Search

Transcranial magnetic stimulation combined with electroencephalography is a powerful tool to probe human cortical excitability. The EEG response to TMS stimulation is altered by drugs active in the brain, with characteristic "fingerprints" obtained for drugs of known mechanisms of action. However, the extraction of specific features related to drug effects is not always straightforward as the complex TMS-EEG induced response profile is multi-dimensional. Analytical approaches can rely on a-priori assumptions within each dimension or on the implementation of cluster-based permutations which do not require preselection of specific limits but may be problematic when several experimental conditions are tested. We here propose an alternative data-driven approach based on PARAFAC tensor decomposition, which provides a parsimonious description of the main profiles underlying the multidimensional data. We validated reliability of PARAFAC on TMS-induced oscillations before extracting the features of two common anti-epileptic drugs (levetiracetam and lamotrigine) in an integrated manner. PARAFAC revealed an effect of both drugs, significantly suppressing oscillations in the alpha range in the occipital region. Further, this effect was stronger under the intake of levetiracetam. This study demonstrates, for the first time, that PARAFAC can easily disentangle the effects of subject, drug condition, frequency, time and space in TMS-induced oscillations.

Individualized dosing is often required in pharmacotherapy, particularly for pediatric and geriatric patients and adjustment of drugs that demand dose adaptation. This study aimed to evaluate critical quality attributes (CQAs) of doses obtained by distinct approaches for achieving individual dosing. Approaches were evaluated as follows: subdivision of tablets by splitter and hand (haloperidol) and delivery by plastic dropper bottle (haloperidol), glass dropper bottle (clonazepam), dosing cup (sodium valproate), and dosing syringe (carbamazepine), including brand name, generic, and similar marketed products. Measuring devices were packaged with their respective product. Drug content uniformity was assessed to each substance according to pharmacopeial methods. Tablets subdivided by splitter had the poorest performance among all approaches, in which doses ranged around 60% of the labeled amount (Acceptance Value = 58.1 and RSD = 23.2%). The greatest performances were observed for the dosing syringe which fulfilled all the requirements for dose precision and for the glass dropper bottle. There were significant differences in dose delivery between manufacturers of the same medicine when measuring the same volume or number of drops. High drug content variability is extremely harmful to pharmacotherapy and may result in therapeutic failure or toxicity. It is crucial that measuring devices and scoring of tablets be checked for functionality and standardized for different manufacturers of the same medicine. Part of the approaches for achieving individual dosing did not meet the quality needs for drug content and uniformity. Yet, our findings show that more accurate and precise dosing can be accessed when using the dosing syringe and glass dropper bottle.

Background: Effective acute pain management following injury is critical to improve short-and long-term patient outcomes. Analgesics can effectively reduce pain intensity, yet half of injury patients report moderate to severe pain during hospitalization., Purpose: The primary aim of this study was to identify the analgesic, different analgesic combinations, or analgesic and adjuvant analgesic combination that generated the largest percent change from pre- to post-analgesic pain score., Design: This was a descriptive retrospective cohort study of 129 adults admitted with lower extremity fractures to a trauma center., Methods: Name, dose, and frequency of analgesics and adjuvant analgesics administered from admission to discharge were collected from medical records. Percent change was calculated from pain scores documented on the 0-10 numeric rating scale., Results: The analgesic with largest percent change from pre- to post-administration pain score was hydromorphone 2 mg IV (53%) for the emergency department and morphine 4 mg IV (54%) for the in-patient unit. All analgesics administered in the emergency department and ∼50% administered on the in-patient unit produced a minimal (15%) decrease in pain score., Conclusions: This study revealed that few analgesics administered in the emergency department and the in-patient unit to patients with lower extremity fractures provide adequate pain relief. In the emergency department, all analgesics administered resulted in at least minimal improvement of pain. On the in-patient unit 13 analgesic doses resulted at least minimal improvement in pain while nine doses did not even reach 20% change in pain. Findings from this study can be used guide the treatment of fracture pain in the hospital., (Copyright © 2019 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.)

People who are 60 years old and older have the highest incidence of developing new-onset epilepsy. The increase of the ageing population has resulted in a greater number of patients with new-onset epilepsy or at risk of developing the condition. Previously published review articles regarding epilepsy in older patients have had a broad focus, including people who were diagnosed with epilepsy in their childhood or middle age. The present review focuses on the causes, treatment, prognosis and psychosocial impact of new-onset epilepsy in people aged ≥60 years. Following a search of the medical electronic databases and relevant references, we identified 22 studies overall that met the inclusion criteria. Only four randomized clinical trials (RCTs) were identified that compared different antiepileptic drug treatments in this population, demonstrating that newer-generation antiepileptic drugs (e.g. lamotrigine and levetiracetam) were generally better tolerated. One uncontrolled study provided promising evidence of good outcomes and safety for surgical resection as a treatment for people with uncontrolled seizures. Five studies reported that people ≥60 years with new-onset epilepsy have significant cognitive impairments (e.g. memory loss) and psychological issues including depression, anxiety and fatigue. We found that there is limited evidence to guide treatment in people with Alzheimer's disease and epilepsy. The specific features of new-onset epilepsy in this target population significantly influences the choice of treatment. Cognitive and psychiatric screening before treatment may be useful for management. Two studies with proposed guidelines were identified but no formal clinical practice guidelines exist for this special population to assist with appropriate management. There is a need for more RCTs that investigate effective treatments with limited side effects. More research studies on the psychosocial effects of new-onset epilepsy, and long-term outcomes, for people aged ≥60 years are also required., (© 2018 The British Pharmacological Society.)

