Prescribing patterns of antiepileptic drugs in Italy: a nationwide population-based study in the years 2000-2005

Indications and prescribing patterns of antiseizure medications in children in New Zealand

AIM

To determine indications and prescribing patterns for antiseizure medications (ASMs) in children by age, sex, and socioeconomic status.

METHOD

This retrospective study searched the New Zealand database of ASM prescriptions dispensed to individuals aged 18 years or under during 2015 in three regions of New Zealand (48% paediatric population). Medical records were reviewed by a paediatric neurologist for indication. ASMs were grouped into old or new (1993 onwards).

RESULTS

In total, 2594 children (0 to 18 years, mean age 11 years 2 months, median 12 years; 51% male) were dispensed 3557 ASMs for seizures (76%), pain (6%), headache (5%), mental health (3%), and movement disorders (2%). After 10 years of age, lamotrigine was more likely and valproate less likely to be prescribed in females than males. No sex difference was observed for valproate prescriptions for non-seizure indications. Topiramate prescriptions increased in adolescent females. Prescriptions for non-seizure indications increased from 7% in children aged 6 years or under to 31% in 16- to 18-year-olds. The proportion of children receiving a new ASM compared to an old ASM was greater in children from higher than lower socioeconomic areas.

INTERPRETATION

Our results highlight a need for focused ASM teratogenicity messaging to clinicians prescribing ASMs for non-seizure indications. In addition, to improve equity of epilepsy care, it is critical for health policies to consider socioeconomic factors that impact on ASM prescribing.

Bonaventura C, Marras CE, Palestini C, Ferlazzo E, Venturelli E, Dainese F, Martella F, Paladin F, Villani F, Capizzi G, Napoleoni L, Stanzani L, Stragapede L, Zummo L, Balducci M, Eoli M, Rizzi M, Vernaleone M, Messina R, Vittorini R, Gasparini S, Ius T, Cianci V, Manfioli V, Mariani V, Capovilla G. First-line levetiracetam versus enzyme-inducing antiseizure medication in glioma patients with epilepsy

OBJECTIVE

This study aimed to directly compare the effectiveness of first-line monotherapy levetiracetam (LEV) versus enzyme-inducing antiseizure medications (EIASMs) in glioma patients.

METHODS

In this nationwide retrospective observational cohort study, Grade 2-4 glioma patients were included, with a maximum duration of follow-up of 36 months. Primary outcome was antiseizure medication (ASM) treatment failure for any reason, and secondary outcomes were treatment failure due to uncontrolled seizures and due to adverse effects. For estimation of the association between ASM treatment and ASM treatment failure, multivariate cause-specific cox proportional hazard models were estimated, adjusting for potential confounders.

RESULTS

In the original cohort, a total of 808 brain tumor patients with epilepsy were included, of whom 109 glioma patients were prescribed first-line LEV and 183 glioma patients first-line EIASMs. The EIASM group had a significantly higher risk of treatment failure for any reason compared to LEV (adjusted hazard ratio [aHR] = 1.82, 95% confidence interval [CI] = 1.20-2.75, p = .005). Treatment failure due to uncontrolled seizures did not differ significantly between EIASMs and LEV (aHR = 1.32, 95% CI = .78-2.25, p = .300), but treatment failure due to adverse effects differed significantly (aHR = 4.87, 95% CI = 1.89-12.55, p = .001).

SIGNIFICANCE

In this study, it was demonstrated that LEV had a significantly better effectiveness (i.e., less ASM treatment failure for any reason or due to adverse effects) compared to EIASMs, supporting the current neuro-oncology guideline recommendations to avoid EIASMs in glioma patients.

Social Media Analytics for Pharmacovigilance of Antiepileptic Drugs

Epilepsy is a common neurological disorder worldwide and antiepileptic drug (AED) therapy is the cornerstone of its treatment. It has a laudable aim of achieving seizure freedom with minimal, if any, adverse drug reactions (ADRs). Too often, AED treatment is a long-lasting journey, in which ADRs have a crucial role in its administration. Therefore, from a pharmacovigilance perspective, detecting the ADRs of AEDs is a task of utmost importance. Typically, this task is accomplished by analyzing relevant data from spontaneous reporting systems. Despite their wide adoption for pharmacovigilance activities, the passiveness and high underreporting ratio associated with spontaneous reporting systems have encouraged the consideration of other data sources such as electronic health databases and pharmaceutical databases. Social media is the most recent alternative data source with many promising potentials to overcome the shortcomings of traditional data sources. Although in the literature some attempts have investigated the validity and utility of social media for ADR detection of different groups of drugs, none of them was dedicated to the ADRs of AEDs. Hence, this paper presents a novel investigation of the validity and utility of social media as an alternative data source for the detection of AED ADRs. To this end, a dataset of consumer reviews from two online health communities has been collected. The dataset is preprocessed; the unigram, bigram, and trigram are generated; and the ADRs of each AED are extracted with the aid of consumer health vocabulary and ADR lexicon. Three widely used measures, namely, proportional reporting ratio, reporting odds ratio, and information component, are used to measure the association between each ADR and AED. The resulting list of signaled ADRs for each AED is validated against a widely used ADR database, called Side Effect Resource, in terms of the precision of ADR detection. The validation results indicate the validity of online health community data for the detection of AED ADRs. Furthermore, the lists of signaled AED ADRs are analyzed to answer questions related to the common ADRs of AEDs and the similarities between AEDs in terms of their signaled ADRs. The consistency of the drawn answers with the existing pharmaceutical knowledge suggests the utility of the data from online health communities for AED-related knowledge discovery tasks.

Carbamazepine Levels Related to the Demographic Indicators in Groundwater of Densely Populated Area

Consumption of pharmaceuticals by people is growing. Carbamazepine (CBZ) is an extensively used anti-epileptic drug that is recalcitrant to degradation. As a result, CBZ has been widely detected in the aquatic ecosystem due to its daily consumption and drainage in sewage systems. Leakages from sewage networks and septic tanks may represent one of the main sources of CBZ in groundwater. In this study, CBZ concentrations in groundwater and their correlations with the demographic structure of the population were investigated in the densely populated Milan urban area. Seventy-six demographic variables were retrieved from the Italian Population and Housing census. Twenty-one groundwater samples were collected from unconfined and semi-confined aquifers of the Milan area and the concentration of CBZ was measured. Groundwater CBZ levels in both aquifers were associated with the demographic data within a circular buffer with a radius of 1.5 km. All data were analyzed using a multivariate statistical approach. The results showed a significant association (p < 0.05) between CBZ concentrations and specific demographic segments of the population. Higher CBZ concentrations were found to be associated with the population aged 70 years and over (aging index), and with families having children aged under 5 years (family index). In addition, the divorce index was correlated with the high concentration of CBZ, whereas the educated and sexagenarian population showed a negative correlation. Our results indicated that the contamination of CBZ follows the same pattern in unconfined and semi-confined aquifers, which are used for drinking water purposes in Milan area. Therefore, changing the CBZ consumption pattern or replacing CBZ with other drugs may strongly influence groundwater contamination of the investigated area.

Trends in prescribing patterns of antiepileptic drugs among older adult inpatients in a Brazilian tertiary center

BACKGROUND

Data on prescribing patterns of antiepileptic drugs (AEDs) to older adult inpatients are limited.

