Therapeutic Salivary Monitoring of Perampanel in Patients with Epilepsy Using a Volumetric Absorptive Microsampling Technique.

The objective of this study was to validate a novel assay using the volumetric absorptive microsampling (VAMS) technique combined with liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) for the determination of the antiseizure medication perampanel in saliva and its clinical applicability in patients with epilepsy. VAMS tips were loaded with 30 µL of saliva and dried for 60 min. Analytes were extracted with methanol. The supernatant was evaporated under a gentle stream of nitrogen and reconstituted with 60 µL of methanol. Separation and quantification were achieved on a monolithic column connected to a mass spectrometer. Calibration curves were linear between 0.5 and 300 ng/mL. Intra- and inter-day accuracy was within 85.6-103.2% and intra-day and inter-day precision did not exceed 12.1%. Perampanel was stable in samples collected by VAMS and stored under different storage conditions. The VAMS-LC-MS/MS method was validated according to internationally accepted criteria and tested in patients with epilepsy who were receiving a combination of perampanel and other antiseizure medications. The method showed adequate bioanalytical performances, holding great potential as an alternative strategy to support domiciliary TDM in patients with epilepsy treated with perampanel according to the simplicity of sample collection.

Melatonin versus Sleep Deprivation for Sleep Induction in Nap Electroencephalography: Protocol for a Prospective Randomized Crossover Trial in Children and Young Adults with Epilepsy.

Electroencephalography (EEG) continues to be a pivotal investigation in children with epilepsy, providing diagnostic evidence and supporting syndromic classification. In the pediatric population, electroencephalographic recordings are frequently performed during sleep, since this procedure reduces the number of artifacts and activates epileptiform abnormalities. To date, no shared guidelines are available for sleep induction in EEG. Among the interventions used in the clinical setting, melatonin and sleep deprivation represent the most used methods. The main purpose of this study is to test the non-inferiority of 3-5 mg melatonin versus sleep deprivation in achieving sleep in nap electroencephalography in children and young adult patients with epilepsy. To test non-inferiority, a randomized crossover trial is proposed where 30 patients will be randomized to receive 3-5 mg melatonin or sleep deprivation. Each enrolled subject will perform EEG recordings during sleep in the early afternoon for a total of 60 EEGs. In the melatonin group, the study drug will be administered a single oral dose 30 min prior to the EEG recording. In the sleep deprivation group, parents will be required to subject the child to sleep deprivation the night before registration. Urinary and salivary concentrations of melatonin and of its main metabolite 6-hydroxymelatonin will be determined by using a validated LC-MS method. The present protocol aims to offer a standardized protocol for sleep induction to be applied to EEG recordings in those of pediatric age. In addition, melatonin metabolism and elimination will be characterized and its potential interference in interictal abnormalities will be assessed.

On-Line Solid Phase Extraction High Performance Liquid Chromatography Method Coupled With Tandem Mass Spectrometry for the Therapeutic Monitoring of Cannabidiol and 7-Hydroxy-cannabidiol in Human Serum and Saliva.

Cannabidiol is a novel antiseizure medication approved in Europe and the US for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome and tuberous sclerosis complex. We describe in this article a new and simple liquid chromatography-mass spectrometry method (LC-MS/MS) for the determination of cannabidiol and its active metabolite 7-hydroxy-cannabidiol in microvolumes of serum and saliva (50 µl), to be used as a tool for therapeutic drug monitoring (TDM) and pharmacokinetic studies. After on-line solid phase extraction cannabidiol, 7-hydroxy-cannabidiol and the internal standard cannabidiol-d3 are separated on a monolithic C18 column under gradient conditions. Calibration curves are linear within the validated concentration range (10-1,000 ng/ml for cannabidiol and 5-500 ng/ml for 7-hydroxy-cannabidiol). The method is accurate (intraday and interday accuracy within 94-112% for cannabidiol, 91-109% for 7-hydroxy-cannabidiol), precise (intraday and interday precision <11.6% for cannabidiol and <11.7% for 7- hydroxy-cannabidiol) and sensitive, with a LOQ of 2.5 ng/ml for cannabidiol and 5 ng/ml for 7-hydroxy-cannabidiol. The stability of the analytes was confirmed under different storage conditions. Extraction recoveries were in the range of 81-129% for cannabidiol and 100-113% for 7-hydroxy-cannabidiol. The applicability of the method to TDM was demonstrated by analysis of human serum and saliva samples obtained from patients with epilepsy treated with cannabidiol.