Objective: Epilepsy is a major public health issue in low- and middle-income countries, where the availability and accessibility of quality treatment remain important issues, the severity of which may be aggravated by poor quality antiepileptic drugs (AEDs). The primary objective of this study was to measure the quality of AEDs in rural and urban areas in 3 African countries., Methods: This cross-sectional study was carried out in Gabon, Kenya, and Madagascar. Both official and unofficial supply chains in urban and rural areas were investigated. Samples of oral AEDs were collected in areas where a patient could buy or obtain them. Pharmacological analytical procedures and Medicine Quality Assessment Reporting Guidelines were used to assess quality., Results: In total, 102 batches, representing 3782 units of AEDs, were sampled. Overall, 32.3% of the tablets were of poor quality, but no significant difference was observed across sites: 26.5% in Gabon, 37.0% in Kenya, and 34.1% in Madagascar (P = .7). The highest proportions of substandard medications were found in the carbamazepine (38.7%; 95% confidence interval [CI] 21.8-57.8) and phenytoin (83.3%; 95% CI 35.8-99.5) batches, which were mainly flawed by their failure to dissolve. Sodium valproate was the AED with the poorest quality (32.1%; 95% CI 15.8-42.3). The phenobarbital (94.1%; 95% CI 80.3-99.2) and diazepam (100.0%) batches were of better quality. The prevalence of substandard quality medications increased in samples supplied by public facilities (odds ratio [OR] 9.9; 95% CI 1.2-84.1; P < .04) and manufacturers located in China (OR 119.8; 95% CI 8.7-1651.9; P < .001). The prevalence of AEDs of bad quality increased when they were stored improperly (OR 5.4; 95% CI 1.2-24.1; P < .03)., Significance: No counterfeiting was observed. However, inadequate AED storage conditions are likely to lead to ineffective and possibly dangerous AEDs, even when good-quality AEDs are initially imported., (Wiley Periodicals, Inc. © 2018 International League Against Epilepsy.)

Background: Parenteral antiepileptic drugs are frequently used in critically ill patients for seizure control therapy or prevention. Many of these patients require additional parenteral nutrition (PN). Therefore, a parallel infusion of the frequently used antiepileptic drug levetiracetam (LEV) is interesting in terms of the restricted i.v. lines (e.g., neonates). The potential interactions of the complex PN admixture with the drug product and the appropriate admixing of a drug at effective dosages require physicochemical lab assessments to obtain specific and reliable pharmaceutical documentation for the intended admixing., Aim: To assess the of compatibility and stability of LEV, a neutral and hydrophilic drug, in commercial all-in-one (AiO) PN admixtures using simple validated tests to provide necessary data in a timely manner and to allow convenient, documented and safe treatment with PN as the drug vehicle., Methods: Different concentrations of LEV were injected into two different AiO PN admixtures with no further additives. Stability and compatibility tests for the drug and the PN admixtures were performed over seven days at +4°C, +23±1°C and +37°C without light protection. Stability and sample characteristics were observed by visual inspection and the validated light microscope method. Moreover, the pH level of the admixture was checked, as were the concentrations of LEV over time in the PN admixtures, using an established LC-MS/MS method., Results: The stability controls of LEV at different temperatures were within absolute ±20% of the theoretical value in a concentration range of 98.91-117.84% of the initial value. No changes in pH occurred (5.55±0.04) and no microscopic out of specification data or visual changes were observed. The mean value of the largest lipid droplet in each visual field over seven days was 2.4±0.08μm, comparable to that of the drug-free AiO admixture. Samples stored at +37°C showed yellowish discolorations after 96h of storage., Conclusion: LEV showed compatibility and stability over seven days in the selected PN admixtures, and the described methods represented a valuable and timely approach to determine the stability and compatibility of the highly hydrophilic, not dissociated LEV in AiO admixtures under conditions of use. Further studies with clinically relevant and representative examples of physicochemically different drug classes are needed., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Aim: Recently, polytherapy regimen has been introduced for the treatment of epileptic patients for better seizure control with lesser side effects and better control of multiple seizure types., Methodology: A simple, sensitive and highly specific reversed-phase HPLC method was developed for simultaneous determination of four antiepileptic drugs (AEDs), levetiracetam, lamotrigine, oxcarbazepine and carbamazepine, in real human plasma without interference from endogenous components of plasma., Conclusion: The method was proved to be linear in the range of 0.5-50 µg/ml for all drugs. It was successfully applied for clinical PK study of the AEDs in healthy volunteers following single administration. Also, this method was applied for simultaneous determination of the studied drugs in volunteers' plasma receiving synergistic binary combinations from the four AEDs when used as add-on therapy. The good precision and selectivity of the developed method allow it to be used for routine therapeutic drug monitoring of such drugs as a useful tool in epilepsy management.

