Drug-induced QT-interval shortening following antiepileptic treatment with oral rufinamide

Disproportionality analysis of the safety profile of rufinamide in the real world: an evaluation of the FDA Adverse Event Reporting System database

BACKGROUND

Rufinamide (RUF) is an antiepileptic drug recently introduced for managing seizures in Lennox-Gastaut syndrome (LGS), but its adverse reactions are not well understood. This study aims to evaluate RUF's safety profile using data from the FDA Adverse Event Reporting System (FAERS).

METHODS

Disproportionality analysis was conducted to assess RUF-associated adverse drug events (ADEs), using reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and multi-item gamma-Poisson shrinker (MGPS).

RESULTS

We collected 338 ADE reports related to RUF. Nervous system disorders were the most frequently reported signals, and several new ADEs were detected, including atonic seizures, sudden unexplained death in epilepsy, seizure clusters, multi-drug resistance, and Stevens-Johnson syndrome. Nearly half of the ADEs in pediatric patients were psychological or neurological. Disproportionality analysis within 4 weeks of treatment showed high RORs for QT shortening, sudden death, and atonic seizures.

CONCLUSIONS

Our study revealed prospective signals of new ADEs linked to RUF as well as revealed that both prescribers and patients were more conscious of the risks involved in its clinical use.

Congenital short QT syndrome: A review focused on electrocardiographic features

Congenital short QT syndrome is a very low prevalence inherited primary arrhythmia syndrome first reported in 2000 by Gussak et al., who described two families with a short QT interval, syncope, and sudden cardiac death. In 2004, Ramon Brugada et al. identified the first genetic type of this entity. To date, a total of nine genotypes have been described. The diagnosis is easy from the electrocardiogram (ECG), not only due to the short QT duration, but also based on other aspects covered in this review. During 24-h Holter monitoring, paroxysmal atrial fibrillation spontaneously converting to sinus rhythm may be found. Even though the T wave may appear symmetric on the ECG, the T loop of the vectorcardiogram confirms that the T wave is constantly asymmetric due to the presence of dashes closer to each other in the efferent branch. In this review, we also describe the minus-plus T wave sign that we have described in a previously published article. In addition to congenital causes, we briefly highlight the existence of numerous acquired causes of short QT interval.

Stable Gastric Pentadecapeptide BPC 157 Therapy: Effect on Reperfusion Following Maintained Intra-Abdominal Hypertension (Grade III and IV) in Rats

Given in reperfusion, the use of stable gastric pentadecapeptide BPC 157 is an effective therapy in rats. It strongly counteracted, as a whole, decompression/reperfusion-induced occlusion/occlusion-like syndrome following the worst circumstances of acute abdominal compartment and intra-abdominal hypertension, grade III and grade IV, as well as compression/ischemia-occlusion/occlusion-like syndrome. Before decompression (calvariectomy, laparotomy), rats had long-lasting severe intra-abdominal hypertension, grade III (25 mmHg/60 min) (i) and grade IV (30 mmHg/30 min; 40 mmHg/30 min) (ii/iii), and severe occlusion/occlusion-like syndrome. Further worsening was caused by reperfusion for 60 min (i) or 30 min (ii/iii). Severe vascular and multiorgan failure (brain, heart, liver, kidney, and gastrointestinal lesions), widespread thrombosis (peripherally and centrally) severe arrhythmias, intracranial (superior sagittal sinus) hypertension, portal and caval hypertension, and aortal hypotension were aggravated. Contrarily, BPC 157 therapy (10 µg/kg, 10 ng/kg sc) given at 3 min reperfusion times eliminated/attenuated venous hypertension (intracranial (superior sagittal sinus), portal, and caval) and aortal hypotension and counteracted the increases in organ lesions and malondialdehyde values (blood ˃ heart, lungs, liver, kidney ˃ brain, gastrointestinal tract). Vascular recovery promptly occurred (i.e., congested inferior caval and superior mesenteric veins reversed to the normal vessel presentation, the collapsed azygos vein reversed to a fully functioning state, the inferior caval vein-superior caval vein shunt was recovered, and direct blood delivery returned). BPC 157 therapy almost annihilated thrombosis and hemorrhage (i.e., intracerebral hemorrhage) as proof of the counteracted general stasis and Virchow triad circumstances and reorganized blood flow. In conclusion, decompression/reperfusion-induced occlusion/occlusion-like syndrome counteracted by BPC 157 therapy in rats is likely for translation in patients. It is noteworthy that by rapidly counteracting the reperfusion course, it also reverses previous ischemia-course lesions, thus inducing complete recovery.

hERG agonists pose challenges to web-based machine learning methods for prediction of drug-hERG channel interaction

Pharmacological blockade of the IKr channel (hERG) by diverse drugs in clinical use is associated with the Long QT Syndrome that can lead to life threatening arrhythmia. Various computational tools including machine learning models (MLM) for the prediction of hERG inhibition have been developed to facilitate the throughput screening of drugs in development and optimise thus the prediction of hERG liabilities. The use of MLM relies on large libraries of training compounds for the quantitative structure-activity relationship (QSAR) modelling of hERG inhibition. The focus on inhibition omits potential effects of hERG channel agonist molecules and their associated QT shortening risk. It is instructive, therefore, to consider how known hERG agonists are handled by MLM. Here, two highly developed online computational tools for the prediction of hERG liability, Pred-hERG and HergSPred were probed for their ability to detect hERG activator drug molecules as hERG interactors. In total, 73 hERG blockers were tested with both computational tools giving overall good predictions for hERG blockers with reported IC50s below Pred-hERG and HergSPred cut-off threshold for hERG inhibition. However, for compounds with reported IC50s above this threshold such as disopyramide or sotalol discrepancies were observed. HergSPred identified all 20 hERG agonists selected as interacting with the hERG channel. Further studies are warranted to improve online MLM prediction of hERG related cardiotoxicity, by explicitly taking into account channel agonism as well as inhibition.

