Availability of antiepileptic drugs across Europe

Anti-seizure medication prescription preferences: a Moroccan multicenter study

Background

The management of epilepsy is mainly based on antiseizure medications (ASMs). More than 20 ASMs have been introduced in clinical practice, providing a multitude of prescription choices. To date, there are no published data on the trends in ASMs prescriptions in Morocco. Therefore, we conducted a survey among practicing neurologists in seven tertiary referral hospitals in Morocco to study the current ASMs prescription preferences and their modifying factors.

Methods

Our descriptive and analytical cross-sectional study was based on a survey sent between January and April 2022 to neurologists practicing in seven tertiary referral hospitals in Morocco. Information regarding the prescription of ASMs was collected using an exploitation form and analyzed using the SPSS version 13 software.

Results

Based on questionnaire responses, our results showed that Valproic acid (96.3%) and Lamotrigine (59.8%) were the two most prescribed ASMs for generalized seizure types. For focal seizure types, Carbamazepine (98.8%) and Levetiracetam (34.1%) were the most commonly prescribed drugs, whereas for combined focal and generalized seizure types, the combination of Valproic acid and Carbamazepine (38.55%) was the most prescribed. Phenobarbital was the most commonly prescribed ASM for status epilepticus (40.2%). These prescription preferences were mainly due to seizure types, cost, health insurance coverage, years of experience, and additional epileptology training (p < 0.05).

Conclusion

Our results show a shift in the prescription of ASMs in Morocco. Similar to many other countries, valproic acid and carbamazepine are considered the first-line treatments for generalized and focal seizure types. Some factors remain as major challenges in enhancing epilepsy management in Morocco.

Ion-Channel Antiepileptic Drugs: An Analytical Perspective on the Therapeutic Drug Monitoring (TDM) of Ezogabine, Lacosamide, and Zonisamide

The term seizures includes a wide array of different disorders with variable etiology, which currently represent one of the most important classes of neurological illnesses. As a consequence, many different antiepileptic drugs (AEDs) are currently available, exploiting different activity mechanisms and providing different levels of performance in terms of selectivity, safety, and efficacy. AEDs are currently among the psychoactive drugs most frequently involved in therapeutic drug monitoring (TDM) practices. Thus, the plasma levels of AEDs and their metabolites are monitored and correlated to administered doses, therapeutic efficacy, side effects, and toxic effects. As for any analytical endeavour, the quality of plasma concentration data is only as good as the analytical method allows. In this review, the main techniques and methods are described, suitable for the TDM of three AEDs belonging to the class of ion channel agents: ezogabine (or retigabine), lacosamide, and zonisamide. In addition to this analytical overview, data are provided, pertaining to two of the most important use cases for the TDM of antiepileptics: drug–drug interactions and neuroprotection activity studies. This review contains 146 references.

Current role of carbamazepine and oxcarbazepine in the management of epilepsy

Epilepsy is one of the most common neurological disorders, affecting approximately 50 million people worldwide. Despite a dramatic increase in treatment options over the past 30 years, it still ranks fourth in the world's disease burden. There are now close to 30 antiepileptic drugs (AEDs), with more than two thirds introduced to the market after carbamazepine (CBZ) and one third after its derivative, oxcarbazepine (OXC). Following the introduction of these newer AEDs, the role of CBZ and OXC in the therapeutic armamentarium for seizure control and effective epilepsy management needs to be reviewed. The main guidelines list both CBZ and OXC as first-line options or second-line alternatives for the treatment of focal-onset epilepsy and primary generalized tonic-clonic seizures. While evidence suggests that overall AEDs have similar efficacy, some newer AEDs may be better tolerated than CBZ. In line with this, there have been changes in treatment patterns, with many variations across different countries. However, CBZ remains among the two or three most prescribed drugs for focal epilepsy in many countries, and is widely used across Europe, Africa, South America, and Asia, where it represents a good compromise between cost, availability, and effectiveness. OXC is among the first-choice options for the initial treatment of focal-onset seizures in several countries, including the US and China, where the oral suspension is commonly prescribed. This review provides guidance on the optimal use of these two drugs in clinical practice, including in children, the elderly, and in pregnancy.

