Antiepileptic use for epilepsy and nonepilepsy disorders: A population-based study (1998-2013)

Gabapentinoids related psychiatric disorders: an analysis based on the FAERS database from 2004 to 2023

BACKGROUND

Gabapentinoids, including gabapentin and pregabalin, are commonly used for neuropathic pain but have safety concerns. This study analyzed U.S. Food and Drug Administration's (FDA) Adverse Event Reporting System (FAERS) data to assess risks of psychiatric disorders as adverse effects.

RESEARCH DESIGN AND METHODS

Data from 2004 to 2023 were extracted for disproportionality analysis using reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian Confidence Propagation Neural Network (BCPNN), and the Multi-Item Gamma Poisson Shrinker (MGPS) to evaluate the association between gabapentinoids and psychiatric AEs. Kaplan-Meier and log-rank tests assessed the incidence and onset profiles, while chi-square examined mortality and hospitalization rates differences.

RESULTS

Of 174,321 AE reports, 22.67% involved psychiatric disorders. Gabapentinoids increased psychiatric disorder incidence at SOC level, with events like anxiety and suicidal ideation. Differences in incidence and health outcomes between gabapentin and pregabalin were significant (p < 0.05).

CONCLUSION

There is a correlation between the use of gabapentinoids and psychiatric disorders. Further research is needed into the mechanisms and prevention strategies for these adverse effects.

Trends of antiseizure medication utilization among pregnant people in four Canadian provinces from 1998 to 2023; a study from the Canadian mother-child cohort active surveillance initiative (CAMCCO)

Background

Epilepsy management during pregnancy is crucial for both the mother and fetus. The use of antiseizure medications (ASMs) during pregnancy requires careful consideration due to their potential effects on maternal and fetal health.

Methods

This study analyzed trends in ASMs use among pregnant people in four Canadian provinces over 20 years (Manitoba, Saskatchewan, Alberta, and Quebec). Descriptive statistics were utilized to examine the characteristics of the population, with the frequency and patterns of ASM use estimated throughout each trimester. Linear regression models were developed to analyze yearly patterns of ASM utilization for the overall study population, as well as for people with and without epilepsy.

Results

Among 1,317,141 pregnant individuals across four provinces, 0.7% had epilepsy. Of the total pregnancies, 1.7% (n = 22,783) were exposed to ASMs, comprising 4,392 from pregnant people with epilepsy (PPWE) and 18,391 from those without epilepsy (PPWOE). Results demonstrated varying trends in ASM usage between provinces, with an overall increase in usage among people without epilepsy in Manitoba, Saskatchewan, and Alberta. ASM use among PPWOE surged significantly in Manitoba (24.2-149.1 per 10,000 pregnant people), Saskatchewan (29.4-107.0 per 10,000), and Alberta (65.7-241.7 per 10,000) (p < 0.05). In Alberta, PPWE's ASM exposure also rose, from 23.6 in 2008 to 43.0 per 10,000 pregnant people in 2021, while Quebec witnessed a decrease from 59.2 in 1998 to 45.5 per 10,000 pregnancies in 2015. Analysis of ASM use by trimester illustrated a substantial decline among PPWOE from 365 days pre-pregnancy to the third trimester in all provinces. ASM utilization by drug class showcased significant shifts, with second-generation ASMs experiencing a notable rise. Carbamazepine, once prominent, declined, making way for lamotrigine. Regional variations underscore diverse preferences, such as clonazepam's sustained popularity in Manitoba and Quebec.

Conclusion

The study identified increasing trends in ASM use, particularly the increased use of second-generation ASMs, and differences in prescription patterns for pregnant individuals with and without epilepsy. These findings reveal changing ASM use patterns, including increased second-generation ASM use and regional disparities, providing valuable insights into real-world prescription practices.

Risks of congenital malformations and neonatal intensive care unit admissions with gabapentin use in pregnancy: A cohort study and scoping review with meta-analysis

BACKGROUND

The increasing and prevalent use of gabapentin among pregnant people highlights the necessity to assess its neonatal safety.

OBJECTIVES

This study aimed to investigate the foetal safety of gabapentin during pregnancy using a cohort study and scoping review with a meta-analysis of published evidence.

METHODS

We conducted a population-based cohort study using the Manitoba health databases between 1995 and 2019. We examined the association between gabapentin use during pregnancy and the prevalence of major congenital malformations, cardiac and orofacial malformations, and neonatal intensive care unit (NICU) admissions using multivariate regression models. We searched the literature in MEDLINE and EMBASE databases from inception to October 2022 to identify relevant observational studies and conducted a meta-analysis using random-effects models, including our cohort study results.

