Epileptogenic drugs: a systematic review

Diagnosing epileptic seizures in patients with Alzheimer's disease and deciding on the appropriate treatment plan

INTRODUCTION

Alzheimer's disease (AD) is the predominant cause of dementia and a significant contributor to morbidity among the elderly. Patients diagnosed with AD face an increased risk of epileptic seizures.

AREAS COVERED

Herein, the authors review the challenges in the diagnosis of seizures in patients with AD, the risks of seizures related to medications used in AD and the pharmacological treatment of seizures in AD. The authors also provide the reader with their expert opinion on the subject matter and future perspectives.

EXPERT OPINION

Healthcare professionals should maintain a vigilant approach to suspecting seizures in AD patients. Acute symptomatic seizures triggered by metabolic disturbances, infections, toxins, or drug-related factors often have a low risk of recurrence. In such cases, addressing the underlying cause may suffice without initiating antiseizure medications (ASMs). However, unprovoked seizures in certain AD patients carry a higher risk of recurrence over time, warranting the use of ASMs. Although data is limited, both lamotrigine and levetiracetam appear to be reasonable choices for controlling seizures in elderly AD patients. Decisions should be informed by the best available evidence, the treating physician's clinical experience, and the patient's preferences.

Measuring Real-Time Medication Effects From Electroencephalography

PURPOSE

Evaluating the effects of antiseizure medication (ASM) on patients with epilepsy remains a slow and challenging process. Quantifiable noninvasive markers that are measurable in real-time and provide objective and useful information could guide clinical decision-making. We examined whether the effect of ASM on patients with epilepsy can be quantitatively measured in real-time from EEGs.

METHODS

This retrospective analysis was conducted on 67 patients in the long-term monitoring unit at Boston Children's Hospital. Two 30-second EEG segments were selected from each patient premedication and postmedication weaning for analysis. Nonlinear measures including entropy and recurrence quantitative analysis values were computed for each segment and compared before and after medication weaning.

RESULTS

Our study found that ASM effects on the brain were measurable by nonlinear recurrence quantitative analysis on EEGs. Highly significant differences ( P < 1e-11) were found in several nonlinear measures within the seizure zone in response to antiseizure medication. Moreover, the size of the medication effect correlated with a patient's seizure frequency, seizure localization, number of medications, and reported seizure frequency reduction on medication.

CONCLUSIONS

Our findings show the promise of digital biomarkers to measure medication effects and epileptogenicity.

Comparative assessment of Ca2+ oscillations in 2- and 3-dimensional hiPSC derived and isolated cortical neuronal networks

Human induced Pluripotent Stem Cell (hiPSC) derived neural cells offer great potential for modelling neurological diseases and toxicities and have found application in drug discovery and toxicology. As part of the European Innovative Medicines Initiative (IMI2) NeuroDeRisk (Neurotoxicity De-Risking in Preclinical Drug Discovery), we here explore the Ca2+ oscillation responses of 2D and 3D hiPSC derived neuronal networks of mixed Glutamatergic/GABAergic activity with a compound set encompassing both clinically as well as experimentally determined seizurogenic compounds. Both types of networks are scored against Ca2+ responses of a primary mouse cortical neuronal 2D network model serving as an established comparator assay. Parameters of frequency and amplitude of spontaneous global network Ca2+ oscillations and the drug-dependent directional changes to these were assessed, and predictivity of seizurogenicity scored using contingency table analysis. In addition, responses between models were compared between both 2D models as well as between 2D and 3D models. Concordance of parameter responses was best between the hiPSC neurospheroid and the mouse primary cortical neuron model (77% for frequency and 65% for amplitude). Decreases in spontaneous Ca2+ oscillation frequency and amplitude were found to be the most basic shared determinants of risk of seizurogenicity between the mouse and the neurospheroid model based on testing of clinical compounds with documented seizurogenic activity. Increases in spontaneous Ca2+ oscillation frequency were primarily observed with the 2D hIPSC model, though the specificity of this effect to seizurogenic clinical compounds was low (33%), while decreases to spike amplitude in this model were more predictive of seizurogenicity. Overall predictivities of the models were similar, with sensitivity of the assays typically exceeding specificity due to high false positive rates. Higher concordance of the hiPSC 3D model over the 2D model when compared to mouse cortical 2D responses may be the result of both a longer maturation time of the neurospheroid (84-87 days for 3D vs. 22-24 days for 2D maturation) as well as the 3-dimensional nature of network connections established. The simplicity and reproducibility of spontaneous Ca2+ oscillation readouts support further investigation of hiPSC derived neuronal sources and their 2- and 3-dimensional networks for neuropharmacological safety screening.

Contrast Media Adverse Drug Reactions in Highly Polluted Environment

Iodinated- (ICM) and gadolinium-based (GCM) contrast media are used in radiology imaging techniques, such as computer tomography (CT) and magnetic resonance (MR), respectively. The paper aims to analyze the adverse drug reactions of ICM and GCM on different sites of the body in a highly polluted environment. We analyzed the pharmacovigilance in contrast media on the basis of reports submitted to the Regional Center for Monitoring of Adverse Drug Reactions (ADR) at the Department of Clinical Pharmacology in Wrocław. Safety profiles were compared between different ICM and GCM and at the system organ level using the proportional reporting ratio (PRR). We analyzed 124 reports of adverse reactions related to contrast agents between 2006 and 2021. Our findings revealed that ADR combinations occurred more frequently after the use of iodinated contrast agents (72.08%) than gadolinium contrast agents (27.92%). Iomeprol and Iopromide were identified as the most frequently reported media. Each medium presented a different safety profile. Skin disorders are the most common adverse drug reactions among patients using both iodine- and gadolinium-based contrast media. Gadolinium-based contrast agents are characterized by similar organ toxicity. Conversely, iodine-based contrast agents are more diverse—some of which show tissue specificity, such as Iodixanol for the gastrointestinal system or Iohexol for the respiratory tract. This study shows relatively high occurrence of respiratory tract related ADRs in Wrocław. We also prove that it is possible to choose the most optimal contrast agent for patients with specific organ site problems to omit the possible complications.