Individuals with chronic epilepsy have elevated P-wave heterogeneity comparable to patients with atrial fibrillation

OBJECTIVE

Identification of epilepsy patients with elevated risk for atrial fibrillation (AF) is critical given the heightened morbidity and premature mortality associated with this arrhythmia. Epilepsy is a worldwide health problem affecting nearly 3.4 million people in the United States alone. The potential for increased risk for AF in patients with epilepsy is not well appreciated, despite recent evidence from a national survey of 1.4 million hospitalizations indicating that AF is the most common arrhythmia in people with epilepsy.

METHODS

We analyzed inter-lead heterogeneity of P-wave morphology, a marker reflecting arrhythmogenic nonuniformities of activation/conduction in atrial tissue. The study groups consisted of 96 patients with epilepsy and 44 consecutive patients with AF in sinus rhythm before clinically indicated ablation. Individuals without cardiovascular or neurological conditions (n = 77) were also assessed. We calculated P-wave heterogeneity (PWH) by second central moment analysis of simultaneous beats from leads II, III, and aVR ("atrial dedicated leads") from standard 12-lead electrocardiography (ECG) recordings from admission day to the epilepsy monitoring unit (EMU).

RESULTS

Female patients composed 62.5%, 59.6%, and 57.1% of the epilepsy, AF, and control subjects, respectively. The AF cohort was older (66 ± 1.1 years) than the epilepsy group (44 ± 1.8 years, p < .001). The level of PWH was greater in the epilepsy group than in the control group (67 ± 2.6 vs. 57 ± 2.5 μV, p = .046) and reached levels observed in AF patients (67 ± 2.6 vs. 68 ± 4.9 μV, p = .99). In multiple linear regression analysis, PWH levels in individuals with epilepsy were mainly correlated with the PR interval and could be related to sympathetic tone. Epilepsy remained associated with PWH after adjustments for cardiac risk factors, age, and sex.

SIGNIFICANCE

Patients with chronic epilepsy have increased PWH comparable to levels observed in patients with AF, while being ~20 years younger, suggesting an acceleration in structural change and/or cardiac electrical instability. These observations are consistent with emerging evidence of an "epileptic heart" condition.

Innate Vascular Failure by Application of Neuroleptics, Amphetamine, and Domperidone Rapidly Induced Severe Occlusion/Occlusion-like Syndromes in Rats and Stable Gastric Pentadecapeptide BPC 157 as Therapy

Even before behavioral disturbances, neuroleptics, amphetamine, and domperidone application rapidly emerged severe occlusion/occlusion-like syndrome, shared innate vascular and multiorgan failure in rats, comparable to occlusion/occlusion-like syndrome described with vessel(s) occlusion or similar noxious procedures application. As therapy, i.e., activation of the collateral pathways, "bypassing key" (activated azygos vein pathway, direct blood flow delivery), the stable gastric pentadecapeptide BPC 157 is a novel solution. Recently, BPC 157 therapy particularly counteracted neuroleptic- or L-NAME-induced catalepsy, lithium intoxication, and schizophrenia positive and negative symptoms (amphetamine/methamphetamine/apomorphine/ketamine). In rats with complete calvariectomy, medication (BPC 157 10 µg/kg, 10 ng/kg ip or ig) was given 5 min after distinctive dopamine agents (mg/kg ip) (haloperidol (5), fluphenazine (5), clozapine (10), risperidone (5), olanzapine (10), quetiapine (10), or aripiprazole (10), domperidone (25), amphetamine (10), and combined amphetamine and haloperidol) and assessed at 15 min thereafter. All neuroleptic-, domperidone-, and amphetamine-induced comparable vascular and multiorgan failure severe syndrome was alleviated with BPC 157 therapy as before major vessel(s) occlusion or other similar noxious procedures. Specifically, all severe lesions in the brain (i.e., immediate swelling, hemorrhage), heart (i.e., congestion, arrhythmias), and lung (i.e., congestion, hemorrhage), as well as congestion in the liver, kidney, and gastrointestinal (stomach) tract, were resolved. Intracranial (superior sagittal sinus), portal, and caval hypertension and aortal hypotension were attenuated or eliminated. BPC 157 therapy almost annihilated arterial and venous thrombosis, peripherally and centrally. Thus, rapidly acting Virchow triad circumstances that occur as dopamine central/peripheral antagonists and agonist essential class-points, fully reversed by BPC 157 therapy, might be overwhelming for both neuroleptics and amphetamine.

Cardiac Repolarization in Health and Disease

Abnormal cardiac repolarization is at the basis of life-threatening arrhythmias in various congenital and acquired cardiac diseases. Dysfunction of ion channels involved in repolarization at the cellular level are often the underlying cause of the repolarization abnormality. The expression pattern of the gene encoding the affected ion channel dictates its impact on the shape of the T-wave and duration of the QT interval, thereby setting the stage for both the occurrence of the trigger and the substrate for maintenance of the arrhythmia. Here we discuss how research into the genetic and electrophysiological basis of repolarization has provided us with insights into cardiac repolarization in health and disease and how this in turn may provide the basis for future improved patient-specific management.

