pharmacokinetics, but should be part of a wider strategy that includes therapeutic drug monitoring, improved healthcare provider-patient dialogue, patient education, and the use of "reminder" technology.

Introduction Most antiseizure medications (ASM) need to be titrated before the optimal dose is achieved. Titration can last several weeks to months. We assessed the impact titration schedules have on ASM treatment-related decisions in the United States (US). Methods An online survey was conducted with different healthcare providers (HCPs) in the US involved in the treatment and management of patients with epilepsy. The survey contained three sections: the first section with screening questions; the second on key factors that influence a HCP’s decision-making when selecting treatments for different types of seizures and different treatment lines; and the third on the HCP’s knowledge and perceptions regarding ASM titration for the treatment of patients with epilepsy. Results One-hundred and fifty HCPs (63% neurologists) completed the survey. Most HCPs considered titration schedule to be important, with only 1–3% of HCPs, depending on type of seizure, considering the titration schedule to be “not important at all” when prescribing therapy. Healthcare providers’ acceptance of titration increased with shorter durations (≥50% accepted titration periods of ≤2 weeks), and lower number of tablets/capsules per dose (≥50% accepted ≤3 tablets/capsules per dose), doses (≥50% accepted ≤2 doses/day), and steps (≥50% accepted ≤3 steps/dose change). Most HCPs (68–91% depending on type of seizure) considered a titration duration of 6 or more weeks only somewhat acceptable or somewhat or highly unacceptable. Almost all HCPs selected “somewhat familiar”, “familiar”, or “very familiar” as the attribute that best defines their knowledge level of titration, with only 4% selecting “a little familiar”. While 87% of HCPs agreed or strongly agreed that they could easily understand titration schedules, only 27% of them agreed or strongly agreed that patients could easily understand titration schedules and 58% of HCPs considered that adhering to the titration schedule was difficult for patients. Most HCPs agreed or strongly agreed that a complex or long titration schedule renders it difficult to achieve their treatment objectives. Conclusions Healthcare providers take into account the duration and complexity of the titration period in their ASM prescribing decision-making and prefer shorter and simpler titration schedules, particularly for patients who are experiencing convulsive seizures and starting monotherapy. There was a clear difference between the HCP’s belief in their own ability to understand a titration schedule, and their belief that the patient would be able to follow the titration schedule appropriately

The objective of this analysis was to determine possible interactions between lamotrigine (LTG) and coffee or cigarette use. As part of the statistical analysis of factors influencing LTG pharmacokinetics (PK) in the Equigen chronic dose study, we collected prospective data from enrolled patients on their use of coffee and cigarettes. Subjects were part of a crossover replication study of generic LTG products with rigorous blood sampling and were instructed to not change their typical consumption of these products for the duration of the study. A total of 35 subjects were enrolled, with 33 subjects having sufficient data for analysis. Higher consumption of coffee was associated with a significantly lower area under the curve (AUC) and maximum concentration (Cmax) of lamotrigine (LTG). Higher cigarette use did not result in a significant change in AUC or Cmax. Coffee, but not cigarette use, either induces LTG metabolism or inhibits LTG absorption.

The benzodiazepine midazolam (MDZ) is commonly used as first-line treatment in patients with acute seizures. This review summarizes the pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of MDZ nasal spray (MDZ-NS), which can be administered by non–health care providers in the outpatient, ambulatory setting. Intranasal administration leads to rapid (tmax 9.0–21.5 min), consistent, and extensive absorption of MDZ, with fast distribution to the central nervous system (CNS), as demonstrated by the onset of sedation within 10 min after administration and the occurrence of peak psychomotor impairment at approximately 17–120 min after administration. Rapid plasma clearance of MDZ and its active metabolite 1-OH-MDZ (t½ 3.6–8.1 h) results in a return to baseline alertness and psychomotor functionality by approximately 240 min post dose. The lack of first-pass metabolism reduces the potential for drug–drug interactions compared with oral dosing. Age (≥ 12 years), sex, race, body weight, body mass index, normal to moderately impaired renal function, and concomitant administration of cytochrome P450 (CYP)3A-inducing drugs are not considered important factors for MDZ-NS dosing. However, coadministration of MDZ-NS with moderate or strong CYP3A4 inhibitors should be avoided, and MDZ-NS should be used with caution when coadministered with mild CYP3A4 inhibitors, as these may result in prolonged MDZ effects owing to a decrease in plasma clearance. Taken together, the PK and PD properties of MDZ-NS, with a short tmax that translates into rapid CNS PD effects of sedation and psychomotor impairment, demonstrate rapid CNS penetration and onset of action, supporting its use for acute treatment of seizure clusters.

Purpose of review The aim of the study was to provide an overview of the prevalence, risk factors, burden, and current and emerging pharmacologic treatments for seizure clusters in patients with epilepsy. Recent findings Close to half of patients with active epilepsy experience seizure clusters, and the clinical, social, and financial burdens of seizure clusters are high. However, there is no widely accepted definition of seizure clusters; their prevalence is underappreciated, contingencies for addressing them (seizure action plans) are often lacking, and their effects are not well-studied. These issues have resulted in an insufficient number of investigations and approved medications for this condition. Novel formulations are in late-stage development to meet this unmet need.

Objective To evaluate the time course of changes in perampanel levels when co-administered with carbamazepine, and following carbamazepine discontinuation, using a physiologically based pharmacokinetic (PBPK) model. Methods The PBPK model was developed, verified using clinical PK data, and used to simulate the effect of abrupt discontinuation and down-titration (75 mg twice daily [bid]/wk) of co-administered carbamazepine 300 mg bid on the PK of perampanel once daily (qd). Perampanel dose tapering (8-4 mg) and up-titration (2-6 mg) were simulated during abrupt carbamazepine 300 mg bid discontinuation to identify a titration schedule that minimizes changes in perampanel plasma concentrations. Results The PBPK model accurately reproduced perampanel plasma concentration-time profiles from clinical studies in single- and multiple-dose regimen simulations, including multiple-dose carbamazepine co-administration. The time course of return to pre-induced perampanel levels occurred more slowly following carbamazepine down-titration (~48 days after first down-titration) vs abrupt discontinuation (~25 days). Perampanel dose tapering (8-4 mg) at abrupt carbamazepine discontinuation produced minimal changes in steady-state concentrations, which returned to the levels observed during carbamazepine co-administration in ~15 days from the time of carbamazepine discontinuation. When perampanel was up-titrated in the presence of carbamazepine, return to steady state occurred more slowly when carbamazepine was down-titrated weekly (~45 days) vs abrupt discontinuation (~24 days). Conclusion This PBPK model simulated and predicted optimal perampanel dose tapering and up-titration schedules for maintaining perampanel levels during conversion to monotherapy. These results may guide physicians when managing conversion from perampanel polytherapy with concomitant enzyme-inducing anti-seizure medications to monotherapy.