Differential Electrographic Signatures Generated by Mechanistically-Diverse Seizurogenic Compounds in the Larval Zebrafish Brain

We assessed similarities and differences in the electrographic signatures of local field potentials (LFPs) evoked by different pharmacological agents in zebrafish larvae. We then compared and contrasted these characteristics with what is known from electrophysiological studies of seizures and epilepsy in mammals, including humans. Ultimately, our aim was to phenotype neurophysiological features of drug-induced seizures in larval zebrafish for expanding knowledge on the translational potential of this valuable alternative to mammalian models. LFPs were recorded from the midbrain of 4-d-old zebrafish larvae exposed to a pharmacologically diverse panel of seizurogenic compounds, and the outputs of these recordings were assessed using frequency domain analysis. This included analysis of changes occurring within various spectral frequency bands of relevance to mammalian CNS circuit pathophysiology. From these analyses, there were clear differences in the frequency spectra of drug-exposed LFPs, relative to controls, many of which shared notable similarities with the signatures exhibited by mammalian CNS circuits. These similarities included the presence of specific frequency components comparable to those observed in mammalian studies of seizures and epilepsy. Collectively, the data presented provide important information to support the value of larval zebrafish as an alternative model for the study of seizures and epilepsy. These data also provide further insight into the electrophysiological characteristics of seizures generated in nonmammalian species by the action of neuroactive drugs.

Drug-Induced Seizures: Considerations for Underlying Molecular Mechanisms

A broad spectrum of chemical entities have been associated with drug-induced seizure (DIS), emphasizing the importance of this potential liability across various drug classes (e.g., antidepressants, antipsychotics, antibiotics, and analgesics among others). Despite its importance within drug safety testing, an understanding of the molecular mechanisms associated with DIS is often lacking. The etiology of DIS is understood to be a result of either a deficit in inhibitory (e.g., gamma aminobutyric acid) or an elevated excitatory (e.g., glutamate) signaling, leading to synchronous neuronal depolarization affecting various brain regions and impairing normal neurological functions. How this altered neuronal signaling occurs and how these changes interact with other non-brain receptor driven DIS-associated changes such as metabolic disturbances, electrolyte imbalances, altered drug metabolism, and withdrawal effects are poorly understood. Herein, we discuss important molecular mechanisms identified in DIS for several drugs and/or drug classes. With a better understanding of the molecular mechanisms associated with DIS, in vivo or in vitro models may be applied to characterize and mitigate DIS risk during drug development. Susceptibility stratification for DIS presents species differences in the following order beagle dogs > rodents and cynomolgus monkeys > Göttingen minipigs with a more than 2-fold difference between canines and minipigs, which is important to consider during non-clinical species selection. While clinical signs such as myoclonus, severe muscle jerks, or convulsions are often associated with abnormal epileptiform EEG activity, tremors are most of the time physiological and rarely observed with concurrent epileptiform EEG activity which need to be considered during DIS risk evaluation.

Functional brain imaging in larval zebrafish for characterising the effects of seizurogenic compounds acting via a range of pharmacological mechanisms

BACKGROUND AND PURPOSE

Functional brain imaging using genetically encoded Ca2+ sensors in larval zebrafish is being developed for studying seizures and epilepsy as a more ethical alternative to rodent models. Despite this, few data have been generated on pharmacological mechanisms of action other than GABAA antagonism. Assessing larval responsiveness across multiple mechanisms is vital to test the translational power of this approach, as well as assessing its validity for detecting unwanted drug-induced seizures and testing antiepileptic drug efficacy.

EXPERIMENTAL APPROACH

Using light-sheet imaging, we systematically analysed the responsiveness of 4 days post fertilisation (dpf; which are not considered protected under European animal experiment legislation) transgenic larval zebrafish to treatment with 57 compounds spanning more than 12 drug classes with a link to seizure generation in mammals, alongside eight compounds with no such link.

KEY RESULTS

We show 4dpf zebrafish are responsive to a wide range of mechanisms implicated in seizure generation, with cerebellar circuitry activated regardless of the initiating pharmacology. Analysis of functional connectivity revealed compounds targeting cholinergic and monoaminergic reuptake, in particular, showed phenotypic consistency broadly mapping onto what is known about neurotransmitter-specific circuitry in the larval zebrafish brain. Many seizure-associated compounds also exhibited altered whole brain functional connectivity compared with controls.

CONCLUSIONS AND IMPLICATIONS

This work represents a significant step forward in understanding the translational power of 4dpf larval zebrafish for use in neuropharmacological studies and for studying the events driving transition from small-scale pharmacological activation of local circuits, to the large network-wide abnormal synchronous activity associated with seizures.