OBJECTIVE

To assess changes in prescribing patterns of AEDs to older adult inpatients with late-onset epilepsy between 2009-2010 and 2015-2019, and to interpret any unexpected patterns over the 2015-2019 period.

METHODS

Patients aged ≥60 years with late-onset epilepsy from a tertiary center were selected. Demographic data, seizure characteristics and etiology, comorbidities, and comedications were analyzed, in addition to prescription regimens of inpatients taking AEDs to treat epilepsy. AED regimens were categorized into two groups: group 1 included appropriate AEDs (carbamazepine, oxcarbazepine, valproic acid, gabapentin, clobazam, lamotrigine, levetiracetam, topiramate, and lacosamide); and group 2 comprised suboptimal AEDs (phenytoin and phenobarbital). Multivariate logistic regression analysis was performed to identify risk factors for prescription of suboptimal AEDs.

RESULTS

134 patients were included in the study (mean age: 77.2±9.6 years). A significant reduction in the prescription of suboptimal AEDs (from 73.3 to 51.5%; p<0.001) was found; however, phenytoin remained the most commonly prescribed AED to older adult inpatients. We also found an increase in the prescription of lamotrigine (from 5.5 to 33.6%) and levetiracetam (from 0 to 29.1%) over time. Convulsive status epilepticus (SE) and acute symptomatic seizures associated with remote and progressive etiologies were risk factors for the prescription of suboptimal AEDs.

CONCLUSIONS

Phenytoin was the main suboptimal AED prescribed in our population, and convulsive SE and acute symptomatic seizures associated with some etiologies were independent risk factors for phenytoin prescription. These results suggest ongoing commitment to reducing the prescription of suboptimal AEDs, particularly phenytoin in Brazilian emergence rooms.

Co-prescription of gabapentinoids and opioids among adults with and without osteoarthritis in the United Kingdom between 1995 and 2017

Objectives

To produce national and regional estimates and trends for gabapentinoid–opioid co-prescribing rates in patients with OA, both in absolute terms and relative to matched controls without OA.

Methods

Using the UK Clinical Practice Research Datalink database we first constructed age–sex–practice–date 1:1 matched cohorts of patients aged ≥40 years with and without a new diagnosis of OA between 1995–2017 and estimated the relative incidence of a first gabapentinoid prescription. Incident gabapentinoid users in both cohorts were followed to estimate and compare the event rate of gabapentinoid–opioid co-prescription (prescription from both classes within the same 28-day window).

Results

The incidence of first gabapentinoid prescription was 3-fold higher in patients with OA than in matched controls [n = 215 357; incidence rate ratio (IRR) 2.93; 95% CI: 2.87, 3.00]. Among incident gabapentinoid users with OA (n = 27 374, median follow-up 3.9 years) the event rate of gabapentinoid–opioid co-prescription was 4.03 (4.02–4.05) per person-year. The rate was higher in OA patients classed as long-term gabapentinoid users (6.24; 6.22–6.26). These rates were significantly higher than in incident gabapentinoid users without OA [adjusted-IRR: 1.29 (1.28–1.30)]. This elevated risk was observed across age, sex, geographic regions, and calendar years, when restricted to strong opioids and to long-term gabapentinoid users, and when co-prescription was defined as within 14 days and same-day prescribing.

Conclusions

Patients with OA not only have a higher risk of being prescribed a gabapentinoid but, once prescribed a gabapentinoid, are also at greater risk of opioid co-prescription. Strict restriction of gabapentinoid–opioid co-prescription, and improved access to, and uptake of, effective non-pharmacological and surgical alternatives for OA are required.

Psychotropic Drug-Associated Pneumonia in Older Adults

The use of psychotropic drugs (antipsychotics, benzodiazepines and benzodiazepine-related drugs, and antidepressants) is common, with a prevalence estimates range of 19-29% among community dwelling older adults. These drugs are often prescribed for off-label use, including neuropsychiatric symptoms. The older adult population also has high rates of pneumonia and some of these cases may be associated with adverse drug events. In this narrative review, we summarize the findings from current observational studies on the association between psychotropic drug use and pneumonia in older adults. In addition to studies assessing the use of psychotropics, we included antiepileptic drugs, as they are also central nervous system-acting drugs, whose use is becoming more common in the aging population. The use of antipsychotics, benzodiazepine, and benzodiazepine-related drugs are associated with increased risk of pneumonia in older adults (≥ 65 years of age), and these findings are not limited to this age group. Minimal and conflicting evidence has been reported on the association between antidepressant drug use and pneumonia, but differences between study populations make it difficult to compare findings. Studies regarding antiepileptic drug use and risk of pneumonia in older persons are lacking, although an increased risk of pneumonia in antiepileptic drug users compared with non-users in persons with Alzheimer's disease has been reported. Tools such as the American Geriatric Society Beers Criteria and the STOPP/START criteria for potentially inappropriate medications aids prescribers to avoid these drugs in order to reduce the risk of adverse drug events. However, risk of pneumonia is not mentioned in the current criteria and more research on this topic is needed, especially in vulnerable populations, such as persons with dementia.

Trends in sodium valproate prescriptions among children aged 0 to 14 years between 2010 and 2016: A study based on the French National Health Insurance Database

PURPOSE

After a huge campaign of information on the teratogenic risk of sodium valproate (VPA) having taken place in France we aimed to evaluate the trend of its prescriptions in young epileptic girls.

METHOD

Using the French National Health Insurance Database we searched for patients aged 0-14 years being supplied an antiepileptic drug (AED) between 2010 and 2016.

RESULTS

113,362 children received at least one AED, 61,259 boys and 52,103 girls. Compared to 2010-2014 years, VPA was less prescribed in 2016 as first AED (29% vs 37.3% respectively). The difference between the two periods was greater for girls (-41%) than for boys (-12%).

CONCLUSION

The changing trend of VPA as first AED prescribed, particularly in girls, reflects published evidence in terms of safety.

Gabapentin and Pregabalin and Risk of Atrial Fibrillation in the Elderly: A Population-Based Cohort Study in an Electronic Prescription Database

Introduction

Gabapentin and pregabalin are widely prescribed to elderly people, but data on their pharmacokinetics, safety, and efficacy in this population are scarce. Neurological adverse effects are common. Atrial fibrillation (AF) associated with their use has been described in several case reports and case series, but the incidence is unknown.

Objective

The aim of this study was to assess the association between exposure to gabapentin or pregabalin and AF in the elderly.

Methods

Patients ≥ 65 years of age starting treatment with either gabapentin or pregabalin between January 1 and March 31, 2015, free of cardiovascular disease, and who did not receive the alternate study medications were studied. They were compared with patients who initiated treatment with an analgesic opiate or with alprazolam or diazepam. The two primary outcome variables were a first claim of an oral anticoagulant plus an antiarrhythmic drug (OAC + AA), or of an oral anticoagulant or an antiplatelet agent plus an antiarrhythmic drug (OAC/APA + AA), in the 3 months after treatment initiation.