Background A formal single ascending and multiple dose pharmacokinetic (PK) trial of cannabidiol (CBD) oral solution was required to determine the safety and tolerability of CBD, the maximum tolerated dose, and to examine the effect of food on CBD PK parameters. Objective This trial assessed the safety, tolerability and PK of CBD oral solution in healthy adult volunteers, as well as the effect of food on CBD PK parameters. Methods The study consisted of three arms: single ascending dose (1500, 3000, 4500 or 6000 mg CBD [n = 6 per group]/placebo [n = 8; 2 per CBD dose group]), multiple dose (750 or 1500 mg CBD [n = 9 per group]/placebo [n = 6; 3 per CBD dose group] twice daily), and food effect (1500 mg CBD single dose [n = 12]). All subjects completed all trial arms and were analyzed as planned. Results CBD was generally well tolerated. Diarrhea, nausea, headache, and somnolence were the most common adverse events (AEs) across all trial arms, with an increased incidence of some gastrointestinal and nervous system disorder AEs (most notably diarrhea and headache) apparent in subjects taking CBD compared with placebo. All AEs were of mild or moderate severity; none were severe or serious. There were no deaths or discontinuations in the trial. After single oral doses, CBD appeared rapidly in plasma; time to maximum plasma concentration (tmax) was approximately 4–5 h. The major circulating metabolite was 7-carboxy-CBD, then parent CBD, 7-hydroxy-CBD (active metabolite), and 6-hydroxy-CBD (a relatively minor metabolite). Plasma exposure to CBD [maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to time t (AUCt)] increased in a less than dose-proportional manner (Cmax slope 0.73; AUCt slope 0.64). Oral clearance of CBD was high (1111–1909 L/h) and apparent volume of distribution was large (20,963–42,849 L). CBD reached steady state after approximately 2 days, with moderate accumulation (1.8- to 2.6-fold) after 750 and 1500 mg CBD twice daily. After 7 days, a twofold increase in CBD dose resulted in 1.6- and 1.9-fold increases in geometric mean Cmax and area under the plasma concentration-time curve over a dosing interval (AUCτ), respectively. CBD elimination was multiphasic; the terminal elimination half-life was approximately 60 h after 750 and 1500 mg CBD twice daily; and effective half-life estimates ranged from 10 to 17 h. Cmax was 541.2 ng/mL and AUCτ was 3236 ng·h/mL after 1500 mg CBD twice daily. A high-fat meal increased CBD plasma exposure (Cmax and AUCt) by 4.85- and 4.2-fold, respectively; there was no effect of food on tmax or terminal half-life. Conclusion CBD was generally well tolerated. Most AEs were mild in severity; none were severe or serious. The safety and PK profile support twice-daily administration of CBD.

Objective: To update the 2004 American Academy of Neurology (AAN) guideline for treating new-onset focal or generalized epilepsy (GE) with second- and third-generation antiepileptic drugs (AEDs). Methods: The 2004 AAN criteria was used to systematically review literature (January 2003 to November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength. Results: Several second-generation AEDs are effective for new-onset focal epilepsy. Data are lacking on efficacy in new-onset generalized tonic–clonic seizures, juvenile myoclonic epilepsy, or juvenile absence epilepsy, and on efficacy of third-generation AEDs in new-onset epilepsy. Recommendations: Lamotrigine (LTG) should (Level B) and levetiracetam (LEV) and zonisamide (ZNS) may (Level C) be considered in decreasing seizure frequency in adults with new-onset focal epilepsy. LTG should (Level B) and gabapentin (GBP) may (Level C) be considered in decreasing seizure frequency in patients ≥60 years with new-onset focal epilepsy. Unless there are compelling adverse-effect–related concerns, ethosuximide (ETS) or valproic acid (VPA) should be considered before LTG to decrease seizure frequency in treating absence seizures in childhood absence epilepsy (Level B). No high-quality studies suggest clobazam, eslicarbazepine, ezogabine, felbamate, GBP, lacosamide, LEV, LTG, oxcarbazepine, perampanel, pregabalin, rufinamide, tiagabine, topiramate, vigabatrin, or ZNS is effective in treating new-onset epilepsy because no high-quality studies exist in adults of various ages. A recent FDA strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years old and perampanel as monotherapy received FDA approval.

Objective: To update the 2004 American Academy of Neurology (AAN) guideline for managing treatment-resistant (TR) epilepsy with second- and third-generation antiepileptic drugs (AEDs). Methods: 2004 criteria were used to systematically review literature (January 2003 to November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength. Results: Forty-two articles were included. Recommendations: The following are established as effective to reduce seizure frequency (Level A): immediate-release pregabalin and perampanel for TR adult focal epilepsy (TRAFE); vigabatrin for TRAFE (not first-line treatment; rufinamide for Lennox–Gastuat syndrome (LGS) (add-on therapy). The following should be considered to decrease seizure frequency (Level B): lacosamide, eslicarbazepine, and extended-release topiramate for TRAFE (ezogabine production discontinued); immediate- and extended-release lamotrigine for generalized epilepsy with TR generalized tonic–clonic (GTC) seizures in adults; levetiracetam (add-on therapy) for TR childhood focal epilepsy (TRCFE) (1 month to 16 years), TR GTC seizures, and TR juvenile myoclonic epilepsy; clobazam for LGS (add-on therapy); zonisamide for TRCFE (6–17 years); oxcarbazepine for TRCFE (1 month to 4 years). The text presents Level C recommendations. AED selection depends on seizure/syndrome type, patient age, concomitant medications, and AED tolerability, safety, and efficacy. This evidence-based assessment informs AED prescription guidelines for TR epilepsy and indicates seizure types and syndromes needing more evidence. A recent FDA strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years of age and perampanel as monotherapy received FDA approval.

ObjectiveTo update the 2004 American Academy of Neurology (AAN) guideline for treating new-onset focal or generalized epilepsy with second- and third-generation antiepileptic drugs (AEDs).MethodsThe 2004 AAN criteria were used to systematically review literature (January 2003–November 2015), classify pertinent studies according to the therapeutic rating scheme, and link recommendations to evidence strength.ResultsSeveral second-generation AEDs are effective for new-onset focal epilepsy. Data are lacking on efficacy in new-onset generalized tonic-clonic seizures, juvenile myoclonic epilepsy, or juvenile absence epilepsy, and on efficacy of third-generation AEDs in new-onset epilepsy.RecommendationsLamotrigine (LTG) should (Level B) and levetiracetam (LEV) and zonisamide (ZNS) may (Level C) be considered in decreasing seizure frequency in adults with new-onset focal epilepsy. LTG should (Level B) and gabapentin (GBP) may (Level C) be considered in decreasing seizure frequency in patients ≥60 years of age with new-onset focal epilepsy. Unless there are compelling adverse effect–related concerns, ethosuximide or valproic acid should be considered before LTG to decrease seizure frequency in treating absence seizures in childhood absence epilepsy (level B). No high-quality studies suggest clobazam, eslicarbazepine, ezogabine, felbamate, GBP, lacosamide, LEV, LTG, oxcarbazepine, perampanel, pregabalin, rufinamide, tiagabine, topiramate, vigabatrin, or ZNS is effective in treating new-onset epilepsy because no high-quality studies exist in adults of various ages. A recent Food and Drug Administration (FDA) strategy allows extrapolation of efficacy across populations; therefore, for focal epilepsy, eslicarbazepine and lacosamide (oral only for pediatric use) as add-on or monotherapy in persons ≥4 years old and perampanel as monotherapy received FDA approval.

Objectives Eslicarbazepine acetate (ESL) is a once-daily (QD) oral antiepileptic drug (AED) for focal-onset seizures (FOS). Pharmacokinetic (PK) and pharmacodynamic (PD) models were developed to assess dose selection, identify significant AED drug interactions, and quantitate relationships between exposure and safety and efficacy outcomes from Phase 3 trials of adjunctive ESL. Methods Eslicarbazepine (the primary active metabolite of ESL) population PK was evaluated using data from 1351 subjects enrolled in 14 studies (11 Phase 1 and three Phase 3 studies) after multiple oral doses ranging from 400 to 1200 mg. Population PK and PD models related individual eslicarbazepine exposures to safety outcomes and efficacy responses. Results Eslicarbazepine PK was described by a one-compartment model with linear absorption and elimination. The probability of a treatment-emergent adverse event (TEAE; dizziness, headache, or somnolence) was higher with an initial dose of ESL 800 mg than with an initial dose of ESL 400 mg QD. Body weight, sex, region, and baseline use of carbamazepine (CBZ) or lamotrigine were also found to influence the probability of TEAEs. Eslicarbazepine exposure influenced serum sodium concentration, standardized seizure frequency, and probability of response; better efficacy outcomes were predicted in patients not from Western Europe (WE; vs WE patients) and those not taking CBZ (vs taking CBZ) at baseline. Conclusions Pharmacokinetic and PK/PD modeling were implemented during the development of ESL for adjunctive treatment of FOS in adults. This quantitative approach supported decision-making during the development of ESL, and contributed to dosing recommendations and labeling information related to drug interactions.