A Phase 1 Clinical Study Evaluating the Effects of Cenobamate on the QT Interval

Cenobamate is an antiseizure medication for uncontrolled focal seizures. This thorough QT study assessed the effects of therapeutic and supratherapeutic cenobamate doses (maximum recommended dose, 400 mg/day) on correct QT interval (QTc) in healthy adults (N = 108) randomly assigned to 1 of 3 treatments: (A) cenobamate (days 1-63) up-titrated by 50-mg increments weekly to a 200 mg/day therapeutic dose (day 35) and then by 100 mg weekly to a 500 mg/day supratherapeutic dose (day 63), with placebo-moxifloxacin (days -1 and 64); (B) moxifloxacin 400 mg (day -1; positive control), placebo-cenobamate (days 1-63), and placebo-moxifloxacin (day 64); and (C) placebo-moxifloxacin (day -1), placebo-cenobamate (days 1-64), and moxifloxacin 400 mg (day 64). The primary end point was baseline-adjusted, placebo-corrected QTc (ΔΔQTcF; corrected for heart rate [HR] by Fridericia's method) with cenobamate 200 and 500 mg/day. Baseline electrocardiographic parameters were balanced across groups. Mean ΔΔQTcF was negative throughout for cenobamate doses (largest: day 35, -10.8 milliseconds; day 63, -18.4 milliseconds). Based on concentration-QTc analysis, ∆∆QTcF effect was predicted as -9.85 and -17.14 milliseconds at mean peak plasma levels of therapeutic (200 mg/day; 23.06 μg/mL) and supratherapeutic (500 mg/day; 63.96 μg/mL) doses. Cenobamate had no clinically relevant prolonging effect on electrocardiographic parameters (eg, PR, QRS); HR effects were similar to placebo. Cenobamate showed slight dose-related shortening of QTc, but to a degree not known to be clinically relevant (no reductions ≤340 milliseconds). Cenobamate had no clinically relevant effects on HR or electrocardiographic parameters and no QTc-prolonging effect at therapeutic/supratherapeutic doses. Cenobamate is contraindicated in patients with short-QT syndrome and caution should be used when coadministering with drugs that shorten QT interval.

Cardiac adverse effects of antiseizure medications

INTRODUCTION

Patients with severe epilepsy are at increased risk of cardiovascular disease and arrhythmias. Although antiseizure medications (ASMs) may have indirect protective effects against cardiovascular events by reducing seizure frequency and hence sudden death in epilepsy, some of them exert cardiotoxic effects.

AREAS COVERED

Patients with epilepsy, mainly those with severe forms, are at higher risk of cardiac disease because their heart can have structural alterations and electrical instability as a consequence of repeated seizures. Some ASMs have direct protective effects through anti-inflammatory, antioxidant, hypotensive, and lipid-reducing properties. Antiseizure medications can also have toxic cardiac effects including both long-term consequences, such as the increased risk of atherogenesis and subsequent cardiovascular disease due to the influence on lipid profile and pro-inflammatory milieu, and immediate effects as the increased risk of potentially fatal arrhythmias due to the influence on ion channels. Sodium channel blocking ASMs may also affect cardiac sodium channels and this effect is particularly observed in subjects with genetic mutations in cardiac ion channels. Fenfluramine cause valvulopathies in obese subjects and this effect need to be evaluated in epilepsy patients.

EXPERT OPINION

For the selection of treatment, cardiotoxic effects of ASMs should be considered; cardiac monitoring of treatment is advisable.

Practical guidance for the management of adults receiving adjunctive cenobamate for the treatment of focal epilepsy-expert opinion

Clinical trial results have demonstrated that adjunctive cenobamate (CNB) substantially decreases seizure frequency in adults with uncontrolled focal onset seizures with an acceptable and well-identified safety profile. This manuscript summarizes an expert panel's recommendations regarding optimized CNB treatment of epilepsies with focal onset seizures. Cenobamate, when slowly titrated to the target maintenance dose, represents an effective new antiseizure medication (ASM) with a comparatively high rate of seizure freedom relative to existing treatment options. This paper reviews selection of suitable CNB treatment candidates, realistic treatment expectations and goals, appropriate CNB target doses, and methods to mitigate or avoid potential adverse events. Cenobamate can be a promising therapeutic choice for adult people with epilepsy with focal onset seizures who do not reach adequate seizure control despite treatment with conventional ASMs.

Flavonoids and hERG channels: Friends or foes?

The cardiac action potential is regulated by several ion channels. Drugs capable to block these channels, in particular the human ether-à-go-go-related gene (hERG) channel, also known as K_V11.1 channel, may lead to a potentially lethal ventricular tachyarrhythmia called "Torsades de Pointes". Thus, evaluation of the hERG channel off-target activity of novel chemical entities is nowadays required to safeguard patients as well as to avoid attrition in drug development. Flavonoids, a large class of natural compounds abundantly present in food, beverages, herbal medicines, and dietary food supplements, generally escape this assessment, though consumed in consistent amounts. Continuously growing evidence indicates that these compounds may interact with the hERG channel and block it. The present review, by examining numerous studies, summarizes the state-of-the-art in this field, describing the most significant examples of direct and indirect inhibition of the hERG channel current operated by flavonoids. A description of the molecular interactions between a few of these natural molecules and the Rattus norvegicus channel protein, achieved by an in silico approach, is also presented.

COVID-19 Drugs Chloroquine and Hydroxychloroquine, but Not Azithromycin and Remdesivir, Block hERG Potassium Channels

Drug-induced long QT syndrome (LQTS) is an established cardiac side effect of a wide range of medications and represents a significant concern for drug safety. The rapidly and slowly activating delayed rectifier K⁺ currents, mediated by channels encoded by the human ether-a-go-go-related gene (hERG) and KCNQ1 + KCNE1, respectively, are two main currents responsible for ventricular repolarization. The common cause for drugs to induce LQTS is through impairing the hERG channel. For the recent emergence of COVID-19, caused by severe acute respiratory syndrome coronavirus 2, several drugs have been investigated as potential therapies; however, there are concerns about their QT prolongation risk. Here, we studied the effects of chloroquine, hydroxychloroquine, azithromycin, and remdesivir on hERG channels. Our results showed that although chloroquine acutely blocked hERG current (I_hERG), with an IC₅₀ of 3.0 µM, hydroxychloroquine acutely blocked I_hERG 8-fold less potently, with an IC₅₀ of 23.4 µM. Azithromycin and remdesivir did not acutely affect I_hERG When these drugs were added at 10 µM to the cell culture medium for 24 hours, remdesivir increased I_hERG by 2-fold, which was associated with an increased mature hERG channel expression. In addition, these four drugs did not acutely or chronically affect KCNQ1 + KCNE1 channels. Our data provide insight into COVID-19 drug-associated LQTS and cardiac safety concerns. SIGNIFICANCE STATEMENT: This work demonstrates that, among off-label potential COVID-19 treatment drugs chloroquine, hydroxychloroquine, azithromycin, and remdesivir, the former two drugs block hERG potassium channels, whereas the latter two drugs do not. All four drugs do not affect KCNQ1 + KCNE1. As hERG and KCNQ1 + KCNE1 are two main K⁺ channels responsible for ventricular repolarization, and most drugs that induce long QT syndrome (LQTS) do so by impairing hERG channels, these data provide insight into COVID-19 drug-associated LQTS and cardiac safety concerns.