RESULTS

Of the 289,227 included pregnancies, 870 pregnant people were exposed to gabapentin. Gabapentin exposure during the First trimester was not associated with an increased risk of any malformations (adjusted relative risk [aRR]) 1.16 (95% confidence interval [CI] 0.92, 1.46), cardiac malformations (aRR 1.29, 95% CI 0.72, 2.29), orofacial malformations (aRR 1.37, 95% CI 0.50, 3.75), and major congenital malformations (aRR 1.00, 95% CI 0.73, 1.36). whereas exposure during any trimester was associated with an increased NICU admission risk (aRR, 1.99, 95% CI 1.70, 2.32). The meta-analysis of unadjusted results revealed an increased risk of major congenital malformations (RR 1.44, 95% CI 1.28, 1.61, I2 = 0%), cardiac malformations (RR 1.66, 95% CI 1.11, 2.47, I2 = 68%), and NICU admissions (RR 3.15, 95% CI 2.90, 3.41, I2 = 10%), and increased trend of orofacial malformations (RR 1.98, 95% CI 0.79, 5.00, I2 = 0%).

CONCLUSIONS

Gabapentin use was associated with an increased risk of NICU admissions in the cohort study and pooled meta-analysis. Clinicians should prescribe gabapentin with caution during pregnancy and further studies are warranted.

Gabapentinoids and Risk for Severe Exacerbation in Chronic Obstructive Pulmonary Disease : A Population-Based Cohort Study

BACKGROUND

North American and European health agencies recently warned of severe breathing problems associated with gabapentinoids, including in patients with chronic obstructive pulmonary disease (COPD), although supporting evidence is limited.

OBJECTIVE

To assess whether gabapentinoid use is associated with severe exacerbation in patients with COPD.

DESIGN

Time-conditional propensity score-matched, new-user cohort study.

SETTING

Health insurance databases from the Régie de l'assurance maladie du Québec in Canada.

PATIENTS

Within a base cohort of patients with COPD between 1994 and 2015, patients initiating gabapentinoid therapy with an indication (epilepsy, neuropathic pain, or other chronic pain) were matched 1:1 with nonusers on COPD duration, indication for gabapentinoids, age, sex, calendar year, and time-conditional propensity score.

MEASUREMENTS

The primary outcome was severe COPD exacerbation requiring hospitalization. Hazard ratios (HRs) associated with gabapentinoid use were estimated in subcohorts according to gabapentinoid indication and in the overall cohort.

RESULTS

The cohort included 356 gabapentinoid users with epilepsy, 9411 with neuropathic pain, and 3737 with other chronic pain, matched 1:1 to nonusers. Compared with nonuse, gabapentinoid use was associated with increased risk for severe COPD exacerbation across the indications of epilepsy (HR, 1.58 [95% CI, 1.08 to 2.30]), neuropathic pain (HR, 1.35 [CI, 1.24 to 1.48]), and other chronic pain (HR, 1.49 [CI, 1.27 to 1.73]) and overall (HR, 1.39 [CI, 1.29 to 1.50]).

LIMITATION

Residual confounding, including from lack of smoking information.

CONCLUSION

In patients with COPD, gabapentinoid use was associated with increased risk for severe exacerbation. This study supports the warnings from regulatory agencies and highlights the importance of considering this potential risk when prescribing gabapentin and pregabalin to patients with COPD.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research and Canadian Lung Association.

Narrative Review of Topiramate: Clinical Uses and Pharmacological Considerations

Due to the diverse mechanisms of action of antiseizure drugs, there has been a rise in prescriptions of these drugs for non-epileptic pathologies. One drug that is now being used for a variety of conditions is topiramate. This is a narrative review that used PubMed, Google Scholar, MEDLINE, and ScienceDirect to review literature on the clinical and pharmacologic properties of topiramate. Topiramate is a commonly prescribed second-generation antiseizure drug. The drug works through multiple pathways to prevent seizures. In this regard, topiramate blocks sodium and calcium voltage-gated channels, inhibits glutamate receptors, enhances gamma-aminobutyric acid (GABA) receptors, and inhibits carbonic anhydrase. Topiramate is approved by the Food and Drug Administration (FDA) for epilepsy treatment and migraine prophylaxis. Topiramate in combination with phentermine is also FDA-approved for weight loss in patients with a body mass index (BMI) > 30. The current target dosing for topiramate monotherapy is 400 mg/day and 100 mg/day to treat epilepsy and migraines, respectively. Commonly reported side effects include paresthesia, confusion, fatigue, dizziness, and change in taste. More uncommon and serious adverse effects can include acute glaucoma, metabolic acidosis, nephrolithiasis, hepatotoxicity, and teratogenicity. Related to a broad side effect profile, physicians prescribing this drug should routinely monitor for side effects and/or toxicity. The present investigation reviews various anti-seizure medications before summarizing indications of topiramate, off-label uses, pharmacodynamics, pharmacokinetics, adverse effects, and drug-drug interactions.

Diagnostic Accuracy of Ambulatory EEG vs Routine EEG in Patients With First Single Unprovoked Seizure

Background and Objective

To evaluate the diagnostic accuracy of the ambulatory EEG (aEEG) at detecting interictal epileptiform discharges (IEDs)/seizures compared with routine EEG (rEEG) and repetitive/second rEEG in patients with a first single unprovoked seizure (FSUS). We also evaluated the association between IED/seizures on aEEG and seizure recurrence within 1 year of follow-up.