To evaluate the effects of eslicarbazepine acetate (ESL) on lipid metabolism and to determine whether reduced statin exposure during ESL therapy has clinical consequences.We conducted a post-hoc analysis of pooled data for serum lipids (laboratory values) from three phase III, multicenter, randomized, double-blind, placebo-controlled trials of adjunctive ESL therapy (400, 800, or 1200 mg once daily) in patients with treatment-refractory partial-onset seizures. Changes from baseline in serum lipid levels were analyzed according to use of statins and/or enzyme-inducing antiepileptic drugs (EIAEDs) during the baseline period.In total, 426 and 1021 placebo- and ESL-treated patients, respectively, were included in the analysis. With regard to the changes from baseline in serum concentrations, there were statistically significant differences between the placebo and ESL 1200 mg QD groups, for both total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C), but the effect sizes were small (+4.1 mg/dL and +1.8 mg/dL, respectively). A small but significant difference in low-density lipoprotein cholesterol (LDL-C; -5.0 mg/dL) was observed between the ESL 400 mg QD group and the placebo group. In patients not taking a concomitant EIAED, there were no changes with ESL 400 mg QD, but modest and statistically significant increases in cholesterol fractions (TC, LDL-C and HDL-C) with ESL 800 mg QD (6 mg/dL) and ESL 1200 mg QD (10 mg/dL). ESL had no consistent effect on lipids in patients taking a concomitant EIAED. In patients taking statins during baseline, there were no clinically relevant changes in serum lipids during use of ESL, although the subgroups were small.These results suggest that ESL does not appear to have clinically significant effects on serum lipids, nor does the pharmacokinetic interaction between ESL and statins have an impact on serum lipid concentrations.

There has been growing recognition of the possible abuse potential of newer generation antiepileptic drugs, and several of these agents have been categorized as controlled substances in the United States. To properly schedule a new medication, the abuse potential, or the potential for a drug to be used for its nonmedical positive subjective effects, must be determined. Performing a human abuse potential study is one step in the overall abuse potential assessment. These studies analyze the abuse potential of a new drug in a very specific population of known recreational drug users. Studying the test drug in this population enables a more meaningful assessment of abuse, and likely represents the population most probable to abuse. In these double-blind, single-dose, active and placebo controlled studies subjects may report their subjective liking, estimated street value, and rate euphoric or depressive sensations of the test drug compared with placebo and scheduled active comparators with a known abuse potential. In order to provide an enhanced understanding of the abuse potential assessment and how it relates to controlled substance scheduling, this review will examine the human abuse potential studies of perampanel, eslicarbazepine, lacosamide, and brivaracetam.

Objective: To evaluate the impact of incorporating pre-advanced pharmacy practice experience (pre-APPE) student pharmacists into three different population health management (PHM) projects. Methods: The prospective quality improvement projects incorporated three third-year student pharmacists who developed and conducted individual PHM projects over the course of three to seven months. The projects included hypoglycemia screening, hepatitis C virus and human immunodeficiency virus screening, and statin use evaluations for atherosclerotic cardiovascular disease risk reduction. Under the guidance of a clinical pharmacist, students developed project materials, conducted patient chart reviews, and contacted patients to make interventions such as recommendations for therapy, ambulatory patient monitoring, patient education, and arranging provider follow-up. Student impact was evaluated through the number of patients screened, the number of eligible patients contacted, and the total number of interventions or recommendations made. Student time spent was tracked throughout the projects. Results: Out of 244 patients screened, 198 patients met inclusion criteria and 162 patients were contacted or assessed by a student pharmacist. Students made a total of 319 interventions, including patient education (132), patient monitoring (132), pharmacotherapy recommendations (28), and arranging follow-up (27). On average students screened 33 patients per month, and, per patient, required 8.6 minutes for eligibility assessment and approximately 6 minutes for telephone interviews. Conclusion: This report demonstrates that pre-APPE student pharmacists are well-equipped to design and implement PHM projects. Utilization of student pharmacists in similar PHM programs can expand the pharmacist’s impact on patient care in the ambulatory care setting. Article Type: Original Research

Background The association of antiseizure medication (ASM) and bone density abnormalities has long been recognized; however, there remains a lack of consensus on efficacy and optimal vitamin D dosing in patients receiving enzyme inducing and non-inducing ASMs. The objective was to explore the relationship between ASMs and vitamin D supplementation requirements in a population of adult patients with epilepsy. Methods Patients with a diagnosis of epilepsy receiving supplemental vitamin D were included in this retrospective chart review. All instances of 25-hydroxyvitamin D3 (25−OHD) measured among those patients were compared between patients taking an enzyme inducing antiseizure medication (EIASM) to patients receiving ASM regimens only containing non-enzyme inducing antiseizure medications (NIASM). ASM use, prescription and over the counter (OTC) vitamin D use, 25-OHD plasma concentration, presence of chronic kidney disease (CKD), age, gender, and ethnicity were collected. Multiple linear regression was used to adjust for potentially confounding variables; the model included a cluster by participant term to account for repeated patients in the dataset. Results There were 542 vitamin D levels evaluated from 172 unique patients. There was an 11.5 % higher absolute percent increase in patients who achieved a 25-OHD level over 30 ng/mL in the NIASM (p = 0.012). Patients on EIASMs were supplemented with an additional 508 units of vitamin D daily (95 %CI 136–878, p = 0.007). When adjusted for CKD, OTC vitamin D use, OTC multivitamin use, age, gender, and ethnicity, patients on EIASMs were supplemented with an additional 445 units of vitamin D (95 %CI -69 to 960, p = 0.089) compared to NIASM use. Conclusions Patients taking EIASMs had an increase in vitamin D deficiency and vitamin D supplementation suggesting that EIASMs impact vitamin D metabolism. Closer monitoring of vitamin D status in patients with epilepsy, especially those on EIASMs, is warranted. This evaluation suggests that for patients taking ASM, use of a lower dose OTC requires closer monitoring of vitamin D status in patients with epilepsy, especially those on EIASMs, is warranted. vitamin D agent may not be adequate.

Objective The study assesses the bioavailability of diazepam after intranasal administration (diazepam nasal spray) in healthy volunteers. Comparative agents were diazepam rectal gel, which served as the regulatory reference product; and oral diazepam, a product with decades of clinical use. Tolerability of diazepam nasal spray was also assessed. Methods This was a phase 1, open‐label, randomized, single‐dose, three‐treatment, three‐period, six‐sequence crossover study in 48 healthy adult subjects that consisted of a screening period, a baseline period, and an open‐label treatment period. Interperiod intervals were at least 28 days. Results Forty‐eight healthy volunteer subjects were enrolled, two of whom discontinued before receiving study medication. For all routes of administration, the onset of diazepam absorption was rapid, with measurable concentrations of drug present by the first sample time point. The t max (time to reach maximum plasma concentration) was similar for diazepam nasal spray and diazepam rectal gel, both of which were slower than oral diazepam in fasted individuals. Variability (as defined by % coefficient of variation of geometric mean) in peak plasma concentration and area under the curve0‐∞ was lowest with oral diazepam, followed by diazepam nasal spray, with diazepam rectal gel showing the greatest variability. Overall, 131 treatment‐emergent adverse events (TEAEs) were considered mild (42 subjects, 91.3%), four TEAEs were considered moderate (four subjects, 8.3%), and no TEAEs were considered severe. The most commonly reported TEAE was somnolence at 56.5% (26/46) during diazepam nasal spray treatment, 89.1% (41/46) with the rectal diazepam gel treatment, and 82.6% (38/46) with oral diazepam treatment. No nasal irritation was observed for the majority of the subjects at any time point after administration, with no score higher than 2 (“minor bleeding that stops within 1 minute”). Significance Diazepam nasal spray shows predicable pharmacokinetics and represents a potential novel therapeutic approach to control bouts of increased seizure activity (cluster seizures, acute repetitive seizures).

