Adverse reactions to new anticonvulsant drugs

Therapeutic Drug Monitoring of 6 New-Generation Antiseizure Medications Using a Mass Spectrometry Method: Analysis of 2-Year Experience in a Large Cohort of Korean Epilepsy Patients

CONTEXT.—

New-generation antiseizure medications (ASMs) are increasingly prescribed, and therapeutic drug monitoring (TDM) has been proposed to improve clinical outcome. However, clinical TDM data on new-generation ASMs are scarce.

OBJECTIVE.—

To develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for therapeutic drug monitoring (TDM) of 6 new-generation ASMs in serum and analyze the clinical TDM data from a large cohort of Korean patients with epilepsy.

DESIGN.—

Stable isotope-labeled internal standards were added to protein precipitations of serum. One microliter of sample was separated on an Agilent Poroshell EC-C18 column, and lacosamide, perampanel, gabapentin, pregabalin, vigabatrin, and rufinamide were simultaneously quantified by Agilent 6460 triple-quad mass spectrometer in multiple-reaction monitoring mode. Linearity, sensitivity, precision, accuracy, specificity, carryover, extraction recovery, and matrix effect were evaluated. TDM data of 458 samples from 363 Korean epilepsy patients were analyzed.

RESULTS.—

The method was linear with limit of detection less than 0.05 μg/mL in all analytes. Intraassay and interassay imprecisions were less than 5% coefficient of variation. Accuracy was within ±15% bias. Extraction recovery ranged from 85.9% to 98.8%. A total of 88% (403 of 458) were on polypharmacy, with 29% (118 of 403) using concomitant enzyme inducers. Only 38% (175 of 458) of the concentrations were therapeutic, with 53% (244 of 458) being subtherapeutic. Drug concentration and concentration-to-dose ratio were highly variable among individuals for all 6 ASMs.

CONCLUSIONS.—

A simple and rapid LC-MS/MS method for TDM of 6 ASMs was developed and successfully applied to clinical practice. These large-scale TDM data could help establish an effective monitoring strategy for these drugs.

Drug reaction with eosinophilia and systemic symptoms (DRESS) associated with the use of antiseizure medications-An overview of clinical data

The United States Food and Drug Administration (US FDA) released a warning regarding Drug Reactions with Eosinophilia and Systemic Symptoms (DRESS) linked to the use of antiseizure drugs, including levetiracetam and clobazam, on November 28, 2023. Hence, our review focuses on DRESS associated with the use of antiseizure drugs, including Levetiracetam, Clobazam, Carbamazepine, Phenytoin, Phenobarbital, Valproate, Oxcarbazepine, and Lamotrigine. The online databases, such as Medline/Pubmed/PMC, Scopus, Web of Science, Google Scholar, Science Direct, Ebsco, Embase, and reference lists, were searched for relevant publications. Several case reports and reviews of pharmacovigilance data by different regulatory bodies were published regarding DRESS associated with antiseizure drugs. Management strategies for DRESS may include immediate discontinuation of offending medication, administration of systemic corticosteroids, and administration of cyclosporine and intravenous immunoglobulin in cases that are not responding to systemic corticosteroids. Early detection and treatment of DRESS by healthcare professionals is necessary to lower mortality and improve outcomes. The US FDA advises healthcare professionals to be aware of the connection between DRESS and specific antiseizure medications. Patients should be informed by medical professionals about the symptoms and signs of DRESS as well as the risks associated with it. In conclusion, DRESS syndrome, though rare, is a serious hypersensitivity reaction linked to antiseizure drugs like levetiracetam and clobazam. Early detection and discontinuation of the offending drug, coupled with systemic corticosteroids, are essential for effective management. Healthcare professionals must be vigilant in identifying DRESS to reduce mortality and improve patient outcomes.

Management of epilepsy during pregnancy and lactation

Epilepsy is a group of neurological diseases characterized by susceptibility to recurrent seizures. Antiseizure medications (ASMs) are the mainstay of treatment, but many antiseizure medications with variable safety profiles have been approved for use. For women with epilepsy in their childbearing years, the safety profile is important for them and their unborn children, because treatment is often required to protect them from seizures during pregnancy and lactation. Since no large randomized controlled trials have investigated safety in this subgroup of people with epilepsy, pregnancy registries, cohort and case-control studies from population registries, and a few large prospective cohort studies have played an important role. Valproate, in monotherapy and polytherapy, has been associated with elevated risk of major congenital malformations and neurodevelopmental disorders in children born to mothers who took it. Topiramate and phenobarbital are also associated with elevated risks of congenital malformations and neurodevelopmental disorders, though the risks are lower than those of valproate. Lamotrigine and levetiracetam are relatively safe. Insufficient data exist to reach strong conclusions about the newest antiseizure medications such as eslicarbazepine, perampanel, brivaracetam, cannabidiol, and cenobamate. Besides antiseizure medications, other treatments such as vagal nerve stimulation, responsive neurostimulation, and deep brain stimulation are likely safe. In general, breastfeeding does not appear to add any additional long term risks to the child. Creative ways of optimizing registry enrollment and data collection are needed to enhance patient safety.

Pathophysiology of drug-resistant canine epilepsy

Drug resistance continues to be a major clinical problem in the therapeutic management of canine epilepsies with substantial implications for quality of life and survival times. Experimental and clinical data from human medicine provided evidence for relevant contributions of intrinsic severity of the disease as well as alterations in pharmacokinetics and -dynamics to failure to respond to antiseizure medications. In addition, several modulatory factors have been identified that can be associated with the level of therapeutic responses. Among others, the list of potential modulatory factors comprises genetic and epigenetic factors, inflammatory mediators, and metabolites. Regarding data from dogs, there are obvious gaps in knowledge when it comes to our understanding of the clinical patterns and the mechanisms of drug-resistant canine epilepsy. So far, seizure density and the occurrence of cluster seizures have been linked with a poor response to antiseizure medications. Moreover, evidence exists that the genetic background and alterations in epigenetic mechanisms might influence the efficacy of antiseizure medications in dogs with epilepsy. Further molecular, cellular, and network alterations that may affect intrinsic severity, pharmacokinetics, and -dynamics have been reported. However, the association with drug responsiveness has not yet been studied in detail. In summary, there is an urgent need to strengthen clinical and experimental research efforts exploring the mechanisms of resistance as well as their association with different etiologies, epilepsy types, and clinical courses.

Pharmacotherapy for post-stroke aphasia: what are the options?

INTRODUCTION

Aphasia is a common, long-lasting aftermath of stroke lesions. There is an increased integration of pharmacotherapy as an adjunctive strategy to speech and language therapy (SLT) for post-stroke aphasia (PSA). Nevertheless, more research in pharmacotherapy for acute and chronic PSA is necessary, including the election of drugs that target different neurotransmitter systems and deficits in specific language domains.

AREAS COVERED

This article updates the role of pharmacotherapy for PSA, focusing the spotlight on some already investigated drugs and candidate agents deserving of future research. Refining the precision of drug election would require using multimodal biomarkers to develop personalized treatment approaches. There is a solid need to devise feasible randomized controlled trials adapted to the particularities of the PSA population. The emergent role of multimodal interventions combining one or two drugs with noninvasive brain stimulation to augment SLT is emphasized.