Pharmacoresponse in genetic generalized epilepsy: a genome-wide association study

Aim: Pharmacoresistance is a major burden in epilepsy treatment. We aimed to identify genetic biomarkers in response to specific antiepileptic drugs (AEDs) in genetic generalized epilepsies (GGE). Materials & methods: We conducted a genome-wide association study (GWAS) of 3.3 million autosomal SNPs in 893 European subjects with GGE – responsive or nonresponsive to lamotrigine, levetiracetam and valproic acid. Results: Our GWAS of AED response revealed suggestive evidence for association at 29 genomic loci (p <10-5) but no significant association reflecting its limited power. The suggestive associations highlight candidate genes that are implicated in epileptogenesis and neurodevelopment. Conclusion: This first GWAS of AED response in GGE provides a comprehensive reference of SNP associations for hypothesis-driven candidate gene analyses in upcoming pharmacogenetic studies.

Assessment and effect of a gap between new-onset epilepsy diagnosis and treatment in the US

Objective

To estimate the treatment gap between a new epilepsy diagnosis and antiepileptic drug (AED) initiation in the United States.

Methods

Retrospective claims-based cohort study using Truven Health MarketScan databases (commercial and supplemental Medicare, calendar years 2010–2015; Medicaid, 2010–2014) and a validation study using PharMetrics Plus Database linked to LRx claims database (2009–2014). Persons met epilepsy diagnostic criteria, had an index date (first epilepsy diagnosis) with a preceding 2-year baseline (1 year for persons aged 1 to <2 years; none for persons <1 year), and continuous medical and pharmacy enrollment without epilepsy/seizure diagnosis or AED prescription during baseline. Outcomes included percentage of untreated persons (no AED prescription) up to 3 years' follow-up and comparative outcomes (incidence rate ratio: untreated persons/treated persons), including medical events and health care resource utilization.

Results

In the primary study, 59,970 persons met selection (or inclusion) criteria; 36.7% of persons with newly diagnosed epilepsy remained untreated up to 3 years after diagnosis. In the validation study (N = 30,890), 31.8% of persons remained untreated up to 3 years after diagnosis. Lack of AED treatment was associated with an adjusted incidence rate ratio (95% confidence interval) of 1.2 (1.2–1.3) for medical events, 2.3 (2.2–2.3) for hospitalizations, and 2.8 (2.7–2.9) for emergency department visits.

Conclusions

One-third of newly diagnosed persons remain untreated up to 3 years after epilepsy diagnosis. The increased risk of medical events and health care utilization highlights the consequences of delayed treatment after epilepsy diagnosis, which might be preventable.

The provision of epilepsy care across Europe 2017: A 17-year follow-up survey

OBJECTIVE

To assess the resources available in the provision of epilepsy care across Europe and the developments since the International League Against Epilepsy (ILAE) survey published in 2003 (data collected in 2000).

METHODS

An updated online version of the European Epilepsy Services Inventory was distributed to all European chapters of the ILAE (N = 47) and responses were obtained from 33 chapters (response rate 70%). To assess trends and allow comparisons with the survey published in 2003, the responding countries were divided into 4 groups (Western, Central, Southern, and Eastern). Responses from European Union (EU) member states are reported as a subgroup (N = 23), since the current survey is a part of the EU-funded European Study on the Burden and Care of Epilepsy (ESBACE, www.esbace.eu).

RESULTS

The total number of physicians involved in epilepsy care had increased since 2000, with the largest increase seen for neurologists. The gap between the best- and the least-provided areas with regard to the competence of the providers had diminished. However, the density of comprehensive multidisciplinary epilepsy teams had not changed to any greater degree. The main problems reported by the chapters were to a large extent the same as in 2000 and included lack of specialists and specialist care, lack or underuse of epilepsy surgery, and problems regarding financing and resource allocation. Several chapters also highlighted problems with healthcare structure and organization.

SIGNIFICANCE

Although there have been some improvements concerning the availability of care for people with epilepsy in Europe over the last 17 years, there are still a number of problem areas with little improvement or where there are important regional differences.

Medication adherence and adverse effect profile of antiepileptic drugs in Nigerian patients with epilepsy

Aim: Medication adherence remains a major challenge among patients with epilepsy (PWE) with the adverse effect profile of antiepileptic drugs (AEDs) as one of its main drivers. Methods: This was a cross-sectional questionnaire-based study among PWE in selected Nigerian tertiary healthcare facilities using the Morisky Medication Adherence Scale and the Liverpool Adverse Effect Profile (LAEP). Results: 126 PWE from four tertiary healthcare facilities were included in this study comprising of 59 (46.8%) males and 67 (53.2%) females. Carbamazepine (104/70.7%), sodium valproate (23/15.6%) and phenytoin (11/7.5%) were the most commonly prescribed AEDs. Using the Morisky Medication Adherence Scale, 17.2, 38.3 and 44.5% of patients were classified as having high, medium and low adherence, respectively. The mean LAEP score was 23.69 ± 6.07. The most common reported adverse effects among respondents were tiredness (30.4%) and headache (22.5%). Conclusion: Medication adherence to AED was poor among patients in this study.