A Case of Generalized Seizure after Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a severe mucocutaneous adverse reaction characterized by extensive necrosis and epidermal detachment involving more than 30% of the body surface area (BSA). It is commonly triggered by antiepileptics, sulfonamide antibiotics, and non-steroidal anti-inflammatory drugs. A 22-year-old female without any underlying medical history presented with painful multiple erythematous bullae and plaques of varied sizes throughout the body for 1 day. On the second hospitalization day (HD), the bullae progressively coalesced, leading to epidermal detachment involving 60% of the BSA. On the fifth HD, the patient had a tonic–clonic seizure with eyeball deviation for 5 minutes. She was transferred to the intensive care unit (ICU) and administered lorazepam 4 mg and levetiracetam 1,500 mg. Brain computed tomography, magnetic resonance imaging, and cerebrospinal fluid examination showed no abnormalities. Although the patient had delirium and additional seizures while in the ICU, her condition improved without any complications after 5 weeks of inpatient treatment. Several complications of TEN such as dehydration, malnutrition, sepsis, and ophthalmic and pulmonary complications have been reported; however, seizures have not been reported yet. Herein, we report a case of seizure in a patient during treatment for TEN.

Antipsychotic Polypharmacy and High-Dose Antipsychotics in Involuntary Patients: a Seven-Year Audit of Discharge Prescriptions in an Acute Care Unit

Antipsychotic polypharmacy (APP) is a psychopharmacological practice in which two or more antipsychotics are prescribed simultaneously. Despite the absence of evidence to support it, it is highly prevalent in clinical settings. Another recurrent practice strongly associated with APP is the prescription of high-dose antipsychotics (HDAs). Compulsory treatment is a legal means to impose treatment on an individual suffering from mental illness who refuses therapeutic intervention. Compulsory treatment has been associated with APP and HDAs and rates of both have been proposed to represent indicators of the quality of prescribing. We aimed to perform an antipsychotic prescription audit in a vulnerable psychiatric population, at the psychiatry department of a district hospital in Portugal, across 7 years. We evaluated APP and HDAs in 403 compulsorily admitted patients by reviewing their files at discharge. We used logistic regression to search for factors associated with APP and HDAs. APP was found in 70.5% of individuals, whereas HDAs were found in 51.4%. After adjustment, APP was significantly associated with male gender (Odds Ratio[OR] = 1.85 [1.04; 3.30] 95% Confidence Interval [CI]), involuntary outpatient treatment (OR = .40 [.18; .82] 95% CI), activation of the hospital social services (OR = 1.91 [1.08; 3.38] 95%CI), prescription of antidepressants (OR = .43 [.22; .82] 95%CI) and long-acting injectables (LAI) (OR = 28.29 [13.13; 60.97] 95%CI). HDAs were associated with male gender (OR = 1.76 [1.06; 2.94] 95%CI), the prescription of LAI (OR = 12.92 [6.93; 24.09] 95%CI) and oral first-generation antipsychotics (OR = 2.90 [1.51; 5.60] 95%CI).

Association between methylphenidate treatment and risk of seizure: a population-based, self-controlled case-series study

BACKGROUND

Individuals with attention-deficit hyperactivity disorder (ADHD) are at increased risk of seizures. Stimulant medications such as methylphenidate are the most commonly prescribed treatment for ADHD, but the association between their therapeutic use and the risk of seizures is unclear. We aimed to investigate the association between methylphenidate treatment and the risk of seizure.

METHODS

For this population-based observational study, we used the electronic medical record database of the Hong Kong Clinical Data Analysis And Reporting System to identify individuals aged 6-25 years who received at least one methylphenidate prescription during the study period. Individuals with records of seizure or epilepsy before the study period were excluded. Individuals treated with methylphenidate who had seizures during the study period were included in the subsequent analyses, and a self-controlled case-series design was used to control for time-invariant individual characteristics. We did additional analyses using skin infection as a negative control outcome. We compared relative incidence of seizure during periods when individuals were exposed to methylphenidate with that during non-exposed periods.

FINDINGS

Of 29 604 individuals prescribed methylphenidate between Jan 1, 2001, and Dec 31, 2017, 269 (199 males and 70 females) had incident seizures. The mean age at baseline was 6·66 years (SD 2·01) and the median age at the incident seizure was 9·69 years (IQR 7·62-12·99). The overall incidence of seizure during methylphenidate treatment was 4·4 per 10 000 patient-years. We detected an increased risk of seizure during the first 30 days of methylphenidate treatment compared with that during non-exposed periods, with an incidence rate ratio of 4·01 (95% CI 2·09-7·68). No increase in risk was identified during the following 31-180 days of treatment (1·13, 0·56-2·25) or during subsequent treatment (1·38, 0·92-2·07). We did not identify an increased risk in any risk window for the negative control outcome analysis. No individuals died because of a seizure during the study period.

INTERPRETATION

The incidence of seizures was higher in the period immediately after the start of methylphenidate treatment than in the non-exposed period. No increased risk was observed during continuation of methylphenidate treatment. The association between methylphenidate treatment and seizures immediately after initiation of medication can be seen as a potential safety signal. Monitoring of neurological outcomes in individuals with ADHD is recommended when they first start methylphenidate treatment.

FUNDING

Hong Kong Research Grants Council.