Purpose: To examine the implementation of the clinical practice guideline "first epileptic seizure and epilepsy in adulthood" published in 2008 to patients with newly diagnosed epilepsy between 2008 and 2014., Method: This retrospective, population-based analysis was performed on patient data of 4.1 million insurants from the German statutory health insurance. Prevalent and incident cases in adults were identified based on ICD-10 codes, using a hierarchical diagnosis selection algorithm. The first anticonvulsive agent in a newly diagnosed epilepsy patient was validated against the clinical practice guideline., Results: We determined an annual crude prevalence rate in adults between 0.946% and 1.090% and incidence rates of at least 156 per 100,000. A significant increase in guideline compliant monotherapy was found in patients with a focal epilepsy syndrome, while, among patients with idiopathic generalised epilepsies, the share of guideline noncompliant monotherapy increased. Both changes are likely due to the overall increase in prescription of levetiracetam from 19.6% in 2008 to 58.9% in 2014 in all newly treated patients. Overall, the proportion of enzyme-inducing anticonvulsants fell significantly from 20.7% in 2008 to 4.3% in 2014 (p<0.001). The likelihood to receive non-enzyme-inducing antiepileptic drugs was 5.82 (95% CI 4.62-7.33) higher in 2014 than in 2008., Conclusion: Initial monotherapy for focal epilepsy is in line with current clinical practice guidelines and mainly implemented by prescription of levetiracetam. Further evaluations should address the question of whether patients treated in line with the guidelines have a favorable outcome, compared to patients not treated in line with current guidelines., (Copyright © 2016 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)

Epilepsy is one of the most common chronic neurological diseases and represents a significant burden for patients, their families and society. In more than 75 % of patients anticonvulsant therapy consists of valproate, carbamazepine, lamotrigine or levetiracetam. There is a need for polytherapy in drug-refractory patients and they suffer from negative effects on quality of life and employment that is associated with high indirect costs. To allow a comprehensive treatment in this patient group, access to new anticonvulsants with novel modes of action is needed; however, all applications for new antiepileptic drugs failed to prove added benefits during the Pharmaceutical Market Restructuring Act (AMNOG) in Germany. One of the main reasons is the mandatory definition of a standard comparative therapy. It remains unclear whether there will be studies in the future which will fulfill the requirements of the current version of AMNOG. Observational studies after approval and marketing of new antiepileptic drugs could be better alternatives to prove added benefits for individual patients in the current German healthcare system.

Valproic acid (VPA) is one of the most widely prescribed antiepileptic drugs for the treatment of epileptic seizures. Although it is well known that the doses of VPA and its plasma concentrations are highly correlated, the plasma concentrations do not correlate well with the therapeutic effects of the VPA. In this study, we developed a population-based pharmacokinetic (PK)-pharmacodynamic (PD) model to determine the optimal concentration of VPA according to the clinical characteristics of each patient. This retrospective study included 77 VPA-treated Japanese patients with epilepsy. A nonlinear mixed-effects model best represented the relationship between the trough concentrations of VPA at steady-state and an over 50% reduction in seizure frequency. The model was fitted using a logistic regression model, in which the logit function of the probability was a linear function of the predicted trough concentration of VPA. The model showed that the age, seizure locus, the sodium channel neuronal type I alpha subunit rs3812718 polymorphism and co-administration of carbamazepine, clonazepam, phenytoin or topiramate were associated with an over 50% reduction in the seizure frequency. We plotted the receiver operating characteristic (ROC) curve for the logit(Pr) value of the model and the presence or absence of a more than 50% reduction in seizure frequency, and the areas under the curves with the 95% confidence interval from the ROC curve were 0.823 with 0.793-0.853. A logit(Pr) value of 0.1 was considered the optimal cut-off point (sensitivity = 71.8% and specificity = 80.4%), and we calculated the optimal trough concentration of VPA for each patient. Such parameters may be useful to determine the recommended therapeutic concentration of VPA for each patient, and the procedure may contribute to the further development of personalized pharmacological therapy for epilepsy.