EXPERT OPINION

Pharmacotherapy can improve language deficits not fully alleviated by SLT. In addition, the 'drug-only' approach can also be adopted when administering SLT is not possible. The primary goal of pharmacotherapy is reducing the overall aphasia severity, although targeting language-specific deficits (i.e. naming, spoken output) also contributes to improving functional communication. Unfortunately, there is still little information for recommending a drug for specific language deficits.

Translational veterinary epilepsy: A win-win situation for human and veterinary neurology

Epilepsy is a challenging multifactorial disorder with a complex genetic background. Our current understanding of the pathophysiology and treatment of epilepsy has substantially increased due to animal model studies, including canine studies, but additional basic and clinical research is required. Drug-resistant epilepsy is an important problem in both dogs and humans, since seizure freedom is not achieved with the available antiseizure medications. The evaluation and exploration of pharmacological and particularly non-pharmacological therapeutic options need to remain a priority in epilepsy research. Combined efforts and sharing knowledge and expertise between human medical and veterinary neurologists are important for improving the treatment outcomes or even curing epilepsy in dogs. Such interactions could offer an exciting approach to translate the knowledge gained from people and rodents to dogs and vice versa. In this article, a panel of experts discusses the similarities and knowledge gaps in human and animal epileptology, with the aim of establishing a common framework and the basis for future translational epilepsy research.

Second Generation of Antiepileptic Drugs and Oxidative Stress

Epilepsy is a chronic disease of the central nervous system characterized by recurrent epileptic seizures. As a result of epileptic seizure or status epilepticus oxidants are excessively formed, which may be one of the causes of neuronal death. Given the role of oxidative stress in epileptogenesis, as well as the participation of this process in other neurological conditions, we decided to review the latest state of knowledge regarding the relationship between selected newer antiepileptic drugs (AEDs), also known as antiseizure drugs, and oxidative stress. The literature review indicates that drugs enhancing GABA-ergic transmission (e.g., vigabatrin, tiagabine, gabapentin, topiramate) or other antiepileptics (e.g., lamotrigine, levetiracetam) reduce neuronal oxidation markers. In particular, levetiracetam may produce ambiguous effects in this regard. However, when a GABA-enhancing drug was applied to the healthy tissue, it tended to increase oxidative stress markers in a dose-dependent manner. Studies on diazepam have shown that it exerts a neuroprotective effect in a "U-shaped" dose-dependent manner after excitotoxic or oxidative stress. Its lower concentrations are insufficient to protect against neuronal damage, while higher concentrations produce neurodegeneration. Therefore, a conclusion follows that newer AEDs, enhancing GABA-ergic neurotransmission, may act similarly to diazepam, causing neurodegeneration and oxidative stress when used in high doses.

Pharmacokinetics of zonisamide after oral single dosing and multiple-dose escalation administration in domestic chickens (Gallus gallus)

Background

There are few effective drugs for treatment of seizures in avian species.

Objectives

To investigate the pharmacokinetics and safety of zonisamide in chickens.

Methods

Phase 1: chickens (n = 4) received a single oral dose of zonisamide at 20 mg/kg. Blood samples were collected intermittently for 36 hr after dosing. Phase 2: chickens (n = 8) received zonisamide in a dose escalation protocol (20, 30, 60 and 80 mg/kg orally every 12 hr). The dose was increased weekly, and peak and trough blood samples were collected on Days 1, 3, and 7 each week. Two birds were randomly euthanized at the end of each week. Plasma zonisamide concentrations were analysed using a commercial immunoassay. Drug concentration vs. time data were subjected to non‐compartmental pharmacokinetic analysis.

Results

For Phase 1, peak plasma zonisamide (C_max) was 15 ± 3 µg/ml at 2 ± 1 hr (T_max). The disappearance half‐life was 6.5 ± 1 hr. Mean plasma concentrations remained within the (human) therapeutic range (10–40 µg/ml) for 6 hr. For Phase 2 of the study, plasma concentrations of zonisamide remained within or close to the recommended mammalian therapeutic range for birds in the 20 and 30 mg/kg dose. Area under the curve (AUC) and C_max were dose dependent. Two birds developed immune‐mediated haemolytic anaemia.

Conclusions

Zonisamide appears to be a viable drug for use in chickens at a dose of 20 mg/kg orally every 12 hr.

Health-related quality of life in pediatric patients with partial onset seizures or primary generalized tonic-clonic seizures receiving adjunctive perampanel

RATIONALE

Study 311 (E2007-G000-311; NCT02849626) was a Phase 3, multicenter, open-label single-arm study of adjunctive perampanel oral suspension in pediatric patients (aged 4 to <12 years) with partial-onset seizures (POS) (with/without secondarily generalized tonic-clonic seizures [SGTCS]) or primary generalized tonic-clonic seizures (PGTCS). Health-related quality of life (HRQoL) was an exploratory endpoint initially analyzed through simple descriptive summaries. The aim of this post hoc analysis was to provide a more thorough assessment of HRQoL.

METHODS

This analysis focused on EQ-5D-Y data collected at Baseline, Week 23, and Week 52. Individual dimensions, visual analog scale (VAS) and summed misery index (MI) were evaluated at all visits and compared by seizure type (POS versus SGTCS versus PGTCS), age (4 to <7 versus 7 to <12), and use of concomitant enzyme-inducing antiepileptic drugs (EIAEDs) (yes versus no). Paretian Classification of Health Change (PCHC) analysis summarized the proportion of patients who showed improvement or deterioration in HRQoL. Waterfall plots assessed changes in EQ-5D-Y scores by treatment-emergent adverse events (TEAEs) and by reduction in seizure frequency. Health state utility values associated with differing seizure frequency states were estimated using a linear mixed model.

RESULTS

One hundred and fifteen patients completed EQ-5D-Y at relevant study visits (Seizure type: POS n = 84 [of which 21 had SGTCS], PGTCS n = 31; Age: 4 to <7 years n = 30, 7 to <12 years n = 85; Concomitant EIAEDs: Yes n = 35, No n = 80). Completion rates out of those expected to complete EQ-5D-Y were high at both timepoints (84.4% at Week 23 and 97.2% at Week 52). Overall, VAS/MI remained stable over time (did not exceed minimal important difference); this was similar according to seizure type, age, and EIAED usage. In patients with 'no problems' on any EQ-5D-Y dimension at Baseline, nearly all retained their full health at Week 23 (94.7%), and all retained it at Week 52 (100.0%). PCHC analysis showed fewer patients with POS experienced deterioration in EQ-5D-Y than patients with PGTCS at Week 23 (24.1% versus 42.1%). Not experiencing a TEAE, or remaining seizure-free, was associated with improvements in VAS score at Week 23 compared to those experiencing TEAEs or seizures, respectively. Health state utility values (HSUVs) were estimated as follows: seizure free (LS Mean 0.914 [95% CIs 0.587, 1.240]), ≥1 seizure per year (0.620 [0.506, 0.734]), ≥1 seizure per month (0.596 [0.338, 0.855]), ≥1 seizure per week (0.284 [-0.014, 0.582]).

CONCLUSIONS

An in-depth analysis of EQ-5D-Y data allowed for a more nuanced exploration of HRQoL than previous descriptive summaries. Our findings provide evidence that perampanel as adjunctive therapy did not result in deterioration of patient HRQoL. The association between TEAEs or remaining seizure-free and HRQoL warrants further exploration. Increasing seizure frequency was associated with decreasing HSUVs; these can inform cost-effectiveness modeling of perampanel and other therapies aiming to reduce seizure frequency in pediatric patients.