Results

Compared with opiate analgesics, both gabapentin and pregabalin were associated with an increased risk of initiating OAC/APA + AA. The incidence was 6 of 668 (9.0 per 1000 patients) with gabapentin, versus 12 of 3889 (3.1 per 1000) with opiates, relative risk (RR) 2.91 (95% confidence interval [CI] 1.10–7.73), and for pregabalin it was 6 of 698 (8.6 per 1000) RR 2.79 (95% CI 1.05–7.40). The comparison with alprazolam/diazepam gave similar results. The risks did not vary by age, sex, or co-treatment with NSAIDs, and they increased with dose.

Conclusion

In elderly patients free of cardiovascular disease, an association between new exposure to gabapentin or pregabalin and initiating treatment for AF was found. These results should be confirmed in other studies.

Electronic supplementary material

The online version of this article (10.1007/s40264-018-0695-6) contains supplementary material, which is available to authorized users.

Frequency of drug combinations between enzyme-inducing first-generation antiepileptic drugs and inducible drugs in patients with epilepsy

OBJECTIVE

The objective of the study was to systematically assess, through the analysis of administrative data, the frequency of combinations of first-generation enzyme-inducing (EI) antiepileptic drugs (AEDs) with drugs frequently prescribed in patients with epilepsy whose metabolism is induced by EIAEDs.

METHODS

From the population of Tuscany (a region in Italy of about 3,750,000 habitants), patients who had been treated with at least one first-generation EIAEDs (carbamazepine, phenytoin, phenobarbital, and primidone) and had received prescriptions of an inducible non-AED (NON-AED) included in a prespecified list of 103 inducible drugs were identified.

RESULTS

At the index date, 9221 patients with epilepsy were treated with at least one traditional EIAED, and there were 2538 drug combinations between EIAEDs and NON-AEDs, which may result in potentially serious clinical consequences, and 3317 combinations with NON-AEDs that have their metabolism consistently increased.

CONCLUSIONS

Patients with epilepsy treated with traditional EIAEDs are at a very high risk of drug interactions.

Intentional Drug Overdose Involving Pregabalin and Gabapentin: Findings from the National Self-Harm Registry Ireland, 2007-2015

INTRODUCTION

Intentional drug overdose (IDO) is a significant public health problem. Concerns about the misuse of gabapentinoids, i.e. pregabalin and gabapentin, including their consumption in IDO have grown in recent years. This paper examines the trends in the prevalence of gabapentinoids taken in IDO, the profile of individuals taking them, and associated overdose characteristics.

METHODS

Presentations to emergency departments involving IDO, recorded by the National Self-Harm Registry Ireland between 1 January 2007 and 31 December 2015 were examined. Data items included patient demographics, drug names, total tablet quantity consumed and alcohol involvement.

RESULTS

Gabapentinoids were involved in 2115 (2.9%) of the 72,391 IDOs recorded. Presentations involving a gabapentinoid increased proportionally from 0.5% in 2007 to 5.5% in 2015. The majority of IDOs involving a gabapentinoid were made by females (59.9%), with over one-third (37.2%) involving alcohol. Compared with IDOs involving other drugs, presentations with a gabapentinoid were made by persons who were older (median 37 vs. 32 years) and involved a significantly greater median quantity of tablets (30 vs. 21, p ≤ 0.001), with over one-quarter (27.4%) of these involving the ingestion of 50 tablets or more. Admission to hospital was significantly more common following IDOs with a gabapentinoid compared with those without (49.4% vs. 41.4%, p ≤ 0.001).

CONCLUSIONS

This study identified the increasing use of gabapentinoids in IDO, describing the profile and overdose characteristics of presentations. It is important for clinicians to exercise vigilance while prescribing gabapentinoids, including being aware of other medications that their patients may have access to. Our findings support the need for routine monitoring for signs of misuse among those prescribed gabapentinoids.

Development of an algorithm to identify pregnancy episodes and related outcomes in health care claims databases: An application to antiepileptic drug use in 4.9 million pregnant women in France

Purpose

Access to claims databases provides an opportunity to study medication use and safety during pregnancy. We developed an algorithm to identify pregnancy episodes in the French health care databases and applied it to study antiepileptic drug (AED) use during pregnancy between 2007 and 2014.

Methods

The algorithm searched the French health care databases for discharge diagnoses and medical procedures indicative of completion of a pregnancy. To differentiate claims associated with separate pregnancies, an interval of at least 28 weeks was required between 2 consecutive pregnancies resulting in a birth and 6 weeks for terminations of pregnancy. Pregnancy outcomes were categorized into live births, stillbirths, elective abortions, therapeutic abortions, spontaneous abortions, and ectopic pregnancies. Outcome dates and gestational ages were used to calculate pregnancy start dates.

Results

According to our algorithm, live birth was the most common pregnancy outcome (73.9%), followed by elective abortion (17.2%), spontaneous abortion (4.2%), ectopic pregnancy (1.1%), therapeutic abortion (1.0%), and stillbirth (0.4%). These results were globally consistent with French official data. Among 7 559 701 pregnancies starting between 2007 and 2014, corresponding to 4 900 139 women, 6.7 per 1000 pregnancies were exposed to an AED. The number of pregnancies exposed to older AEDs, comprising the most teratogenic AEDs, decreased throughout the study period (−69.4%), while the use of newer AEDs increased (+73.4%).

Conclusions

We have developed an algorithm that allows identification of a large number of pregnancies and all types of pregnancy outcomes. Pregnancy outcome and start dates were accurately identified, and maternal data could be linked to neonatal data.

The Use of Zonisamide for the Treatment of Psychiatric Disorders: A Systematic Review

OBJECTIVE

Traditional pharmacotherapy has undoubtedly improved the outcome of patients with psychiatric disorders, but partial efficacy or poor tolerability persists in a number of these subjects. Among different compounds, zonisamide has been used to address unmet needs of standard pharmacotherapy. The purpose of the present article is to provide a review about the use of zonisamide for the treatment of psychiatric conditions.

METHODS

A research in the main database sources has been conducted to obtain an overview of the use of zonisamide in psychiatric disorders or associated conditions (obesity and smoking cessation).

RESULTS

Most available data indicate the possible effectiveness of zonisamide for the treatment of acute phases of bipolar disorder, binge-eating disorder (BED), alcohol misuse, and obesity. A further assessment of the safety and tolerability of zonisamide is made necessary by the fact that, with the exception of BED, for all other disorders at least some data come from studies with combined pharmacological therapies.

CONCLUSIONS

Zonisamide may have some utility, especially as an adjunctive therapy, for the management of acute phases and weight gain in bipolar disorder and for prevention of alcohol misuse. Preliminary evidence indicates zonisamide as a candidate compound for the treatment of BED and obesity. However, open-label design and small sample sizes of most available studies prevent from drawing sound conclusions about the utility of this compound in psychiatry.

Newer Antiepileptic Drugs in Status Epilepticus: Prescription Trends and Outcomes in Comparison with Traditional Agents

INTRODUCTION

Newer antiepileptic drugs (AEDs) are increasingly prescribed; however, relatively limited data are available regarding their use in status epilepticus (SE) and the impact on outcome.

OBJECTIVES

The aim of this study was to explore the evolution in prescription patterns of newer and traditional AEDs in this clinical setting, and their association with prognosis.