Methods

We prospectively evaluated 100 consecutive patients with FSUS at the provincial Single Seizure Clinic. They underwent 3 sequential EEG modalities: first rEEG, second rEEG, and aEEG. Clinical epilepsy diagnosis was ascertained based on the 2014 International League Against Epilepsy definition by a neurologist/epileptologist at the clinic. An EEG-certified epileptologist/neurologist interpreted all 3 EEGs. All patients were followed up for 52 weeks until they had either second unprovoked seizure or maintained single seizure status. Accuracy measures (sensitivity, specificity, negative and positive predictive values, and likelihood ratios), receiver operating characteristic (ROC) analysis, and area under the curve (AUC) were used to evaluate the diagnostic accuracy of each EEG modality. Life tables and the Cox proportional hazard model were used to estimate the probability and association of seizure recurrence.

Results

Ambulatory EEG captured IED/seizures with a sensitivity of 72%, compared with 11% for the first rEEG and 22% for the second rEEG. The diagnostic performance of the aEEG was statistically better (AUC: 0.85) compared with the first rEEG (AUC: 0.56) and second rEEG (AUC: 0.60). There were no statistically significant differences between the 3 EEG modalities regarding specificity and positive predictive value. Finally, IED/seizure on the aEEG was associated with more than 3 times the hazard of seizure recurrence.

Discussion

The overall diagnostic accuracy of aEEG at capturing IED/seizures in people presenting with FSUS was higher than the first and second rEEGs. We also found that IED/seizures on the aEEG were associated with an increased risk of seizure recurrence.

Classification of Evidence

This study provides Class I evidence supporting that, in adults with First Single Unprovoked Seizure (FSUS), 24-h ambulatory EEG has increased sensitivity when compared with routine and repeated EEG.

The North American Antiepileptic Drug Pregnancy Registry: A Canadian Subgroup Analysis

BACKGROUND

The North American AED Pregnancy Registry (NAAPR) provides crucial data for understanding the risks of antiepileptic drug (AED) exposure in pregnancy. This study aims to quantify the Canadian contribution to NAAPR and compare AED usage in pregnancy in Canada and the USA.

METHODS

Enrollment rate ratios (ERR) to NAAPR, adjusted for the populations of women of childbearing age, were calculated for the USA, Canada, and for the different Canadian provinces. Methods of enrollment to NAAPR and AED usage were compared between the two countries using chi-squared tests.

RESULTS

Between 1997 and 2019, 10,215 pregnant women enrolled into NAAPR: 4.1% were Canadian (n = 432, ERR = 0.39, CI_95% = 0.35-0.43). Within Canada, no patients were enrolled from the three northern territories or from Prince Edward Island. While fewer patients than expected enrolled from Quebec (ERR = 0.35, CI_95% = 0.19-0.58), Nova Scotia had the highest enrollment rate (ERR = 1.55; CI_95% = 0.66-3.11). Compared with their American peers, Canadians were less likely to have been enrolled by their healthcare provider and more likely to have been enrolled via social media (p < 0.01). Canadian women were more likely to be taking carbamazepine (24% vs. 15%; p < 0.01) or valproic acid (8% vs. 4%; p < 0.01).

CONCLUSION

The proportion of Canadian enrollees into NAAPR was less than expected based on the relative population size of Canadian women of reproductive age. Greater Canadian enrollment to NAAPR would contribute to ongoing worldwide efforts in assessing the risks of AEDs use in pregnant women and help quantify rates of AED usage, major congenital malformations, and access to subspecialized epilepsy care within Canada.

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.

Prescription trends of antiseizure medications before and during the COVID-19 pandemic

Introduction

Given the lack of evidence on how the COVID-19 pandemic impacted antiseizure medication (ASM) use, we examined the trends of ASMs before and during COVID-19.

Methods

We conducted a population-based study using provincial-level health databases from Manitoba, Canada, between 1 June 2016 and 1 March 2021. We used interrupted time series autoregressive models to examine changes in the prevalence and incidence of ASM prescription rates associated with COVID-19 public health restrictions.

Results

Among prevalent users, the COVID-19 pandemic led to a significant increase in new-generation ASMs with a percentage change of 0.09% (p = 0.03) and a significant decrease in incidence use of all ASMs with a percentage change of -4.35% (p = 0.04). Significant trend changes were observed in the prevalent use of new-generation ASMs (p = 0.04) and incidence use of all (p = 0.04) and new-generation ASMs (p = 0.02). Gabapentin and clonazepam prescriptions contributed 37% of prevalent and 54% of incident use.

Conclusion

With the introduction of public health measures during COVID-19, small but significant changes in the incident and prevalent use of ASM prescriptions were observed. Further studies are needed to examine whether barriers to medication access were associated with potential deterioration in seizure control among patients.