Purpose: The literature on the efficacy and safety of rufinamide in childhood-onset epilepsy syndromes currently includes approximately 600 paediatric patients. This paper summarizes the views of a panel of experienced European epileptologists with regard to the current role of rufinamide in the treatment of childhood epilepsies., Results: Rufinamide is effective in decreasing the seizure frequency in the Lennox-Gastaut syndrome (LGS), especially tonic and atonic seizures. It might consequently be preferred to other drugs as a second-line treatment for LGS when drop-attacks are frequent. The mean responder rate in the published studies is 38% with seizure freedom achieved in 2.4% of patients. Rufinamide has shown some efficacy in epileptic encephalopathies other than LGS. It can be also effective as adjunctive therapy in children and adolescents with drug-resistant partial seizures. The available data suggest that rufinamide has an acceptable risk/benefit ratio with quite a low risk of aggravating seizures. Common adverse effects (somnolence, nausea and vomiting) are usually mild and self-limiting; they are more frequently observed during titration than in the maintenance phase, suggesting that low escalation rates might be associated with fewer adverse effects. Rufinamide appears to have a favourable cognitive profile compared with other antiepileptic drugs., Conclusion: Rufinamide is only approved for adjunctive treatment of seizures associated with LGS in children 4 years of age and older. There are very few data on rufinamide treatment at the onset of LGS or early in the course of the disorder; whether early treatment will improve outcome has yet to be determined., (Copyright © 2014 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Retigabine was the first neuronal potassium channel opener for the treatment of epilepsy. During the manufacture of retigabine, two unknown impurities were present in laboratory batches in the range of 0.05-0.1% based upon HPLC analysis. These unknown impurities were obtained from the enriched reaction mother liquor by column chromatography. The structure of these process-related impurities were elucidated using FT-IR, (1)H NMR, (13)C NMR, 2D NMR (HSQC, HMBC, NOESY) and MS spectral data. Based on the complete spectral analysis and knowledge of the synthetic route of retigabine, these two new impurities were designated as ethyl 4-fluorobenzyl(2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)carbamate (impurity-II) and diethyl 5-((ethoxycarbonyl)(4-fluorobenzyl)amino)-2-oxo-1H-benzo[d]imidazole-1,3(2H)-dicarboxylate (impurity-III). Impurity identification, structure elucidation and the formation of impurities were also discussed., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Objective: To evaluate the efficacy and safety of conversion to lacosamide 400 mg/day monotherapy in adults with focal epilepsy., Methods: This historical-controlled, double-blind study (NCT00520741) enrolled patients aged 16-70 years on stable doses of 1-2 antiepileptic drugs (AEDs) and experiencing 2-40 partial-onset seizures per 28 days during the 8-week prospective Baseline. Patients were randomized to lacosamide 400 or 300 mg/day (3:1 ratio), starting at 200 mg/day and titrated over 3 weeks to randomized dose. Patients then withdrew background AEDs over 6 weeks and entered a 10-week Monotherapy Phase. The primary assessment was the Kaplan-Meier-predicted percentage of patients on 400 mg/day in the full analysis set (FAS) meeting ≥ 1 predefined seizure-related exit criterion by day 112, compared with the historical-control threshold (65.3%)., Results: Four hundred twenty-five patients were enrolled and were eligible for safety analyses (400 mg/day, n = 319; 300 mg/day, n = 106). A total of 271 (63.8%) of 425 patients completed the Lacosamide Maintenance Phase (combined AED Withdrawal and Monotherapy Phases). Among 284 patients in the 400 mg/day group in the FAS, 82 (28.9%) met ≥ 1 exit criterion; the Kaplan-Meier-predicted exit percentage at day 112 for 400 mg/day (30.0%; 95% confidence interval [CI] 24.6-35.5%) was lower than the historical control. When exit events, withdrawal due to treatment-emergent adverse events (TEAEs), and withdrawal due to lack of efficacy were summed (n = 90), the predicted exit percentage (32.3%; 95% CI 26.8-37.8%) was also lower than the historical control. Most patients receiving 400 mg/day reported some improvement on the Clinical Global Impression of Change (75.4%) and Patient Global Impression of Change (74.3%). Overall, the most common (>10%) TEAEs were dizziness (24.0%), headache (14.4%), nausea (13.4%), convulsion (11.5%), somnolence (10.4%), and fatigue (10.1%); most (74.1%) were mild-to-moderate in intensity. Seventy-two patients (16.9%) discontinued due to TEAEs. Seventeen patients (4%, all receiving 400 mg/day) experienced serious AEs., Significance: Lacosamide 400 mg/day monotherapy was effective, with a favorable safety profile in patients with focal epilepsy., (Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.)

Diabetic neuropathy is a common complication of diabetes mellitus affecting 30-50% of patients and is a major cause for increased costs, morbidity and mortality. Strict diabetes control prevents this complication and may restore neurologic deficits in the early stages. Several efforts have been undertaken to alter the natural history of this complication, including the use of aldose reductase and protein kinase-C inhibitors, as well as antioxidants. Available data so far do not support the use of aldose reductase inhibitors due to safety issues and efficacy. Protein kinase-C inhibitors have provided encouraging initial results but their development has been halted. Antioxidants, like a-lipoic acid, improve some neurological deficits and painful symptoms. There are effective and safe medications such as anticonvulsants, antidepressants and opioids for the management of patients with painful symptoms. In this revew we present standard and emerging treatment modalities for the etiologic and symptomatic treatment of diabetic neuropathy.

Background: Generic prescription drugs are bioequivalent to brand-name versions but may not have consistent color or shape, which can cause confusion and lead to interruptions in medication use. We sought to determine whether switching among different-appearing antiepileptic drugs (AEDs) is associated with increased rates of medication nonpersistence, which can have serious medical, financial, and social consequences., Methods: We designed a nested case-control study of commercially insured patients in the United States who initiated an AED. Cases were patients who became nonpersistent, defined as failure to fill a prescription within 5 days of the elapsed days supplied. Controls had no delay in refilling and were matched by sex, age, number of refills, and the presence of a seizure disorder diagnosis. We evaluated the 2 refills preceding nonpersistence and determined whether pill color and/or shape matched ("concordant") or did not match ("discordant"). We compared the odds of discordance among cases and controls using multivariate conditional logistic regression, adjusting for baseline characteristics, and drug type. We repeated our analysis among patients with a seizure diagnosis., Results: The AEDs dispensed had 37 colors and 4 shapes. A total of 11,472 patients with nonpersistence were linked to 50,050 controls. Color discordance preceded 136 cases (1.20%) but only 480 controls (0.97%) (adjusted odds ratio [OR], 1.27 [95% CI, 1.04-1.55]). Shape discordance preceded 18 cases (0.16%) and 54 controls (0.11%) (OR, 1.47 [95% CI, 0.85-2.54]). Within the seizure disorder diagnosis subgroup, the risk of nonpersistence after changes in pill color was also significantly elevated (OR, 1.53 [95%, CI 1.07-2.18])., Conclusions: Changes in pill color significantly increase the odds of nonpersistence; this may have important clinical implications. Our study supports a reconsideration of current regulatory policy that permits wide variation in the appearance of bioequivalent drugs.