Objective To evaluate the impact of eslicarbazepine acetate (ESL) monotherapy on markers of bone and lipid metabolism. Methods We conducted a post-hoc analysis of data pooled from two Phase III, dose-blind, conversion-to-ESL (1600 mg and 1200 mg) monotherapy studies in patients with focal seizures. Laboratory measurements included lipids (total cholesterol [TC]; high-density lipoprotein cholesterol [HDL-C]; low-density lipoprotein cholesterol; and triglycerides) and markers of bone metabolism (alkaline phosphatase; 25-hydroxyvitamin D; osteocalcin; and parathyroid hormone [PTH]); measurements were taken at baseline, Week 18, and Month 12, and analyzed according to enzyme-inducing antiepileptic drugs (EIAEDs) use at baseline (+EIAED and –EIAED subgroups). Results Data from 337 treatment-compliant patients were used for the Week 18 analyses (+EIAED subgroup, n = 119; –EIAED subgroup, n = 218); data from 161 treatment-compliant patients were used for the Month 12 analyses (+EIAED subgroup, n = 53; –EIAED subgroup, n = 108). At baseline, alkaline phosphatase and PTH concentrations were higher in the + EIAED versus –EIAED subgroup. Changes from baseline in markers of bone turnover were generally insignificant, except for some elevation in alkaline phosphatase in the –EIAED subgroup (18 weeks and 12 months) and osteocalcin in both subgroups (18 weeks only). Regarding lipids, TC and HDL-C concentrations were higher in the + EIAED versus –EIAED subgroup at baseline. Concentrations of markers of lipid metabolism fell in the + EIAED group and rose in the –EIAED group, reaching very similar values that were intermediate between the –EIAED and + EIAED baseline values. Conclusions Based on this retrospective analysis, ESL seems to have had only a modest and primarily clinically insignificant impact on plasma lipids. More prospective data are needed to definitively ascertain the effects of ESL on bone metabolism.

Objective The goal of this study was to characterize the drug–drug interactions between clobazam and 2 antiseizure drugs, cannabidiol and stiripentol, for treatment of refractory seizures through the use of pharmacokinetic modeling. Methods A population pharmacokinetic/pharmacodynamic model was developed to characterize the combined effect of clobazam and its active metabolite, N-desmethylclobazam (i.e., N-clobazam), on seizure protection in patients with Lennox–Gastaut syndrome using data from the phase 3 CONTAIN trial. Drug–drug interactions between clobazam and cannabidiol were examined by comparing model-generated data to data from a study of 13 patients taking concomitant clobazam and cannabidiol. Modeling data were also descriptively compared with studies of patients administered both clobazam and stiripentol. Sedation-related adverse events from CONTAIN were analyzed to determine the exposure–somnolence relationship of clobazam. Results Exposure-efficacy analysis from the pharmacokinetic/pharmacodynamic model using CONTAIN data indicated that clobazam (half-maximal effective concentration [EC50], 303 ng/mL) was 3 times more potent than N-clobazam (EC50, 899 ng/mL). After administration of clobazam, when both clobazam and N-clobazam concentrations were each 1 to 2 times the EC50 value (clobazam dose, 20 mg), 70.0%–74.9% seizure protection was predicted; when concentrations were > 2 times the EC50 value (clobazam dose, 40 mg), 74.0%–96.9% seizure protection was predicted. Generalized additive model analyses demonstrated decreased seizure probability with higher plasma concentration of clobazam. Coadministration of stiripentol and clobazam resulted in increased respective median plasma concentrations of clobazam and N-clobazam (1.1–1.2 times and 5.2–8.2 times) compared with administration of placebo and clobazam. Probability of somnolence significantly increased with age and higher N-clobazam plasma concentration. Significance Awareness of drug–drug interactions between clobazam and cannabidiol is needed when adding cannabidiol or stiripentol to a regimen of clobazam or vice versa. Based upon our population pharmacokinetic/pharmacodynamic model, we predict that an increase in N-clobazam levels, which patient data show may enhance efficacy and/or make adverse events such as somnolence more likely.

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening syndrome of hyperinflammatory responses with aberrant activation of lymphocytes and macrophages resulting in hypercytokinemia (a positive feedback loop between cytokines and immune cells, with highly elevated levels of various cytokines).1 The syndrome has multiple etiologies including genetic mutations, infectious diseases (e.g., HIV), autoinflammatory and autoimmune diseases, malignancy, immunosuppression, stem cell and organ transplantation, metabolic diseases, and drug exposure.1

Introduction We report outcomes from an open-label, non-randomized, 24-week study of eslicarbazepine acetate (ESL) in adults at earlier and later stages of their treatment history for focal seizures, conducted in a real-world clinical setting. Methods ESL was taken as the first adjunctive therapy to levetiracetam (LEV) or lamotrigine (LTG) monotherapy (Arm 1), or as a later adjunctive therapy in treatment-resistant patients (Arm 2). The primary objective was to evaluate the effectiveness of ESL (by retention rates). Secondary objectives were to evaluate efficacy (seizure frequency), safety, tolerability, behavioral changes, mood, and health-related quality of life (HRQoL) associated with ESL treatment. Results The modified intent-to-treat population included 96 patients (Arm 1: n = 41; Arm 2: n = 55) and the safety population included 102 patients (Arm 1: n = 44; Arm 2: n = 58). Overall, 81.8 % of patients in Arm 1 and 63.8 % of patients in Arm 2 completed the 24-week maintenance period. Median reductions in standardized seizure frequency (SSF) were markedly higher in Arm 1 (72.8 %) than Arm 2 (22.8 %), as were responder rates (≥50 % reduction in SSF; Arm 1: 62.5 %; Arm 2: 38.5 %) and rates of seizure freedom (Arm 1: 25.0 %; Arm 2: 9.6 %). Efficacy outcomes were generally more favorable in patients taking ESL in combination with LEV versus other anti-seizure medications (ASMs). Treatment-emergent adverse events (TEAEs; 81 % vs 73 %) and TEAEs leading to discontinuation (16 % vs 2 %) were reported more frequently in Arm 2 than Arm 1, respectively. Serious adverse events were reported infrequently (Arm 1: 0; Arm 2: 7 %). The most common TEAEs were dizziness, nausea, headache, somnolence, fatigue, nasopharyngitis, vomiting, and anxiety. There were no notable changes in depressive symptoms, mood status, or aggression throughout the study. Health and HRQoL scores were generally high at baseline and did not change throughout the study. However, on average, both clinicians and patients perceived improvement in illness over the course of the study. Conclusions ESL was effective and well tolerated both as the first adjunctive therapy to either of the most prescribed first-line ASMs, LEV or LTG, and as a later adjunctive therapy in treatment-resistant patients.