Does screening for adverse effects improve health outcomes in epilepsy? A randomized trial.

OBJECTIVE: To determine whether systematic screening for adverse effects of antiepileptic drugs (AEDs) reduces toxicity burden and improves health-related quality of life in patients with epilepsy. METHODS: Consecutive patients with uncontrolled seizures aged ≥16 years and a high Adverse Event Profile (AEP) score were randomized to 2 groups and followed up for 18 months at 11 referral centers. AEP scores were made available to treating physicians at all visits in the intervention group, but not in the control group. Co-primary endpoints were changes in AEP scores and Quality of Life Inventory for Epilepsy-31 (QOLIE-31) scores. RESULTS: Of 809 enrolled patients able to complete the AEP questionnaire, 222 had AEP scores ≥45 and were randomized to the intervention (n = 111) or control group (n = 111). A total of 206 patients completed the 18-month follow-up. Compared with baseline, AEP scores decreased on average by 7.2% at 6 months, 12.1% at 12 months, and 13.8% at 18 months in the intervention group (p < 0.0001), and by 7.7% at 6 months, 9.2% at 12 months, and 12.0% at 18 months in controls (p < 0.0001). QOLIE-31 scores also improved from baseline to final visit, with a mean 20.7% increase in the intervention group and a mean 24.9% increase in the control group (p < 0.0001). However, there were no statistically significant differences in outcomes between groups for the 2 co-primary variables. CONCLUSIONS: Contrary to findings from a previous study, systematic screening for adverse effects of AEDs using AEP scores did not lead to a reduced burden of toxicity over usual physician treatment. ITALIAN MEDICINES AGENCY AIFA IDENTIFIER: FARM52K2WM_003. CLINICALTRIALSGOV IDENTIFIER: NCT03939507 (registered retrospectively in 2019; the study was conducted during the 2006-2009 period and registration of clinical trials was not a widely established practice when this study was initiated). CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that the additional collection of formal questionnaires regarding adverse effects of AEDs does not reduce toxicity burden over usual physician treatment.

Relationship between saliva and plasma rufinamide concentrations in patients with epilepsy.

The assay of saliva samples provides a valuable alternative to the use of blood samples for therapeutic drug monitoring (TDM), at least for certain categories of patients. To determine the feasibility of using saliva sampling for the TDM of rufinamide, we compared rufinamide concentrations in paired samples of saliva and plasma collected from 26 patients with epilepsy at steady state. Within-patient relationships between plasma rufinamide concentrations and dose, and the influence of comedication were also investigated. Assay results in the two tested fluids showed a good correlation (r2  = .78, P < .0001), but concentrations in saliva were moderately lower than those in plasma (mean saliva to plasma ratio = 0.7 ± 0.2). In eight patients evaluated at three different dose levels, plasma rufinamide concentrations increased linearly with increasing dose. Patients receiving valproic acid comedication had higher dose-normalized plasma rufinamide levels than patients comedicated with drugs devoid of strong enzyme-inducing or enzyme-inhibiting activity. Overall, these findings indicate that use of saliva represents a feasible option for the application of TDM in patients treated with rufinamide. Because rufinamide concentrations are lower in saliva than in plasma, a correction factor is needed if measurements made in saliva are used as a surrogate for plasma concentrations.

Psychosocial impact of sport activity in neuromuscular disorders.

Previous studies demonstrated the benefits of motor exercise and physical activity in neuromuscular disorders. However, very few papers assessed the effects of sport practise. The aim of this multicentre study was to assess the impact of sport activity on self-esteem and emotional regulation in a cohort of athletes with neuromuscular disorders. The 38 patients with Duchenne, Becker or other types of muscular dystrophy or spinal muscular atrophy practising sport (aged 13-49 years) and 39 age-, gender-, disability- and disease-matched patients not practising sport were enrolled. Testing procedures to assess self-esteem, anxiety and depression disorder, personality trait and quality of life (QoL) were used. Patients practising sport had a significantly higher self-esteem, lower level of depression, greater social own identity and adherence and QoL. Frequency of sport activity may represent a complementary therapy in neuromuscular disorders to improve mental and social well-being.

Determination of Perampanel in Dried Plasma Spots: Applicability to Therapeutic Drug Monitoring.