Objective: To develop guidelines for selection of antiepileptic drugs (AEDs) among people with HIV/AIDS., Methods: The literature was systematically reviewed to assess the global burden of relevant comorbid entities, to determine the number of patients who potentially utilize AEDs and antiretroviral agents (ARVs), and to address AED-ARV interactions., Results and Recommendations: AED-ARV administration may be indicated in up to 55% of people taking ARVs. Patients receiving phenytoin may require a lopinavir/ritonavir dosage increase of ~50% to maintain unchanged serum concentrations (Level C). Patients receiving valproic acid may require a zidovudine dosage reduction to maintain unchanged serum zidovudine concentrations (Level C). Coadministration of valproic acid and efavirenz may not require efavirenz dosage adjustment (Level C). Patients receiving ritonavir/atazanavir may require a lamotrigine dosage increase of ∼50% to maintain unchanged lamotrigine serum concentrations (Level C). Coadministration of raltegravir/atazanavir and lamotrigine may not require lamotrigine dosage adjustment (Level C). Coadministration of raltegravir and midazolam may not require midazolam dosage adjustment (Level C). Patients may be counseled that it is unclear whether dosage adjustment is necessary when other AEDs and ARVs are combined (Level U). It may be important to avoid enzyme-inducing AEDs in people on ARV regimens that include protease inhibitors or nonnucleoside reverse transcriptase inhibitors, as pharmacokinetic interactions may result in virologic failure, which has clinical implications for disease progression and development of ARV resistance. If such regimens are required for seizure control, patients may be monitored through pharmacokinetic assessments to ensure efficacy of the ARV regimen (Level C).

Although a majority of persons with epilepsy in developing countries are diagnosed, treated, and followed up by primary care doctors, few efforts have been made to examine their understanding with respect to epilepsy management. Through a questionnaire survey, we gathered information about the epilepsy management behavior of 500 primary care doctors distributed across the south Indian state of Kerala. Very few of them ever had diagnosed focal seizures, and the majority of them overutilize EEGs, prescribe continuous antiepileptic drug (AED) prophylaxis for febrile convulsions, use relatively expensive AEDs often in combination and in suboptimal doses, and did not know about alternate management options for AED-resistant epilepsies. A substantial proportion of the current large treatment gap in epilepsy in developing countries could be minimized by educating the primary care physicians about the diagnosis of epileptic seizures, cost-effective AED treatment, and need-based referral for specialized care., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The aim of the present study was to investigate the effect of the variability of commercially available carbamazepine (CBZ) samples on the intrinsic dissolution behavior in order to recommend a strategy to maintain product quality by monitoring the variability of critical parameters of the bulk drug. Extensive physical characterization of nine anhydrous CBZ samples from three different sources and their respective dihydrates showed that the commercial anhydrous CBZ samples exhibited the same polymorphic form, but different morphology and particle size distribution which led to a variation in the kinetics of conversion from anhydrous to the dihydrate CBZ and therefore to variation in the kinetics of solubility. Disc intrinsic dissolution rate (DIDR) tests showed different intrinsic dissolution behavior of the samples, whereby the transition points of anhydrous to dihydrate conversion varied between 15 and 25 min. On the other hand, converting the anhydrous CBZ's to dihydrate eliminated the variation in intrinsic dissolution behavior. Tablets of the different CBZs and Ludipress were prepared by direct compression. The amount of CBZ dissolved after 15 min showed the same rank order as the rank order of the transition points determined by intrinsic dissolution test. Therefore, the intrinsic dissolution test with specific acceptance criteria can be a valuable and simple tool for monitoring, respectively reducing the variability of the CBZ bulk material., (Copyright 2009 Elsevier B.V. All rights reserved.)

The purpose of this research was to evaluate the quality of anti-epileptic drugs (AEDs) in a central city of South Vietnam. A cross-sectional study was conducted in all the outlets for AEDs. Out of 33 pharmacies 54% had AEDs. Where the drugs were available, 89% of the pharmacies, 10 units were purchased, choosing the cheapest ones. The information on the packaging, the galenic form and the aspect of the drug were studied. Each sample's tablet was weighted and was considered satisfactory if it was within +/-10% of the average. A HPLC method was used for dosing the active ingredient (AI), which was considered satisfactory within +/-10% of the theoretical value. Eight samples were based on carbamazepin and eight on phenytoin. None of the 16 samples collected were past their expiring date. Tablets were homogeneous in shape, dimension and color. The uniformity of weight was satisfactory but the AI results were alarming for Carbamazepin and more often for Phenytoin. Only 35% of the tablets were correctly dosed. Because of differences of sensitivities of AEDs to storage conditions, environmental factors (heat, light and humidity) could be responsible for this result. Best results were achieved in structures where storage seemed to be better. The influence of storage conditions must be further studied to confirm this conclusion.

Status epilepticus (SE) is a neurological emergency that requires prompt diagnosis and treatment, as delay is associated with a higher likelihood of poor response to treatment and worse outcome. Lorazepam has been well established as a first-line therapy. Subsequent steps are less established, and there are many reasonable options, including intravenous fosphenytoin, valproate, midazolam, propofol, and phenobarbital. If intravenous access is not immediately available, rectal diazepam or nasal or buccal midazolam should be given; this can also be used as out-of-hospital treatment to prevent or treat SE. For refractory SE, continuous intravenous midazolam and propofol, separately or in combination, are rapidly effective, with pentobarbital remaining the gold standard for prolonged cases. If a patient does not awaken after treatment, urgent electroencephalogram (EEG) should be obtained to rule out nonconvulsive seizure activity. In refractory SE, continuous EEG monitoring is required to recognize recurrence of seizure activity, as most seizures will be nonconvulsive.

Learning from one's mistakes is the best learning tool in medicine and this applies as well to epilepsy. This article is a compilation of some of the frequent mistakes that are made in the evaluation and management of patients with epilepsy. It encompasses errors in the clinical diagnosis that result in the choice of the erroneous antiepileptic drug (AED), errors in the way auxiliary tests like the electroencephalogram and magnetic resonance imaging studies are ordered, mistakes in the recognition of subclinical status epilepticus, errors in the selection of AEDs, consequences of the failure to factor in the pharmacokinetic and pharmacodynamic properties of AEDs in the choice and dosification of medication, misconceptions on the expectations of therapeutic effect of AEDs, delay in recognition of refractory epilepsy with consequent delay in a timely identification of patients whose epilepsy can be cured with surgical treatment, and mistakes in the recognition and management of comorbid psychiatric disorders. In addition to a discussion of the reasons for the errors, the article provides practical solutions.