Brivaracetam is an antiepileptic drug (AED) indicated for the treatment of focal seizures, with improved safety and tolerability vs first-generation AEDs. Brivaracetam binds with high affinity to synaptic vesicle protein 2A in the brain, which confers its antiseizure activity. Brivaracetam is rapidly absorbed and extensively biotransformed, and exhibits linear and dose-proportional pharmacokinetics at therapeutic doses. Brivaracetam does not interact with most metabolizing enzymes and drug transporters, and therefore does not interfere with drugs that use these metabolic routes. The favorable pharmacokinetic profile of brivaracetam and lack of clinically relevant drug-drug interactions with commonly prescribed AEDs or oral contraceptives allows administration without dose adjustment, and avoids potential untoward events from decreased efficacy of an AED or oral contraceptive due to a drug-drug interaction. Few agents have been reported to affect the pharmacokinetics of brivaracetam. The strong enzyme-inducing AEDs carbamazepine, phenytoin and phenobarbital/primidone have been shown to moderately lower brivaracetam plasma concentrations, with no adjustment of brivaracetam dose needed. Dose adjustment should be considered when brivaracetam is coadministered with the more potent CYP inducer, rifampin. Additionally, caution should be used when adding or ending treatment with the strong enzyme inducer, St. John's wort. In summary, brivaracetam (50-200 mg/day) has a favorable pharmacokinetic profile and is associated with few clinically relevant drug-drug interactions.

Purpose: The effects of antiseizure medications (ASMs) on bone metabolism is inconsistent. Most studies are in high income settings and none from sub-Saharan Africa. Methods: A hospital based cross-sectional study in a paediatric epilepsy service with a comparison group assessed vitamin D metabolism. Results: Seventy-five children with epilepsy and 75 comparison group were recruited. Median age for children with epilepsy was 9 years (range 1–17 years) and controls 3 years (range 1–12 years). Vitamin D deficiency occurred in 11(16.2%) children with epilepsy versus 6 (8.8%) control group (p = 0.29). Vitamin D insufficiency occurred in 30 (44.1%) children with epilepsy compared to 27(39.7%) control group. Children on ASMs had lower mean vitamin D levels than the control group (p = 0.02). Children on enzyme-inducing ASMs had lower mean vitamin D levels (p = 0.08), vitaminD2 (p = 0.0018), vitaminD3 (p = 0.004), serum phosphate levels (p = 0.000), and higher mean parathyroid hormone levels (p = 0.03) compared to controls. There was no difference in dietary intake and ancestry, although the dietary content of both groups was low in vitamin D products. Conclusions: Low vitamin D levels were common in children from both groups, but statistically lower for the children on ASMs. Children on enzyme-inducing ASMs need screening for vitamin D deficiency. The literature supports extending this for all children on ASMs. This is the first study to report that children on enzyme-inducing ASMs have lower levels of Vitamin D2 and D3 levels, probably as result of increased destruction of vitamin D. Improved vitamin D intake for children in vulnerable settings is important.

Plasma protein binding and effects on volume of distribution and pharmacologically active, circulating-drug concentrations are complex issues. Protein-binding displacement often underlies drug–drug interactions. Perampanel is a once-daily oral anti-seizure drug for focal seizures and primary generalized tonic-clonic seizures. Perampanel is also indicated for monotherapy use for focal seizures in the United States. Perampanel is extensively but slowly metabolized via CYP3A4. Its elimination t½ is about 100 h, and it displays substantial plasma protein binding (>95%). Here, we examine perampanel’s potential to displace highly bound anti-seizure drugs and the ability of warfarin, a standard highly protein-bound drug, to displace perampanel. Protein binding of perampanel, phenytoin, valproate, and warfarin was assessed using equilibrium dialysis. Plasma samples containing each compound were dialyzed against phosphate buffered saline. For phenytoin, valproate, and warfarin, plasma samples were also dialyzed in the presence of perampanel. After 24 h equilibrium dialysis, amounts of test compounds were analyzed to calculate plasma protein binding. At clinically relevant concentrations, perampanel did not displace other highly bound drugs or vice versa. Protein-binding displacement may confound therapeutic drug monitoring of extensively protein-bound medications. Without empirical data, clinicians might be concerned that addition of perampanel could alter unbound concentrations of other medications, resulting in adverse effects. Our data indicate perampanel has low potential for drug interactions resulting from protein-binding displacement.

Purpose Conversion to lamotrigine (LTG) monotherapy from sodium valproate (VPA) is complicated by the robust pharmacokinetic interaction between the two AEDs. This study examined changes in LTG serum concentrations immediately following VPA discontinuation. Methods Ten healthy female and male adult subjects were initiated on LTG (Lamictal) 10 mg orally every morning for 30 days and VPA (Depakote ER) 500 mg orally every morning for 14 days. Morning trough (pre-dose) venous blood samples were obtained for determination of LTG and VPA concentrations on study days 14, 15, 16, 18, 20, 22, 24, 26, 28, and 30. Following the collection of the blood sample on day 15, VPA was discontinued. Results Despite stable LTG dosage serum concentrations on study day 20, 22, 24, 26, and 28, all were significantly lower compared to baseline (p Conclusions These observations demonstrate that the pharmacokinetic interaction between LTG and VPA is reversible, and that de-inhibition appears to follow a predictable time course. Complete offset, or reversal of this interaction takes place 10–14 days after VPA discontinuation. Our data also confirms the observation that LTG oral clearance may be inhibited by very low concentrations of VPA. These data support the conversion algorithm suggested by the manufacturer, and provide guidance to the clinician. These data provide clinically useful information in developing a dosing algorithm for converting patients to LTG monotherapy.

Objective: Evaluate the impact of concomitant enzyme (CYP3A4)-inducer antiepileptic drugs (EIAEDs) on the efficacy and safety of perampanel in patients from the 3 phase-III clinical trials. Methods: Patients with pharmacoresistant partial-onset seizures in the 3 phase-III clinical studies were aged 12 years and older and receiving 1 to 3 concomitant antiepileptic drugs. Following 6-week baseline, patients were randomized to once-daily, double-blind treatment with placebo or perampanel 8 or 12 mg (studies 304 and 305) or placebo or perampanel 2, 4, or 8 mg (study 306). Results: Treatment response assessed by median percent reduction in seizure frequency and responder rates improved with perampanel compared with placebo. However, at 8 and 12 mg, the treatment response was significantly greater in patients receiving non-EIAEDs. The treatment effect (perampanel–placebo) also demonstrated a dose-dependent increase in all patients. The overall incidence of treatment-emergent adverse events was similar regardless of the presence of EIAEDs. Occurrence of some adverse events, such as fatigue, somnolence, dizziness, irritability, was greater in patients receiving non-EIAEDs, as was discontinuation because of adverse events. Conclusions: Perampanel shows efficacy and safety in the presence and absence of EIAEDs. As systemic exposure to perampanel increases, so does efficacy. Given the extensive metabolism of perampanel, systemic exposure is clearly reduced with concomitant administration of CYP3A4 inducers. This supports the strategy of dosing perampanel to clinical effect. Recognition of these pharmacokinetic interactions will be important in the optimization of this novel medication. Classification of evidence: This study provides Class II evidence that 2 to 12 mg/d doses of perampanel reduced seizure frequency and improved responder rate in the presence and absence of EIAEDs.