BACKGROUND: Although therapeutic drug monitoring of antiepileptic drugs is typically based on the analysis of plasma samples, alternative matrices, such as dried plasma spots (DPSs), may offer specific advantages. The aims of this work were to (1) develop and validate a bioanalytical method for the quantitative determination of the second-generation antiepileptic drug perampanel in DPSs; (2) assess short- and long-term stability of perampanel in DPSs; and (3) test the clinical applicability of the developed method. METHODS: Two hundred microliters of plasma were dispensed on a glass paper filter and dried. Glass paper filter discs were then inserted into clean tubes. After addition of the internal standard (ie, promethazine), the analytes were extracted with 5-mL methanol, dried at room temperature (23 ± 2°C), and reconstituted. Separation and quantification were achieved on 2 serial reverse-phase monolithic columns connected to an UV detector (λ = 320 nm). RESULTS: Calibration curves were linear in the validated concentration range (25-1000 ng/mL). Intraday and interday accuracy were in the range of 99.2%-111.4%, whereas intraday and interday precision (coefficient of variation) ranged from 2.8% to 8.6%. The lowest limit of quantitation was 25 ng/mL. The stability of the analyte in DPSs was assessed and confirmed under different storage conditions. Perampanel concentrations estimated in DPS samples from patients receiving therapeutic doses were equivalent to those measured in plasma samples. CONCLUSIONS: This simple method enables the quantitation of perampanel in DPSs with adequate accuracy, precision, specificity, and sensitivity. The short- and long-term stabilities of perampanel in DPSs are highly beneficial for sample shipment or storage at ambient temperature. Moreover, DPSs decreases the costs associated with storage and transportation compared with conventional wet samples.

A simple and rapid HPLC-UV method for the determination of retigabine in human plasma.

A simple and rapid high-performance liquid chromatographic method with ultraviolet detection was developed for the quantitative determination of retigabine, known also as ezogabine, in human plasma. The assay uses a simple solid-phase extraction for sample preparation and direct injection of the extract into the chromatograph. Flupirtine is used as an internal standard. Chromatographic separation is achieved on a C18 Chromolith column (Chromolith Performance, 100 × 4.6 mm i.d.), using as mobile phase water/acetonitrile/methanol (72:18:10 v/v/v) mixed with 0.1% of 85% phosphoric acid. Isocratic elution is conducted at a flow rate of 1.5 mL min-1 . The total duration of a chromatographic run is 7 min. Calibration curves are linear over the 25-2000 ng mL-1 concentration range, with a limit of quantitation of 25 ng mL-1 . Other performance characteristics include high precision (intra- and inter-day coefficients of variation ≤12.6%) and high accuracy (99.7%-108.7%). The method is suitable for the investigation of concentration-response relationships in patients receiving therapeutic doses of retigabine.

Development and Validation of an HPLC-UV Assay for the Therapeutic Monitoring of the New Antiepileptic Drug Perampanel in Human Plasma.

BACKGROUND: Perampanel, a new specific non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor antagonist, has been recently approved in the United States and the European Union for the adjunctive treatment of focal seizures and primary generalized tonic-clonic seizures associated with idiopathic generalized epilepsy. A positive relationship between plasma perampanel concentration and improvement in seizure control has been identified in regulatory trials, suggesting that therapeutic drug monitoring could be useful in optimizing clinical response in patients with epilepsy treated with perampanel. The development of a simple and broadly applicable method for measuring plasma perampanel concentrations is desirable to permit the use of TDM for this drug in clinical practice. METHODS: A high-performance liquid chromatographic method with ultraviolet detection for the quantitative determination of perampanel in small aliquots of human plasma (200 µL) has been developed and validated. Sample preparation involves a simple precipitation step followed by solvent evaporation. High-performance liquid chromatographic separation is achieved on 2 reverse-phase monolithic columns in sequence connected to an ultraviolet detector (320 nm), using as mobile phase water/acetonitrile (60:40 vol/vol) mixed with 1 mL/L phosphoric acid, at a flow rate of 1.5 mL/min. Promethazine hydrochloride is used as internal standard. RESULTS: Calibration curves were linear over a perampanel concentration range of 25-1000 ng/mL, with correlation coefficients equal or greater than 0.998 ± 0.001 and a limit of quantitation set at 25 ng/mL. Intra- and inter-day coefficients of variation did not exceed 7.4%, and the accuracy ranged from 96.4% to 113.3%. No interference was observed from commonly coprescribed drugs. CONCLUSIONS: The present assay is simple, specific, and cost effective with performance characteristics suitable for TDM use.