[Drug-induced seizures: prevalence, risk factors, treatment and prevention]

There is a growing interest to the problem of drug-induced epileptic seizures (ES) due to their relatively high prevalence, poor prognosis, a large number of different drugs associated with the development of drug-induced ES, and low awareness among general practitioners. Drug-induced ES are most often associated with the use of antidepressants, antipsychotics, antiepileptic drugs (overdose or as a result of discontinuation), antibiotics, immunosuppressants and immunomodulators, antitumor agents, analgesics, central nervous system stimulators, anesthetics etc. The prevalence of drug-induced ES varies with different drugs. It is estimated that about 6.1% of the first occurring ES are drug-induced. Risk factors for drug-induced ES include a history of epilepsy or ES, cancer, blood-brain barrier dysfunction, several concomitant neurological diseases, mental disorders, childhood, old and very old age, fever, impaired liver metabolism in patients with liver diseases, impaired drug excretion in patients with kidney diseases, polypharmacy, pharmacokinetic properties of the drugs themselves, allowing them to penetrate the blood-brain barrier in the central nervous system (lipophilicity, transport and communication with blood plasma proteins), drug concentration in blood serum, method and frequency of drug administration, single and daily doses of drugs. No clinical guidelines for the management of patients with drug-induced ES are available. It is recommended to identify patients at risk: elderly patients, patients with impaired liver and kidney function and patients receiving drugs that can cause ES and/or lower the seizure threshold. Benzodiazepines are the first-line treatment in drug-induced status epilepticus, barbiturates and propofol are the second-line treatment. The general principles for the prevention of drug-induced ES include careful selection of the optimal dose of drugs that can cause ES, especially in patients with impaired liver and/or kidney function, monitoring of several parameters in blood serum (for example, liver enzymes, electrolytes, glucose etc.), monitoring of the blood plasma concentration of certain drugs, avoiding the simultaneous administration of several drugs that stimulate the central nervous system, and a rapid discontinuation of such drugs.

Optogenetic and chemogenetic therapies for epilepsy

Drug-resistant epilepsy remains a significant health-care burden. The most effective treatment is surgery, but this is suitable for very few patients because of the unacceptable consequences of removing brain tissue. In contrast, gene therapy can regulate neuronal excitability in the epileptic focus whilst preserving function. Optogenetics and chemogenetics have the advantage that they are titratable therapies. Optogenetics uses light to control the excitability of specific neuronal populations. Optogenetics can be used in a closed-loop paradigm in which the light source is activated only when seizures are detected. However, expression of foreign proteins raises concerns about immunogenicity. Chemogenetics relies on the modification of an endogenous receptor or the production of a modified chimeric receptor that responds to an exogenous ligand. The main chemogenetic approach applied to epilepsy is to use designer receptors exclusively activated by designer drugs (DREADDs), which have been mainly modified muscarinic receptors or kappa-opioid receptors. Genetically modified human muscarinic receptor DREADDs are activated not by acetylcholine but by specific drugs such as clozapine-n-oxide or olanzepine. The dose of the drugs can be titrated in order to suppress seizures without adverse effects. Lastly, there is a chemogenetic approach that is activated by an endogenous ligand, glutamate. This takes advantage of invertebrate glutamate receptors that are chloride permeable. These bind glutamate released during seizure activity, and the resultant chloride current inhibits neuronal activity. The exogenous ligand, ivermectin, can also be given to reduce neuronal activity either chronically or as a rescue medication. The translation of this technology is hampered by the expression of a foreign protein. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Dealing with the storm: An overview of seizure precipitants and spontaneous seizure worsening in drug-resistant epilepsy

In drug-resistant epilepsy, periods of seizure stability may alternate with abrupt worsening, with frequent seizures limiting the individual's independence and physical, social, and psychological well-being. Here, we review the literature focusing on different clinical scenarios related to seizure aggravation in people with drug-resistant epilepsy. The role of antiseizure medication (ASM) changes is examined, especially focusing on paradoxical seizure aggravation after increased treatment. The external provocative factors that unbalance the brittle equilibrium of seizure control are reviewed, distinguishing between unspecific triggering factors, specific precipitants, and 'reflex' mechanisms. The chance of intervening surgical or medical conditions, including somatic comorbidities and epilepsy surgery failure, causing increased seizures is discussed. Spontaneous exacerbation is also explored, emphasizing recent findings on subject-specific circadian and ultradian rhythms. Awareness of external precipitants and understanding the subject-specific spontaneous epilepsy course may allow individuals to modify their lifestyles. It also allows clinicians to counsel appropriately and to institute suitable medical treatment to avoid sudden loss of seizure control.

Methotrimeprazine for the management of End-Of-Life Symptoms in Infants and Children

Objective: This retrospective chart review assessed the efficacy, dose, and safety of methotrimeprazine in palliating end-of-life symptoms in children and infants. Methods: A retrospective chart review was conducted of 18 hospitalized pediatric patients who were treated with methotrimeprazine in their last two weeks of life. Data collected included age, diagnosis, symptoms, methotrimeprazine dose, route, efficacy, and any documented adverse effects. Results: Patients’ ages ranged from 16 days to 17 years. Underlying conditions included malignancies, trauma, and various neurodegenerative and congenital diseases. All patients (n=18) were treated for symptoms of agitation, delirium, or restlessness. Most patients also experienced respiratory secretions/congestion (n=15), pain (n=13), and/ or dyspnea (n=9). Less common symptoms included nausea/emesis (n=5) and spasticity (n=1). Methotrimeprazine dosages ranged from 0.02 mg/kg/dose to 0.5 mg/kg/dose. Routes of administration included intravenous (n=13), oral/gastrostomy tube (n=6), or subcutaneous (n=4). Sedation (n=6) was the only documented adverse effect, although when agitation was present, this was potentially an intended and perceived-to-be-beneficial effect. Conclusion: Methotrimeprazine, an old drug with diverse receptor activity and multiple routes of administration, appears to be an effective tool in treating complicated end-of-life symptoms in children and infants. This study provides a foundation for analysis with prospective and comparative trials, which may further quantify its benefit.

Can perfusion CT unmask postictal stroke mimics?

Objective

To study the diagnostic value of volume perfusion CT (VPCT) in patients with transient focal neurologic deficits following and during epileptic seizures, that mimic symptoms of stroke.