Given the complexities managing Lennox-Gastaut syndrome (LGS)-comorbid conditions, multiple associated seizure types that tend to be refractory to treatment-dosage optimization of antiepileptic drug (AED) treatment is a challenge. In the absence of clinical trial data on optimization of AED dosage in patients with LGS, dose titration is guided by personal experience, anecdotal evidence, and specific patient factors (age, comorbid conditions and medications, seizure types, etc.). The goal of this study was to determine whether a 20% increase in adjunctive clobazam was a reasonable benchmark for improved seizure response in patients with LGS who had responded to adjunctive clobazam treatment during a 12-week lead-in trial. This was a post hoc analysis of data from a long-term, open-label extension (OLE) study, which comprised patients who completed 1 of 2 pivotal clobazam lead-in studies. During the lead-in studies, patients received either placebo or clobazam (0.25, 0.50, or 1.0mg/kg/d) (maximum 40mg/d); during OLE, patients received clobazam up to 2.0mg/kg/d (maximum 80mg/d). The post hoc analysis population comprised patients who had ≥25%, ≥50%, or ≥75% seizure reduction from baseline during lead-in clobazam treatment and ≥12months of follow-up data during OLE. Successful dosage increase (i.e., dosage optimization) was defined as ≥20% clobazam dosage increase from OLE baseline, and improved seizure control from OLE baseline (improvement in seizure responder status, or >50% reduction in total seizure frequency). Patients were stratified by responder status after lead-in treatment (OLE baseline) and by lead-in clobazam dosage received. The findings of the analysis indicated that clobazam dosage increases of ≥20% during long-term treatment improved seizure control >80% of patients with LGS who responded to clobazam during lead-in treatment. Rates of successful dosage increase during OLE were high regardless of lead-in dosage received, with the highest rate of successful dosage increase among patients who received low-dosage clobazam during lead-in. Similarly, rates of successful dose increase were high regardless of lead-in seizure responder category, with the highest rates occurring in patients with the highest (≥75%) lead-in response.

Importance Switching between generic antiepileptic drugs is a highly debated issue that affects both clinical care and overall health care costs. Objective To evaluate the single-dose pharmacokinetic bioequivalence of 3 (1 branded and 2 generic drugs) on-market, immediate-release lamotrigine drug products. Design, Setting, and Participants The Equivalence Among Antiepileptic Drug Generic and Brand Products in People With Epilepsy (EQUIGEN) single-dose study is a crossover, prospective, sequence-randomized, replicate pharmacokinetic study conducted at 5 US academic epilepsy centers. Fifty adults (≥18 years) with epilepsy who were taking concomitant antiepileptic drugs and not currently receiving lamotrigine were enrolled between July 18, 2013, and January 19, 2015. Every participant was randomly assigned to 1 of 3 equivalent sequences, each comprising 6 study periods, during which they had blood draws before and after medication administration. Forty-nine participants were included in intention-to-treat analyses. Interventions Participants received a single 25-mg dose of immediate-release lamotrigine at the start of each period, with the branded and the 2 most disparate generic products each studied twice. Lamotrigine was selected as the antiepileptic drug of interest because of its wide use, publications indicating problems with generic switches, and complaints to the US Food and Drug Administration regarding generic products. Both participants and study personnel were blinded to the specific generic products selected. Main Outcomes and Measures The primary outcome was bioequivalence between products. Maximum plasma concentration (Cmax) and area under the concentration–time curve (AUC) were compared, and average bioequivalence (ABE) was established if the 90% CIs of the ratios of the 2 products were within equivalence limits (80%-125%). Results Of the 50 randomized participants, 49 (98%) received all 3 lamotrigine products and completed at least 3 pharmacokinetic assessments and 46 (92%) completed all 6 pharmacokinetic assessments. Among the 49 participants, 28 (57%) were men and 21 (43%) were women, 42 (86%) self-identified as white, and 46 (16) years was the mean (SD) age. The 3 drug products were considered bioequivalent because the 90% CIs were within equivalence limits (lowest and highest CI limits for Cmax, 92.6% and 110.4%; for AUC 0-96 , 96.9% and 101.9%). Replicate testing demonstrated no significant differences in within-subject variability across the 3 products (likelihood ratios, χ 2 2 for log-transformed variables: AUC 0-96 , 2.58; Cmax, 0.64; and AUC 0-∞ , 4.05; P ≥ .13) and that the 3 products were also bioequivalent according to scaled ABE and individual bioequivalence criteria with no subject × formulation interaction (Cmax, 0.00; AUC 0-96 , 0.54; and AUC 0-∞ , 0.36; P ≥ .76). Conclusions and Relevance This study provides evidence that the disparate lamotrigine products studied are bioequivalent when tested in people with epilepsy taking concomitant antiepileptic drugs. Trial Registration clinicaltrials.gov Identifier:NCT01733394

Introduction Patients with partial-onset seizures and comorbid cardiovascular disease may concomitantly receive eslicarbazepine acetate (ESL), an antiepileptic drug, and rosuvastatin, an HMG-CoA reductase inhibitor. This study evaluated the effect of multiple-dose ESL on the pharmacokinetic (PK) parameters of a single dose of rosuvastatin in healthy subjects. Methods This was a Phase I, single-center, fixed-sequence, open-label study. Healthy subjects received two treatments, in sequence. Treatment A: a single 40mg oral dose of rosuvastatin on Day 1, followed by a washout period (Days 1–4); treatment B: titration of ESL (400–800mg once daily) on Days 5–18, followed by ESL 1200mg once daily on Days 19–35, with a single dose of rosuvastatin (40mg) on Day 32. Subjects then entered a 2-week follow-up period. Plasma concentrations of rosuvastatin were quantified for PK analyses. Safety and tolerability were assessed throughout the study. Results Thirty-three healthy subjects were enrolled and 30 completed the study. Mean rosuvastatin (standard deviation) t 1/2 was similar when rosuvastatin was used concomitantly with ESL and when it was used alone (26.5 [16.3]h, and 22.4 [9.5]h, respectively). The geometric least squares mean ratios (90% confidence intervals) of rosuvastatin exposure levels between rosuvastatin used concomitantly with ESL and rosuvastatin used alone were as follows: C max , 64.0% (55.9–73.3%); AUC (0–∞) , 63.0% (57.1–69.4%); and AUC (0–last) , 60.9% (55.2–67.1%). Concomitant use of ESL and rosuvastatin was generally well tolerated. Conclusions Rosuvastatin exposure was 36–39% lower with steady-state administration of ESL, potentially due to reduced oral bioavailability of rosuvastatin. Consequently, when rosuvastatin is used with ESL, a rosuvastatin dose adjustment may be necessary if a clinically significant change in lipids is noted.

SummaryPurpose Although there is a general paucity of published pharmacokinetic (PK) data for new antiepileptic drugs (AEDs), PK analyses of pooled data from clinical studies of perampanel have recently been presented. We present PK/pharmacodynamic (PD) analyses of pooled data from phase III studies of perampanel describing efficacy and safety as a function of exposure, in order to determine whether a predictable concentration–effect relationship exists for perampanel efficacy and/or adverse events (AEs). The effects of concomitant enzyme-inducing AEDs (EIAEDs) and non–enzyme-inducing AEDs on the exposure, efficacy, and safety of perampanel are also considered. Methods Three multicenter, randomized, double-blind, placebo-controlled phase III studies investigated the efficacy and safety of perampanel 2–12 mg in patients with uncontrolled partial-onset seizures despite prior therapy with two or more AEDs. From baseline onward, patients also received ongoing treatment with stable doses of one to three approved concomitant AEDs. AEs were monitored throughout the studies. Changes from baseline in seizure frequency and 50% responder rates were evaluated. Exposure to perampanel was predicted based on the actual (last) dose using a previously established PK model. A population PK/PD model for the relationship between perampanel exposure and seizure frequency was estimated using nonlinear mixed-effect modeling with first-order conditional estimation, whereas logistic analyses for responder rate and AEs were performed using SAS analysis software. Key Findings The PK/PD population included 1,109 patients. Seizure frequency decreased linearly as predicted perampanel average steady-state plasma concentrations increased. Concomitant EIAEDs (carbamazepine, oxcarbazepine, and phenytoin) reduced exposure to perampanel but had no effect on the slope of the PD model–predicted relationship between exposure and reduction in seizure frequency. The probability of patients achieving a response was predicted to increase as perampanel average plasma concentration at steady state increased. No demographic, AED, region, or study covariate had any effect on the probability of achieving a positive treatment response to perampanel or on the slope of the exposure–response curve. Across the phase III studies, there were reports of dizziness (32.9%), somnolence (21.7%), fatigue (13.9%), irritability (12.3%), gait disturbance (9.1%), weight increase (6.1%), dysarthria (4.5%), and euphoric mood (0.5%); the model-predicted probability of these AEs increased significantly at higher exposure to perampanel (all p

