Clobazam and Its Use in Epilepsy

Safety profile of clobazam in the real world: an analysis of FAERS database and systematic review of case reports

BACKGROUND

Most of the safety data of clobazam came from well-designed clinical trials, while the real-world information is insufficient.

RESEARCH DESIGN AND METHODS

We performed a disproportionality analysis of the FDA Adverse Event Reporting System (FAERS) database through OpenVigil 2 and conducted a systematic review of case reports regarding adverse drug reactions (ADR) linked to clobazam.

RESULTS

The analysis of FAERS identified 595 ADR signals. Nervous system disorders cantains the most positive signals among all system organ classes (SOCs). Except for seizure (n = 1696) and somnolence (n = 813), drug interactions (n = 492) were the most frequently reported positive signals. A total of 502 unique citations were initially retrieved and 31 individual cases from 28 publications were included. Skin reactions were the most reactions (n = 9), containing three types of severe reactions not alerted in the instruction. Five cases were caused by interactions between clobazam and other antiepileptic drugs, etravirine-based antiretroviral therapy, omeprazole, or meropenem. One patient died of aspiration pneumonia.

CONCLUSIONS

Clinicians must pay attention to severe skin reactions and monitor the signs of suspicious respiratory infections/inflammations and central sedation. Patients with skin reactions will benefit from the withdrawal of clobazam and the treatment with glucocorticoids. The drug reactions between clobazam with severe or moderate cytochrome P450 (CYP) 3A4 or CYP2C19 inhibitors or other antiepileptic drugs should also be alerted.

Clinical and Genetic Features of Dravet Syndrome: A Prime Example of the Role of Precision Medicine in Genetic Epilepsy

Dravet syndrome (DS), also known as severe myoclonic epilepsy of infancy, is a rare and drug-resistant form of developmental and epileptic encephalopathies, which is both debilitating and challenging to manage, typically arising during the first year of life, with seizures often triggered by fever, infections, or vaccinations. It is characterized by frequent and prolonged seizures, developmental delays, and various other neurological and behavioral impairments. Most cases result from pathogenic mutations in the sodium voltage-gated channel alpha subunit 1 (SCN1A) gene, which encodes a critical voltage-gated sodium channel subunit involved in neuronal excitability. Precision medicine offers significant potential for improving DS diagnosis and treatment. Early genetic testing enables timely and accurate diagnosis. Advances in our understanding of DS's underlying genetic mechanisms and neurobiology have enabled the development of targeted therapies, such as gene therapy, offering more effective and less invasive treatment options for patients with DS. Targeted and gene therapies provide hope for more effective and personalized treatments. However, research into novel approaches remains in its early stages, and their clinical application remains to be seen. This review addresses the current understanding of clinical DS features, genetic involvement in DS development, and outcomes of novel DS therapies.

Myoclonus as a Manifestation of Reflex Seizures

SUMMARY

Myoclonus is a motor symptom commonly associated with reflex seizures in people with idiopathic generalized epilepsies. The most frequently observed triggers of myoclonus are related to visual stimuli, including flashing lights or patterns; nonetheless, myoclonus can also be activated by movement, speech or reading, calculations, and praxis. Reflex myoclonic seizures may be the hallmark of a reflex epilepsy, but it may lead to the diagnosis of generalized epilepsy syndromes. In the setting of idiopathic generalized epilepsies, reflex myoclonus can persist despite optimal medical therapies and may be a marker for active, even medically intractable, epilepsy. In this article, the clinical significance, diagnosis, and treatment of myoclonus, associated with visual stimulation, movement, and praxis, will be reviewed.