The advent of multiple new antiepileptic drugs (AEDs) in the past 15 years has provided new options for clinicians treating patients with epilepsy, but has also created a need for guidelines in AED use. For selection of the most appropriate AED, the neurologist must know the pharmacological properties of the AEDs and has to balance their benefits and potential risks for the individual patient. A key consideration in AED selection is spectrum of efficacy for seizure types and epileptic syndrome. Other factors in AED selection include safety and tolerability, ease of use and titration rate, potential interactions, and efficacy in coexisting nonepileptic conditions. Comorbid conditions may favor or exclude the use of certain AEDs in a particular patient. Special considerations apply in specific epilepsy populations, such as women of childbearing age, children, and the elderly. This article analyzes the various factors involved in choosing an AED.

Inadequate adherence to a prescribed medication regimen, so-called noncompliance (NC), occurs in 30-50% of patients with epilepsy and is thought to be a major cause of insufficient seizure control. This article gives an overview on how NC can be diagnosed, its causes, which patient groups are at risk, and which interventions are suitable to improve or maintain compliance.

The purpose of present study was to evaluate commercial preparations of carbamazepine tablets with respect to drug release through a defined sequence of experiments using Minitab software. The compliance of products with respect to United States Pharmacopeia (USP) dissolution test and comparison of the products with respect to drug release in different dissolution conditions is reported in the present paper. The different dissolution conditions studied include dissolution medium (1% SLS in purified water, 0.1 N HCl), volume (900 and 1,000 ml), rpm (50 rpm, 75 rpm). Studies indicated that all six products complied with USP dissolution criteria. However, the extent of influence of dissolution conditions on drug release was varied among the products. Distinct dissolution profiles were observed and there was no correlation with disintegration time in certain products. The in vitro dissolution experimentation helped in identifying the discriminatory dissolution conditions and also the formulations that were unaffected with change of dissolution variables. In summary, commercial preparations of carbamazepine vary widely in their dissolution behavior in multi dissolution run experimentation. Identifying this behavior of the products was essential as an in vitro tool for screening a good and a bad formulation.

The availability of generic products of antiepileptic drugs (AEDs) has raised the following concerns: (1) Do generic AEDs work as well as brand AEDs in terms of their efficacy, safety and quality? (2) Can generic AEDs be used as substitutions for brand AEDs? and (3) Can generic products of AEDs be used interchangeably? The traditional average bioequivalence analysis addresses concern 1 but does not provide a complete adequate response to concerns 2 and 3. Drug interchangeability can be classified as drug prescribability or drug switchability. Drug prescribability refers to the situation where a patient is treated for the first time so that either a brand or a bioequivalent generic AED can be chosen. Drug switchability refers to the situation in which a brand AED is switched to a bioequivalent generic product of the same AED. The traditional average bioequivalence approach is sufficient to evaluate the prescribability of generic products, but does not ensure the switchability between prescribable formulations. The necessity of assuring switchability of two formulations can be addressed by individual bioequivalence. While the switch to generic AEDs is well tolerated by many patients and in general cost-effective, seizure control should not be sacrificed on the basis of cost alone, as the major end point in treating epilepsy with AEDs is seizure control without side effects. Until we have individual (within patient) bioequivalence data on generic AEDs and/or the tools to a priori identify the subset of patients susceptible to the generic switch, a switch of AED products in seizure-free patients is not recommended.

Key Points: (1) A large number of treatment options have shown generally moderate efficacy in the treatment of diabetic painful neuropathy.(2) Tricyclic antidepressants are the mainstay of therapy, with anticonvulsants, opioids and serotonin-noradrenaline reuptake inhibitors also having a place.(3) Head-to-head trials of current treatments are needed. Meanwhile, selection of therapeutic agents should be individualised.

Purpose: In developing countries, availability and quality of drugs are critical factors for effective management and control of epilepsy. This study investigated the availability and costs of antiepileptic drugs (AEDs), and the quality of phenobarbital in Vientiane Municipality, Lao PDR., Methods: In March 2004, we enrolled all pharmacies (categories I and II) of four central districts of Vientiane eligible to sell AEDs. Two hundred and eight pharmacies of category III (75.1% of all registered pharmacies) were excluded as the sale of AEDs was not authorized. All pharmacists were interviewed with a standard questionnaire. Whenever phenobarbital was available, a sample was purchased and assayed by liquid chromatography. Phenobarbital was defined as being of correct quality if the active substance average content corresponded to +/-15% of the indicated amount., Results: 66 pharmacies were enrolled (13 and 45 of categories I and II, respectively, and 8 hospital pharmacies). Six generics of AEDs were found (phenobarbital, phenytoin, valproic acid, clonazepam, carbamazepine, diazepam) and all pharmacies sold at least 1 AED. The 2 most widely available drugs were diazepam (5 mg) and phenobarbital (100 mg), present in 87.9 and 53.0% of the pharmacies, respectively. All 34 phenobarbital samples examined showed a correct concentration of the active compound. However, the concentration of phenobarbital 100 mg tablets produced in Lao PDR (mean concentration 94.7 mg) was significantly lower (p = 0.005) than the imported equivalent (mean concentration 99.7 mg). The direct drug costs of a yearly treatment with phenobarbital were estimated to be at least 25.2 USD., Conclusions: A variety of AEDs are present. Their availability, particularly of phenobarbital, is restricted to higher-category pharmacies and within those it is rather limited. To meet the costs of AEDs in this setting is a major challenge for people with epilepsy. However, the quality of the available phenobarbital was rather satisfactory., (Copyright (c) 2007 S. Karger AG, Basel.)