Epilepsy and quality of life: what does really matter?

PURPOSE

To assess quality of life (QoL) in adult people with epilepsy (PWE) and identify the main factors affecting it.

METHODS

We enrolled consecutively 122 PWE. They were interviewed for a careful collection of demographic and clinical data. Patients completed dedicated questionnaires for the assessment of the quality of life (Quality of Life in Epilepsy Scale-31) (Q31) as well as psychosocial features: depressive symptoms (DS) (Beck Depression Inventory-II/BDI-II), difficulties of emotion regulation (Difficulties of Emotion Regulation Scale/DERS), and stigma related to epilepsy (Stigma Scale of Epilepsy/SSE and Jacoby's Stigma Scale/JSS). The results of Q31 and their subscales were correlated with clinical details of PWE, as well as the other scores. A stepwise multiple regression analysis was applied to identify the main factors affecting QoL.

RESULTS

Quality of life is inversely correlated mostly with psychosocial features, as DS, emotion dysregulation, and stigma perception, as well as with epilepsy-related factors, as the seizure frequency and number of antiseizure medications (ASMs). The combination of DS, perceived stigma, and number of ASMs best explained the QoL. Worse features of QoL were detected in females and in patients with age of epilepsy onset in adulthood.

CONCLUSION

Quality of life in adult PWE is predominantly affected by psychosocial factors more than epilepsy-related ones. These findings suggest that effective epilepsy management requires more than seizure control, and early detection of psychological dysfunction and tailored interventions to improve the QoL should be considered.

Why we urgently need improved epilepsy therapies for adult patients

PURPOSE

Up to a third of patients with epilepsy suffer from recurrent seizures despite therapeutic advances.

RESULTS

Current epilepsy treatments are limited by experiential data from treating different types of epilepsy. For example, we lack evidence-based approaches to efficacious multi-drug therapies or identifying potentially serious or disabling adverse events before medications are initiated. Despite advances in neuroscience and genetics, our understanding of epilepsy pathogenesis and mechanisms of treatment-resistance remains limited. For most patients with epilepsy, precision medicine for improved seizure control and reduced toxicity remains a future goal.

CONCLUSION

A third of epilepsy patients suffer from ongoing seizures and even more suffer from adverse effects of treatment. There is a critical need for more effective and safer therapies for epilepsy patients with frequent comorbitidies, including depression, anxiety, migraine, and cognitive impairments, as well as special populations (e.g., women, elderly). Advances from genomic sequencing techniques may identify new genes and regulatory elements that influence both the depth of the epilepsies' roots within brain circuitry as well as ASD resistance. Improved understanding of epilepsy mechanisms, identification of potential new therapeutic targets, and their assessment in randomized controlled trials are needed to reduce the burden of refractory epilepsy. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Adverse drug reactions associated with six commonly used antiepileptic drugs in southern China from 2003 to 2015

BACKGROUND

This active, open observational study aimed to investigate adverse drug reactions (ADRs) associated with six commonly used antiepileptic drugs (AEDs) in southern Chinese outpatients with epilepsy from 2003 to 2015.

METHODS

The Wenzhou Epilepsy Follow-Up Registry Database (WEFURD) was established by a single epilepsy center in China in January 2003 to record AED efficacy and the associated ADRs by registered outpatients diagnosed with epilepsy. We reviewed the data of outpatients who had only taken one or more of six commonly used AEDs, namely, carbamazepine (CBZ), valproate (VPA), lamotrigine (LTG), oxcarbazepine (OXC), topiramate (TPM) and levetiracetam (LEV), and were registered in the WEFURD between 2003 and 2015. We evaluated the ADRs caused by the single or combined use of the above six specific AEDs based on the WHO-UMC scale. The data of the ADRs were categorized by age, sex, number of AEDs related to ADRs, medications, seriousness of ADRs, causality levels of the WHO-UMC scale and system organ class (SOC). The unit of analysis was one ADR.

RESULTS

A total of 3069 epilepsy outpatients (1807 outpatients with 5049 eligible ADRs and 1262 outpatients without ADRs) were included. The overall ADR rate was 58.88% (1807/3069). An average of 2.79 ADRs (5049/1807) occurred per patient with an ADR; 53.8% of the 5049 ADRs were recorded in females, and 50.4% were caused by monotherapy. Of the ADRs, 10.6% (537/5049) were severe adverse reactions (SARs), including 34 serious adverse effects (SAEs). The SAR rates caused by one, two and three or more AEDs were 9.9, 10.0 and 19.6%, respectively (p <  0.001). Eighteen SOC categories were identified, and the top three were psychiatric disorders (1633/5049, 32.3%), neurological disorders (1222/5049, 24.2%) and gastrointestinal disorders (564/5049, 11.2%). Of the 537 SARs, skin and appendage disorders accounted for 24.4% (131/537). Among the 34 SAEs, serious allergies, fetal malformations, renal calculus and pancreatitis accounted for the majority.

CONCLUSIONS

Our findings suggest that clinicians should pay attention to psychiatric ADRs and be alert for SARs, especially when three or more AEDs are used together. Moreover, active surveillance might provide another method of pharmacovigilance in China.

An update on medications and noninvasive brain stimulation to augment language rehabilitation in post-stroke aphasia

INTRODUCTION

Aphasia is among the most debilitating outcomes of stroke. Aphasia is a language disorder occurring in 10-30% of stroke survivors. Speech and Language Therapy (SLT) is the gold standard, mainstay treatment for aphasia, but gains from SLT may be incomplete. Pharmaceutical and noninvasive brain stimulation (NIBS) techniques may augment the effectiveness of SLT. Areas covered: Herein reviewed are studies of the safety and efficacy of these adjunctive interventions for aphasia, including randomized placebo-controlled and open-label trials, as well as case series from Pubmed, using search terms 'pharmacological,' 'tDCS' or 'TMS' combined with 'aphasia' and 'stroke.' Expert commentary: Relatively small studies have included participants with a range of aphasia types and severities, using inconsistent interventions and outcome measures. Results to-date have provided promising, but weak to moderate evidence that medications and/or NIBS can augment the effects of SLT for improving language outcomes. We end with recommendations for future approaches to studying these interventions, with multicenter, double-blind, randomized controlled trials.

Cognitive and Language Function in Aphasic Patients Assessed With the Korean Version of Mini-Mental Status Examination

Objective

To assess the clinical usefulness of the relatively short instrument, the Korean version of the Mini-Mental State Examination (MMSE-K), for testing the association between cognition and language function in subacute post-stroke aphasia patients.

Methods

Medical charts of 111 post-stroke patients (65 men; age 69.6±10.0 years; 124.6±80.6 days post-onset) were reviewed retrospectively. All patients were assessed longitudinally for aphasia using the validated Korean version of the Western Aphasia Battery (K-WAB) and for cognition using the MMSE-K. Patients were categorized and analyzed according to 3 aphasia-severity clusters.

Results

All subscales of the K-WAB showed significant improvement in follow-up assessments in all groups (p<0.05 or p<0.01). Only the scores of orientation, language function, and total score of MMSE-K showed significant improvement in all groups (p<0.01). The more severely impaired group showed stronger Pearson correlation coefficients between cognition and language function. Additionally, comparisons between correlation coefficients showed that the association of improvement in orientation with that of fluency and AQ% (aphasia quotient %) was significant in the more severely impaired group.

Conclusion

Among subacute post-stroke aphasic patients, patients with more severe aphasia showed greater impairments to cognitive function; in addition, recovery of orientation may be related to recovery of language function.