Methods

A retrospective case-control study was performed on 159 patients who presented with a seizure and received an emergency VPCT within the first 3.5 hours of admission, after being misjudged to have an acute stroke. The reference test was a clinical-based, EEG-supported diagnostic algorithm for seizure.

Results

We included 133 patients: 94 stroke-mimicking cases with postictal focal neurologic deficits (“Todd phenomenon,” n = 67) or ongoing seizure on hospital admission (“ictal patients,” n = 27), and 39 postictal controls without focal neurologic deficits. Patients with Todd phenomenon showed normal perfusion (64%), hypoperfusion (21%), and hyperperfusion (14%) on early VPCT. Ictal patients displayed more hyperperfusion compared to postictal patients (p = 0.015). Test sensitivity of hyperperfusion for ictal patients is 38% (95% confidence interval [CI] 20.7%–57.7%), specificity 86% (95% CI 77.3%–91.7%), positive predictive value is 42% (95% CI 27.5%–58.7%), and the negative predictive value 83% (95% CI 78.6%–86.9%). A cortical distribution was seen in all hyperperfusion scans, compared to a cortico-subcortical pattern in hypoperfusion (p < 0.001). A history of complex focal seizure and age were associated with hyperperfusion (p = 0.046 and 0.038, respectively).

Conclusion

VPCT can differentiate ictal stroke mimics with hyperperfusion from acute ischemic stroke, but not postictal patients who display perfusion patterns overlapping with ischemic stroke.

Classification of evidence

This study provides Class IV evidence that VPCT accurately differentiates ictal stroke mimics from acute ischemic stroke.

Presentation and management of community-onset vs hospital-onset first seizures

BACKGROUND

New-onset seizures are frequently encountered in community and hospital settings. It is likely that seizures presenting in these distinct settings have different etiologies and prognoses, requiring different investigation and treatment approaches. We directly compare the presentation and management of patients with community- and hospital-onset first seizures attending the same hospital.

METHODS

We reviewed the medical records of patients aged 18 years or older with discharge International Classification of Diseases, Australian Classification (ICD-10-AM) codes of G40 (epilepsy), G41 (status epilepticus), and R56.8 (unspecified convulsions), who attended a general hospital in Melbourne, Australia, from January 1, 2008, through November 30, 2016. Patients with new-onset seizures were included for analysis.

RESULTS

A total of 367 patients were discharged with a relevant ICD-10-AM code. Among them, 151 patients met the inclusion criteria: 97 presented to the emergency department with community-onset seizure (median age 70 years), and 54 experienced seizures during hospitalization for other indications (median age 80.5 years). Provoked seizures were more common in the latter group (26.8% vs 63.0%, p < 0.001), with exposure to proconvulsant drugs a major risk factor. Despite not fulfilling the International League Against Epilepsy (ILAE) diagnostic criteria, 72.5% (58/80) who survived to discharge were prescribed antiepileptic drug (AED) therapy, whereas 19.0% (12/63) of those who met the ILAE criteria were not.

CONCLUSIONS

Hospitalized elderly patients are at an increased risk of provoked seizures, and caution should be exercised when prescribing potential proconvulsant medications and procedures. A more standardized approach to AED prescribing is needed. Further studies should consider morbidity, mortality, and health economic effects of first seizures and assess optimal management to improve outcomes in this cohort.

Three clinical pearls in the treatment of patients with seizures and comorbid psychiatric disorders

A strong association exists between epilepsy and psychiatric comorbidities, especially depression, anxiety, attention deficit disorders, and psychosis. The impact of psychotropic medications in lowering seizure threshold both directly and indirectly, hypersensitivity reactions to antiepileptic and other psychotropic medications, and how antiepileptic drugs affect psychiatric disorders are explored through three patient cases. Ultimately, in selecting an appropriate psychotropic medication for an individual with epilepsy and psychiatric comorbidities, it is important to consider the clinical and quality-of-life impacts that a particular medication will have on that individual.

Identifying patients at risk of acute symptomatic seizure after ischemic stroke

BACKGROUND

Contributors to post-stroke seizure research have advocated the need for prospective studies of acute symptomatic seizures after stroke. Identification of the patient at risk of seizure and the impact of the event on outcome is a prerequisite for this kind of research. The aim of this study was to identify risk factors, make an outline for a risk score, and look at consequences of seizure on short-time clinical outcomes.

METHODS

This registry-based study included patients with ischemic stroke admitted between 2007 and 2013. We identified variables associated with the presence of acute symptomatic seizures and made a risk score. Clinical outcome measures were modified Rankin scale, National Institute of Health Stroke Scale (NIHSS), and death at discharge or at day seven.

RESULTS

A total of 2598 ischemic stroke patients were included, 66 experiencing seizure within seven days of stroke. We found diabetes mellitus, NIHSS on admission, and cortical lesion to be associated with the risk of seizure. The risk score had a sensitivity of 58%, specificity of 85%, and a positive predictive value of 9% with a three-point cutoff. We found a negative effect of seizure on survival in mild-to-moderate strokes after adjusting for infections and stroke severity.

CONCLUSIONS

Because of low incidence and the lack of specific risk factors, acute symptomatic seizure after ischemic stroke is hard to predict. The negative effect of seizure on stroke outcome is uncertain, and more thorough studies are needed because of possible subtle or non-overt seizures.