METHODS

We analyzed our prospective adult SE registry over a 10-year period (2007-2016) and assessed the yearly use of newer and traditional AEDs and their association with mortality, return to baseline conditions at discharge, and SE refractoriness, defined as treatment resistance to two AEDs, including benzodiazepines.

RESULTS

In 884 SE episodes, corresponding to 719 patients, the prescription of at least one newer AED increased from 0.38 per SE episode in 2007 to 1.24 per SE episode in 2016 (mostly due to the introduction of levetiracetam and lacosamide). Traditional AEDs (excluding benzodiazepines) decreased over time from 0.74 in 2007 to 0.41 in 2016, correlating with the decreasing use of phenytoin. The prescription of newer AEDs was independently associated with a lower chance of return to baseline conditions at discharge (odds ratio [OR] 0.58, 95% confidence interval [CI] 0.40-0.84) and a higher rate of SE refractoriness (OR 19.84, 95% CI 12.76-30.84), but not with changes in mortality (OR 1.08, 95% CI 0.58-2.00).

CONCLUSION

We observed a growing trend in the prescription of newer AEDs in SE over the last decade; however, our findings might suggest an associated increased risk of SE refractoriness and new disability at hospital discharge. Pending prospective, comparative studies, this may justify some caution in the routine use of newer AEDs in SE.

Preventive Gabapentin versus Pregabalin to Decrease Postoperative Pain after Lumbar Microdiscectomy: A Randomized Controlled Trial

Study Design

Randomized controlled trial.

Purpose

The purpose of this study was to compare pregabalin and gabapentin for mean postoperative visual analog score (VAS) for pain in patients undergoing single-level lumbar microdiscectomy for intervertebral disc prolapse at a tertiary care hospital.

Overview of Literature

Pregabalin has a superior pharmacokinetic profile and analgesic effect at lower doses than gabapentin; however, analgesic efficacy must be established during the perioperative period after lumbar spine surgery.

Methods

This randomized controlled trial was carried out at our institute from February to October 2011 on 78 patients, with 39 participants in each study group. Patients undergoing lumbar microdiscectomy were randomized to group A (gabapentin) or group B (pregabalin) and started on trial medicines one week before surgery. The VAS for pain was recorded at 24 hours and one week postoperatively.

Results

Both groups had similar baseline variables, with mean ages of 42 and 39 years in groups A and B, respectively, and a majority of male patients in each group. The mean VAS values for pain at 24 hours for gabapentin vs. pregabalin were comparable (1.97±0.84 vs. 1.6±0.87, respectively; p=0.087) as were the results at one week after surgery (0.27±0.45 vs. 0.3±0.46, respectively; p=0.79). None of the patients required additional analgesia postoperatively. After adjusting for age and sex, the VAS value for group B patients was 0.028 points lower than for group A patients, but this difference was not statistically significant (p=0.817, R²=0.018).

Conclusions

Pregabalin is equivalent to gabapentin for the relief of postoperative pain at a lower dose in patients undergoing lumbar microdiscectomy. Therefore, other factors, such as dose, frequency, cost, pharmacokinetics, and side effects of these medicines, should be taken into account whenever it is prescribed.

Automatic identification of type 2 diabetes, hypertension, ischaemic heart disease, heart failure and their levels of severity from Italian General Practitioners' electronic medical records: a validation study

OBJECTIVES

The Italian project MATRICE aimed to assess how well cases of type 2 diabetes (T2DM), hypertension, ischaemic heart disease (IHD) and heart failure (HF) and their levels of severity can be automatically extracted from the Health Search/CSD Longitudinal Patient Database (HSD). From the medical records of the general practitioners (GP) who volunteered to participate, cases were extracted by algorithms based on diagnosis codes, keywords, drug prescriptions and results of diagnostic tests. A random sample of identified cases was validated by interviewing their GPs.

SETTING

HSD is a database of primary care medical records. A panel of 12 GPs participated in this validation study.

PARTICIPANTS

300 patients were sampled for each disease, except for HF, where 243 patients were assessed.

OUTCOME MEASURES

The positive predictive value (PPV) was assessed for the presence/absence of each condition against the GP's response to the questionnaire, and Cohen's κ was calculated for agreement on the severity level.

RESULTS

The PPV was 100% (99% to 100%) for T2DM and hypertension, 98% (96% to 100%) for IHD and 55% (49% to 61%) for HF. Cohen's kappa for agreement on the severity level was 0.70 for T2DM and 0.69 for hypertension and IHD.

CONCLUSIONS

This study shows that individuals with T2DM, hypertension or IHD can be validly identified in HSD by automated identification algorithms. Automatic queries for levels of severity of the same diseases compare well with the corresponding clinical definitions, but some misclassification occurs. For HF, further research is needed to refine the current algorithm.

Utilization of antiepileptic drugs in Israel

PURPOSE

The aim of the study was to identify trends in utilization of antiepileptic drugs (AEDs) over time in a nation-wide population in Israel.

METHODS

Data on AED utilization (for all indications) for the period 2010-2014 were obtained from pharmaceutical companies that distribute AEDs in Israel. Prevalence of AED utilization was reported as defined daily doses (DDD)/1000 inhabitants/day.

RESULTS

The utilization of most AEDs included in our analysis remained stable over the study period. The greatest increases in utilization of drugs established in Israel were observed for lamotrigine (33%), oxcarbazepine (31%), and primidone (18%). Decreases in use were recorded for carbamazepine (18%) and phenobarbital (15%). Use of older AEDs appeared to be relatively high, compared with the use of newer AEDs.

CONCLUSIONS

During the study period of 2010-2014, conventional AEDs remained a main treatment choice in Israel, in certain cases in contrast to current recommendations and guidelines, for reasons yet to be revealed in further research.

Prevalence of Different Combinations of Antiepileptic Drugs and CNS Drugs in Elderly Home Care Service and Nursing Home Patients in Norway

Introduction. Antiepileptic drugs (AEDs) are used to treat different conditions in elderly patients and are among the drug classes most susceptible to be involved in drug-drug interactions (DDI). The aim of the study was to describe and compare use of AEDs between home care service and nursing home patients, as these patients are not included in nationwide databases of drug utilization. In the combined population, we investigate DDI of AEDs with other central nervous system- (CNS-) active drugs and DDIs involving AEDs in general. Materials and Methods. Point-prevalence study of Norwegian patients in home care services and nursing homes in 2009. At the patient level, we screened for different DDIs involving AEDs. Results. In total, 882 patients (7.8%) of 11,254 patients used AEDs and number of users did not differ between home care services and nursing homes (8.2% versus 7.7%). In the combined population, we identified 436 potential DDIs in 45% of the patients. Conclusions. In a large population of elderly, home care service and nursing home patients do not differ with respect to exposure of AEDs but use more AEDs as compared to the general population of similar age. The risk of DDIs with AEDs and other CNS-active drugs should be taken into consideration and individual clinical evaluations are assessed in this population.

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.

The Risk of Specific Congenital Anomalies in Relation to Newer Antiepileptic Drugs: A Literature Review

BACKGROUND

More information is needed about possible associations between the newer anti-epileptic drugs (AEDs) in the first trimester of pregnancy and specific congenital anomalies of the fetus.