Antiepileptic rufinamide and QTc interval shortening in a patient with long QT syndrome: case report

Background

There is limited pharmacologic therapy to reduce the QT interval in hereditary long QT syndrome (LQTS).

Case summary

We describe a child with Allan–Herndon–Dudley syndrome, Lennox–Gastaut epileptic syndrome (LGS), and LQTS Type 1 (LQTS1). Rufinamide was added to his antiepileptic medications to improve seizure control and was noted to be associated with a marked improvement in electrocardiogram QT interval. To the best of our knowledge, this is the first reported case of successful pharmacologic shortening of the QT interval in LQTS1.

Discussion

This case report highlights the potential benefits of rufinamide, a drug associated with mild QT shortening in normal individuals, to markedly reduce and normalize QT duration in a subject with LQTS1.

Electrocardiographic changes associated with epilepsy beyond heart rate and their utilization in future seizure detection and forecasting methods

The ability to assess seizure risk may help provide timely warnings and more personalized treatment plans for people with epilepsy (PWE). ECG changes are commonly observed in epilepsy which make ECG a promising candidate to monitor seizure risk. Most ECG research in this domain has focused on heart rate-related changes. However, several studies have identified a range of other peri-ictal ECG parameter changes that may potentially prove useful for seizure detection and forecasting. Here, we offer a systematic review of ECG changes in epilepsy outside of heart rate. We performed the systematic literature review according to PRISMA guidelines using key words related to ECG, SUDEP and epilepsy. We identified and screened 502 abstracts, read 110 full papers, and included 24 papers in the final review. Our results suggest that PWE may be more prone to cardiac conduction abnormalities than healthy controls. During interictal periods, PWE were more likely to have abnormal QTc intervals, ST segment abnormalities, elevated T Waves, early repolarization (ER), increased P Wave dispersion and PR intervals when compared to controls. Apart from these baseline abnormalities, changes during the pre-ictal and ictal states have been reported, with arrhythmias, QTc prolongation and ST segment changes being the most common. A better understanding of these state-dependent changes may afford less-cumbersome and less-stigmatizing epilepsy monitoring tools in the future.

Adjunctive Rufinamide in Children with Lennox-Gastaut Syndrome: A Literature Review

Lennox-Gastaut syndrome (LGS) is a severe, childhood-onset, developmental epileptic encephalopathy, with different etiologies and co-morbidities. Seizure treatment in LGS represents a major challenge; new antiepileptic drugs (AEDs) are developed to especially address seizures resulting in high morbidity and mortality, such as drop seizures. Rufinamide (RFN) is one of the latest AEDs licensed for patients with LGS. Its mechanism of action involves sodium channels in a way that is unrelated to other AEDs. Here we discuss the use of adjunctive RFN in children and adolescents with LGS and its efficacy and safety profile, based on a systematic literature review. RFN shows a very favorable profile in terms of adverse events and drug-interactions in children. It is particularly effective on tonic-atonic seizures and spasms, impacting on the quality of life of the patients. Further studies are needed to clarify the interaction profile with the newest AEDs for LGS and to assess correlations between the etiology of LGS and drug response to individualize treatment and maximize efficacy.

Long-Term Follow-Up of Patients With Short QT Syndrome: Clinical Profile and Outcome

Background

Short QT syndrome (SQTS) is a rare inheritable disease associated with sudden cardiac death. Data on long‐term outcomes of families with SQTS are limited.

Methods and Results

Seventeen patients with SQTS in 7 independent families (48% men; median age, 42.4 years; corrected QT interval, 324.9±40.8 ms) were followed up for 13.5±2.5 years. A history of sudden cardiac death was documented in 71% of families. A large number of them showed sudden cardiac deaths at a younger age, with a predominance of men (67%). Five patients had syncope (29%) and 9 (53%) had atrial fibrillation or atrial flutter. An SQTS‐related gene was found in 76% of the patients as follows: KCNH2 (SQTS 1) in 4, CACNA1C (SQTS 4) in 3, and CACNb2 (SQTS 5) in 6. Five patients (29%) received an implantable cardioverter‐defibrillator and 5 patients received long‐term prophylaxis with hydroquinidine. During follow‐up, 1 patient received an appropriate implantable cardioverter‐defibrillator shock attributable to ventricular fibrillation. The patient received no further implantable cardioverter‐defibrillator shocks after treatment with hydroquinidine.

Conclusions

The risk of sudden cardiac death in SQTS families is high. However, after appropriate risk assessment and individualized treatment options (hydroquinidine and/or implantable cardioverter‐defibrillator), the long‐term outcome is relatively benign when patients are seen at a reference center.