Risk of seizure associated with use of acid-suppressive drugs: An observational cohort study

OBJECTIVES

Previous, large, prescription-event monitoring studies in patients receiving PPI therapy recorded instances of convulsion or seizure. The objective of this study was to quantify the relative risk of seizure associated with the use of proton pump inhibitors (PPIs) and histamine-2 receptor antagonists (H2RAs) in a general population, overall and stratified by epilepsy status, and to determine the effects of demographics and comorbidities.

METHODS

In this observational study (NCT01744301), patients aged 20-84years in the study period from 1 January 2005 to 31 December 2011 were identified from The Health Improvement Network. In a nested case-control analysis, 8605 patients with seizure were matched to 40000 controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression.

RESULTS

After adjustment, there were no associations between current PPI use and seizure risk in the overall population (OR: 1.05; 95% CI: 0.87-1.27), the subcohort with epilepsy (OR: 0.87; 95% CI: 0.49-1.53), and the subcohort without epilepsy (OR: 1.05; 95% CI: 0.87-1.28). There were no associations between current H2RA use and seizure risk in the overall population (OR: 1.16; 95% CI: 0.62-2.18) and the subcohort without epilepsy (OR: 1.02; 95% CI: 0.51-2.01). Seizures were less frequent in women than in men. Dementia/psychosis, anxiety, depression, and use of anxiolytics, antidepressants, and paracetamol were associated with an increased seizure risk.

CONCLUSIONS

Our study revealed that the use of PPIs and the use of H2RAs were not associated with an increased risk of seizures in the overall population or in the cohorts stratified by epilepsy status.

Seizures: awareness and observation in the ward environment

The preconceived 'foaming' and 'violent' seizure stereotypes are misrepresentations, particularly by non-specialist health professionals. Thus the vast semiology (signs and symptoms) of seizures and their subtle signs too easily go unrecognised by the untrained eye. Nevertheless, a significant proportion of adult patients admitted to the ward for treatment of their current illness will have a pre-existing seizure disorder (epilepsy). Furthermore, such hospitalised patients are more likely to suffer a seizure within the ward environment as triggering factors are unavoidably present. Thus, it is essential that nurses are prepared to encounter seizures, irrespective of the reason for admission. This article discusses the clinical semiology of the various seizure types in association with the underpinning neuropathophysiology, as well as the potential seizure triggers. It thereby enhances nurses' awareness and observations of seizure activity in patients in the ward environment.

Antipsychotic drug use and the risk of seizures: follow-up study with a nested case-control analysis

OBJECTIVE

To investigate the association between antipsychotic drug use and the development of first-time seizures in patients with schizophrenia, affective disorders, or dementia.

METHODS

We used data from the UK-based Clinical Practice Research Datalink database to conduct a follow-up study with a nested case-control analysis between 1998 and 2013. We identified patients with schizophrenia, affective disorders, or dementia, and estimated incidence rates of seizures among users of four antipsychotic drug subclasses, defined according to existing hypotheses on their seizure-inducing potential (1, olanzapine or quetiapine; 2, amisulpride, aripiprazole, risperidone, or sulpiride; 3, low-to-medium potency first-generation antipsychotic drugs [chlorpromazine, zuclopenthixol, flupenthixol, pericyazine, promazine, thioridazine]; 4, medium-to-high potency first-generation antipsychotic drugs [haloperidol, prochlorperazine, trifluoperazine]), and among those who did not use antipsychotic drugs. To adjust for confounding, we estimated odds ratios for seizures separately among patients with affective disorders or dementia, stratified by antipsychotic drug use and timing of use.

RESULTS

In the total cohort of 60,121 patients (who had schizophrenia, affective disorders, or dementia), the incidence rate of seizures per 10,000 person-years was 32.6 (95 % confidence interval [CI] 22.6-42.6) in users of olanzapine or quetiapine, 24.1 (95 % CI 13.2-34.9) in users of amisulpride, aripiprazole, risperidone, or sulpiride, 49.4 (95 % CI 27.7-71.0) in users of low-to-medium potency antipsychotic drugs, 59.1 (95 % CI 40.1-78.2) in users of medium-to-high potency antipsychotic drugs, and 11.7 (95 % CI 10.0-13.4) in non-users of antipsychotic drugs. Patients with dementia had significantly higher incidence rates of first-time seizures compared with patients with affective disorders, irrespective of antipsychotic drug use. In patients with affective disorders, current use of medium-to-high potency first-generation antipsychotic drugs was associated with an increased risk of seizures (adjusted odds ratio 2.51 [95 % CI 1.51-4.18]) compared with non-use, while use of other antipsychotic drugs was not associated with seizures. In patients with dementia, current use of olanzapine or quetiapine (adjusted odds ratio 2.37 [95 % CI 1.35-4.15]), low-to-medium potency first-generation antipsychotic drugs (adjusted odds ratio 3.08 [95 % CI 1.34-7.08]), and medium-to-high potency first-generation antipsychotic drugs (adjusted odds ratio 2.24 [95 % CI 1.05-4.81]) was associated with an increased risk of seizures compared with non-use, but current use of amisulpride, aripiprazole, risperidone, or sulpiride (adjusted odds ratio 0.92 [95 % CI 0.48-1.75]) was not. Use of antipsychotic drugs in patients with schizophrenia could not be investigated because of small numbers.

CONCLUSIONS

Current use of medium-to-high potency first-generation antipsychotic drugs was associated with a 2.5-fold increased risk of seizures compared with non-use of antipsychotic drugs in patients with affective disorders. In these patients, current use of all other antipsychotic drug subclasses was not associated with seizures. In patients with dementia, current and past use of all antipsychotic drug subclasses, except amisulpride, aripiprazole, risperidone, or sulpiride, was associated with an increased risk of seizures.