OBJECTIVES

We performed a literature review to find signals for potential associations between newer AEDs (lamotrigine, topiramate, levetiracetam, gabapentin, oxcarbazepine, eslicarbazepine, felbamate, lacosamide, pregabalin, retigabine, rufinamide, stiripentol, tiagabine, vigabatrin, and zonisamide) and specific congenital anomalies.

METHODS

We searched PubMed and EMBASE to find observational studies with pregnancies exposed to newer AEDs and detailed information on congenital anomalies. The congenital anomalies in the studies were classified according to the congenital anomaly subgroups of European Surveillance of Congenital Anomalies (EUROCAT). We compared the prevalence of specific congenital anomalies in fetuses exposed to individual AEDs in the combined studies with that of the general population in a reference database. A significantly higher prevalence based on three or more fetuses with anomalies was considered a signal.

RESULTS

Topiramate showed a higher rate of congenital anomalies than the other newer AEDs. Four signals were found. The signals for associations between topiramate and cleft lip with/without cleft palate and hypospadias were considered strong. Associations between lamotrigine and anencephaly and transposition of great vessels were found within one study and were not supported by other studies. No signals were found for the other newer AEDs, or the information was too limited to provide such a signal.

CONCLUSION

In terms of associations between monotherapy with a newer AED in the first trimester of pregnancy and a specific congenital anomaly, the signals for topiramate and cleft lip with/without cleft palate and hypospadias should be investigated further.

Indications of newer and older anti-epileptic drug use: findings from a southern Italian general practice setting from 2005-2011

AIMS

The aim of the study was to analyze the prescribing pattern of both newer and older AEDs.

METHODS

A population of almost 150 000 individuals registered with 123 general practitioners was included in this study. Patients who received at least one AED prescription over 2005-2011 were identified. The 1 year prevalence and cumulative incidence of AED use, by drug class and individual drug, were calculated over the study period. Potential predictors of starting therapy with newer AEDs were also investigated.

RESULTS

The prevalence of use per 1000 inhabitants of older AEDs increased from 10.7 (95% CI10.1, 11.2) in 2005 to 13.0 (95% CI12.4, 13.6) in 2011, while the incidence remained stable. Newer AED incidence decreased from 9.4 (95% CI 8.9, 9.9) in 2005 to 7.0 (95% CI 6.6, 7.5) in 2011, with a peak of 15.5 (95% CI 14.8, 16.1) in 2006. Phenobarbital and valproic acid were the most commonly prescribed AEDs as starting therapy for epilepsy. Gabapentin and pregabalin accounted for most new pain-related prescriptions, while valproic acid and lamotrigine were increasingly used for mood disorders. Female gender (OR 1.36, 95% CI 1.20, 1.53), age ranging between 45-54 years (OR 1.39, 95% CI 1.16, 1.66) and pain as an indication (OR 16.7, 95% CI, 13.1, 21.2) were associated with newer AEDs starting therapy.

CONCLUSIONS

Older AEDs were mainly used for epileptic and mood disorders, while newer drugs were preferred for neuropathic pain. Gender, age, indication of use and year of starting therapy influenced the choice of AED type. The decrease of newer AED use during 2007 is probably related to the restricted reimbursement criteria for gabapentin and pregabalin.

Antiepileptic medications and the risk for sudden cardiac death caused by an acute coronary event: a prospective case-control study

BACKGROUND

Epilepsy is associated with sudden death, but the reasons for this association are not well known. Objective We studied the role of antiepileptic drugs (AEDs) as a factor contributing to sudden cardiac death (SCD) in The Finnish Study of the Genotype and Phenotype Characteristics of Sudden Cardiac Death (FinGesture).

METHODS AND RESULTS

The FinGesture study compares the characteristics of victims of SCD caused by an autopsy-verified acute coronary event (cases) vs. survivors of an acute coronary event (ACS) (controls). The study population comprised 3737 cases (mean age 64 ± 12 y) and 3081 controls (mean age 66 ± 12 y). The use of AED was obtained from death certificates, autopsy/hospital records, national drug imbursement register, and interviews with the relatives. AEDs were more commonly used by the victims of SCD vs. controls (5.5% vs. 2.2%, adjusted odds ratio 2.7, 95% CI; 1.9-3.9; p < 0001). The use of AED for non-epilepsy indications was also more common in the cases than in controls (1.5% vs. 1.0%, p = 0.005).

CONCLUSION

A higher rate of AED was observed in victims of SCD than in a control group of ACS patients. Concomitant use of AED could be responsible for a small fraction of deaths due to acute coronary events. Key message Epilepsy has been associated with sudden cardiac death. The use of antiepileptic drugs seems to be associated with an increased risk of sudden cardiac death during a coronary event. Physicians should be aware of the risk related to antiepileptic drugs especially when used for other reasons than epilepsy.

Trends in Antiepileptic Drug Prescriptions for Childhood Epilepsy at a Tertiary Children's Hospital in Korea, 2001-2012

OBJECTIVES

Longitudinal prescription patterns of antiepileptic drugs (AEDs) have not been described to date in Korea. Here we aimed to describe AED prescribing trends over a 12-year period and assess age differences in AED prescribing patterns in a pediatric epilepsy population.

METHODS

We retrieved and analyzed all AED prescribing and dispensing data in 2001-2012 in patients aged 0-18 years with an established diagnosis of epilepsy at the largest tertiary children's hospital in Korea. AEDs included for analysis were classified as older (i.e., carbamazepine, ethosuximide, phenobarbital, phenytoin, and valproic acid) and newer (i.e., gabapentin, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, topiramate, vigabatrin, zonisamide, lacosamide, and rufinamide) on the basis of market availability before versus after 1991.

RESULTS

A total of 5593 patients with epilepsy were prescribed an AED during the 12-year period. The proportion of newer AED prescriptions was 52.6 % in 2001 and continuously increased to 74.3 % in 2012. Oxcarbazepine was most widely used, followed by valproic acid. While carbamazepine and vigabatrin use progressively decreased over the 12-year period, those of lamotrigine and topiramate rapidly increased. Age differences in prescribing patterns were observed. Polytherapy was observed in 49.7 % of the total population, while 83.9 % of new users were prescribed monotherapy.

CONCLUSION

This study provided updated information on AED prescription trends for childhood epilepsy. We found a progressive increase in the use of newer AEDs. However, valproic acid, the only prevalent older AED, continued to be widely prescribed. A high rate of polytherapy among the prescriptions overall raises some safety concerns.

Availability of antiepileptic drugs across Europe

Europe consists of 53 countries with widely different economic conditions and different political, educational, and health care systems. This study was aimed at determining the availability of antiepileptic drugs (AEDs) across Europe. An electronic questionnaire was submitted to all 43 European chapters of the International League Against Epilepsy (ILAE). Outcome measures were availability of older, newer, and newest AEDs, generic products, indications, reimbursement rules, and reasons for lack of availability of AEDs. Countries were divided according to economic status as defined by the World Bank. Thirty-four chapters (79%) provided data. There were large differences in AED availability across countries, especially between high-income countries and the other countries. The newest AEDs were not available in any of the 12 non-high-income countries. Availability was higher in countries with public reimbursement systems. Reimbursement policies ranged from full reimbursement for all AEDs to complete lack of reimbursement. Main hurdles for poor access to AEDs included lack of regulatory approval, high prices and reimbursement restrictions. The availability of AEDs differs across European countries, with many hurdles hampering access to epilepsy medicines, particularly to new medications. These findings raise major concerns on the quality of epilepsy care in many countries.