Comorbidity between epilepsy and cardiac arrhythmias: Implication for treatment

Epilepsy is often comorbid with either neurological or nonneurological diseases. The association between epilepsy and cardiac arrhythmias is not infrequent, mostly in patients with severe forms of epilepsy or critically ill. Remarkably, these medical conditions share many similarities. Vascular and genetic disorders may predispose to both seizures and abnormalities of cardiac electrophysiology. Repeated and uncontrolled seizures may favor potentially life-threatening arrhythmias. Antiepileptic drugs (AEDs) may facilitate the occurrence of cardiac arrhythmias by acting on ionic channels at heart level. Antiarrhythmic drugs (AADs) can have effects on ionic channels expressed in the brain, as suggested by their efficacy in treating patients with rare forms of epilepsy; AADs may also be proconvulsant, mainly during their overdosage. In clinical practice, the AEDs with the lowest risk to influence cardiac electrophysiology are to be preferred in patients presenting with either seizures or arrhythmias. Traditional AEDs should be avoided because of their arrhythmogenic properties and enzyme-inducing effects, which may make ineffective the concomitant treatment with AADs. Some of the newer AEDs can rarely affect cardiac rhythm, and electrocardiogram (ECG) monitoring should be warranted.

Safety and tolerability profile of new antiepileptic drug treatment in children with epilepsy

INTRODUCTION

Treatment of pediatric epilepsy requires a careful evaluation of the safety and tolerability profile of antiepileptic drugs (AEDs) to avoid or minimize as much as possible adverse events (AEs) on various organs, hematological parameters, and growth, pubertal, motor, cognitive and behavioral development.

AREAS COVERED

Treatment-emergent AEs (TEAEs) reported in the literature 2000-2018 regarding second- and third-generation AEDs used in the pediatric age, with exclusion of the neonatal period that exhibits specific peculiarities, have been described on the basis of their frequency, severity/tolerability, and particular association with a given AED.

EXPERT OPINION

Somnolence/sedation and behavioral changes, like irritability and nervousness, are among the most commonly observed TEAEs associated with almost all AEDs. Lamotrigine, Gabapentin, Oxcarbazepine, and Levetiracetam appear to be the best-tolerated AEDs with a ≤2% withdrawal rate, while Tiagabine and Everolimus are discontinued in up to >20% of the patients because of intolerable TEAEs. For some AEDs, literature data are scanty to draw a high-level evidence on their safety and tolerability profile. The reasons are: insufficient population size, short duration of treatments, or lack of controlled trials. A future goal is that of identifying clearer, easier, and more homogeneous methodological strategies to facilitate AED testing in pediatric populations.

Evidence for cardiotoxicity associated with sertraline in rats

Sertraline is an antidepressant that is frequently prescribed to treat depression, obsessive-compulsive disorder, panic disorder, and anxiety. This drug had a safe cardiotoxicity profile, until the reporting of cases of sertraline-associated cardiotoxicities in the early 2000s. Since then, there have been conflicting results on the cardiotoxicity of this drug. In the study reported here we aimed to identify the cardiotoxic effects of sertraline by evaluating serum cardiac biomarkers, such as serum aspartate aminotransferase (AST), creatinine phosphokinase-myoglobin band (CK-MB), lactate dehydrogenase (LDH), and cardiac troponin T (cTn-T) levels as well as electrocardiographic parameters, DNA damage in cardiomyocytes, and histological findings of heart tissue in rats that were administered oral doses of 5, 10, or 20 mg kg-1 of sertraline for 28 days. Additionally, to investigate the possible mechanisms underlying cardiotoxicity, glutathione and malondialdehyde levels in cardiac tissue were determined to evaluate oxidative stress. According to our results, AST, LDH, and cTn-T levels were significantly increased in the 10 and 20 mg kg-1 sertraline groups when compared to the control group. Heart rates were increased, PR intervals prolonged, a short QTc value was observed, and T-wave amplitudes were decreased significantly in the 20 mg kg-1 sertraline group when compared to the control group. Significant DNA damage was observed in the high-dose groups. Histopathological investigations also revealed some degenerative changes in the 10 and 20 mg kg-1 sertraline groups. Glutathione levels were significantly decreased in the 10 and 20 mg kg-1 sertraline groups when compared with the control group. In conclusion, our findings support the cardiotoxic potential of sertraline and also suggest that oxidative stress may play a role in the toxicity of sertraline.

Utility of the JT Peak Interval and the JT Area in Determining the Proarrhythmic Potential of QT-Shortening Agents

Drug-induced long QT increases the risk of ventricular tachyarrhythmia known as torsades de pointes (TdP). Many biomarkers have been used to predict TdP. At present, however, there are few biomarkers for arrhythmias induced by QT-shortening drugs. The objective of the present study was to identify the best biomarkers for predicting arrhythmias caused by the 4 potassium channel openers ICA-105574, NS-1643, R-L3, and pinacidil. Our results showed that, at higher concentrations, all 4 potassium channel openers induced ventricular tachycardia (VT) and ventricular fibrillation (VF) in Langendorff-perfused guinea pig hearts, but not in rabbit hearts. The electrocardiography parameters were measured including QT/QTc, JT peak, Tp-e interval, JT area, short-term beat-to-beat QT interval variability (STV), and index of cardiac electrophysiological balance (iCEB). We found that the potassium channel openers at test concentrations shortened the QT/QTc and the JT peak interval and increased the JT area. Nevertheless, even at proarrhythmic concentrations, they did not always change STV, Tp-e, or iCEB. Receiver operating characteristic curve analysis showed that the JT peak interval representing the early repolarization phase and the JT area reflecting the dispersion of ventricular repolarization were the best predictors of VT/VF. Action potential recordings in guinea pig papillary muscle revealed that except for pinacidil, the potassium channel openers shortened APD₃₀ in a concentration-dependent manner. They also evoked early or delayed afterdepolarizations at fast pacing rates. Patch-clamp recordings in guinea pig ventricular cardiomyocytes showed that the potassium channel openers enhanced the total outward currents during the early phase of action potential repolarization, especially at proarrhythmic concentrations. We concluded that the JT peak interval and the JT area are surrogate biomarkers identifying the risk of proarrhythmia associated with the administration of QT-shortening agents. The acceleration of early-phase repolarization and the increased dispersion of ventricular repolarization may contribute to the occurrence of arrhythmias.