Neuroprotective Effect of Lercanidipine- A Novel Calcium Channel Blocker in Albino Mice

BACKGROUND

The available conventional antiepileptics do not afford cure or prophylactic treatment and henceforth there is always a quest to explore new targets for management of convulsions. In this perspective, dihydropyridine calcium channel blockers have been investigated in various animal models of epilepsy. Lercanidipine, a newer dihydropyridine calcium antagonist, is a potential candidate with its favourable lipid profile and longer duration of action.

OBJECTIVE

(1) To evaluate the anticonvulsant effect of lercanidipine alone and in combination with standard drug in adult male Swiss albino mice. (2) To evaluate the muscle relaxant and spontaneous locomotor activity of lercanidipine in adult male Swiss albino mice.

MATERIALS AND METHODS

Adult male Swiss albino mice weighing 20-30g were used to study the anticonvulsant, muscle relaxant and spontaneous locomotor activity using electroconvulsometer, rotarod and actophotometer apparatus respectively. The mice were divided into six groups of six animals in each group. Group 1 and 2 served as control (vehicle treated) and standard group respectively. Standard drug used to evaluate anticonvulsant effect is phenytoin sodium 25 mg/kg I.P. whereas muscle relaxant activity and locomotor activity is diazepam 4 mg/kg I.P., Group 3 and 4 received lercanidipine 1 and 3 mg/kg I.P., respectively. Anticonvulsant models included group 5 and 6 and they were given combination of phenytoin sodium 12.5 mg/kg I.P., with lercanidipine 1 and 3 mg/kg i.p, respectively. Abolition or reduction of tonic hind limb extension was considered as index of anticonvulsant activity whereas the balancing time of the animals in rod was recorded to asses muscle relaxant activity. The locomotor activity was recorded for 5 minutes. The data were analysed with one-way Analysis of Variance followed by post-hoc 'Dunnett t-test'.

RESULTS

Lercanidipine given alone in a dose of 1 and 3 mg/kg had significantly reduced the tonic hind limb extension. Combination of lercanidipine (3 mg/kg) and phenytoin had offered 100% protection. The results also revealed that the test drug didn't impair the motor coordination and locomotor activity in mice.

CONCLUSION

The present study had demonstrated that lercanidipine could be potential novel candidate for the treatment of convulsions.

International Veterinary Epilepsy Task Force consensus proposal: medical treatment of canine epilepsy in Europe

In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authors' experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible.

A prospective study of adverse drug reactions to antiepileptic drugs in children

OBJECTIVES

To prospectively determine the nature and rate of adverse drug reactions (ADRs) in children on antiepileptic drugs (AEDs) and to prospectively evaluate the effect of AEDs on behaviour.

SETTING

A single centre prospective observational study.

PARTICIPANTS

Children (<18 years old) receiving one or more AEDs for epilepsy, at each clinically determined follow-up visit.

PRIMARY AND SECONDARY OUTCOMES

Primary outcome was adverse reactions of AEDs. Behavioural and cognitive functions were secondary outcomes.

RESULTS

180 children were recruited. Sodium valproate and carbamazepine were the most frequently used AEDs. A total of 114 ADRs were recorded in 56 of these children (31%). 135 children (75%) were on monotherapy. 27 of the 45 children (60%) on polytherapy had ADRs; while 29 (21%) of those on monotherapy had ADRs. The risk of ADRs was significantly lower in patients receiving monotherapy than polytherapy (RR: 0.61, 95% CI 0.47 to 0.79, p<0.0001). Behavioural problems and somnolence were the most common ADRs. 23 children had to discontinue their AED due to an ADR.

CONCLUSIONS

Behavioural problems and somnolence were the most common ADRs. Polytherapy significantly increases the likelihood of ADRs in children.

TRAIL REGISTRATION NUMBER

EudraCT (2007-000565-37).

Health-Related Quality of Life and Willingness to Pay per Quality-Adjusted Life-Year Threshold-A Study in Patients with Epilepsy in China

OBJECTIVES

To assess the health-related quality of life (HRQOL) and willingness to pay (WTP) per quality-adjusted life-year (QALY) amount of patients with epilepsy in China.

METHODS

Adults with epilepsy and a healthy control were recruited in two tertiary hospitals in China. Participants completed two indirect utility elicitation instruments (Quality of Well-being Scale-self administered version and EuroQol five-dimensional questionnaire) and a WTP questionnaire. Correlations between sociodemographic or epilepsy-specific variables (age of epilepsy onset, duration of epilepsy, seizure types, types of antiepileptic drug treatment, etc.) and HRQOL or WTP/QALY were assessed to identify the candidate predictor. Multiple linear regression models were adopted to investigate the predictive performances of identified candidate predictors. Data analyses were performed on SPSS 20.0 (SPSS, Inc., Chicago, IL).

RESULTS

For utilities of both the Quality of Well-being Scale-self administered version and the EuroQol five-dimensional questionnaire, patients with epilepsy had statistically lower values than did the control group (P < 0.0001). In terms of the WTP/month, the percentage of WTP accounting for the monthly income and the WTP/QALY values from the epilepsy group were substantially higher than those from the control group (P < 0.0001). [Formula: see text] The multiple linear regression model identified working status (P = 0.05), seizure types (P = 0.022), income (P = 0.006), and self-rating health state (P < 0.05) as predictors of HRQOL while income (P = 0.000) and self-rating health state (P < 0.05) statistically contributed to the variations in WTP/QALY value for the epilepsy group.

CONCLUSIONS

Patients with epilepsy had substantially lower HRQOL than did the healthy population.

Validation of a Chinese version of the Quality of Well-Being Scale-Self-Administered (QWB-SA) in patients with epilepsy

PURPOSE

Generic preference-based health-related quality of life (HRQoL) instruments are increasingly used to estimate the quality-adjusted life years (QALYs) in cost-effectiveness/utility studies. However, no such tool has been used and validated in epilepsy patients in China. This study was conducted to validate a generic preference-based HRQoL instrument, namely the Quality of Well-Being Scale-Self-Administered (QWB-SA) in Chinese patients with epilepsy.

METHODS

Accepted translation procedures were followed to develop the Chinese QWB-SA. An epilepsy group (adults with established diagnosis of epilepsy) and a control group (adults without manifested cognitive problems) were recruited between July and October, 2012, from two tertiary hospitals in China. After giving informed consent, each subject completed both the QWB-SA and the EuroQol (EQ-5D) as well as provided sociodemographic data. Construct validity was examined by six (convergent) and two (discriminative) a priori hypotheses. Sensitivity was compared by ability to differentiate epilepsy-specific variable-based subgroups. Agreement between the QWB-SA and EQ-5D was assessed by intraclass correlation coefficient (ICC) and Bland-Altman plot.

KEY FINDINGS

One hundred forty-four epilepsy patients and 323 control subjects were enrolled, respectively. The utility medians (interquartile range, IQR) for the QWB-SA and EQ-5D were 0.673 (0.172), 0.848 (0.275) for epilepsy group and 0.775 (0.258), 1.000 (0.152) for control group, respectively. The difference in utilities between the two measures were significant (p < 0.0001). Construct validity was demonstrated by six a priori hypotheses. In addition, the QWB-SA was able to discriminate across different seizure frequency and antiepileptic drug (AED) treatment subgroups. Agreement between the QWB-SA and EQ-5D was demonstrated by ICC (0.725). Finally, the multiple linear regression analysis indicated that group and the EQ-VAS had influences on the utility difference of these two measures, whereas seizure frequency and number of AEDs were predictors of HRQoL as measured by the QWB-SA.