Changing incidence of hyperammonemia in Japan from 2006 to 2013: expansion of new antiepileptic drugs reduces the risk of hyperammonemia

PURPOSE

The purpose of the present study was to examine the relationship between the incidence of hyperammonemia and changes in the prescribing of concomitant antiepileptic drugs (AEDs) in patients receiving valproic acid.

METHODS

We evaluated 40,363 plasma samples from 6009 epilepsy patients obtained from 2006 to 2013. Hyperammonemia was defined as a plasma ammonia level exceeding 100 μg/dL.

RESULTS

In 2006, 32.6 % of the plasma samples were from patients with concomitant use of phenytoin but this decreased to 16.0 % in 2013. Lamotrigine and levetiracetam were approved in 2008 and 2010, respectively, and were prescribed for patients who provided 27.8 and 14.9 % of the plasma samples in 2013. The incidence rate of hyperammonemia (per 100 person years) decreased markedly from 40.8 (95 % confidence interval (CI), 37.7-43.9) in 2006 to 14.2 (95 % CI, 12.5-15.9) in 2013. In any year reviewed, concomitant use of phenytoin, phenobarbital, carbamazepine, or carbonic anhydrase inhibitors was a risk factor for hyperammonemia. Among enzyme-inducing AEDs, concomitant use of phenytoin was associated with the highest risk of hyperammonemia.

CONCLUSION

Drug interactions caused by enzyme-inducing AEDs, especially phenytoin, are closely related to the development of hyperammonemia. This study demonstrated that introduction of new AEDs changed the co-prescribing pattern in patients receiving valproic acid, resulting in a marked decrease of hyperammonemia. Although their higher cost may be problematic, new AEDs are beneficial for reducing the risk of drug interactions.

Drug utilisation study in patients receiving antiepileptic drugs in Colombia

INTRODUCTION

This study examines the indications according to which antiepileptic drugs are prescribed and used in a population of patients enrolled in the Colombian national health system (SGSSS).

METHODS

Retrospective cross-sectional study. From the pool of individuals in 34 Colombian cities who used antiepileptic drugs between 18 July, 2013 and 31 August, 2014 during a period of no less than 12 months, we obtained a random sample stratified by city. Socio-demographic, pharmacological and comorbidity variables were analysed. Continuous and categorical variables were compared, and logistic regression models were used.

RESULTS

Our patient total was 373 patients, with 197 women (52.1%) and a mean age of 41.9 ± 21.7 years; 65.4% of the patients were treated with monotherapy. The most frequently used drugs were valproic acid (53.1%) and carbamazepine (33.2%). Epilepsy was the most frequent indication (n=178; 47.7%); however, 52.3% of the patients were prescribed antiepileptics for different indications, especially neuropathic pain (26.8%), affective disorders (14.2%) and migraine prophylaxis (12.3%). A total of 81 patients with epilepsy (46.6%) displayed good seizure control while another 25 (14.4%) had drug-resistant epilepsy. In the multivariate analysis, medication adherence was associated with a lower risk of treatment failure in patients with epilepsy (OR: 0.27; 95%CI, 0.11-0.67).

CONCLUSIONS

In Colombia, antiepileptic drugs are being used for indications other than those originally intended. Monotherapy is the most commonly used treatment approach, together with the use of classic antiepileptic drugs.

Antiepileptic drug prescribing before, during and after pregnancy: a study in seven European regions

PURPOSE

The aim of this study was to explore antiepileptic drug (AED) prescribing before, during and after pregnancy as recorded in seven population-based electronic healthcare databases.

METHODS

Databases in Denmark, Norway, the Netherlands, Italy (Emilia Romagna/Tuscany), Wales and the Clinical Practice Research Datalink, representing the rest of the UK, were accessed for the study. Women with a pregnancy starting and ending between 2004 and 2010, which ended in a delivery, were identified. AED prescriptions issued (UK) or dispensed (non-UK) at any time during pregnancy and the 6 months before and after pregnancy were identified in each of the databases. AED prescribing patterns were analysed, and the choice of AEDs and co-prescribing of folic acid were evaluated.

RESULTS

In total, 978 957 women with 1 248 713 deliveries were identified. In all regions, AED prescribing declined during pregnancy and was lowest during the third trimester, before returning to pre-pregnancy levels by 6 months following delivery. For all deliveries, the prevalence of AED prescribing during pregnancy was 51 per 10 000 pregnancies (CI95 49-52%) and was lowest in the Netherlands (43/10 000; CI95 33-54%) and highest in Wales (60/10 000; CI95 54-66%). In Denmark, Norway and the two UK databases lamotrigine was the most commonly prescribed AED; whereas in the Italian and Dutch databases, carbamazepine, valproate and phenobarbital were most frequently prescribed. Few women prescribed with AEDs in the 3 months before pregnancy were co-prescribed with high-dose folic acid: ranging from 1.0% (CI95 0.3-1.8%) in Emilia Romagna to 33.5% (CI95 28.7-38.4%) in Wales.

CONCLUSION

The country's differences in prescribing patterns may suggest different use, knowledge or interpretation of the scientific evidence base. The low co-prescribing of folic acid indicates that more needs to be done to better inform clinicians and women of childbearing age taking AEDs about the need to offer and receive complete preconception care.

Urgent global opportunities to prevent birth defects

Birth defects are an urgent global health priority. They affect millions of births worldwide. But their prevalence and impact are largely under-ascertained, particularly in middle- and low-income countries. Fortunately, a large proportion of birth defects can be prevented. This review examines the global prevalence and primary prevention methods for major preventable birth defects: congenital rubella syndrome, folic acid-preventable spina bifida and anencephaly, fetal alcohol syndrome, Down syndrome, rhesus hemolytic disease of the fetus and the newborn; and those associated with maternal diabetes, and maternal exposure to valproic acid or iodine deficiency during pregnancy. Challenges to prevention efforts are reviewed. The aim of this review is to bring to the forefront the urgency of birth defects prevention, surveillance, and prenatal screening and counseling; and to help public health practitioners develop population-based birth defects surveillance and prevention programs, and policy-makers to develop and implement science-based public health policies.

The role of phenytoin in the treatment of localization related epilepsy: an international internet-based survey of neurologists and epileptologists

Phenytoin (PHT) has been the most widely used medication to treat both partial and generalized seizures. However, over the past twenty years, a variety of new compounds have been released with comparable efficacy, fewer adverse effects, and more predictable pharmacokinetic properties. We surveyed neurologists and epileptologists to determine current practice patterns relating to the use of PHT using an online survey instrument. A total of 200 responses were obtained though response rates for each survey question varied. Of the respondents, 78.1% were epilepsy specialists; 60% were adult practitioners; and the remainder saw either, only children or both adults and children. For new onset partial seizures only 10 respondents said PHT would be their first or second choice, while 45% reported that they would not consider PHT. This study shows that in the era of newer medications, the role of PHT has been placed in the category of a reserve medication in intractable epilepsy.