Conference presentation

The results from this study have been presented as an oral presentation at the 38th ICPE, International Society of Pharmacoepidemiology (ISPE) annual conference in Copenhagen.

Predicting Hepatic Clearance of Psychotropic Drugs in Isolated Perfused Fish Livers Using a Combination of Two In Vitro Assays

In vitro biotransformation assays with primary trout hepatocytes (RT-HEP) or liver subcellular fractions (RT-S9) have been proposed as valuable tools to help scientists and regulators better understand the toxicokinetics of chemicals. While both assays have been applied successfully to a diversity of neutral organic chemicals, only the RT-S9 assay has been applied to a large number of ionizable organic chemicals. Here, a combination of an in vitro biotransformation assay with RT-HEP with an active transport assay based on the permanent rainbow trout liver cell line RTL-W1 was used to qualitatively predict the potential hepatic clearance of nine psychotropic drugs with various degrees of ionization. Predictions were compared with rates of clearance measured in isolated perfused rainbow trout livers, and the importance of active transport was verified in the presence of the active transport inhibitor cyclosporin A. For the first time, it was demonstrated that a combination of biotransformation and active transport assays is powerful for the prediction of rates of hepatic clearance of ionizable chemicals. Ultimately, it is expected that this approach will allow for use of fewer animals while at the same time improving our confidence in the use of data from in vitro assays in chemical risk assessment.

Trends of Utilization of Antiseizure Medications Among Pregnant Women in Manitoba, Canada: A 20-Year Population-Based Study

Background: Evidence from developed countries demonstrates that the use of antiseizure medications (ASMs) has been increasing in the last decade. Pregnant women have a very challenging risk benefit trade-off in terms of ASM utilization, and it is crucial to know if increased utilization is seen among pregnant women. Objective: To examine time-trends of utilization of ASM therapies among pregnant women in Manitoba, Canada. Methods: We conducted a population-based cohort study using de-identified, linked administrative databases from Manitoba. Pregnancies between 1995 and 2018 were included. Four groups of pregnant people were created based on ASM exposure and epilepsy diagnosis. Results: Of 273,492 pregnancies, 812 (3/1000) had epilepsy diagnosis and were exposed to ASMs, 963 (3.5/1000) had epilepsy diagnosis and were unexposed, and 2742 (10/1000) were exposed to ASMs and did not have epilepsy diagnosis. Overall, the number of pregnancies exposed to ASMs increased significantly from 0.56% in 1997 to 2.21% in 2018 (p < 0.0001). Subgroup analysis by epilepsy diagnosis showed no significant change in ASMs exposure among pregnant women with epilepsy [the proportion of women exposed to ASM from all pregnancies was 0.37% (in 1997) and 0.36% (in 2018), p = 0.24]. A drop in carbamazepine use was observed, while the number of lamotrigine prescriptions increased from 6.45% in 1997 to 52% by 2018. ASM use among pregnant women without epilepsy increased significantly from 0.19% in 1997 to 1.85% in 2018 (p < 0.0001). In the total cohort of pregnancies, 1439 (0.53%) were exposed during their entire pregnancy, and 1369 (0.5%) were exposed only in their first trimester. Clonazepam was the most used ASM during the study period (1953 users, 0.71%), followed by gabapentin (785 users, 0.29%) and carbamazepine (449 users, 0.16%). Conclusion: No major shifts in the quantity of ASM use over the study period were observed among pregnant women with epilepsy. However, there was a significant increase in ASM use among pregnant women without epilepsy. The study results warrant further investigation into the implications of ASM use in pregnancy for indications other than epilepsy.

Twenty-year trends in the use of anti-seizure medication among pregnant women in the Netherlands

BACKGROUND

Anti-seizure medications (ASMs) are used to treat conditions such as epilepsy and bipolar disorder. Some of these drugs are associated with an increased risk of congenital malformations and adverse developmental outcomes.

OBJECTIVES

To examine trends in use of ASMs among pregnant women in the Netherlands according to medication safety profile.

METHODS

Using population-based data from the PHARMO Perinatal Research Network, we assessed trends in use of ASMs among pregnant women in the Netherlands between 1999 and 2019, stratified by medication safety profile. Individual treatment patterns were also assessed.

RESULTS

In total, 671,709 pregnancies among 446,169 women were selected, of which 2405 (3.6 per 1000) were ASM-exposed. Over the study period, a significant increase was observed for use of known safest ASMs (0.7-18.0 per 10,000 pregnancies) as well as for those with uncertain risk (5.3-13.4 per 10,000 pregnancies). Use of ASMs with higher risk of congenital malformations decreased significantly (24.8-14.5 per 10,000 pregnancies), except for topiramate (0-6.7 per 10,000 pregnancies). Switches between ASM safety risk categories before and during pregnancy were uncommon; women rather discontinued treatment or switched within the same category. There was no clear change for the proportion using polytherapy during pregnancy (12% overall), however a non-significant trend toward inclusion of known safest ASMs was observed over time (1.9-3.6%).