SIGNIFICANCE

The QWB-SA is a valid and sensitive HRQoL measure in Chinese patients with epilepsy. Compared to the EQ-5D, the QWB-SA showed superiority in coverage of health dimensions, sensitivity, and ceiling effects. However, future study is still needed to ascertain its responsiveness.

Canine epilepsy as a translational model?

Dogs with spontaneous diseases can exhibit a striking similarity in etiology, clinical manifestation, and disease course when compared to human patients. Therefore, dogs are intensely discussed as a translational model of human disease. In particular, genetic studies in selected dog breeds serve as an excellent tool to identify epilepsy disease genes. In addition, canine epilepsy is discussed as a translational platform for drug testing. On one hand, epileptic dogs might serve as an interesting model by allowing the evaluation of drug efficacy and potency under clinical conditions with a focus on chronic seizures resistant to standard medication, preventive strategies, or status epilepticus. On the other hand, several limitations need to be considered including owner-based seizure monitoring, species differences in pharmacokinetics and drug interactions, as well as cost-intensiveness. The review gives an overview on the current state of knowledge regarding the etiology, clinical manifestation, pathology, and drug response of canine epilepsy, also pointing out the urgent need for further research on specific aspects. Moreover, the putative advantages, the disadvantages, and limitations of antiepileptic drug testing in canine epilepsy are critically discussed.

Pharmacogenetics of the antiepileptic drugs phenytoin and lamotrigine

Patients treated with antiepileptic drugs can exhibit large interindividual variability in clinical efficacy or adverse effects. This could be partially due to genetic variants in genes coding for proteins that function as drug metabolizing enzymes, drug transporters or drug targets. The purpose of this article is to provide an overview of the current knowledge on the pharmacogenetics of two commonly prescribed antiepileptic drugs with similar mechanisms of action; phenytoin (PHT) and lamotrigine (LTG). These two drugs have been selected in order to model the pharmacogenetics of Phase I and Phase II metabolism for PHT and LTG, respectively. In light of the present evidence, patients treated with PHT could benefit from CYP2C9 and CYP2C19 genotyping/phenotyping. For those under treatment with LTG, UGT1A4 and UGT2B7 genotyping might be of clinical use and could contribute to the interindividual variability in LTG concentration to dose ratio in epileptic patients.

Levetiracetam induced angioedema in a patient with previous anticonvulsant hypersensitivity reaction to phenytoin and lamotrigine

Allergic reactions to antiepileptic drugs in the form of skin rash are not uncommon but angioedema, an acute life threatening reaction is rare. Angioedema has been reported with the use of oxcarbazepine and carbamazepine. We report a case of a 33-year-old woman with focal epilepsy who developed angioedema following levetiracetam monotherapy. The patient had previous skin rashes with both phenytoin and lamotrigine. Levetiracetam was stopped and she improved after treatment with norepinephrine, antihistamines and corticosteroids.

Canadian guidelines for the evidence-based treatment of tic disorders: pharmacotherapy

This article seeks to provide the practising clinician with guidance on the pharmacological management of tic disorders in children and adults. We performed a systematic review of the literature on the treatment of tic disorders. A multi-institutional group of 14 experts in psychiatry, child psychiatry, neurology, pediatrics, and psychology engaged in a consensus meeting. The evidence was presented and discussed, and nominal group techniques were employed to arrive at consensus on recommendations. A strong recommendation is made when the benefits of treatment clearly outweigh the risks and burdens, and can apply to most patients in most circumstances without reservation. With a weak recommendation, the benefits, risks, and burdens are more closely balanced, and the best action may differ depending on the circumstances. Based on these principles, weak recommendations were made for the use of pimozide, haloperidol, fluphenazine, metoclopramide (children only), risperidone, aripiprazole, olanzapine, quetiapine, ziprasidone, topiramate, baclofen (children only), botulinum toxin injections, tetrabenazine, and cannabinoids (adults only). Strong recommendations were made for the use of clonidine and guanfacine (children only). While the evidence supports the efficacy of many of the antipsychotics for the treatment of tics, the high rates of side effects associated with these medications resulted in only weak recommendations for these drugs. In situations where tics are not severe or disabling, the use of a medication with only a weak recommendation is not warranted. However, when tics are more distressing and interfering, the need for tic suppression to improve quality of life is stronger, and patients and clinicians may be more willing to accept the risks of pharmacotherapy.

Topiramate induced pruritus in a patient with alcohol dependence

Topiramate is an antiepileptic medication frequently used for the management of alcohol dependence and in other psychiatric disorders. Though cutaneous side effects are known to occur with it, isolated pure pruritus is rarely reported with topiramate in the literature. We wish to report a case of pruritus associated with topiramate use in a male with alcohol dependence syndrome.

Predictors of health-related quality of life and costs in adults with epilepsy: a systematic review

PURPOSE

Given the high burden of epilepsy on both health-related quality of life (HRQoL) and costs, identification of factors that are predictive of either reduced HRQoL or increased expenditure is central to the better future targeting and optimization of existing and emerging interventions and management strategies for epilepsy.

METHODS

Searches of Medline, Embase, and Cochrane Library (up to July 2010) to identify studies examining the association between demographic, psychosocial, and condition-related factors and HRQoL, resource utilization or costs in adults with epilepsy. For each study, predictor factor associations were summarized on the basis of statistical significance and direction; the results were then combined across studies.

KEY FINDINGS

Ninety-three HRQoL and 16 resource utilization/cost studies were included. Increases in seizure frequency, seizure severity, level of depression, and level of anxiety and presence of comorbidity were strongly associated with reduced HRQoL. The majority of studies were cross-sectional in design and had an overall methodologic quality that was judged to be "moderate" for HRQoL studies and "poor" for health care resource or costs studies. In the 53 multivariate studies, age, gender, marital status, type of seizure, age at diagnosis, and duration of epilepsy did not appear to be associated with HRQoL, whereas the predictive influence of educational and employment status, number of antiepileptic drugs (AEDs) and AED side effects was unclear. The association between predictive factors and HRQoL appeared to be consistent across individuals whether refractory or seizures controlled or managed by AEDs. There were insufficient multivariate studies (five) to reliably comment on the predictors of resource utilization or cost in epilepsy.

SIGNIFICANCE

In addition to seizure control, effective epilepsy management requires the early detection of those most at risk of psychological dysfunction and comorbidity, and the targeting of appropriate interventions. There is need for more rigorous studies with appropriate multivariate statistical methods that prospectively investigate the predictors of HRQoL, resource utilization, and costs in epilepsy.

Mortality rates and causes of death in children with epilepsy prescribed antiepileptic drugs: a retrospective cohort study using the UK General Practice Research Database

BACKGROUND

Patients with epilepsy, including children, have an increased risk of mortality compared with the general population. Antiepileptic drugs (AEDs) were the most frequent class of drugs reported in a study looking at fatal suspected adverse drug reactions in children in the UK.

OBJECTIVE

The objective of the study was to identify cases and causes of death in a paediatric patient cohort prescribed AEDs with an associated epilepsy diagnosis.