Drug-induced life-threatening arrhythmias and sudden cardiac death: A clinical perspective of long QT, short QT and Brugada syndromes

Sudden cardiac death is a major public health challenge, which can be caused by genetic or acquired structural or electrophysiological abnormalities. These abnormalities include hereditary channelopathies: long QT, short QT and Brugada syndromes. These syndromes are a notable concern, particularly in young people, due to their high propensity for severe ventricular arrhythmias and sudden cardiac death. Current evidence suggests the involvement of an increasing number of drugs in acquired forms of long QT and Brugada syndromes. However, drug-induced short QT syndrome is still a rarely reported condition. Therefore, there has been speculation on its clinical significance, since few fatal arrhythmias and sudden cardiac death cases have been described so far. Drug-induced proarrhythmia is a growing challenge for physicians, regulatory agencies and the pharmaceutical industry. Physicians should weigh the risks of potentially fatal outcomes against the therapeutic benefits, when making decisions about drug prescriptions. Growing concerns about its safety and the need for more accurate predictive models for drug-induced fatal outcomes justify further research in these fields. The aim of this article is to comprehensively and critically review the recently published evidence with regard to drug-induced life-threatening arrhythmias and sudden cardiac death. This article will take into account the provision of data to physicians that are useful in the identification of the culprit drugs, and thus, contribute to the prompt recognition and management of these serious clinical conditions.

Excess ω-6 fatty acids influx in aging drives metabolic dysregulation, electrocardiographic alterations, and low-grade chronic inflammation

Maintaining a balance of ω-6 and ω-3 fatty acids is essential for cardiac health. Current ω-6 and ω-3 fatty acids in the American diet have shifted from the ideal ratio of 2:1 to almost 20:1; while there is a body of evidence that suggests the negative impact of such a shift in younger organisms, the underlying age-related metabolic signaling in response to the excess influx of ω-6 fatty acids is incompletely understood. In the present study, young (6 mo old) and aging (≥18 mo old) mice were fed for 2 mo with a ω-6-enriched diet. Excess intake of ω-6 enrichment decreased the total lean mass and increased nighttime carbohydrate utilization, with higher levels of cardiac cytokines indicating low-grade chronic inflammation. Dobutamine-induced stress tests displayed an increase in PR interval, a sign of an atrioventricular defect in ω-6-fed aging mice. Excess ω-6 fatty acid intake in aging mice showed decreased 12-lipoxygenase with a concomitant increase in 15-lipoxygenase levels, resulting in the generation of 15( S)-hydroxyeicosatetraenoic acid, whereas cyclooxygenase-1 and -2 generated prostaglandin E₂, leukotriene B_4, and thromboxane B₂. Furthermore, excessive ω-6 fatty acids led to dysregulated nuclear erythroid 2-related factor 2/antioxidant-responsive element in aging mice. Moreover, ω-6 fatty acid-mediated changes were profound in aging mice with respect to the eicosanoid profile while minimal changes were observed in the size and shape of cardiomyocytes. These findings provide compelling evidence that surplus consumption of ω-6 fatty acids, coupled with insufficient intake of ω-3 fatty acids, is linked to abnormal changes in ECG. These manifestations contribute to functional deficiencies and expansion of the inflammatory mediator milieu during later stages of aging. NEW & NOTEWORTHY Aging has a profound impact on the metabolism of fatty acids to maintain heart function. The excess influx of ω-6 fatty acids in aging perturbed electrocardiography with marked signs of inflammation and a dysregulated oxidative-redox balance. Thus, the quality and quantity of fatty acids determine the cardiac pathology and energy utilization in aging.

The Pharmacology and Toxicology of Third-Generation Anticonvulsant Drugs

Epilepsy is a neurologic disorder affecting approximately 50 million people worldwide, or about 0.7% of the population [1]. Thus, the use of anticonvulsant drugs in the treatment of epilepsy is common and widespread. There are three generations of anticonvulsant drugs, categorized by the year in which they were developed and released. The aim of this review is to discuss the pharmacokinetics, drug-drug interactions, and adverse events of the third generation of anticonvulsant drugs. Where available, overdose data will be included. The pharmacokinetic properties of third-generation anticonvulsant drugs include relatively fewer drug-drug interactions, as well as several unique and life-threatening adverse events. Overdose data are limited, so thorough review of adverse events and knowledge of drug mechanism will guide expectant management of future overdose cases. Reporting of these cases as they occur will be necessary to further clarify toxicity of these drugs.

QT Interval Shortening With Isavuconazole: In Vitro and In Vivo Effects on Cardiac Repolarization

The effects of isavuconazole (active moiety of isavuconazonium sulfate) on cardiac ion channels in vitro and cardiac repolarization clinically were assessed in a phase I, randomized, double-blind study in healthy individuals who received isavuconazole (after 2-day loading dose), at therapeutic or supratherapeutic doses daily for 11 days, moxifloxacin (400 mg q.d.), or placebo. A post-hoc analysis of the phase III SECURE trial assessed effects on cardiac safety. L-type Ca2+ channels were most sensitive to inhibition by isavuconazole. The 50% inhibitory concentrations for ion channels were higher than maximum serum concentrations of nonprotein-bound isavuconazole in vivo. In the phase I study (n = 161), isavuconazole shortened the QT interval in a dose- and plasma concentration-related manner. There were no serious treatment-emergent adverse events; palpitations and tachycardia were observed in placebo and supratherapeutic isavuconazole groups; no cardiac safety signals were detected in the SECURE study (n = 257). Isavuconazole was associated with a shortened cardiac QT interval.