Zonisamide in the management of epilepsy in the elderly.

Zonisamide (ZNS), a second-generation antiepileptic drug, indicated as add-on treatment of focal epilepsy, has been recently approved as monotherapy for the treatment of partial seizures in adults affected by newly diagnosed epilepsy in Europe. Evidence on the efficacy and tolerability of antiepileptic drugs in the elderly is still lacking as these patients are frequently excluded from clinical trials. Here, a comprehensive overview of available data regarding the use of ZNS in the treatment of epilepsy in elderly people is provided. In a pooled analysis conducted in patients aged ≥65 years, no new/unexpected safety findings have emerged. Few data from uncontrolled investigations suggest that ZNS may be effective and well tolerated when administered as monotherapy or adjunctive antiepileptic treatment in the elderly. However, evidence from these observational studies is less than satisfactory, and randomized controlled trials focused on these patients are still needed.

Comprehensive educational plan for patients with epilepsy and comorbidity (EDU-COM): a pragmatic randomised trial.

BACKGROUND: The impact of educational strategies in the management of adverse treatment effects and drug interactions in adult patients with epilepsy with comorbidities remains undetermined. OBJECTIVE: The EDU-COM study is a randomised, pragmatic trial investigating the effect of a patient-tailored educational plan in patients with epilepsy with comorbidity. METHODS: 174 adult patients with epilepsy with chronic comorbidities, multiple-drug therapy and reporting at least one adverse treatment effect and/or drug interaction at study entry were randomly assigned to the educational plan or usual care. The primary endpoint was the number of patients becoming free from adverse treatment events and/or drug interactions after a 6-month follow-up. The number of adverse treatment events and drug interactions, health-related quality of life (HRQOL) summary score changes and the monetary costs of medical contacts and drugs were assessed as secondary outcomes. RESULTS: The primary endpoint was met by 44.0% of patients receiving the educational plan versus 28.9% of those on usual care (p=0.0399). The control group reported a significantly higher risk not to meet successfully the primary endpoint at the end of the study: OR (95% CI) of 2.29 (1.03 to 5.09). A separate analysis on drug adverse effects and drug interactions showed that the latter were more sensitive to the effect of educational treatment. Quality of life and costs were not significantly different in the two groups. CONCLUSIONS: A patient-tailored educational strategy is effective in reducing drug-related problems (particularly drug interactions) in epilepsy patients with chronic comorbidities, without adding significant monetary costs. Registered at ClinicalTrials.gov, identifier NCT01804322, (http://www.clinicaltrials.gov).

Novel frontiers in epilepsy treatments: preventing epileptogenesis by targeting inflammation.

Currently available epilepsy drugs only affect the symptoms (seizures), and there is a need for innovative treatments that target the underlying disease. Increasing evidence points to inflammation as a potentially important mechanism in epileptogenesis. In the last decade, a new generation of etiologically realistic syndrome-specific experimental models have been developed, which are expected to capture the epileptogenic mechanisms operating in corresponding patient populations, and to exhibit similar treatment responsiveness. Recently, an intervention known to have broad-ranging anti-inflammatory effects (selective brain cooling) has been found to prevent the development of spontaneously occurring seizures in an etiologically realistic rat model of post-traumatic epilepsy. Several drugs used clinically for other indications also have the potential for inhibiting inflammation, and should be investigated for antiepileptogenic activity in these models. If results of such studies are positive, these compounds could rapidly enter Phase III trials in patients at high risk of developing epilepsy.

Determinants of health-related quality of life in pharmacoresistant epilepsy: results from a large multicenter study of consecutively enrolled patients using validated quantitative assessments.