CONCLUSIONS

Over the last two decades, there has been an increase in use of known safest ASMs among pregnant women, together with a trend toward newer ASMs with uncertain risk. Only a small proportion of women switched to a safer alternative before or during pregnancy. Altogether, this highlights the need for an expansion of ASM risk knowledge and communication to healthcare providers and women of reproductive age to improve preconception counseling.

Pharmacokinetic Drug-Drug Interactions among Antiepileptic Drugs, Including CBD, Drugs Used to Treat COVID-19 and Nutrients

Anti-epileptic drugs (AEDs) are an important group of drugs of several generations, ranging from the oldest phenobarbital (1912) to the most recent cenobamate (2019). Cannabidiol (CBD) is increasingly used to treat epilepsy. The outbreak of the SARS-CoV-2 pandemic in 2019 created new challenges in the effective treatment of epilepsy in COVID-19 patients. The purpose of this review is to present data from the last few years on drug–drug interactions among of AEDs, as well as AEDs with other drugs, nutrients and food. Literature data was collected mainly in PubMed, as well as google base. The most important pharmacokinetic parameters of the chosen 29 AEDs, mechanism of action and clinical application, as well as their biotransformation, are presented. We pay a special attention to the new potential interactions of the applied first-generation AEDs (carbamazepine, oxcarbazepine, phenytoin, phenobarbital and primidone), on decreased concentration of some medications (atazanavir and remdesivir), or their compositions (darunavir/cobicistat and lopinavir/ritonavir) used in the treatment of COVID-19 patients. CBD interactions with AEDs are clearly defined. In addition, nutrients, as well as diet, cause changes in pharmacokinetics of some AEDs. The understanding of the pharmacokinetic interactions of the AEDs seems to be important in effective management of epilepsy.

Perampanel and pregnancy

Objective

The objective was to summarize pregnancy and fetal/postnatal outcomes following maternal perampanel exposure using preclinical and clinical data, and to use physiologically based pharmacokinetic (PBPK) modeling to improve understanding of perampanel pharmacokinetics (PK) during pregnancy.

Methods

Preclinical developmental studies with perampanel were conducted in pregnant rats and rabbits. Clinical data were collated from the Eisai global perampanel safety database, comprising reports of perampanel exposure during pregnancy from routine clinical settings, interventional studies, and non‐interventional post‐marketing studies, searched for events coded to Medical Dictionary for Regulatory Activities (MedDRA) high‐level group terms of Pregnancy, Labor, Delivery, and Postpartum Conditions and/or the Standardized MedDRA Query terms of Congenital, Familiar, and Genetic Disorders. A PBPK model was used to predict clinical perampanel PK throughout pregnancy.

Results

Preclinical studies indicated that perampanel may be linked with post‐implantation loss and/or some specific physical development delays but not fertility and early embryonic development. As of August 31, 2018, 96 pregnancies in 90 women receiving perampanel had been reported. No concomitant medications were reported in 26 (28.9%) women taking perampanel. Overall, 43 pregnancies reached full term (all normal live births), 28 did not reach term (induced abortion, n = 18; spontaneous miscarriage, n = 6; incomplete spontaneous miscarriage, n = 2; premature delivery, n = 1; stillbirth [Fallot’s tetralogy], n = 1), 18 were lost to follow‐up, and seven were ongoing at data cut‐off. Adverse events were reported in five full‐term neonates (low Apgar score, n = 2; fatal neonatal aspiration, n = 1; cystic fibrosis and congenital deafness, n = 1; poor sucking reflex and shallow breathing, n = 1). PK simulations predicted perampanel exposure decreases throughout pregnancy and is up to four‐ and three‐fold lower towards the end of pregnancy compared with non‐pregnant women for total and unbound perampanel, respectively.

Significance

These data provide preliminary information on perampanel use during pregnancy and should be interpreted with caution. Further outcome data are required to estimate the prevalence of adverse pregnancy outcomes with perampanel exposure.

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.

Enzyme-inducing antiseizure medication utilization in patients with epilepsy and vascular risk factors

OBJECTIVES

Several lines of evidence have suggested that exposure to enzyme-inducing antiseizure medications (EIASMs) may result in the subsequent development of hyperlipidemia, a well-known risk factor for vascular disease. This may be an issue of concern particularly in the context of additional comorbid vascular risk factors. We therefore aimed to investigate trends of and associations with the use of these medications among adult patients with epilepsy.

METHODS

The cross-sectional Medical Expenditure Panel Survey (MEPS) was interrogated to ascertain the prevalence of use of EIASMs by noninstitutionalized adult patients with epilepsy in the United States between the years 2004 and 2015. Any patient prescribed carbamazepine, phenytoin, phenobarbital, or primidone within a given year was defined as having been prescribed an EIASM. Trends over three-year epochs were evaluated with univariate logistic regression, while associations with demographic factors, vascular risk factors, and vascular disease were evaluated using a chi-square test corrected for survey design as well as multivariate logistic regression.