Therapeutic and clinical foundations of cannabidiol therapy for difficult-to-treat seizures in children and adults with refractory epilepsies

Novel and effective antiseizure medications are needed to treat refractory and rare forms of epilepsy. Cannabinoids, which are obtained from the cannabis plant, have a long history of medical use, including for neurologic conditions. In 2018, the US Food and Drug Administration approved the first phytocannabinoid, cannabidiol (CBD, Epidiolex), which is now indicated for severe seizures associated with three rare forms of developmental and epileptic encephalopathy: Dravet syndrome, Lennox-Gastaut syndrome, and tuberous sclerosis complex. Compelling evidence supports the efficacy of CBD in experimental models and patients with epilepsy. In randomized clinical trials, highly-purified CBD has demonstrated efficacy with an acceptable safety profile in children and adults with difficult-to-treat seizures. Although the underlying antiseizure mechanisms of CBD in humans have not yet been elucidated, the identification of novel antiseizure targets of CBD preclinically indicates multimodal mechanisms that include non-cannabinoid pathways. In addition to antiseizure effects, CBD possesses strong anti-inflammatory and neuroprotective activities, which might contribute to protective effects in epilepsy and other conditions. This article provides a succinct overview of therapeutic approaches and clinical foundations of CBD, emphasizing the clinical utility of CBD for the treatment of seizures associated with refractory and rare epilepsies. CBD has shown to be a safe and effective antiseizure medicine, demonstrating a broad spectrum of efficacy across multiple seizure types, including those associated with severe epilepsies with childhood onset. Despite such promise, there are many perils with CBD that hampers its widespread use, including limited understanding of pharmacodynamics, limited exposure-response relationship, limited information for seizure freedom with continued use, complex pharmacokinetics with drug interactions, risk of adverse effects, and lack of expert therapeutic guidelines. These scientific issues need to be resolved by further investigations, which would decide the unique role of CBD in the management of refractory epilepsy.

Determination of Clobazam and Its Major Metabolite N-desmethylclobazam in Human Plasma with High-Performance Liquid Chromatography

Clobazam (CLB) is a benzodiazepine that is used in many types of epilepsy. Although therapeutic drug monitoring (TDM) of CLB is not routine, there is evidence that TDM may be of value in conditions where pharmacokinetic alterations are suspected. Therefore, determination of both CLB and its active metabolite concentrations is essential for TDM. Herein, we present a simple and practical method for determination of CLB and N-desmethylclobazam (NDMCLB) in human plasma by high-performance liquid chromatography (HPLC). The drugs were extracted by hexane:dichloromethane (1:1, v/v) from 0.3 mL plasma. The separation was carried out with a C18 reverse phase column using a mobile phase of water:acetonitrile (57:43, v/v) pumped at 0.8 mL/min. The analytes were detected at 228 nm. The method was linear over the concentration range 20–500 ng/mL for CLB and 200–3000 ng/mL for NDMCLB. The intra-day coefficient of variation (CV) was <10% for CLB and <6% for NDMCLB, while the inter-day CV for CLB was <16%. The metabolite inter-day CV was <6%. The accuracy of intra- and inter-day assessments determined for CLB and NDMCLB was within ±10%. This paper describes a rapid, reliable, and simple method for measuring CLB and its metabolite NDMCLB in human plasma. This UV-HPLC procedure offers acceptable precision and accuracy to quantify CLB and its metabolite in human plasma.

Experimental GABA A Receptor Agonists and Allosteric Modulators for the Treatment of Focal Epilepsy

GABA A receptors are ubiquitous in the central nervous system and there is a huge diversity of receptor subtypes in almost all regions of the brain. However, the expression of GABA A receptor subtypes is altered in both the gray and white matter of patients with focal epilepsy. Although there is a number of anticonvulsants with marketing authorization for the treatment of focal epilepsy which act through GABA A receptors, potentiating the inhibitory effects of GABA, it is necessary to develop more potent and more specific GABAergic anticonvulsants that are effective in drug-resistant patients with focal epilepsy. There are three orthosteric and at least seven allosteric agonist binding sites at the GABA A receptor. In experimental and clinical studies, full agonists of GABA A receptors showed a tendency to cause desensitization of the receptors, tolerance, and physical dependence; therefore, partial orthosteric agonists and positive allosteric modulators of GABA A receptors were further developed. Preclinical studies demonstrated the anticonvulsant efficacy of positive allosteric modulators with selective action on GABA A receptors with α2/α3 subunits, but only a handful of them were further tested in clinical trials. The best results were obtained for clobazam (already marketed), ganaxolone (in phase III trials), CVL-865 (in phase II trials), and padsevonil (in phase III trials). Several compounds with more selective action on GABA A receptors, perhaps only in certain brain regions, have the potential to become effective drugs against specific subtypes of focal-onset epilepsy. However, their development needs time, and in the near future we can expect only one or two new GABA A agonists to obtain marketing authorization for focal epilepsy, an advance that would be of use for just a fraction of patients with drug-resistant epilepsy.