PURPOSE: To evaluate the relative contribution of demographic and epilepsy-related variables, depressive symptoms, and adverse effects (AEs) of antiepileptic drugs (AEDs) to health-related quality of life (HRQOL) in adults with pharmacoresistant epilepsy. METHODS: Individuals with epilepsy whose seizures failed to respond to at least one AED were enrolled consecutively at 11 tertiary referral centers. HRQOL was assessed by the Quality of Life in Epilepsy Inventory-31 (QOLIE-31), AEs by the Adverse Event Profile (AEP), and depressive symptoms by the Beck Depression Inventory-II (BDI-II). Multivariate linear regression models were used to identify variables associated with QOLIE-31 total score and subscale scores. KEY FINDINGS: Of 933 enrolled individuals aged 16 years or older, 809 (87%) were able to complete the self-assessment instruments and were included in the analysis. Overall, 61% of the variance in QOLIE-31 scores was explained by the final model. The strongest predictors of HRQOL were AEP total scores (ß = -0.451, p < 0.001) and BDI-II scores (ß = -0.398, p < 0.001). These factors were also the strongest predictors of scores in each of the seven QOLIE-31 subscales. Other predictors of HRQOL were age (ß = -0.060, p = 0.008), lack of a driving license (ß = -0.053, p = 0.018), pharmacoresistance grade, with higher HRQOL in individuals who had failed only one AED (ß = 0.066, p = 0.004), and location of the enrolling center. Epilepsy-related variables (seizure frequency, occurrence of tonic-clonic seizures, age of epilepsy onset, disease duration) and number of AEDs had no significant predictive value on HRQOL. The AEP total score was the strongest negative predictor of HRQOL in the subgroup of 362 patients without depressive symptoms (BDI-II score <10), but even in this subgroup the BDI-II score was retained as a significant predictor. SIGNIFICANCE: In individuals with pharmacoresistant epilepsy, AEs of medication and depressive symptoms are far more important determinants of HRQOL than seizures themselves. When seizure freedom cannot be achieved, addressing depressive comorbidity and reducing the burden of AED toxicity is likely to be far more beneficial than interventions aimed at reducing the frequency of seizures.

Novel medications for epilepsy.

Despite the introduction of many second-generation antiepileptic drugs (AEDs) in the last 2 decades, the proportion of individuals with pharmacoresistant epilepsy has not been reduced substantially compared with the late 1960s. All currently available AEDs also have limitations in terms of adverse effects and susceptibility to be involved in clinically important drug-drug interactions. Therefore, the search for potentially more effective and better tolerated agents is continuing. This article reviews the pharmacological and clinical profile of the latest compounds to receive marketing authorization. Since the beginning of 2008, three novel AEDs, lacosamide, eslicarbazepine acetate and retigabine (also known as ezogabine), have become commercially available in Europe, with lacosamide and retigabine also being licensed in the US. All three agents are indicated for the adjunctive treatment of focal seizures in adults. Eslicarbazepine acetate is a produg for eslicarbazepine, which acts by blocking voltage-dependent sodium channels. Lacosamide enhances the slow inactivation phase of voltage-dependent sodium channels, and retigabine potentiates neuronal M-currents by opening Kv 7.2-7.5 potassium channels. All three agents, which are well absorbed from the gastrointestinal tract, exhibit linear pharmacokinetics. Lacosamide is also available as an intravenous formulation intended as replacement therapy for patients temporarily unable to take oral medications. All three drugs are eliminated partly unchanged in urine and partly by biotransformation through glucuronide conjugation (eslicarbazepine, retigabine), N-acetylation (retigabine) and oxidative demethylation (lacosamide). The half-life is in the order of 8-20 hours for eslicarbazepine, 12-16 hours for lacosamide and 6-10 hours for retigabine. Based on the limited information available to date, the ability of these agents to cause pharmacokinetic drug interactions appears to be relatively modest, although eslicarbazepine can cause a significant decrease in the blood levels of ethinylestradiol, levonorgestrel and simvastatin. The approved effective dose ranges are 200-400 mg/day in two divided doses for lacosamide, 800-1200 mg/day once daily for eslicarbazepine acetate, and 600-1200 mg/day in three divided doses for retigabine. In phase III, randomized, double-blind, adjunctive therapy trials, responder rates (proportion of patients with ≥50% reduction in seizure frequency vs baseline) at the highest approved dose were comparable for the three drugs (eslicarbazepine acetate: 37-43% vs 13-20% for placebo; lacosamide: 38-41% vs 18-26% for placebo; retigabine: 33-44% vs 16-18% for placebo). The adverse events most commonly reported with active treatment compared with placebo included dizziness, diplopia and nausea for lacosamide; dizziness, somnolence and nausea for eslicarbazepine acetate; and dizziness, somnolence and fatigue for retigabine. The role of these agents in the treatment algorithm will be increasingly defined as clinical experience accumulates. At present, their use is largely restricted to the adjunctive treatment of focal seizures, with or without secondary generalization, in adults with epilepsy who failed to achieve seizure freedom after having tried two or more first-line agents.