RESULTS

A total of 2281 (unweighted) patients were identified, representing 1,781,237 individuals. Between 2004 and 2015, 45.9% (95% confidence interval [CI]: 42.4%-49.4%) were prescribed EIASMs. Approximately one-quarter of patients aged 65 years and above used EIASMs compared with 18.5% of younger patients (odds ratio [OR]: 1.83, 95% CI = 1.27-2.65). Female patients (OR = 0.61, 95% CI = 0.47-0.79) and those with heart disease (OR: 0.63, 95% CI = 0.45-0.89) were significantly less likely to be prescribed EIASMs. Among those prescribed EIASMs, 38.9% had hypertension, 12.2% had diabetes, 61.6% were overweight or obese, 17.3% heart disease, 17.2% had a history of a cerebrovascular event, and 28.5% had diagnosed hyperlipidemia. Nonetheless, between 2004-2006 and 2013-2015, the odds of EIASM prescription decreased significantly (OR: 0.39, 95% CI: 0.28-0.55).

CONCLUSIONS

A substantial proportion of patients with comorbid vascular disease or vascular risk factors (e.g., hypertension and older age) is prescribed EIASMs. This could potentially increase patients' risk for subsequent negative outcomes such as cardiovascular or cerebrovascular disease. Though utilization of these medications has decreased, further efforts toward increasing use of newer antiseizure medications (ASMs) that are not associated with similar risks may be warranted.

Patterns of anticonvulsant use and adverse drug events in older adults

PURPOSE

To examine indications for, duration of use, and rate of adverse drug events (ADE) attributable to anticonvulsant initiation, as adjudicated by expert review of electronic health records (EHR) of older adults.

METHODS

We identified a cohort of community dwelling Medicare beneficiaries with linked EHR (aged 65+, continuously enrolled with a large health system/until death between 2012 and 2014, n = 20 945) and drew a stratified EHR review sample (n = 1534). An expert reviewed all records to adjudicate anticonvulsant use, years of use, indication for use, and evidence of ADEs attributable to anticonvulsant initiation. After excluding patients with insufficient EHR data (n = 37; 2%), we reconstructed the cohort using inverse probability weights to resemble the original cohort of eligible beneficiaries (n = 20 380). Among incident users of a single anticonvulsant, we estimated the rate of ADEs and described the type and severity of ADEs.

RESULTS

Overall, 12% (n = 2469) of eligible beneficiaries used at least one anticonvulsant in the 2012 to 2014 period (4% [n = 757] incident users, 8% [n = 1712] prevalent users). Incident users were most frequently prescribed gabapentin (n = 461/757, 61%), benzodiazepines (n = 122/757, 16%), and levetiracetam (n = 74/757, 10%); the most common indication was pain relief (n = 214; 28%) followed by epilepsy (n = 53; 7%). Among incident users, the overall ADE rate was 10/100 person-years (95% CI 4-20/100 person-years), of which 29% (n = 28/97) were life threatening (eg, somnolence). Most ADEs among incident monotherapy users were nervous system related (68%, n = 66/97).

CONCLUSION

Many older adult community dwelling traditional Medicare beneficiaries had clinically significant ADEs likely attributable to the initiation of anticonvulsant therapy, which was begun for a range of indications.

Trends in gabapentinoid prescribing, co-prescribing of opioids and benzodiazepines, and associated deaths in Scotland

BACKGROUND

Gabapentinoid drugs (gabapentin and pregabalin) are effective in neuropathic pain, which has a prevalence of ∼7%. Concerns about increased prescribing have implications for patient safety, misuse, and diversion. Drug-related deaths (DRDs) have increased and toxicology often implicates gabapentinoids. We studied national and regional prescribing rates (2006-2016) and identified associated sociodemographic factors, co-prescriptions and mortality, including DRDs.

METHODS

National data from the Information Service Division, NHS Scotland were analysed for prescribing, sociodemographic, and mortality data from the Health Informatics Centre, University of Dundee. DRDs in which gabapentinoids were implicated were identified from National Records of Scotland and Tayside Drug Death Databases.

RESULTS

From 2006 to 2016, the number of gabapentin prescriptions in Scotland increased 4-fold (164 630 to 694 293), and pregabalin 16-fold (27 094 to 435 490). In 2016 'recurrent users' (three or more prescriptions) had mean age 58.1 yr, were mostly females (62.5%), and were more likely to live in deprived areas. Of these, 60% were co-prescribed an opioid, benzodiazepine, or both (opioid 49.9%, benzodiazepine 26.8%, both 17.1%). The age-standardised death rate in those prescribed gabapentinoids was double that in the Scottish population (relative risk 2.16, 95% confidence interval 2.08-2.25). Increases in gabapentinoids contributing to cause of DRDs were reported regionally and nationally (gabapentin 23% vs 15%; pregabalin 21% vs 7%). In Tayside, gabapentinoids were implicated in 22 (39%) of DRDs, 17 (77%) of whom had not received a prescription.