Efficacy and Side Effect Profile of Clobazam in Children with Different Etiologies of Epilepsy from a Single Center

Objectives:

Clobazam is a long-acting antiepileptic drug that belongs to benzodiazepines used in the polytherapy of childhood epilepsy. In this study, our aim is to retrospectively evaluate the effectiveness and side effect profile of clobazam in children with different etiologies of epilepsy, mostly drug resistant.

Methods:

Forty patients aged 0-18 years that were admitted to Okmeydanı Training and Research Hospital pediatric neurology outpatient clinic between January 2017–January 2019 and prescribed clobazam were included in this study. The data of the patients who gave informed consent were extracted retrospectively from the outpatient clinic files. The patients with no seizures over 50% reduction in seizures were classified as clobazam-responsive, whereas the patients with less than 50% reductions in seizures, patients who had no response, and who manifested side effects and stopped using the drug were classified as clobazam-unresponsive.

Results:

Twenty-three of the patients (57.5%) were male, 17 were (42.5%) were female. The average onset age of epilepsy was 31.8±37.2 months, while the average age for the prescription of clobazam was 70.6±48.9 months. The types of seizures were focal in 23 patients (57.5%) and generalized in 17 (42.5%) patients. Thirty-three (82.5%) patients had been using double or triple combinations of eight different antiepileptic drugs when clobazam was added to their treatment and accepted as drug-resistant epilepsy. The etiology of twenty one patients (52.5%) was unknown. In the remaining 19 patients (47.5%), the most common cause was structural and others were genetic, infectious and metabolic. Thirty one of the patients (77.5%) were responsive to clobazam. Of them, fifteen (37.5%) had no seizures, and 16 had a reduction in seizures (>50%). Nine (22.5%) patients were accepted as unresponsive to clobazam. The mean dose per kg was 0.7±0.3 mg/kg/day with a median of 0.63 mg/kg/day. Side effects of clobazam were encountered in 18 patients (45%); these resulted in the cessation of administration in only six (15%) patients. The side effects that cause the cessation of clobazam were sedation, refusal to take the drug due to the taste, irritability, hypersalivation, and malaise. Four patients (10%) had their doses reduced, seven patients (17.5%) responsive to clobazam although with side effects continued taking the drug as prescribed. The most common side effects of all were hyperactivity and sedation consecutively.

Conclusion:

Clobazam is an effective treatment for ensuring seizure freedom in pediatric epilepsy, mostly drug-resistant. The side effects are at tolerable levels in patients who are responsive to the drug.

Epilepsy and aging

The intersection of epilepsy and aging has broad, significant implications. Substantial increases in seizures occur both in the elderly population, who are at a higher risk of developing new-onset epilepsy, and in those with chronic epilepsy who become aged. There are notable gaps in our understanding of aging and epilepsy at the basic and practical levels, which have important consequences. We are in the early stages of understanding the complex relationships between epilepsy and other age-related brain diseases such as stroke, dementia, traumatic brain injury (TBI), and cancer. Furthermore, the clinician must recognize that the presentation and treatment of epilepsy in the elderly are different from those of younger populations. Given the developing awareness of the problem and the capabilities of contemporary, multidisciplinary approaches to advance understanding about the biology of aging and epilepsy, it is reasonable to expect that we will unravel some of the intricacies of epilepsy in the elderly; it is also reasonable to expect that these gains will lead to further improvements in our understanding and treatment of epilepsy for all age groups.