Development and validation of an HPLC-UV detection assay for the determination of rufinamide in human plasma and saliva.

The development of a simple and rapid high-performance liquid chromatography (HPLC) method for the determination of the new antiepileptic drug rufinamide (RFN) in human plasma and saliva is reported. Samples (250 µl) are alkalinized with ammonium hydroxide (pH 9.25) and extracted with dichloromethane using metoclopramide as internal standard. Separation is achieved with a Spherisorb silica column (250 × 4.6 mm i.d., 5 µm) at 30 °C using as mobile phase a solution of methanol/dichloromethane/n-hexane 10/25/65 (vol/vol/vol) mixed with 6 ml ammonium hydroxide. The instrument used was a Shimadzu LC-10Av chromatograph and flow rate was 1.5 ml min(-1), with a LaChrom L-7400 UV detector set at 230 nm. Calibration curves are linear [r(2) = 0.998 ± 0.002 for plasma (n = 10) and r(2) = 0.999 ± 0.001 for saliva (n = 9)] over the range of 0.25-20.0 µg ml(-1), with a limit of quantification at 0.25 µg ml(-1). Precision and accuracy are within current acceptability standards. The assay is suitable for pharmacokinetic studies in humans and for therapeutic drug monitoring.

A multicenter, randomized, placebo-controlled trial of levetiracetam in children and adolescents with newly diagnosed absence epilepsy.

PURPOSE: To evaluate the potential efficacy of levetiracetam as an antiabsence agent in children and adolescents with newly diagnosed childhood or juvenile absence epilepsy. METHODS: Patients were randomized in a 2:1 ratio to receive de novo monotherapy with levetiracetam (up to 30 mg/kg/day) or placebo for 2 weeks under double-blind conditions. Responder status (primary end point) was defined as freedom from clinical seizures on days 13 and 14 and from electroencephalographic (EEG) seizures during a standard EEG recording with hyperventilation and intermittent photic stimulation on day 14. The double-blind phase was followed by an open-label follow-up. KEY FINDINGS: Nine of 38 patients (23.7%) were responders in the levetiracetam group, compared with one of 21 (4.8%) in the placebo group (p = 0.08). Seven of 38 patients (18.4%) were free from clinical and EEG seizures during the last 4 days of the trial (including 24-h EEG monitoring on day 14) compared with none of the patients treated with placebo (p = 0.04). Seventeen patients remained seizure-free on levetiracetam after 1 year follow-up. Of the 41 patients who discontinued levetiracetam due to lack of efficacy (n = 39) or adverse events (n = 2), 34 became seizure-free on other treatments. SIGNIFICANCE: Although superiority to placebo just failed to reach statistical significance for the primary end point, the overall findings are consistent with levetiracetam having modest efficacy against absence seizures. Further controlled trials exploring larger doses and an active comparator are required to determine the role of levetiracetam in the treatment of absence epilepsy.

Patterns of prescription of antiepileptic drugs in patients with refractory epilepsy at tertiary referral centres in Italy.

PURPOSE: To evaluate the pattern of prescription of antiepileptic drugs (AEDs) and other medications in a representative population of patients with refractory epilepsy attending tertiary referral centres in Italy. METHODS: Descriptive analysis of data obtained at baseline from 933 adults and 191 children with refractory epilepsy enrolled consecutively in an observational study at 11 tertiary referral centres in Italy. Multivariate logistic regression analysis was used to assess predictors of utilization of the most commonly prescribed AEDs. RESULTS: Polytherapy was used in 79% of adults and 75% of children, with over one-third of adults and children being prescribed ≥3 AEDs. In adults, the most commonly used AEDs were levetiracetam (35%), carbamazepine (34%) and lamotrigine (30%). In children, valproic acid was by far the most commonly used AED (46%), followed by carbamazepine (27%), topiramate (21%), and phenobarbital (20%). The most common AED in partial epilepsy was carbamazepine (331 out of 893 patients, 37%), followed by levetiracetam (33%) and lamotrigine (26%). In generalized or undetermined epilepsies, the AEDs most commonly used were valproic acid (139 out of 223 patients, 62%), lamotrigine (33%) and levetiracetam (28%). Second generation AEDs were prescribed in 81% of adults and 54% of children. Comedications used for indications other than epilepsy were used by 32% of adults and 17% of children. CONCLUSIONS: Prescription patterns were consistent with current evidence about the spectrum of efficacy of individual AEDs in different epilepsy syndromes. The high prevalence of polytherapy, including combinations of three or more AEDs, is a cause for concern.