METHODS

This was a retrospective cohort study supplemented with general practitioner-completed questionnaires, post-mortem reports and death certificates. The setting was UK primary care practices contributing to the General Practice Research Database. Participants were children and adolescents aged 0-18 years prescribed AEDs between 1993 and 2005. Causality assessment was undertaken by a consensus panel comprising paediatric specialists in neuropathology, neurology, neuropsychiatry, paediatric epilepsy, pharmacoepidemiology and pharmacy to determine crude mortality rate (CMR) and standardized mortality ratios (SMRs), and the likelihood of an association between AED(s) and the event of death.

RESULTS

There were 6190 subjects in the cohort (contributing 26,890 person-years of data), of whom 151 died. Median age at death was 8.0 years. CMR was 56.2 per 10,000 person-years and the SMR was 22.4 (95% CI 18.9, 26.2). The majority of deceased subjects had severe underlying disorders. Death was attributable to epilepsy in 18 subjects; in 9 the cause of death was sudden unexpected death in epilepsy (SUDEP) [3.3 per 10 000 person-years (95% CI 1.5, 6.4)]. AEDs were probably (n = 2) or possibly (n = 3) associated causally with death in five subjects. Two status epilepticus deaths were associated causally with AED withdrawal.

CONCLUSIONS

Children prescribed AEDs have an increased risk of mortality relative to the general population. Most of the deaths were in children with serious underlying disorders. A small number of SUDEP cases were identified. AEDs are not a major cause of death but in a small proportion of cases, a causal relationship between death and AEDs could not be excluded.

Mood stabilizers for patients with bipolar disorder: the state of the art

Bipolar disorder (BD) is a prevalent and disabling condition, often comorbid with other medical and psychiatric conditions and frequently misdiagnosed. International treatment guidelines for BD recommend the use of mood stabilizers - either in monotherapy or in association - as the gold standard in both acute and long-term therapy. Commonly used in the clinical practice of BD, mood stabilizers have represented an evolving field over the last few years. The concept of stabilization, in fact, has been stressed as the ultimate objective of the treatment of BD, given the chronic and recurrent nature of the illness, which accounts for its significant levels of impairment and disability. To date, different compounds are included within the broad class of mood stabilizers, with lithium, anticonvulsants and, more recently, atypical antipsychotics being the most representative agents. This article is aimed at providing an updated review of the available literature in relation to the role of mood stabilizers in BD, with particular emphasis on their mechanism of action, main clinical aspects and specific use in the different phases of BD treatment, according to the most recently published international treatment guidelines.

Long-term add-on pregabalin treatment in patients with partial-onset epilepsy: pooled analysis of open-label clinical trials

PURPOSE

To evaluate the safety, tolerability, and efficacy of long-term pregabalin as add-on therapy for patients with poorly controlled partial seizures.

METHODS

Analysis of data from six long-term clinical trials involving 2,061 patients receiving open-label pregabalin 75-600 mg/day adjunctive therapy for partial onset epilepsy refractory to multiple antiepileptic drugs.

RESULTS

Total pregabalin exposure was 3,877 person-years. The mean duration of pregabalin treatment was 534 days (range 0.3-8 years) and 59% completed 1 year. One-third of patients discontinued for lack of efficacy. The most common dose was >or=300 mg/day; over half took >or=450 mg/day. There was a mean reduction in the 28-day seizure rate of 25-40%, and more than 40% of all patients had a >or=50% reduction in seizures from baseline during the last 3 months of treatment. Twelve percent of all patients had a 6-month period continuously free of seizures. In the last year, 6% were seizure-free for the entire year. Pregabalin was generally well-tolerated and the safety profile favorable in patients treated for up to several years, with an adverse event (AE) profile similar to short-term placebo-controlled trials. Common AEs included CNS symptoms (dizziness, somnolence, headache, and asthenia), accidental injury, and weight gain. CNS AEs tended to be mild and transient. Rates of sudden unexpected death in epilepsy (SUDEP), mortality, cancer, and status epilepticus were within the expected range for this population.

CONCLUSIONS

Adjunctive pregabalin was effective, generally well tolerated, and safe in the long-term treatment of partial seizures, and provided clinically meaningful seizure reduction and freedom without evidence of tolerance over 2 years of follow-up.

Comparison of antiepileptic drug prescribing in children in three European countries

PURPOSE

Antiepileptic drug (AED) use in young people is increasing. However, evidence of its use at a multinational level is limited. This study aims to characterize AED prescribing in the young in three European countries and to assess the capacity of drug safety surveillance.

METHODS

A retrospective cohort study was conducted in 2001-2005 using primary care databases: PEDIANET (Italy, 0-11 years), IPCI (The Netherlands, 0-18 years), and IMS Disease Analyzer (United Kingdom, 0-18 years). Prescribing prevalence was calculated by country, patient age, and drug type.

RESULTS

In 2005, AED prevalence in children (0-11 years) was highest in Italy [3.9 subjects/1,000 person-years (PY)] followed by the United Kingdom (3.0 subjects/1,000 PY) and The Netherlands (2.2 subjects/1,000 PY). Over the study period, prescribing prevalence in 0-11 year olds was stable in all countries. In contrast, a steady rise of AED prevalence was observed in adolescents (12-18 years) in the United Kingdom (p = 0.0003) but not in The Netherlands (p = 0.88). All countries showed a slight increase in prevalence for newer AEDs. Simultaneously, the prevalence of conventional AEDs decreased in The Netherlands and Italy, but not in the United Kingdom. In 2005, lamotrigine use was highest in The Netherlands and the United Kingdom, whereas topiramate was favored in Italy.

DISCUSSION

In Europe, conventional AEDs are still the main treatment choice for children with epilepsy, and the use of newer AEDs remains low. Our study highlights a lack of research capacity to conduct multinational AED safety studies in children. Further work should explore large databases and other health care settings to meet these research needs.

Patient-reported cognitive side effects of antiepileptic drugs: predictors and comparison of all commonly used antiepileptic drugs

Subjective cognitive side effects (CSEs) are common in patients taking antiepileptic drugs (AEDs). The objective of this study was to predict which patients are at risk for CSEs, and compare the CSE profiles of all commonly used AEDs. In this nonrandomized retrospective study, medical records of 1694 adult outpatients with epilepsy seen at our center over a 5-year period who had taken one or more AEDs were examined. Non-AED predictors of CSEs were investigated, and rates of AED-related CSEs were compared in 1189 patients (546 on monotherapy) newly started on an AED at our center. The average rate of AED-related intolerable CSEs (leading to dosage change or discontinuation) was 12.8%. On multivariate analysis, no significant non-AED predictors of CSEs were found. Significantly more intolerable CSEs were attributed to topiramate (21.5% of 130 patients) than to most other AEDs, including carbamazepine (9.9%), gabapentin (7.3%), levetiracetam (10.4%), lamotrigine (8.9%), oxcarbazepine (11.6%), and valproate (8.3%). CSE rates with zonisamide (14.9%) were significantly higher than those for gabapentin and lamotrigine. After exclusion of CSEs during the first 8 weeks of therapy, rates of CSEs were lower, but relative differences remained unchanged. In monotherapy, significantly more intolerable CSEs occurred with topiramate (11.1% of 18 patients) than with carbamazepine or valproate, and both phenytoin and zonisamide were associated with more CSEs than valproate. From this study, it can be concluded that intolerable patient-reported CSEs are most common with topiramate, followed by zonisamide, phenytoin, and oxcarbazepine. They are least likely to be reported with gabapentin, valproate, lamotrigine, carbamazepine, and levetiracetam.