Electrocardiographic Effects of a Supratherapeutic Dose of Oritavancin

The purpose of this study was to measure oritavancin's electrocardiographic effects at a supratherapeutic dose of 1600 mg given intravenously (IV) over 3 hours. A cohort of 150 healthy volunteers were randomized to receive placebo, oritavancin, or oral moxifloxacin 400 mg in a parallel designed thorough QT study. A supratherapeutic mean maximum oritavancin concentration (C_max ) of 232 μg/mL was achieved. There was no significant effect on baseline and placebo corrected (dd) QTcF, QRS, or heart rate; ddPR was slightly increased at most time points, with a maximum mean change of 7.7 milliseconds 1 hour after infusion. Linear PK-PD modeling predicted a 3.2-millisecond change in the PR interval for the C_max (138 μg/mL) observed in pivotal phase 3 studies after 1200 mg of oritavancin. Moxifloxacin produced the expected increase in ddQTcF, validating assay sensitivity. At plasma concentrations above the clinical exposures of oritavancin, no clinically or statistically significant effect on QTcF, QRS, or heart rate was observed. The increase in PR is considered clinically insignificant, given the rapid decline in initial plasma concentration of oritavancin after infusion and the expected lower C_max in patients. A therapeutic 1200-mg single dose of oritavancin is not anticipated to cause any clinically significant effect on cardiac electrophysiology.

Treatment of Adults with Lennox-Gastaut Syndrome: Further Analysis of Efficacy and Safety/Tolerability of Rufinamide

INTRODUCTION

Management of Lennox-Gastaut syndrome (LGS) in adulthood can be particularly challenging. Published reports describing the use of rufinamide specifically in adult patients with LGS are scarce. A post hoc subgroup analysis of data from a phase III trial was conducted to investigate the efficacy and safety/tolerability of rufinamide in adults with LGS.

METHODS

A randomized, double-blind, placebo-controlled trial was conducted in patients with LGS, aged 4 years and above. During an 84-day, double-blind treatment period, patients received either adjunctive rufinamide therapy or placebo. Efficacy and safety/tolerability were assessed in a post hoc subgroup analysis of adult patients (≥18 years). Efficacy was assessed as change from baseline in 28-day seizure frequency, 50% responder rate, and seizure freedom rate; each calculated for total seizures and drop attacks. Safety/tolerability assessments included the evaluation of adverse events (AEs).

RESULTS

Thirty-one adults aged 18-37 years with LGS received treatment with either rufinamide (n = 21) or placebo (n = 10). Three patients in the rufinamide group did not complete the trial. The median change from baseline in seizure frequency was -31.5% for rufinamide versus +22.1% for placebo (P = 0.008) for all seizures and -54.9% versus +21.7% (P = 0.002) for drop attacks. Responder rates were 33.3% for rufinamide versus 0% for placebo (P = 0.066) for all seizures and 57.1% versus 10.0% (P = 0.020) for drop attacks. No patient achieved freedom from all seizures but two rufinamide-treated patients (9.5%) became free of drop attacks. Overall, 71.4% of patients treated with rufinamide and 60.0% of patients treated with placebo experienced AEs; most commonly, somnolence (33.3% vs. 20.0%) and vomiting (19.0% vs. 0%). Most AEs were of mild or moderate intensity.

CONCLUSION

Rufinamide demonstrated favorable efficacy and was generally well tolerated when used as adjunctive treatment for adults with LGS.

FUNDING

Eisai.

Cardiac and autonomic mechanisms contributing to SUDEP

Sudden unexpected death in epilepsy is likely caused by a cascade of events affecting the vegetative nervous system leading to cardiorespiratory failure and death. Multiple genetic, electrophysiological, neurochemical, and pharmacological cardiac alterations have been associated with epilepsy, which can affect autonomic regulation of the heart and predispose patients to sudden unexpected death in epilepsy. These cardiac and autonomic changes are more frequently seen in patients with longstanding and medication refractory epilepsy and may be a prerequisite for sudden unexpected death in epilepsy. Cardiac changes are also observed within the immediate periictal period in patients with and without preexisting cardiac pathology and could be the tipping point in the cascade of events compromising autonomic, respiratory, and cardiac function during an epileptic convulsion. Better understanding if and how these cardiac alterations can make a particular individual with epilepsy more susceptible to sudden unexpected death in epilepsy will hopefully lead us to more effective preventative strategies.

Current role of rufinamide in the treatment of childhood epilepsy: literature review and treatment guidelines

PURPOSE

The literature on the efficacy and safety of rufinamide in childhood-onset epilepsy syndromes currently includes approximately 600 paediatric patients. This paper summarizes the views of a panel of experienced European epileptologists with regard to the current role of rufinamide in the treatment of childhood epilepsies.

RESULTS

Rufinamide is effective in decreasing the seizure frequency in the Lennox-Gastaut syndrome (LGS), especially tonic and atonic seizures. It might consequently be preferred to other drugs as a second-line treatment for LGS when drop-attacks are frequent. The mean responder rate in the published studies is 38% with seizure freedom achieved in 2.4% of patients. Rufinamide has shown some efficacy in epileptic encephalopathies other than LGS. It can be also effective as adjunctive therapy in children and adolescents with drug-resistant partial seizures. The available data suggest that rufinamide has an acceptable risk/benefit ratio with quite a low risk of aggravating seizures. Common adverse effects (somnolence, nausea and vomiting) are usually mild and self-limiting; they are more frequently observed during titration than in the maintenance phase, suggesting that low escalation rates might be associated with fewer adverse effects. Rufinamide appears to have a favourable cognitive profile compared with other antiepileptic drugs.

CONCLUSION

Rufinamide is only approved for adjunctive treatment of seizures associated with LGS in children 4 years of age and older. There are very few data on rufinamide treatment at the onset of LGS or early in the course of the disorder; whether early treatment will improve outcome has yet to be determined.