Characteristics of a large population of patients with refractory epilepsy attending tertiary referral centers in Italy.

The characteristics of 1,124 consecutive adults and children with refractory epilepsy attending 11 tertiary referral centers in Italy were investigated at enrollment into a prospective observational study. Among 933 adults (age 16-86 years), the most common syndromes were symptomatic (43.7%) and cryptogenic (39.0%) focal epilepsies, followed by idiopathic (8.1%) and cryptogenic/symptomatic generalized (6.2%) epilepsies. The most common syndrome among 191 children was symptomatic focal epilepsy (35.1%), followed by cryptogenic focal (18.8%), cryptogenic/symptomatic generalized (18.3%), undetermined whether focal or generalized (16.8%), and idiopathic generalized (7.3%). Primarily and secondarily generalized tonic-clonic seizures were reported in 27.8% of adults and 16.8% of children. The most commonly reported etiologies were mesial temporal sclerosis (8.0%) and disorders of cortical development (6.2%) in adults, and disorders of cortical development (14.7%) and nonprogressive encephalopathies (6.8%) in children. More than three-fourths of subjects in both age groups were on antiepileptic drug (AED) polytherapy.

A novel enantioselective microassay for the high-performance liquid chromatography determination of oxcarbazepine and its active metabolite monohydroxycarbazepine in human plasma.

A simple and innovative assay is described that allows the determination of the antiepileptic drug oxcarbazepine and the chiral separation of the two enantiomers of its active metabolite monohydroxycarbazepine (licarbazepine). The assay requires liquid-liquid extraction of the sample (200 microL) into tert-butyl methyl ether and dichloromethane, drying of the organic phase under a nitrogen stream, reconstitution with the mobile phase, and injection in the high-performance liquid chromatography system after filtering. Separation of oxcarbazepine, R-(-)-monohydroxycarbazepine, S-(+)-monohydroxycarbazepine, and the second-step metabolite 10,11-trans-dihydroxycarbamazepine (racemate) is achieved with a Chiralcel ODR column and potassium hexafluorophosphate/acetonitrile as mobile phase. Detection is by ultraviolet absorbance at 210 nm. Standard curves are linear (r2 > or = 0.999) over the range of 0.1 to 25 microg/mL for each analyte with a limit of quantification of 0.1 microg/mL (1 ng injected) for all compounds. Within-day and between-day precision is better than 12% and within-day and between-day accuracy is between 99% and 116% for each compound. These performance characteristics are adequate for pharmacokinetic studies and for therapeutic drug monitoring. However, because the two enantiomers of monohydroxycarbazepine exhibit similar pharmacologic activity, nonenantioselective assays are likely to be more cost-effective for therapeutic drug monitoring purposes.

Stereoselective determination of vigabatrin enantiomers in human plasma by high performance liquid chromatography using UV detection.

A rapid and simple high-performance liquid chromatographic method for the determination of the R-(-)- and S-(+)-enantiomers of the antiepileptic drug vigabatrin in human plasma is described. After adding the internal standard (1-aminomethyl-cycloheptyl-acetic acid), plasma samples (200 microL) are deproteinized with acetonitrile and the supernatant is derivatized with 2,4,6 trinitrobenzene sulfonic acid (TNBSA). Separation is achieved on a reversed-phase cellulose-based chiral column (Chiralcel-ODR, 250 mm x 4.6 mm i.d.) using 0.05 M potassium hexafluorophosphate (pH 4.5)/acetonitrile/ethanol (50:40:10 vol/vol/vol) as mobile phase at a flow-rate of 0.9 mL/min. Chromatographic selectivity is improved by concentrating the derivatives on High Performance Extraction Disk Cartridges prior to injection. Detection is at 340 nm. Calibration curves are linear (r(2)> or =0.999) over the range of 0.5-40 microg/mL for each enantiomer, with a limit of quantification of 0.5 microg/mL for both analytes. The assay is suitable for therapeutic drug monitoring and for single-dose pharmacokinetic studies in man.