PURPOSE To assess the effect of common dosing irregularities on serum concentrations of antiepileptic drug (AED) lamotrigine for the extended-release (XR) formulation, which is recommended for once-daily dosing (QD), and the immediate-release (IR) formulation, which is typically dosed twice daily (BID). METHODS A pharmacokinetic model was constructed for lamotrigine XR and IR formulations in the presence and absence of comedications. The model was then used to simulate concentration time profiles in scenarios of full compliance and various forms of nonadherence such as a delayed dose, a missed dose, and a doubled dose. RESULTS Lamotrigine steady-state serum concentrations stayed in a narrower range for XR-QD than for IR-BID, despite the more frequent dosing of the latter. At the same daily dose, concentrations with IR-BID were outside the range seen with XR-QD for the majority of the day. For XR-QD, concentration decrease due to dosing delay was small (

Objectives Perampanel, a selective, noncompetitive AMPA receptor antagonist, is indicated as adjunctive therapy for the treatment of partial seizures with or without secondarily generalized seizures and primary generalized tonic-clonic seizures in patients with epilepsy aged 12years and older. In vitro studies and Phase I trials indicate that perampanel is metabolized almost exclusively by CYP3A, with an elimination half-life (t 1/2 ) averaging approximately 105h. Understanding of pharmacokinetic (PK) interactions—enzyme inhibition or induction—and anticipating their occurrence are important for management of patients with epilepsy. Here we report PK results from a Phase I drug-drug interaction (DDI) study (Study 005) combining perampanel with the CYP3A inhibitor ketoconazole, as well as supplementary in silico predictions further exploring this interaction. Methods A Phase I, randomized, open-label, two-period, two-treatment, two-way crossover study was conducted in 26 healthy adult male volunteers. Subjects were randomized to 1 of 2 treatment sequences. In one period, subjects received a single 1-mg fasting dose of perampanel (Day1); in the other period, subjects received ketoconazole 400mg once daily for 10days with a single 1-mg perampanel dose while fasting (Day3). Blood samples were drawn at multiple time points up to 288h after the perampanel dose. Pharmacokinetic parameters of perampanel were calculated by noncompartmental analysis, and safety was recorded. An integrated, physiologically based PK model built in Simcyp ® provided additional insight into this interaction. Drug-drug interaction intensity was measured by the ratio of systemic exposure (area under plasma concentration-time curve [AUC]) of perampanel in the presence or absence of concomitant ketoconazole. Results Single oral doses of 1mg perampanel and once-daily oral doses of ketoconazole 400mg were safe and well tolerated. Maximum perampanel plasma concentration (C max ) and time to C max showed no apparent differences when perampanel was administered alone versus with ketoconazole. Ketoconazole co-administration resulted in an approximate 20% increase in perampanel AUC ( P 0.001). This increase, although statistically significant, was a 2-fold) of potential clinical significance could be predicted when using larger doses of ketoconazole (e.g., 200mg every 6h) coadministered for a greater time period (e.g., 30days), with AUC ratio as high as 3.36. Additionally, simulations suggested that a significant interaction with co-administration of perampanel and an inhibitor more potent than ketoconazole (such as itraconazole) could not be ruled out. Conclusions Selecting an appropriate study design is critical to fully characterize the PK interaction for drugs such as perampanel that have a long t 1/2 . Although a negligible effect on perampanel PK was observed following co-administration of ketoconazole 400mg/day for 10days, this is likely due in part to the relatively brief co-administration period of ketoconazole and perampanel ( 1/2 of perampanel). While short-term administration of a CYP3A inhibitor may not significantly increase perampanel exposure, such increases may be expected following chronic and larger dosing or with a more potent inhibitor.

Objective: To evaluate potential development of tolerance to adjunctive clobazam in patients with Lennox-Gastaut syndrome. Methods: Eligible patients enrolled in open-label extension study OV-1004, which continued until clobazam was commercially available in the United States or for a maximum of 2 years outside the United States. Enrolled patients started at 0.5 mg·kg −1 ·d −1 clobazam, not to exceed 40 mg/d. After 48 hours, dosages could be adjusted up to 2.0 mg·kg −1 ·d −1 (maximum 80 mg/d) on the basis of efficacy and tolerability. Post hoc analyses evaluated mean dosages and drop-seizure rates for the first 2 years of the open-label extension based on responder categories and baseline seizure quartiles in OV-1012. Individual patient listings were reviewed for dosage increases ≥40% and increasing seizure rates. Results: Data from 200 patients were included. For patients free of drop seizures, there was no notable change in dosage over 24 months. For responder groups still exhibiting drop seizures, dosages were increased. Weekly drop-seizure rates for 100% and ≥75% responders demonstrated a consistent response over time. Few patients had a dosage increase ≥40% associated with an increase in seizure rates. Conclusions: Two-year findings suggest that the majority of patients do not develop tolerance to the antiseizure actions of clobazam. Observed dosage increases may reflect best efforts to achieve seizure freedom. It is possible that the clinical development of tolerance to clobazam has been overstated. ClinicalTrials.gov identifier: NCT00518713 and NCT01160770. Classification of evidence: This study provides Class III evidence that the majority of patients do not develop tolerance to clobazam over 2 years of treatment.

An 18-year-old girl is a freshman in community college and has a history of focal epilepsy of left frontal origin due to cortical dysplasia. She is managed on oxcarbazepine and has remained seizure free in the past year. She informs you that she is sexually active and has been in stable relationship with her boyfriend in the past 6 months. She is asking you for advice on starting contraception. What form of contraception are you most likely to recommend to her? What will be your advice if she was on lamotrigine, topiramate, or levetiracetam?

Several commonly prescribed antiepileptic drugs (AEDs)-including phenobarbital, phenytoin, and carbamazepine-stimulate the synthesis of a broad range of monooxygenase and conjugating enzymes. These agents are well known to reduce the duration and action of many lipid- and non-lipid-soluble drugs, including anticoagulants, cytotoxics, analgesics, antiretrovirals, glucocorticoids, statins, antihypertensives, oral contraceptives, psychoactive drugs, immunosuppressants, and of course, other AEDs. This process, therefore, may be associated with a number of clinical problems including higher cancer mortality, progressive AIDS, transplant rejection, and unwanted pregnancy. Withdrawal of enzyme-inducing AEDs will increase the concentration of induced drugs, bringing with it substantial risk of toxicity if doses are not concomitantly reduced. Yet the potential widespread adverse health consequences of these interactions, both with AED initiation and withdrawal, remain largely underappreciated. Furthermore, induction also affects enzymes involved in endogenous metabolic pathways, and can alter bone biochemistry, gonadal steroids, and lipid markers. Therefore, enzyme-inducing AEDs may contribute to the development of a number of comorbidities, including osteoporosis, sexual dysfunction, and vascular disease. This process continues as long as the patient takes the inducer. Modern AEDs that do not possess this property have similar efficacy for the common epilepsies. Accordingly, perhaps consideration should be given to starting treatment with, or even switching patients to, non-enzyme-inducing AEDs.