Effects of antipsychotics, antidepressants and mood stabilizers on risk for physical diseases in people with schizophrenia, depression and bipolar disorder

People with severe mental illness have a considerably shorter lifespan than the general population. This excess mortality is mainly due to physical illness. Next to mental illness-related factors, unhealthy lifestyle, and disparities in health care access and utilization, psychotropic medications can contribute to the risk of physical morbidity and mortality. We systematically reviewed the effects of antipsychotics, antidepressants and mood stabilizers on physical health outcomes in people with schizophrenia, depression and bipolar disorder. Updating and expanding our prior systematic review published in this journal, we searched MEDLINE (November 2009 - November 2014), combining the MeSH terms of major physical disease categories (and/or relevant diseases within these categories) with schizophrenia, major depressive disorder and bipolar disorder, and the three major psychotropic classes which received regulatory approval for these disorders, i.e., antipsychotics, antidepressants and mood stabilizers. We gave precedence to results from (systematic) reviews and meta-analyses wherever possible. Antipsychotics, and to a more restricted degree antidepressants and mood stabilizers, are associated with an increased risk for several physical diseases, including obesity, dyslipidemia, diabetes mellitus, thyroid disorders, hyponatremia; cardiovascular, respiratory tract, gastrointestinal, haematological, musculoskeletal and renal diseases, as well as movement and seizure disorders. Higher dosages, polypharmacy, and treatment of vulnerable (e.g., old or young) individuals are associated with greater absolute (elderly) and relative (youth) risk for most of these physical diseases. To what degree medication-specific and patient-specific risk factors interact, and how adverse outcomes can be minimized, allowing patients to derive maximum benefits from these medications, requires adequate clinical attention and further research.

Antiepileptic drugs patterns in elderly inpatients in a Brazilian tertiary center, Salvador, Brazil

Epilepsy is very prevalent among elderly inpatients and treatment is far from ideal. Objective To analyze prescribing patterns of antiepileptic drugs (AEDs) for hospitalized elderly with epilepsy, their relations with comorbidities and comedications. Method We assessed prescription regimen of elderly patients that were under AED use for treatment of epileptic seizures, during hospitalization. One hundred and nine patients were enrolled. AED regimen was categorized into two groups: Group 1 defined as appropriate (carbamazepine, oxcarbazepine, valproic acid, gabapentin, clobazan and lamotrigine) and Group 2 as inappropriate (phenytoin and phenobarbital). Results We found 73.4% of patients used inappropriate AEDs (p<0.001). Monotherapy was prescribed for 71.6% of patients. The most common comorbidity was hypertension. Potentially proconvulsant drugs as comedications were used for nearly half of patients. Conclusion Inappropriate AED therapy was commonly prescribed regimen for elderly inpatients. Some recommendations are discussed for a better care of elderly inpatients with epilepsy.

Acute symptomatic seizures and systemic illness

PURPOSE OF REVIEW

This article addresses the occurrence of acute symptomatic seizures in the setting of many medical illnesses.

RECENT FINDINGS

Many medical illnesses can cause seizures. Metabolic derangements, such as disorders of serum glucose metabolism, cause seizures, as well as other neurologic manifestations. Many medicines (such as antibiotics, antivirals, antidepressants, and antipsychotics), whether used at typical doses or in overdosage, can lead to acute symptomatic seizures.

SUMMARY

Acute symptomatic seizures occur most often in illnesses that directly injure the brain. Trauma, stroke, CNS tumors, and CNS infection very commonly cause seizures. However, many medical illnesses do not directly injure the brain but lead to neurologic signs and symptoms, such as seizures. Recognizing these effects, especially in critically ill patients, is important for optimizing medical care.

Hepatotoxicity and drug interactions in liver transplant candidates and recipients

In this article the medications that have been shown to increase rates of drug-induced liver injury in patients with cirrhosis and the important drug-drug interactions in recipients of liver transplantation are reviewed. In general, the risk of drug-induced liver injury in patients with cirrhosis does not seem to be higher when compared with the noncirrhotic population. There are, however, 2 classes of agents that have been implicated-medications used to treat tuberculosis and medications used to treat human immunodeficiency virus infection. However, with careful monitoring, even significant interactions can be effectively managed.

Rapamycin attenuates aggressive behavior in a rat model of pilocarpine-induced epilepsy

Psychiatric disorders are fairly common comorbidities of epilepsy in humans. Following pilocarpine-induced status epilepticus (SE), experimental animals not only developed spontaneous recurrent seizures, but also exhibited significantly elevated levels of aggressive behavior. The cellular and molecular mechanism triggering these behavioral alterations remains unclear. In the present study, we found that aggression is positively correlated with development of spontaneous seizures. Treatment with rapamycin, a potent mTOR (mammalian target of rapamycin pathway)-pathway inhibitor, markedly diminished aggressive behavior. Therefore, the mTOR pathway may have significance in the underlying molecular mechanism leading to aggression associated with epilepsy.

Pharmacological characterization of GABAA receptors in taurine-fed mice

Background

Taurine is one of the most abundant free amino acids especially in excitable tissues, with wide physiological actions. Chronic supplementation of taurine in drinking water to mice increases brain excitability mainly through alterations in the inhibitory GABAergic system. These changes include elevated expression level of glutamic acid decarboxylase (GAD) and increased levels of GABA. Additionally we reported that GABA_A receptors were down regulated with chronic administration of taurine. Here, we investigated pharmacologically the functional significance of decreased / or change in subunit composition of the GABA_A receptors by determining the threshold for picrotoxin-induced seizures. Picrotoxin, an antagonist of GABA_A receptors that blocks the channels while in the open state, binds within the pore of the channel between the β2 and β3 subunits. These are the same subunits to which GABA and presumably taurine binds.