CNS adverse events associated with antiepileptic drugs

A variety of newer antiepileptic drugs (AEDs) are now available for treating patients with epilepsy in addition to the 'conventional' drugs that have been available throughout a large part of the last century. Since these drugs act to suppress the pathological neuronal hyperexcitability that constitutes the final substrate in many seizure disorders, it is not surprising that they are prone to causing adverse reactions that affect the CNS.Information on adverse effects of the older AEDs has been mainly observational. Equally, whilst the newer drugs have been more systematically studied, their long-term adverse effects are not clearly known. This is illustrated by the relatively late emergence of the knowledge of visual field constriction in the case of vigabatrin, which only became known after several hundred thousand patient-years of use. However, older drugs continue to be studied and there has been more recent comment on the possible effect of valproate (valproic acid) on cognition following exposure to this drug in utero.With most AEDs, there are mainly dose-related adverse effects that could be considered generic, such as sedation, drowsiness, incoordination, nausea and fatigue. Careful dose titration with small initial doses can reduce the likelihood of these adverse effects occurring. Adverse effects such as paraesthesiae are more commonly reported with drugs such as topiramate and zonisamide that have carbonic anhydrase activity. Weight loss and anorexia can also be peculiar to these drugs. Neuropsychiatric adverse effects are reported with a variety of AEDs and may not be dose related. Some drugs, such as carbamazepine when used to treat primary generalized epilepsy, can exacerbate certain seizure types. Rare adverse effects such as hyperammonaemia with valproate are drug specific. There are relatively very few head-to-head comparisons of AEDs and limited information is available in this regard.In this review, we discuss the available literature and provide a comprehensive summary of adverse drug reactions of AEDs affecting the CNS.

Use and safety profile of antiepileptic drugs in Italy

OBJECTIVE

To analyse and discuss the use and the safety profile of individual antiepileptic drugs (AEDs) in Italy.

METHODS

The AED safety data referred to the period January 1988-June 2005 and were obtained from the database of the Italian Interregional Group of Pharmacovigilance (GIF). This database collects all spontaneous reports of suspected adverse drug reactions (ADRs) from six Italian regions which are the main contributors to the Italian spontaneous reporting system. Individual AED consumption data (defined daily dose/1,000 inhabitants per day) in the GIF area and in the whole of Italy referred to the period January 2003-June 2005 and were derived from drug sales data (Institute for Medical Statistics Health).

RESULTS

Phenobarbital was the most frequently used AED in the GIF area (4.26 DDD/1,000 inhabitants per day) followed by carbamazepine (1.97), valproic acid (1.33) and gabapentin (1.10). AED consumption in the whole of Italy showed a similar pattern. Gabapentin was the most frequently used AED among newer AEDs. In the GIF database 37,906 reports (up to June 2005) were present; 666 of them (1.76%) were associated with at least one AED (Anatomical Therapeutic Chemical code N03A). The AED with the highest number of reports was carbamazepine (208 reports) followed by phenobarbital (98), gabapentin (80), phenytoin (56), valproic acid (55), lamotrigine (51), oxcarbazepine (43) and vigabatrin (35). Use and toxicity profile were evaluated only for AEDs associated with at least 30 reports. Skin reactions were the most frequently reported ADRs, followed by haematological, general condition, hepatic, neurological and gastrointestinal adverse reactions. Phenobarbital, lamotrigine, carbamazepine and phenytoin had the highest percentage of skin reactions (69, 67, 60 and 54%, respectively). Many haematological reactions were reported for each AED; the highest percentage was related to valproic acid (25%). Vigabatrin was associated with the highest percentage of reactions related to hearing, vision and other senses (97%). Phenytoin and valproic acid had the highest percentage of hepatic reactions (30 and 20%), whereas gabapentin of nervous system, psychiatric, gastrointestinal and urinary reactions (26, 21, 21 and 14%, respectively) and phenobarbital of musculoskeletal reactions (13%).

CONCLUSIONS

In Italy antiepileptic drug therapy appears to be still dominated by traditional drugs. Our analysis showed a different safety profile related to each AED. Some of the drug-adverse reaction associations discussed are not included in the Italian drug leaflets or have not been reported before in the literature.

Psychiatric and behavioral side effects of the newer antiepileptic drugs in adults with epilepsy

OBJECTIVE

Psychiatric/behavioral side effects (PSEs) are common in patients taking antiepileptic drugs (AEDs). The objective of the study described here was to compare the PSE profiles of the newer AEDs.

METHODS

We examined the charts of 1394 adult outpatients seen at the Columbia Comprehensive Epilepsy Center who had taken one of the newer AEDs. We compared the rate of AED-related PSEs in patients newly started on the newer AEDs both before and after controlling for non-AED predictors of PSEs.

RESULTS

Overall, 221 of 1394 (16%) patients experienced PSEs. The average rate of AED-related PSEs for a single AED was 8.4%, with 6.1% resulting in dosage change and 4.3% resulting in AED discontinuation. Significantly fewer PSEs were attributed to gabapentin (n=160, 0.6% incidence, P<0.001) and lamotrigine (n=547, 4.8% incidence, P<0.001), and significantly more PSEs were attributed to levetiracetam (n=521, 15.7% incidence, P<0.001; 8.8% discontinued LEV because of PSEs). Vigabatrin, felbamate, and oxcarbazepine were associated with similarly low rates of PSEs in many analyses but with fewer of patients. Tiagabine was associated with high PSE rates (similar to those for levetiracetam), but was used much less commonly at our center. Intermediate rates of PSEs were attributed to topiramate and zonisamide (both nonsignificant). Psychiatric history was the most significant nondrug predictor of AED-related PSEs (PSEs occurred in 23% of patients with a psychiatric history vs 12% of patients without such a history, P<0.001). The relative rates of AED-related PSEs were similar when controlling for non-AED predictors and when analyzing only patients on monotherapy.

CONCLUSIONS

There are significant differences between the newer AEDs in terms of their PSE profiles. Patients taking levetiracetan experience significantly more PSEs than average, and patients taking gabapentin and lamotrigine experience significantly fewer PSEs. Even with the medication with the highest rate of PSEs (levetiracetam), less than 10% of patients discontinued it because of PSEs. A past psychiatric condition is the most significant nondrug predictor of AED-related PSEs.

Prioritizing children's medicines for research: a pharmaco-epidemiological study of antiepileptic drugs

AIMS

To investigate the prescribing epidemiology, in UK primary care, of newer antiepileptic drugs (AEDs) compared with conventional AEDs and to identify AEDs for further research in response to the European Medicines Agency report on epilepsy.

METHODS

Subjects aged 0-18 years, from the UK General Practice Research Database, who were prescribed an AED between 1993 and 2005. Prescribing prevalence and incidence, stratified by age and AED, were calculated.

RESULTS

A total of 7721 subjects were included and 70% were prescribed one drug. Overall prescribing prevalence for all AEDs had increased by 19%. The prevalence (95% confidence interval) of newer AED prescribing had increased fivefold from 0.67 (0.58, 0.76) to 3.20 (3.03, 3.37) per 1000 person-years. Conversely, the prevalence of conventional AEDs had declined by 17% from 6.63 (6.34, 6.92) per 1000 person-years to 5.51 (5.28, 5.73). Lamotrigine had 65% of newer AED prescriptions and was the most prescribed newer drug for both the 2-11 years and 12-18 years age groups with prevalences of 1.47 and 2.55 per 1000 person-years, respectively.