A systematic review of the application of spatial analysis in pharmacoepidemiologic research

PURPOSE

Although current reviews of the use of spatial analysis in general epidemiologic research illustrate an important and well-established role in exploring and predicting health, its application has not been reviewed in the subspecialty field of pharmacoepidemiology.

METHODS

We systematically reviewed the scientific literature to assess to what extent spatial analysis has been applied in pharmacoepidemiologic research and explored its potential added value.

RESULTS

A systematic search in PubMed and Embase/MEDLINE yielded 823 potentially relevant articles; 45 articles met our criteria for review. The studies were reviewed on study objective, applied spatial methods and units of analysis, and author-reported added value of the geographic approach used. Of the 45 included studies, 34 (76%) reported a geographic research objective. Comparative spatial methods were most often used (n = 25; 56%). Eleven studies used spatial statistics (32%); cluster analysis (n = 5) and aggregate data analysis (n = 4) being most common. Mapping was done in 15 studies (33%). The most common added value reported was to aid the planning of health policies and interventions (n = 24; 53%). A minority of pharmacoepidemiologic studies used a geographic approach and the applied methods were less advanced compared with the broader field of epidemiology.

CONCLUSIONS

Further advancements are needed to incorporate currently available spatial techniques to impact health care planning.

The long-term safety of antiepileptic drugs

Antiepileptic drugs (AEDs) are used by millions of people worldwide for the treatment of epilepsy, as well as in many other neurological and psychiatric conditions. They are frequently associated with adverse effects (AEs), which have an impact on the tolerability and success of treatment. Half the people who develop intolerable AEs discontinue treatment early on after initiation, while the majority of people will continue to be exposed to their effects for long periods of time. The long-term safety of AEDs reflects their potential for chronic, cumulative dose effects; rare, but potentially serious late idiosyncratic effects; late, dose-related effects; and delayed, teratogenic or neurodevelopmental effects. These AEs can affect every body system and are usually insidious. With the exception of delayed effects, most other late or chronic AEs are reversible. To date, there is no clear evidence of a carcinogenic effect of AEDs in humans. While physicians are aware of the long-term AEs of old AEDs (the traditional liver enzyme-inducing AEDs and valproate), information about AEs of new AEDs (such as lamotrigine, levetiracetam, oxcarbazepine, topiramate or zonisamide), particularly of their teratogenic effects, has emerged over the years. Sporadic publications have raised issues about AEs of the newer AEDs eslicarbazepine, retigabine, rufinamide, lacosamide and perampanel but their long-term safety profiles may take years to be fully appreciated. Physicians should not only be aware of the late and chronic AEs of AEDs but should systematically enquire and screen for these according to the individual AED AE profile. Care should be taken for individuals with comorbid conditions that may render them more susceptible to specific AEs. Prevention and appropriate management of long-term AED AEs is expected to improve adherence to treatment, quality of life and control of epilepsy.

Rational use of generic psychotropic drugs

For economic reasons, the generic substitution of branded medications is common and welcome. These replacements are based on the concept of bioequivalence, which is considered equal to therapeutic equivalence. Regulatory standards for bioequivalence require the 90 % confidence intervals of group averages of pharmacokinetic measures of a generic and the original drug to overlap within ±20 %. However, therapeutic equivalence has been challenged for several psychotropic agents by retrospective studies and case reports. To evaluate the degree of bioequivalence and therapeutic equivalence of branded and generic psychotropic drugs, we performed an electronic search (from database inception until 24 May 2012 and without language restrictions) in PubMed/MEDLINE, Cochrane Library, and Web of Science. Search terms were "(generic) AND (psychotropic OR psychoactive OR antipsychotic OR antiepileptic OR antidepressant OR stimulant OR benzodiazepine)" or the respective individual substances. We included clinical studies, regardless of design, comparing branded with generic psychotropic drug formulations, identifying 35 such studies. We also included case reports/series reporting on outcomes after a switch between brand and generic psychotropics, identifying 145 clinical cases. Bioequivalence studies in healthy controls or animals, in-vitro studies, and health economics studies without medical information were excluded. An overview of the few randomized controlled studies supports that US FDA regulations assure clinically adequate drug delivery in the majority of patients switched from brand to generic. However, with a growing number of competing generic products for one substance, and growing economic pressure to substitute with the currently cheapest generic, frequent generic-generic switches, often unbeknownst to prescribing clinicians, raise concerns, particularly for antiepileptics/mood stabilizers. Generic-generic switches may vary by more than ±20 % from each other in individual patients since the pharmacokinetic properties of each generic may differ from the innovator drug in opposing directions. Ideally, therapeutic equivalence studies in addition to pharmacokinetic equivalence studies would be performed for each generic, reflecting the full variability of clinical responses due to changes of pharmacokinetic properties related to age, sex, ethnicity, genetic factors, and body mass index. This is particularly relevant, as bioequivalence studies are based on single-dose studies in healthy controls who are likely not representative of the patients who are prescribed the psychotropic medications. Additionally, individual case reports suggest potential clinical effects during brand-generic switches. Knowledge and consideration of intra-individual variations can help guide the clinical management during brand-generic or generic-generic switch periods. To optimize outcomes, clinicians need to consider that when using generic psychotropic medications, a change in the patient's clinical status can be related to psychological, interactional, physiological, and pharmacological factors that may or may not be related to the change to a generic drug. In addition, throughout all treatment periods, clinicians need to be aware of the currently dispensed product (i.e., branded or exact generic formulation), particularly when evaluating clinical changes in efficacy, tolerability, and adherence. If clinical problems occur, the first response should be an assessment of adherence and a careful dose adjustments of the generic drug rather than an immediate switch back to the originator.

How phenobarbital revolutionized epilepsy therapy: the story of phenobarbital therapy in epilepsy in the last 100 years

Phenobarbital (phenobarbitone) was first used as an antiepileptic drug 100 years ago, in 1912. This article tells the story of the discovery of its antiepileptic action, its early development, and the subsequent course of its clinical use over the 100-year period. The side effects, pharmacokinetics, and misuse of barbiturates are considered, along with the more recent clinical trials and the drug's current clinical utilization. The introduction of controlled drug regulations, the comparative cost of phenobarbital, and its inclusion on the World Health Organization (WHO) essential drug list are discussed. It is one of the few drugs on the formulary in 1912 that is still listed today, and remarkably its efficacy in epilepsy has not been significantly bettered. The current recommendation by the WHO is that phenobarbital should be offered as the first option for therapy for convulsive epilepsy in adults and children if availability can be ensured. This is rated as a strong recommendation because of the proven efficacy and low cost of phenobarbital, and despite its perceived side-effect profile and the practical problems of access. Whether this recommendation puts "a hierarchy on the brain," as has been suggested, is arguable. Much still needs to be learned about the drug's effects, and the issues raised by phenobarbital have lessons for all antiepileptic drug therapy.

Generic substitution of lamotrigine among medicaid patients with diverse indications: a cohort-crossover study

BACKGROUND

Controversy exists about the safety of substituting generic antiepileptic drugs (AEDs). Lamotrigine, the prototypical newer AED, is often used for psychiatric and neurological conditions other than epilepsy. The safety of generic substitution of lamotrigine in diverse populations of AED users is unclear.

OBJECTIVE

The objective of this study was to evaluate potential associations between generic substitution of lamotrigine and adverse consequences in a population of diverse users of this drug.