Availability and cost of major and first-line antiepileptic drugs: a comprehensive evaluation in the capital of Madagascar

Background

The prevalence of epilepsy is high in Madagascar (23.5/1000), as is the treatment gap (estimated at 92 %). The health system of the country is underfunded; some AEDs are used, and the national drug policy does not encourage price regulation or the administration of generic agents. We conducted a cross-sectional study to assess the availability and cost of solid oral AED formulations in Antananarivo, capital of Madagascar. Data were gathered from all officially registered pharmacies (according to the drug agency list, updated in 2015) by means of telephone interviews lasting no more than 10 min and conducted by a native Malagasy speaker. With regard to other sources (hospitals, illicit sales) data were obtained at specific visits. The study received ethical approval from the Madagascar Ministry of Health.

Findings

A total of 91 of 100 pharmacies (the nine not included were because of an inoperative phone number), two of three public hospitals, and two illegal outlets were investigated. Sodium valproate was available in 84.6 % of the pharmacies, while carbamazepine and phenobarbital were available in 68.1 % and 36.3 % of the pharmacies, respectively, but phenytoin was not available in any supply chain. There were more originator brands than generic formulations, with a higher cost (range 20.3–81.1 %, median 40.7 %) compared to the equivalent generic. The public system had only a very limited choice of AED, but offered the lowest costs. Illicit sources were more expensive by 54.3 % for carbamazepine and 62.5 % for phenobarbital. Concerning the annual cost of treatment, the average percentage of the gross national income per capita based on the purchasing power parity was 29.8 %/19.0 % (brand/generic) for sodium valproate, 16.4 %/7.3 % (brand/generic) for carbamazepine, 8.9 %/5.1 % (brand/generic) for phenobarbital.

Conclusions

The main sources of AEDs were private pharmacies, but the stocks held were low. The financial burden was still important in the capital of Madagascar, mainly the consequence of a highly developed private sector at the expense of the public sector. Although sodium valproate remains the most expensive solution, it still remains the most available instead of phenobarbital. The most striking feature of this study concerns the cost of AEDs in the informal sector, mostly used because they are deemed to provide less costly drugs, the opposite was observed there. The assessment of the cost and availability of medicines was easily and quickly implemented. It provided a relevant focus of the situation in areas difficult to investigate, in terms of road network and geographical situation.

Changes in utilisation of antiepileptic drugs in epilepsy and non-epilepsy disorders-a pharmacoepidemiological study and clinical implications

PURPOSE

The purpose of this study was to investigate changes in utilisation of antiepileptic drugs (AEDs) in epilepsy and non-epilepsy disorders in Norway and furthermore to study the retention rates of the most commonly used AEDs in these indications in long-term use.

METHODS

The data consisted of all prescriptions of AEDs from Norwegian pharmacies in the Norwegian Prescription Database (NorPD) (2004-2012). Variables included anonymous data regarding age, gender, diagnosis specific reimbursement codes and utilisation of AEDs.

RESULTS

In recent years (2008-2012), the utilisation of AEDs in non-epilepsy disorders accounted for 45-53 % of the total use. In epilepsy, the most commonly used AED was lamotrigine, followed by levetiracetam, carbamazepine and valproate. Lamotrigine was also the predominant AED used in psychiatry, while pregabalin and gabapentin were mostly used in neuropathic pain. In migraine, topiramate predominated but accounted for <1 % of the total utilisation of AEDs. The majority of prescriptions were by general practitioners and only 20 % by specialists. Regardless of indication, newer AEDs had higher retention rates (34-48 %) and were used for a longer period before discontinuation.

CONCLUSIONS

The use of AEDs in non-epilepsy disorders is increasing and accounted for 53 % in 2012. Newer AEDs were predominantly used and demonstrated higher retention rates than older AEDs in all indications. This nationwide study demonstrates an increased exposure to AEDs in new patient groups, and details in prescription patterns and clinical and safety considerations should be closely monitored. This contributes to long-term post-marketing data of AED and accordingly improved pharmacovigilance.