Pharmacokinetic and pharmacodynamic interactions between antiepileptics and antidepressants

INTRODUCTION

Antiepileptic-antidepressant combinations are frequently used by clinicians; their pharmacokinetic (PK) and pharmacodynamic (PD) drug interactions (DIs) have not been well studied but are frequently likely to be clinically relevant.

AREAS COVERED

This article provides a comprehensive review of PK DIs between antiepileptics and antidepressants. In the absence of PD DI studies, PD information on pharmacological mechanisms and studies on efficacy and safety of individual drugs are reviewed.

EXPERT OPINION

The clinical relevance of the inductive properties of carbamazepine, phenytoin, phenobarbital and primidone and the inhibitory properties of valproic acid and some antidepressants are well understood; correction factors are provided if appropriate DI studies have been completed. More PK studies are needed for: i) antiepileptics with potent inductive effects for all recently approved antidepressants; ii) high doses of mild CYP3A4 inducers, such as clobazam, eslicarbazepine, oxcarbazepine, rufinamide and topiramate for reboxetine and vilazodone; iii) valproate as a possible inhibitor, mild inducer or both a mild inducer and competitive inhibitor of some antidepressants; and iv) inhibitory effects of long-term fluoxetine use on clobazam, lacosamide, phenobarbital, primidone, carbamazepine, felbamate, tiagabine and zonisamide. Possible synergistic or additive beneficial PD DIs in generalized anxiety disorder, chronic pain, migraine prophylaxis, weight control and menopausal symptoms need study.

The long-term safety of antiepileptic drugs

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

Ictal modulation of cardiac repolarization, but not of heart rate, is lateralized in mesial temporal lobe epilepsy

Objectives

Human and animal studies provided controversial data on asymmetric cortical representation of cardiac function, which may partially be due to different study designs and inter-individual variability. Here, we investigated whether seizure-related changes in heart rate (HR) and cardiac repolarization depend on the side of seizure-activity in people with mesial temporal lobe epilepsy (mTLE).

Methods

To account for inter-individual variability, EEG and ECG data were reviewed from patients with medically refractory mTLE undergoing pre-surgical video-EEG telemetry with at least 2 seizures arising from each hippocampus as assessed by bilateral hippocampal depths electrodes. RR and QT intervals were determined at different timepoints using a one-lead ECG. QT intervals were corrected for HR (QTc) using 4 established formulas.

Results

Eighty-two seizures of 15 patients were analyzed. HR increased by ∼30% during hippocampal activity irrespective of the side (p = 0.411). QTc intervals were lengthened to a significantly greater extent during left hippocampal seizures (e.g. difference of QT intervals between preictal and ictal state using Bazett’s formula; left side 32.0±5.3 ms, right side 15.6±7.7 ms; p = 0.016). Abnormal QTc prolongation occurred in 7 of 41 left hippocampal seizures of 4 patients, and only in 2 of 37 right hippocampal seizures of 2 patients.

Conclusions

Seizure-related modulation of cardiac repolarization, but not of HR, appears to depend on the side of ictal activity, strengthening the hypothesis of asymmetric cerebral representation of cardiac function. The clinical relevance of this is unclear, but may indicate an increased risk of abnormal ictal QT prolongation in people with left mTLE.

Efficacy and safety of rufinamide in pediatric epilepsy

Rufinamide is a novel anticonvulsant medication approved by the US Food and Drug Administration (FDA) in 2008 for the treatment of seizures associated with Lennox-Gastaut syndrome in patients 4 years of age and older, based upon clinical trials demonstrating clinical efficacy and tolerability. Rufinamide is especially effective for tonic-atonic seizures in Lennox-Gastaut syndrome, but is subsequently proving to be safe and effective in clinical practice for a broad patient population with refractory epilepsy. Although further research and clinical experience is needed, rufinamide holds the promise to positively impact the care of children with epilepsy. In this review, we review the use of rufinamide in pediatric epilepsy, with a focus on efficacy and safety.

QTc prolongation by antiepileptic drugs and the risk of torsade de pointes in patients with epilepsy

Sudden unexpected death in epilepsy (SUDEP) is the most common epilepsy-related cause of death. While the precise pathophysiological mechanisms underlying SUDEP are still uncertain, impaired cardiac function including seizure-induced arrhythmias has received increased attention. In addition, the potential role of antiepileptic drugs has been suggested. While the preponderance of clinical data would suggest that use of most antiepileptic drugs does not pose excessive additional risk of QT prolongation, available data also do not provide sufficient evidence that these drugs are entirely free of risk in all patients. In particular, the potential for these medications, either alone or in combination, to prolong the QT interval should be considered. This review will discuss mechanisms for drug-induced QT prolongation and its relationship to potentially fatal arrhythmias such as torsades de pointes.

What's New in the Medical Management of Pediatric Epilepsy?

Epilepsy affects approximately 45 per 100,000 children per year. While many cases respond favorably to antiepileptic therapy, approximately 20% will prove to be medically intractable. This paper reviews some of the recently identified important metabolic and autoimmune etiologies for which there are specific therapies. Additionally, newer antiepileptic medications, including rufinamide, lacosamide, retigabine, eslicarbazepine and brivaracetam and newer dietary options, including the modified Atkins diet and low-glycemic index diet are discussed.

hERG K+ Channels: Structure, Function, and Clinical Significance

The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, Kv11.1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines. However, it is the role that Kv11.1 channels play in the heart that has been best characterized, for two main reasons. First, it is the gene product involved in chromosome 7-associated long QT syndrome (LQTS), an inherited disorder associated with a markedly increased risk of ventricular arrhythmias and sudden cardiac death. Second, blockade of Kv11.1, by a wide range of prescription medications, causes drug-induced QT prolongation with an increase in risk of sudden cardiac arrest. In the first part of this review, the properties of Kv11.1 channels, including biogenesis, trafficking, gating, and pharmacology are discussed, while the second part focuses on the pathophysiology of Kv11.1 channels.