This report addresses: (1) a general update of FDA activity in areas relevant to AED development; (2) an update on issues relevant to the development of AEDs in the pediatric population; and (3) an update on the Agency's approach to the evaluation of AEDs as monotherapy. FDA ACTIONS: Since January 2002, 47 Approval actions for 10 AEDs were issued, but none for a new chemical entity. Nine of the ten Approvable actions taken were relatively minor changes to existing applications. An Approvable letter was issued for Lyrica (pregabalin) for the treatment of post-herpetic neuralgia, painful diabetic neuropathy, and partial seizures in adults. The primary issue to be addressed in the face of post-marketing reports of adverse events is one of causality. The FDA has requested that sponsors search their databases for selected problems under review (e.g., suicidality). PEDIATRICS: The Pediatric Research Equity Act (PREA) and the Best Pharmaceuticals for Children Act (BPCA) require studies in pediatric patients for those indications granted for adults that are relevant for the pediatric population. Current FDA policy asks sponsors to undertake a development program in pediatric patients essentially analogous to that for adults. MONOTHERAPY TRIALS: Establishing the effectiveness of AEDs as monotherapy continues to be desirable, but problematic. Problems include the difficulty of performing monotherapy trials, ethical issues, designation of patients as "newly diagnosed," and endpoints. Historical controls may be acceptable if: (a) there is a consensus that it is essentially impossible to conduct controlled trials designed to demonstrate a difference between treatments; (b) there is an adequate historical database against which the seizure rate seen with the new drug can reasonably be compared; and (c) there is evidence from adequate and well-controlled trials that the treatment is effective as adjunctive therapy. FDA is Agency is reviewing analyses describing historical controls.

Purpose: Epilepsy is a major public-health problem in Africa. The quality of available drugs is a limiting factor for an adequate management. The aim of this study was to describe the proportion of poor-quality phenobarbital (PB) solid-dosage forms and evaluate the factors associated with its quality in Nouakchott (Mauritania)., Methods: A cross-sectional study was carried out within pharmacies, hospitals, and on the parallel market in March 2003. PB samples were bought by a native person and then assayed by a liquid chromatography method. A package was considered to be of good quality if the active-substance average content was between 85 and 115% of the stated content printed on the packet., Results: Forty-five pharmaceutical stores were visited, enabling us to collect 146 samples of PB. Three brand names were available in Nouakchott. They originated from France, Morocco, Senegal, and Egypt. Results: A prevalence of 13.7%[95% confidence interval (CI), 8.8-20.0] of poor-quality PB was found. All samples from Morocco were underdosed. The generic active content was satisfactory, but saccharose, an excipient with a potential side effects, was identified. Two factors associated with the good quality of PB have been put forward: tablets manufactured in France and loose packaging as generics conditioned in such a way were of good quality., Conclusions: This study shows that the quality of antiepileptic drugs in Africa is still worrying. The setting up of medicine quality control in Mauritania is legitimate. Considering the good quality of generic PB and its lower cost, this type of medicine should be promoted in this region.

Drugs are the mainstay of treatment for epilepsy, and are effective for most patients. However, minute differences between generic and branded drugs, and between different brands of the same drug, can affect epilepsy control. It is vital therefore that patients receive the same brand consistently to avoid loss of control.

A specific method for the quantitative determination of valproic acid in human plasma is presented. Valproate was extracted from acidified plasma by hexane extraction and converted to its trimethylsilyl derivative without sample concentration. The derivatives were analyzed without any further purification. Using gas chromatography-electron ionization mass spectrometry, diagnostic useful fragment ions at m/z 201 and 205 were obtained for valproic acid and [(18)O(2)]valproic acid internal standard, respectively. [(18)O(2)]Valproic acid was synthesized from unlabeled valproate by acid-catalyzed exchange reaction in H(2)(18)O. The method was validated in the expected concentration range of a pharmacokinetic study. Thus, calibration graphs were linear within a range of 0.47-120 microgram/ml plasma. Intra-day precision was 2.29% (0.47 microgram/ml), 2.93% (4 microgram/ml), 3.22% (20 microgram/ml) and 4.40% (80 microgram/ml), inter-day variability was found to be 1.49% (0.47 microgram/ml), 3.79% (20 microgram/ml), 2.74% (40 microgram/ml) and 3.03% (80 microgram/ml). Inter-day accuracy showed deviations of 1.94% (0.47 microgram/ml), 0.53% (4 microgram/ml), -0.32% (20 microgram/ml) and 0.06% (80 microgram/ml). The method is rugged and robust and has been applied to the batch analysis of valproate during pharmacokinetic profiling of the drug.