CONCLUSIONS

There is a rapid increase in newer AED prescribing to children and adolescents in UK primary care, while prescribing of conventional AEDs is declining. Since 1997, the prevalence of vigabatrin has fallen, coinciding with the UK safety warnings on visual field defects. The uptake of lamotrigine, topiramate and levetiracetam is rapid and as the safety of these drugs has not been established, they should be prioritized for further research. Following concerns with vigabatrin, long-term safety surveillance of all newer AEDs is strongly recommended.

Clinical development of antiepileptic drugs in adults

Over the last two decades, ten so-called newer antiepileptic drugs (AEDs) have been approved around the world, the majority of which have found and maintained a place in the seizure-fighting armamentarium for the whole spectrum of epilepsies and epileptic syndromes; some of these drugs have features that are improved compared with the older drugs. Within that same time period, the process of clinical development of AEDs has also undergone changes and has become much more complex and costly. Efforts are underway to shift decision-making about the clinical viability of AED candidates to earlier development stages, using the concept of translational medicine. However, thus far all of the newer AEDs have undergone a standard development as an adjunct in the control of adult partial seizures; in some cases, development has been expanded to other seizure types and pediatric syndromes. Currently, the path to global approval for use in monotherapy is under review and is often debated with regulatory authorities. Clinical treatment guidelines consider randomized, blinded, well controlled studies as the premier level of evidence-based medicine; these studies originate mostly in confirmatory phases of the development program. However, with the rigid designs and criteria in regulatory driven trials, effectiveness in the clinical practice setting may not be sufficiently predicted by these studies, leading to frustrations from individual practitioners. Finally, additional safety issues regularly occur only after the postlaunch exposure to a broader population making necessary a continuing, and thorough, pharmacovigilance after the AED has come to market.

The effect of combined administration of ethanol and gabapentin on rabbit electroencephalographic activity

The central effect of ethanol is mainly connected with the effect on GABAergic, glutamatergic, serotonergic and opioid transmission. The mechanism of gabapentin effect suggests that it may alleviate the rewarding effect of ethanol, which may be used in the treatment of addiction. We decided to examine the interaction of ethanol with gabapentin by a pharmaco-electroencephalographic (EEG) method. The influence of gabapentin on the effect of ethanol on EEG of rabbits (midbrain reticular formation, hippocampus, frontal cortex) was tested. Gabapentin was administered at a single dose (25 and 100 mg/kg orally) or repeatedly twice a day at a total dose of 25 mg/kg for 14 days. Ethanol was injected at a dose of 0.8 g/kg 60 min. after gabapentin treatment. Ethanol caused an increase in the slow frequencies (0.5-4 Hz) in the recording, as well as a marked decrease of the fastest frequencies (13-30 and 30-45 Hz). Gabapentin lead to changes in rabbit EEG recording suggesting an depressant effect on the CNS (increase of slow and decrease of fast frequencies). The effects were less pronounced after repeated doses, which may indicate adaptative changes in the receptors. Gabapentin administered both in a single dose and for 7 days markedly enhanced the effect of ethanol on EEG recordings in rabbits. Repeated doses of gabapentin decrease the sensitivity of the hippocampus to the effect of ethanol.

Effect of the administration of tiagabine and gabapentin on rabbit electroencephalogram activity

New generation antiepileptic drugs, including gabapentin and tiagabine, are used in monotherapy or in combination with other drugs for specific seizure types. The multidirectional mechanism of activity and varied pharmacological properties of these drugs suggest that they could also be used in the therapy of other diseases. A possible limitation of new generation antiepileptic drugs is the incidence of CNS-related adverse effects. Few studies have assessed the effect of new antiepileptic drugs on electroencephalogram (EEG) recordings in subjects using these drugs for diseases other than epilepsy. The aim of this study was to determine the effects of tiagabine and gabapentin on EEG recordings from the midbrain reticular formation, dorsal hippocampus and frontal cortex in rabbits. Tiagabine was administered orally at a single dose of 5 and 20 mg kg(-1), or repeatedly at a dose of 5 mg kg(-1) (twice a day) for 14 days. Gabapentin was administered orally at a single dose of 25 and 100 mg kg(-1), or repeatedly at a dose of 25 mg kg(-1) (twice a day) for 14 days. Both tiagabine and gabapentin caused changes indicative of CNS inhibitory properties, which may be associated with the adverse effects of the drugs. After repeated doses of the drugs, the changes in EEG recordings were less pronounced than after single doses, which may indicate adaptive changes. The hippocampus was found to be the least sensitive to the effect of gabapentin.

Current status of augmentation and combination treatments for major depressive disorder: a literature review and a proposal for a novel approach to improve practice

Most patients with major depressive disorder (MDD) do not reach symptom remission. These patients with residual symptoms have worse function and worse prognosis than those who remit. Several augmentation and combination treatments are used to either increase the chances of achieving remission or to eliminate/minimize residual depressive symptoms. Evidence for these pharmacological approaches rests primarily on open, uncontrolled studies, and there are clearly not enough controlled studies. Clinicians should carefully weigh these different treatment options to increase their patients' chances of achieving and sustaining remission from depression. This paper will review the pertinent studies and will propose a novel approach to improve practice involving the use of augmentation or combination strategies at the outset of initial treatment to primarily enhance the chances of remission through synergy and/or a broader spectrum of action. This novel approach could potentially enhance retention and/or increase remission rates since the lack of response with antidepressant monotherapy may lead many depressed patients with little or no benefit to drop out of treatment, precluding the subsequent use of augmentation or combination strategies altogether. In addition, the emergence of certain side-effects (e.g., agitation, insomnia) or the persistence of some initial baseline symptoms (e.g., anxiety, insomnia) may lead to premature discontinuation from monotherapy in the absence of concomitant use of augmenting pharmacological options targeting these symptoms.

Economic evaluation of oral treatments for neuropathic pain

The effectiveness of amitriptyline, carbamazepine, gabapentin, and tramadol for the treatment of neuropathic pain has been demonstrated, but it is unknown which one is the most cost-effective. We designed a cost-utility analysis of a hypothetical cohort with neuropathic pain of postherpetic or diabetic origin. The perspective of the economic evaluation was that of a third-party payor. For effectiveness and safety estimates, we performed a systematic review of the literature. For direct cost estimates, we used average wholesale prices, and the American Medicare and Clinical Laboratory Fee Schedules. For utilities of health states, we used the Health Utilities Index. We modeled 1 month of therapy. For comparisons among treatments, we estimated incremental cost per utility gained. To allow for uncertainty from variations in drug effectiveness, safety, and amount of medication needed, we conducted a probabilistic Monte Carlo simulation. Amitriptyline was the cheapest strategy, followed by carbamazepine, and both were equally beneficial. Gabapentin was the most expensive as well as the least beneficial. A multivariable probabilistic simulation produced similar results to the base-case scenario. In summary, amitriptyline and carbamazepine are more cost-effective than tramadol and gabapentin and should be considered as first-line treatment for neuropathic pain in patients free of renal or cardiovascular disease.

PERSPECTIVE

Prescription practices should be based on the best available evidence, which includes the evaluation of the medication's cost-effectiveness. This does not mean that the cheapest or the most expensive, but rather the most cost-effective medication should be chosen-the one whose benefits are worth the harms and costs. We report a cost-effectiveness evaluation of treatments for neuropathic pain.