CONCLUSIONS

Gabapentinoid prescribing has increased dramatically since 2006, as have dangerous co-prescribing and death (including DRDs). Older people, women, and those living in deprived areas were particularly likely to receive prescriptions. Their contribution to DRDs may be more related to illegal use with diversion of prescribed medication.

Off-label drugs use in neurology outpatient department: A prospective study at a tertiary care teaching hospital

Background:

Off-label drug use refers to any use of an approved or cleared drug that is not included in that product's approved labeling or cleared indications for use. It may be in terms of indication, age group, dosage, or route of administration. Off-label drug prescriptions are common neurology practice.

Aim:

The aim of the study is to evaluate the prevalence pattern of off-label drug use in neurology.

Subjects and Methods:

A prospective, observational, cross-sectional study was carried out in the neurology outpatient department of tertiary care teaching hospital. Data of patients above 18 years were recorded after obtaining their informed consent. The National Formulary of India (NFI) and British National Formulary (BNF) guidelines were used as tools for evaluation of the prevalence of off-label drug use.

Results:

A total of 709 drugs were recorded from the prescription data of 205 patients collected in the duration of 2 months. The results reported 145 (20.45%) and 317 (44.71%) drugs as off-label as per the NFI and BNF, respectively. Prescriptions with minimum 1 off-label drug use were 78.05% – BNF and 46.83% – NFI. The indication was one of the most common causes of drugs being off-label. Out of the total 317 off-label drug uses reported, 84 were unlicensed drug use as per the BNF. There is strong and positive correlation established between the age of the patients, number of drugs prescribed, and total off-label drugs prescribed per patient in the given study. The most common off-label drug use noted was with clonazepam and amitriptyline.

Conclusion:

Off-label prescriptions practice is common in the field of neurology.

Temporal trends and patterns in carbamazepine use, related severe cutaneous adverse reactions, and HLA-B*15:02 screening: A nationwide study

OBJECTIVE

After discovering the association between the HLA-B*15:02 allele and carbamazepine-related severe cutaneous adverse reactions (SCARs), particularly in Southeastern Asian populations, clinical strategies to prevent carbamazepine-related SCARs have changed. We aimed to investigate 10-year trends in carbamazepine use and carbamazepine-related SCARs and to examine the patterns and determinants of HLA-B*15:02 screening in Taiwan.

METHODS

A nationwide study was performed using Taiwan's National Health Insurance Research Database. In the first part of the study, new users of carbamazepine were included, and those who experienced SCAR-related admissions were further identified. In the second part of the study, recipients of HLA-B*15:02 screening (reimbursed by Taiwan's National Health Insurance since June 2010) were included and multivariate logistic regression was used to explore factors associated with the use of screening.

RESULTS

The numbers of new users of carbamazepine and SCAR cases decreased remarkably during the 10-year period (-82.6% and -87.1%, respectively), and the incidence rates of SCARs showed a downward trend after 2011. The screening rate of the HLA-B*15:02 allele increased to 24.9% in 2014. Neurologists (odds ratio 12.33, 95% confidence interval 9.30-16.35), psychiatrists (9.97, 7.31-13.61), and neurosurgeons (3.23, 2.42-4.32) were more likely to perform screening tests than other specialties were. Physicians practicing in medical centers (6.00, 5.51-6.54) were more likely to perform screening tests than those practicing in other hospitals, whereas the screening rates in clinics remained at 0.0% throughout the study period.

SIGNIFICANCE

In recent years, the number of carbamazepine-related SCAR cases has decreased substantially in Taiwan. However, only one-fourth of new users of carbamazepine received HLA-B*15:02 screening, and there were considerable disparities in the screening rates across different physician groups. Policymakers should consider solutions to barriers to implementing screening tests in clinical practice and should not neglect the value of other safety communications and regulations to complement the limitations of pharmacogenomic testing.

Pharmacoeconomic Analysis of Antiepileptic Reimbursement for Neuropathic Pain in Bosnia and Herzegovina - Budget Impact Analysis of Pregabalin

Introduction:

Neuropathic pain resulting from injury to the nervous system. Up to 7% to 8% of the European population is affected. A number of different treatments for neuropathic pain have been studied including antiepileptic. Pregabalin and gabapentin are often considered first-line treatments. Pregabalin provides equivalent efficacy to gabapentin, showing greater potency at much lower doses and is considered as cost-effective intervention. In Federation of Bosnia and Herzegovina (FB&H), gabapentin is fully reimbursed, while pregabalin is enlisted on list B with copayment.

Aim:

To develop simple budget impact (BI) model and assess BI of introducing pregabalin into full reimbursement in FB&H.