Background: The accuracy and precision of methods for the measurement of the anticonvulsants phenytoin, phenobarbital, primidone, carbamazepine, ethosuximide, and valproate in human serum were assessed in 297 laboratories that were participants in the United Kingdom National External Quality Assessment Scheme (UKNEQAS)., Methods: We distributed lyophilized, serum-based materials containing low, medium, and high weighed-in concentrations of the drugs. The 297 participating laboratories received the materials on two occasions, 7 months apart. Expected concentrations were determined by gas chromatography or HPLC methods in five laboratories using serum-based NIST reference materials as calibrators., Results: In general, bias was consistent across concentrations for a method but often differed in magnitude for different drugs. Bias ranged from -1.9% to 8.6% for phenytoin, -2.7% to 3.1% for phenobarbital, -2.7% to 0.5% for primidone, -8.6% to 0.3% for carbamazepine, -5.6% to 2.0% for ethosuximide, and -7.2% to 0.1% for valproate. Intralaboratory sources of imprecision significantly exceeded interlaboratory sources for many drug/method combinations. The mean CVs for intra- and interlaboratory errors for the different drugs were 6.3-7.8% and 3.3-4.2%, respectively., Conclusions: For these long-established and relatively high-concentration analytes, the closed analytical platforms generally performed no better than open systems or chromatography, where use of calibrators prepared in house predominated. To improve the accuracy of measurements, work is required principally by the manufacturers of immunoassays to ensure minimal calibration error and to eliminate batch-to-batch variability of reagents. Individual laboratories should concentrate on minimizing dispensing errors.

Purpose: Treatment with sodium valproate (VPA) may be associated with polycystic ovarian syndrome (PCOS) in some women with epilepsy. By comparing hormone profiles in young adults taking VPA or lamotrigine (LTG) as monotherapy, this study aimed to explore whether a pharmacologic effect of VPA could be responsible for this observation., Methods: Hormone profiles in men and women taking VPA (n = 40) or LTG (n = 36) monotherapy for epilepsy were compared. None of the women were receiving hormonal contraception or replacement. Patients gave details of seizure type and frequency, menstrual cycle, and medical and drug history. Body mass index was calculated, and fasting insulin, glucose, cholesterol, triglycerides (TG), high- and low-density lipoproteins, testosterone, dihydroepiandosterone (DHEA), androstenedione, sex hormone-binding globulin (SHBG), free androgen index (FAI), luteinising hormone (LH), follicle-stimulating hormone (FSH), and antiepileptic drug (AED) concentrations were measured., Results: There were no differences between treatment groups for both sexes in age and seizure control. Only four obese VPA-treated women were hyperinsulinaemic (p = 0.05); three with abnormal menstrual cycles; one with raised testosterone. Testosterone (p = 0.02), FAI (p = 0.03), and TG (p = 0.02) levels were higher, however, in women taking the drug. Obese patients of both sexes (p = 0.01) and VPA-treated men (p = 0.03) had higher insulin concentrations., Conclusions: VPA therapy may be associated with subclinical elevation in fasting insulin levels. Testosterone and TG levels were higher in VPA-treated women compared with the levels in those taking LTG. However, only a minority of obese females exhibited biochemical characteristics suggestive of PCOS. Biochemical screening may allow women at risk of developing PCOS to avoid VPA.

A simple and rapid high-performance liquid chromatographic method has been developed for the determination of vigabatrin concentrations in plasma or serum. The assay uses only 100 microL of specimen and has been found to be linear over a concentration range of 1 to 50 mg/L. The limit of detection has been determined as 1 mg/L, and the between-batch coefficient of variation for the two internal quality controls routinely analysed (n = 33) has been found to be less than 5%. There was no evidence of interferences in the assay from other commonly prescribed anti-epileptic drugs. This method has been applied to routine clinical specimens to determine the concentration of vigabatrin in 47 patient specimens over a 12-month period. It was found that only 63% of the male group and 53% of the female group were within the proposed target concentration of 5 to 35 mg/L. In addition, it was found that 26% of the male group and 36% of the female group were found to have concentrations below 5 mg/L, which may indicate lack of compliance and/or lack of therapeutic efficacy of treatment.

New antiepileptic drugs have been developed and released for the treatment of chronic focal and secondarily generalized epileptic seizures. The anticonvulsant efficacy of these drugs (vigabatrin, lamotrigine, gabapentin, felbamate, tiagabine, topiramate and oxcarbazepine) does not seem to be superior to that of traditional anticonvulsants. The main advantage of these newly developed drugs is a different spectrum of possible adverse events (i.e. these drugs usually do not induce sedation). Moreover, interactions with traditional anticonvulsants are less common, therefore, comedication with these drugs shows an improved tolerability. The availability of new antiepileptic drugs enables us to establish an individually tailored anticonvulsant strategy for each patient.

Therapeutic drug monitoring (TDM) of chronic treatments is justified for several reasons, including relative over- or underdosage due to variable individual elimination, pharmacokinetic interactions in drug combinations, and noncompliance. In all these circumstances, the prescribing physician is interested in having an estimation of the patient's clearance of the drug, even from one measurement. We compare a validated bayesian program, USC*Pack of Jelliffe, found difficult to use in daily routine, with a "home-made" program. The latter, which is capable of taking data from a clinical database, will generate a graphic simulation of daily plasma drug concentrations together with an estimation of steady-state clearance more rapidly than does USC*Pack. Both programs were run with only one measured plasma level. The patients were 83 children or young adults treated with phenobarbital (PB), carbamazepine (CBZ), and/or Valproic acid (VPA) who were resistant to monotherapy and who were to be sampled two to four times between doses. Drugs were routinely assayed by high-performance liquid chromatography (HPLC). Despite the rough character of Phacile (numeric integration and adjustment of only two of three parameters, without an acknowledged minimization algorithm), the results are comparable to those obtained with USC*Pack for estimating clearance and predicting plasma drug concentrations. Phacile algorithm, although simple, has proven of interest in routine TDM and as an introduction for medical students to the bayesian approach of population pharmacokinetics.