STUDY DESIGN

This study was a retrospective cohort-crossover design using state Medicaid claims data from July 2006 through June 2009.

METHODS

Subjects were included in the cohort if they converted from brand to generic lamotrigine and had 2 years of lamotrigine use prior to conversion. The frequency of emergency department (ED) visits, hospitalizations and condition-specific ED visits or hospitalizations were recorded in the 60 days immediately following the conversion to generic lamotrigine, then compared with the incidence of the same events during a randomly selected time period indexed to one of the patient's past refills of branded lamotrigine. Multivariate conditional logistic regression was used to quantify the association between generic conversion and health services utilization while controlling for changes in lamotrigine dose and concurrent drug use.

RESULTS

Of the 616 unique subjects included in this analysis, epilepsy was the most common diagnosis (41%), followed by bipolar disorder (32%), pain (30%) and migraine (18%). Conversion to generic lamotrigine was not associated with a statistically significant increase in the odds of an ED visit (adjusted odds ratio [AOR] = 1.35; 95% confidence interval [CI] 0.92, 1.97), hospitalization (AOR = 1.21; 95% CI 0.60, 2.50) or condition-specific encounter (AOR 1.75; 95 CI 0.87, 3.51).

CONCLUSIONS

A statistically significant increase in ED visits, hospitalizations or condition-specific encounters was not observed following the switch from brand to generic lamotrigine, although a type II error cannot be ruled out.

Population pharmacokinetics of carbamazepine in elderly patients

BACKGROUND

Carbamazepine is a commonly used antiepileptic drug in elderly patients. This study analyzed prospective data collected as part of a randomized, double-blinded trial of newly diagnosed epilepsy patients. The aims of this study were to determine the pharmacokinetic parameters and their variability of carbamazepine in elderly patients and to quantify the effect of covariates on these parameters.

METHODS

Prospectively collected carbamazepine concentrations from 121 patients aged 60 years or older were used to develop a population pharmacokinetic model. Data were analyzed by a nonlinear mixed effects model (NONMEM). A 1-compartment model with first-order absorption and elimination was used to characterize the time course of carbamazepine concentration. Model evaluation and the predictive performance of the final model were assessed using the nonparametric bootstrap approach.

RESULTS

The apparent clearance (CL/F) of carbamazepine in this community-dwelling elderly population was estimated to be 3.59 L/h with an interindividual variability of 18.1%. The CL/F increases 23% in patients comedicated with phenytoin. The volume of distribution (V/F) was estimated to be 102 L with an interindividual variability of 74.7%.

CONCLUSIONS

Carbamazepine clearance was not associated with body weight or any parameterization of body size nor was age or race or any marker of hepatic or renal function in community dwelling elderly patients. Elderly patients on concurrent phenytoin therapy may require a smaller 23% higher dose on average, about half that reported for younger patients.

A retrospective study on the usage of antiepileptic drugs in Asian children from 2000 to 2009 in the largest pediatric hospital in Singapore

PURPOSE

In light of the increasing usage of the newer antiepileptic drugs (AEDs) in other countries, we reviewed the prescribing pattern of AEDs in Singapore over the last 10 years (2000-2009).

METHODS

A retrospective review of pharmacy dispensing records solicited from the only children's hospital in Singapore was performed to analyze the trend in AEDs prescribing in the last 10 years. We also examined the correlation between the serum concentrations of valproic acid (VPA), the most-prescribed AED, and seizure control. Descriptive and inferential statistical analyses were then performed on the findings.

RESULTS

A total of 41 671 prescriptions on AEDs were retrieved and analyzed. Despite the introduction of the second-generation AEDs, the first generation AEDs still dominate epilepsy treatment in Asian children, with VPA being the mostly prescribed AED (about 40% of the total AEDs usage). The majority of patients (62.8%) were on monotherapy. The mean VPA serum concentration in patients with good seizure control was 68.6 µg/ml (SD = 26.4 µg/ml; range = 12.2-138.0 µg/ml), which was statistically higher than the mean VPA concentration of 57.7 µg/ml (SD = 27.1 µg/ml; range = 11.1-149.0 µg/ml) in patients with poor seizure control (p < 0.0001).

CONCLUSION

With VPA being the most prescribed AED in our clinical practice, and the finding in this study that with careful classification of the patients' condition, serum concentrations of VPA generally correlate well with the seizure control, the correct dose titration of VPA with therapeutic drug monitoring is still of paramount importance.

Changes in anticonvulsant prescribing for Australian children: implications for Quality Use of Medicines

AIMS

The evidence-base guiding choices between newer versus established anticonvulsants in children is limited. Inappropriate use exposes children to potentially ineffective and/or harmful medicines. Our objective is to describe recent anticonvulsant prescribing patterns in the Australian paediatric population, evaluating overall trends and extent of off-label prescribing of newer agents.

METHODS

Aggregated national data on 15 anticonvulsants with Pharmaceutical Benefits Scheme subsidy dispensed by community pharmacies for children aged <16 years were obtained from the Drug Utilisation Subcommittee, which is part of the Australian Government Department of Health and Ageing. We analysed trends for the five most prescribed anticonvulsants dispensed between 2002 and 2009 and off-label prescribing for agents where approved Australian product information stipulates a minimum age.

RESULTS

Valproate was the most frequently prescribed anticonvulsant with no marked change in prescription numbers per 1000 children aged 0-16 years (11.3-11.8 prescriptions/year). Lamotrigine was the most frequently prescribed newer anticonvulsant (7.9-9.3 prescriptions/year). Carbamazepine prescriptions decreased by 38% and topiramate prescriptions increased by 19% over the 7-year study period; 3.6% of topiramate prescriptions were off-label (by age) for children aged <2 years. Since Pharmaceutical Benefits Scheme listing in 2003, levetiracetam prescriptions increased steeply to 2.5 prescriptions/year per 1000 children in 2009; 4.2% were off-label for children aged <4 years.

CONCLUSIONS

The substantial reduction in carbamazepine use and corresponding increase in newer anticonvulsant prescribing, including off-label uses, raises questions about potentially suboptimal Quality Use of Medicines. Such major changes in prescribing may have important clinical and economic consequences. Further study to better understand paediatric prescribing choices and outcomes is needed.

Newer antiepileptic drugs in the treatment of status epilepticus: impact on prognosis

Newer antiepileptic drugs (AEDs) are increasingly prescribed and seem to have a comparable efficacy as the classical AEDs; however, their impact on status epilepticus (SE) prognosis has received little attention. In our prospective SE database (2006-2010), we assessed the use of older versus newer AEDs (levetiracetam, pregabalin, topiramate, lacosamide) over time and its relationship to outcome (return to clinical baseline conditions, new handicap, or death). Newer AEDs were used more often toward the end of the study period (42% of episodes versus 30%). After adjustment for SE etiology, SE severity score, and number of compounds needed to terminate SE, newer AEDs were independently related to a reduced likelihood of return to baseline (p<0.001) but not to increased mortality. These findings seem in line with recent findings on refractory epilepsy. Also, in view of the higher price of the newer AEDs, well-designed, prospective assessments analyzing the impact of newer AEDs on efficacy and tolerability in patients with SE appear mandatory.