Material and methods:

Budget impact model was developed using Microsoft Excel 2010. Local epidemiology data and data on drug consumption from government reports in 2016 were used. Two scenarios with three-year time horizon have been developed: 1) without and 2) with pregabalin reimbursed at the same level as gabapentin. Two developed scenarios have been compared from health insurance fund (HIF) perspective.

Results:

In scenario 1 consider both drugs fully reimbursement and without patient switch among alternatives the total cost would be increased for 780,025 KM; 852,027 KM and 943,830 KM over a 3-year period. In scenario 2 considering both drugs fully reimbursed but with patient switch topregabalin total annual cost would be increased for 732,241 KM; 742,395 KM and 751,761 KM. Comparing scenario 1 and 2 it is found that scenario 2 is more favorable from HIF perspective.

Conclusion:

Implementation of pharmacoeconomic principles in reimbursement decisions in Bosnia and Herzegovina would improve access to medicines and contribute rationale resource consumption.

Anti-epileptic drug utilisation in paediatrics: a systematic review

OBJECTIVES

This study aims to determine global anti-epileptic drug (AED) utilisation prevalence and describe utilisation trends in different countries.

METHODS

Databases Embase (1980-May 2017), Medline (1946-May 2017) and PubMed were searched for original research on AED utilisation. All paediatric national or regional database studies and surveys were included.

RESULTS

Twenty-one studies were identified. Five were excluded from the analysis as the data were collected before 2005, leaving 16 studies. Monotherapy regimen varied between 58% and 94% in different countries. In several of the studies, sodium valproate was the most frequently prescribed AED. However, there is a trend towards increasing utilisation of new-generation AEDs, particularly levetiracetam, in some countries.

CONCLUSION

Monotherapy was used in 58%-94%of patients. There is increasing utilisation of the new-generation AEDs, in particular lamotrigine, levetiracetam and topiramate. Old-generation AEDs are still used in the majority of patients. There is a need for up-to-date studies to determine the prevalence of AEDs in children.

Accuracy of claims-based algorithms for epilepsy research: Revealing the unseen performance of claims-based studies

OBJECTIVE

To evaluate published algorithms for the identification of epilepsy cases in medical claims data using a unique linked dataset with both clinical and claims data.

METHODS

Using data from a large, regional health delivery system, we identified all patients contributing biologic samples to the health system's Biobank (n = 36K). We identified all subjects with at least one diagnosis potentially consistent with epilepsy, for example, epilepsy, convulsions, syncope, or collapse, between 2014 and 2015, or who were seen at the epilepsy clinic (n = 1,217), plus a random sample of subjects with neither claims nor clinic visits (n = 435); we then performed a medical chart review in a random subsample of 1,377 to assess the epilepsy diagnosis status. Using the chart review as the reference standard, we evaluated the test characteristics of six published algorithms.

RESULTS

The best-performing algorithm used diagnostic and prescription drug data (sensitivity = 70%, 95% confidence interval [CI] 66-73%; specificity = 77%, 95% CI 73-81%; and area under the curve [AUC] = 0.73, 95%CI 0.71-0.76) when applied to patients age 18 years or older. Restricting the sample to adults aged 18-64 years resulted in a mild improvement in accuracy (AUC = 0.75,95%CI 0.73-0.78). Adding information about current antiepileptic drug use to the algorithm increased test performance (AUC = 0.78, 95%CI 0.76-0.80). Other algorithms varied in their included data types and performed worse.

SIGNIFICANCE

Current approaches for identifying patients with epilepsy in insurance claims have important limitations when applied to the general population. Approaches incorporating a range of information, for example, diagnoses, treatments, and site of care/specialty of physician, improve the performance of identification and could be useful in epilepsy studies using large datasets.

Acute Ataxia in Children: A Review of the Differential Diagnosis and Evaluation in the Emergency Department

Acute ataxia in a pediatric patient poses a diagnostic dilemma for any physician. While the most common etiologies are benign, occasional individuals require urgent intervention. Children with stroke, toxic ingestion, infection, and neuro-inflammatory disorders frequently exhibit ataxia as an essential-if not the only-presenting feature. The available retrospective research utilize inconsistent definitions of acute ataxia, precluding the ability to pool data from these studies. No prospective data exist that report on patients presenting to the emergency department with ataxia. This review examines the reported causes of ataxia and attempts to group them into distinct categories: post-infectious and inflammatory central and peripheral phenomena, toxic ingestion, neurovascular, infectious and miscellaneous. From there, we synthesize the existing literature to understand which aspects of the history, physical exam, and ancillary testing might aid in narrowing the differential diagnosis. MRI is superior to CT in detecting inflammatory or vascular insults in the posterior fossa, though CT may be necessary in emergent situations. Lumbar puncture may be deferred until after admission in most instances, with suspicion for meningitis being the major exception. There is insufficient evidence to guide laboratory evaluation of serum, testing should be ordered based on clinical judgement-recommended studies include metabolic profiles and screening labs for metabolic disorders (lactate and ammonia). All patients should be reflexively screened for toxic ingestions.