Methods

Two-month-old male FVB/NJ mice were subcutaneously injected with picrotoxin (5 mg kg^-1) and observed for a) latency until seizures began, b) duration of seizures, and c) frequency of seizures. For taurine treatment, mice were either fed taurine in drinking water (0.05%) or injected (43 mg/kg) 15 min prior to picrotoxin injection.

Results

We found that taurine-fed mice are resistant to picrotoxin-induced seizures when compared to age-matched controls, as measured by increased latency to seizure, decreased occurrence of seizures and reduced mortality rate. In the picrotoxin-treated animals, latency and duration were significantly shorter than in taurine-treated animas. Injection of taurine 15 min before picrotoxin significantly delayed seizure onset, as did chronic administration of taurine in the diet. Further, taurine treatment significantly increased survival rates compared to the picrotoxin-treated mice.

Conclusions

We suggest that the elevated threshold for picrotoxin-induced seizures in taurine-fed mice is due to the reduced binding sites available for picrotoxin binding due to the reduced expression of the beta subunits of the GABA_A receptor. The delayed effects of picrotoxin after acute taurine injection may indicate that the two molecules are competing for the same binding site on the GABA_A receptor. Thus, taurine-fed mice have a functional alteration in the GABAergic system. These include: increased GAD expression, increased GABA levels, and changes in subunit composition of the GABA_A receptors. Such a finding is relevant in conditions where agonists of GABA_A receptors, such as anesthetics, are administered.

[Anesthesia for procedures other than neurosurgery in the adult with epilepsy]

Epilepsy is a common disease affecting between 1% and 2% of the general population. The incidence increases with age. Given the complicated etiology and pathogenesis of this disease, epileptic patients of all ages may require anesthesia. The perioperative care of these patients involves a number of special considerations, although the main issues to deal with are pharmacologic. This review gives an overview of the etiopathogenesis and pathophysiology of epilepsy and describes the general characteristics of antiepileptic drug therapy. The anesthetic implications of chronic treatment with antiepileptic agents and the interactions between these drugs and common anesthetics are discussed in more detail.

Neurological comorbidity and epilepsy: implications for treatment

Epilepsy is a chronic condition that may be associated with several other diseases. In these cases, we should consider the following points: (1) antiepileptic drug (AED) treatment may positively or negatively affect comorbid disease, (2) drugs used for treatment of co-morbid disease may influence seizure threshold, (3) AED toxicity can be affected by a comorbid condition and (4) co-administration of AEDs with drugs used for treatment of comorbid conditions can be associated with clinically relevant drug-drug interactions. In this article, we discuss problems that are usually encountered when an appropriate AED treatment has to be selected in newly diagnosed epileptic patients who also have (an)other neurological disease(s). Comorbidity of epilepsy with cerebrovascular diseases, dementias, mental retardation, attention deficit and hyperactivity disorder, brain tumours, infections of the CNS, migraine, sleep disturbances (obstructive sleep apnoea syndrome), substance abuse and multiple sclerosis is discussed.

Selective resistance of taurine-fed mice to isoniazide-potentiated seizures: in vivo functional test for the activity of glutamic acid decarboxylase

Taurine, 2-aminoethanesulfonic acid, is one of the most abundant free amino acids especially in excitable tissues, with wide physiological actions. We have previously reported that in mice, supplementation of the drinking water with taurine induces alterations in the inhibitory GABAergic system. In taurine-fed mice we found that the expression level of glutamic acid decarboxylase (GAD), the enzyme responsible for GABA synthesis, is elevated. Increased expression of GAD was accompanied by increased levels of GABA. Here, we investigated pharmacologically the functional significance of taurine-induced increase in GAD expression by determining the threshold for kainic acid-induced seizures after partial inhibition of GAD activity with isoniazide. We found that taurine-fed mice have elevated GAD expression and showed a higher threshold for seizure onset when compared with age-matched controls. Thus, taurine-fed mice have a functional increase in GAD activity which offers some protection in this seizure model. Furthermore, this pharmacological manipulation can be used to determine the level of GAD activity in other model systems that show alterations in GAD expression.

Medically serious adverse effects of newer antidepressants

Although safer than tricyclic antidepressants and monoamine oxidase inhibitors, the newer antidepressants may be associated with certain medically serious adverse effects, of which cardiovascular adverse effects, seizures, abnormal bleeding, hyponatremia, and agranulocytosis are discussed in this review. Data regarding the incidence and risk factors are summarized, and strategies for reducing the risk of these adverse effects and managing them are suggested. Identification of risk factors, appropriate antidepressant choice, and, when possible, careful monitoring may substantially reduce the incidence of these adverse effects and the morbidity associated with them.

Management of a first seizure. Special problems: adults and elderly

A first seizure out of a clear blue sky can be a major life-changing event. Careful history-taking and appropriate investigation together with a clear explanation provided to patient and family are an essential requirement. Although for most patients, pharmacotherapy can be withheld and events awaited, there are circumstances where introduction of antiepileptic drug (AED) therapy should be considered. Medical causes of seizures should also be sought and treated. In addition, a first seizure in HIV-positive patients and in those with underlying neurocysticercosis should usually provoke the introduction of AED therapy. Particular problems can occur in patients with a single episode of provoked status epilepticus, a first tonic-clonic seizure during pregnancy and, particularly, an unprovoked event in older and learning disabled people. Treatment following a first seizure should balance risk factors for recurrence with the informed opinion of the patients and their family.