Over the past few years, increasing public and political pressure has supported legalization of medical marijuana. One of the main thrusts in this effort has related to the treatment of refractory epilepsy—especially in children with Dravet syndrome—using cannabidiol (CBD). Despite initiatives in numerous states to at least legalize possession of CBD oil for treating epilepsy, little published evidence is available to prove or disprove the efficacy and safety of CBD in patients with epilepsy. This review highlights some of the basic science theory behind the use of CBD, summarizes published data on clinical use of CBD for epilepsy, and highlights issues related to the use of currently available CBD products. Cannabidiol is the major nonpsychoactive component of Cannabis sativa. Over the centuries, a number of medicinal preparations derived from C. sativa have been employed for a variety of disorders, including gout, rheumatism, malaria, pain, and fever. These preparations were widely employed as analgesics by Western medical practitioners in the 19th century ( 1 ). More recently, there is clinical evidence suggesting efficacy in HIV-associated neuropathic pain, as well as spasms associated with multiple sclerosis ( 1 ).

Summary Purpose Pharmacokinetic interactions have been demonstrated in enzyme-inducing antiepileptic drugs (EIAEDs) and statins; however, their clinical significance is not well established. The purpose of this study was to evaluate the association of EIAEDs and non-enzyme-inducing antiepileptic drugs (NEIAEDs) on statin dose adjustments and low-density lipoprotein (LDL) cholesterol levels in patients with epilepsy. Methods Retrospective insurance claims from 2000 to 2006 from the Ingenix Impact (formerly Integrated Health Care Information Services) database were analyzed. Two cohorts were compared, EIAEDs + statin and NEIAEDs + statin: 1118 patients were analyzed (58% men; 66% aged >55 years); 506 (45%) initiated with an EIAED. Outcomes assessed included statin dose adjustments and, for a subset of subjects, risk of mean LDL >100 mg/dL during the 12-month follow-up period. Descriptive statistics were calculated and regression models estimated. Results Among the EIAED group, 72% initiated with phenytoin; among the NEIAED group, 57% initiated with gabapentin. For the EIAED group, the risk of upward statin dose adjustments was significantly greater (odds ratio = 1.36; P = 0.04) compared with the NEIAED group; similarly, the risk of having mean LDL >100 mg/dL was significantly greater (odds ratio = 41.22; P = 0.005) and increased during the follow-up period (+26.6 mg/dL; P = 0.001) for the EIAED group. Discussion This study suggests that concomitant use of EIAEDs and statins may be associated with reduced clinical effectiveness of statins. Patients with epilepsy who use EIAEDs and statins concomitantly may require greater vigilance for optimal cholesterol management.

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including antiepileptic drug (AED) teratogenicity and adverse perinatal outcomes. It is highly probable that intrauterine first-trimester valproate (VPA) exposure has higher risk of major congenital malformations (MCMs) compared to carbamazepine (CBZ), and possibly compared to phenytoin (PHT) or lamotrigine (LTG). It is probable that VPA as part of polytherapy and possible that VPA as monotherapy contribute to the development of MCMs. AED polytherapy probably contributes to the development of MCMs and reduced cognitive outcomes compared to monotherapy. Intrauterine exposure to VPA monotherapy probably reduces cognitive outcomes and monotherapy exposure to PHT or phenobarbital (PB) possibly reduces cognitive outcomes. Neonates of WWE taking AEDs probably have an increased risk of being small for gestational age and possibly have an increased risk of a 1-minute Apgar score of

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including preconceptional folic acid and prenatal vitamin K use and the clinical implications of placental and breast-milk transfer of antiepileptic drugs (AEDs). The committee evaluated the available evidence based on a structured literature review and classification of relevant articles. Preconceptional folic acid supplementation is possibly effective in preventing major congenital malformations in the newborns of WWE taking AEDs. There is inadequate evidence to determine if the newborns of WWE taking AEDs have a substantially increased risk of hemorrhagic complications. Primidone and levetiracetam probably transfer into breast milk in clinically important amounts. Valproate, phenobarbital, phenytoin, and carbamazepine probably are not transferred into breast milk in clinically important amounts. Pregnancy probably causes an increase in the clearance and a decrease in the concentrations of lamotrigine, phenytoin, and, to a lesser extent carbamazepine, and possibly decreases the level of levetiracetam and the active oxcarbazepine metabolite, the monohydroxy derivative (MHD). Supplementing WWE with at least 0.4 mg of folic acid before pregnancy may be considered. Monitoring of lamotrigine, carbamazepine, and phenytoin levels during pregnancy should be considered, and monitoring of levetiracetam and oxcarbazepine (as MHD) levels may be considered. A paucity of evidence limited the strength of many recommendations.

A committee assembled by the American Academy of Neurology (AAN) reassessed the evidence related to the care of women with epilepsy (WWE) during pregnancy, including the risk of pregnancy complications or other medical problems during pregnancy, change in seizure frequency, the risk of status epilepticus, and the rate of remaining seizure-free during pregnancy. The committee evaluated the available evidence according to a structured literature review and classification of relevant articles. For WWE who are taking antiepileptic drugs (AEDs), there is probably no substantially increased risk (>2 times expected) of cesarean delivery or late pregnancy bleeding, and probably no moderately increased risk (>1.5 times expected) of premature contractions or premature labor and delivery. There is possibly a substantially increased risk of premature contractions and premature labor and delivery during pregnancy for WWE who smoke. WWE should be counseled that seizure freedom for at least 9 months prior to pregnancy is probably associated with a high likelihood (84-92%) of remaining seizure-free during pregnancy. WWE who smoke should be counseled that they possibly have a substantially increased risk of premature contractions and premature labor and delivery.

Objective: To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy, including preconceptional folic acid use, prenatal vitamin K use, risk of hemorrhagic disease of the newborn, clinical implications of placental and breast milk transfer of antiepileptic drugs (AEDs), risks of breastfeeding, and change in AED levels during pregnancy. Methods: A 20-member committee evaluated the available evidence based on a structured literature review and classification of relevant articles published between 1985 and October 2007. Results: Preconceptional folic acid supplementation is possibly effective in preventing major congenital malformations in the newborns of WWE taking AEDs. There is inadequate evidence to determine if the newborns of WWE taking AEDs have a substantially increased risk of hemorrhagic complications. Primidone and levetiracetam probably transfer into breast milk in amounts that may be clinically important. Valproate, phenobarbital, phenytoin, and carbamazepine probably are not transferred into breast milk in clinically important amounts. Pregnancy probably causes an increase in the clearance and a decrease in the concentration of lamotrigine, phenytoin, and to a lesser extent carbamazepine, and possibly decreases the level of levetiracetam and the active oxcarbazepine metabolite, the monohydroxy derivative. Recommendations: Supplementing women with epilepsy with at least 0.4 mg of folic acid before they become pregnant may be considered (Level C). Monitoring of lamotrigine, carbamazepine, and phenytoin levels during pregnancy should be considered (Level B) and monitoring of levetiracetam and oxcarbazepine (as monohydroxy derivative) levels may be considered (Level C). A paucity of evidence limited the strength of many recommendations.

Objective: To reassess the evidence for management issues related to the care of women with epilepsy (WWE) during pregnancy. Methods: Systematic review of relevant articles published between January 1985 and June 2007. Results: It is highly probable that intrauterine first-trimester valproate (VPA) exposure has higher risk of major congenital malformations (MCMs) compared to carbamazepine and possible compared to phenytoin or lamotrigine. Compared to untreated WWE, it is probable that VPA as part of polytherapy and possible that VPA as monotherapy contribute to the development of MCMs. It is probable that antiepileptic drug (AED) polytherapy as compared to monotherapy regimens contributes to the development of MCMs and to reduced cognitive outcomes. For monotherapy, intrauterine exposure to VPA probably reduces cognitive outcomes. Further, monotherapy exposure to phenytoin or phenobarbital possibly reduces cognitive outcomes. Neonates of WWE taking AEDs probably have an increased risk of being small for gestational age and possibly have an increased risk of a 1-minute Apgar score of