Pharmacological Management of the Genetic Generalised Epilepsies in Adolescents and Adults

Common genetic generalised epilepsy syndromes encountered by clinicians include childhood and juvenile absence epilepsies, juvenile myoclonic epilepsy and generalised tonic-clonic seizures on awakening. Treatment of these syndromes involves largely the use of broad-spectrum antiseizure drugs. Those effective for the generalised epilepsies include sodium valproate, phenobarbital, ethosuximide, clobazam, clonazepam, lamotrigine, levetiracetam, topiramate, zonisamide and, more recently, perampanel and brivaracetam. Results from the few rigorous studies comparing outcomes with drugs for genetic generalised epilepsies show valproate to be the most effective. The majority of patients with genetic generalised epilepsy syndromes will become seizure free on antiseizure monotherapy; those for whom control proves elusive may benefit from combination regimens. Early counselling regarding management may assist the patient to come to terms with their diagnosis and improve long-term outcomes. Treatment can be lifelong in some individuals, although others may remain seizure free without medication. Choice of antiseizure medication depends on the efficacy for specific seizure types, as well as tolerability. For patients prescribed comedication, drug interactions should be considered. In particular, for young women taking oral hormonal contraceptives, ≥ 200 mg/day of topiramate can decrease the circulating concentration of ethinylestradiol and ≥ 12 mg/day of perampanel can induce levonorgestrel metabolism. The use of valproate in women of childbearing potential is limited by associated teratogenic and neurodevelopmental effects in offspring. Given that valproate is often the antiseizure drug of choice for genetic generalised epilepsies, this creates a dilemma for patients and clinicians. Decision making can be aided by comprehensive assessment and discussion of treatment options. Psychiatric comorbidities are common in adolescents and adults with genetic generalised epilepsies. These worsen the prognosis, both in terms of seizure control and quality of life. Attendant lifestyle issues can impact significantly on the individual and society. Frontal lobe dysfunction, which can present in patients with juvenile myoclonic epilepsy, can adversely affect the long-term outlook, regardless of the nature of seizure control. Ongoing management requires consideration of psychosocial and behavioural factors that can complicate diagnosis and treatment. An assured supportive attitude by the neurologist can be an important contributor to a positive outcome. The mechanisms underlying genetic generalised epilepsies, including genetic abnormalities, are unclear at present. As the pathophysiology is unravelled, this may lead to the development of novel therapies and improved outcomes for patients with these syndromes.

Protein precipitation method for determination of clobazam and N-desmethylclobazam in human plasma by LC-MS/MS

A protein precipitation method for the determination of clobazam (CLB) and its major active metabolite N-desmethylclobazam (N-CLB) in human plasma by liquid chromatography tandem mass spectrometry (LC-MS/MS) was established. CLB and N-CLB were extracted from human plasma samples by protein precipitation with methanol. Analyte separation was done using a Phenomenex Kinetex™ Biphenyl (50 × 2.1 mm, 1.7 μm) column using isocratic elution with a mobile phase of 5 mm ammonium formate with 0.01% ammonium hydroxide (40%) and methanol (60%) at a flow rate of 0.4 mL/min and an injection volume of 10 μL. The detection was performed on a triple quadrupole mass spectrometer in multiple reaction monitoring mode to monitor the precursor-to-product ion transitions of m/z 301.1 → 259.0, 306.0 → 263.9 for CLB and CLB-D5 and 287.0 → 245.0, 292.0 → 250.0 for N-CLB and N-CLB-D5 in positive electrospray ionization mode, respectively. The method was validated over a concentration range of 2.0-750 ng/mL for CLB and 0.7-200 ng/mL for N-CLB on SCIEX Triple Quad 4500 MS System. Total run time was 5 min. This method has been designed for bioequivalence study for formulations containing 20 mg of CLB.

Safety and Efficacy of Supratherapeutic Doses of Clobazam

Clobazam is a commonly used long-acting benzodiazepine approved by the US Food and Drug Administration (FDA) to treat seizures associated with Lennox Gastaut syndrome. The FDA approved maximum dosage of clobazam is 1 mg/kg/d or a total of 40 mg a day. Many providers exceed this dosage but there is limited data on the safety, tolerability, and efficacy of supratherapeutic doses. We reviewed retrospective data at our institution and compared patients on supratherapeutic doses to patients on therapeutic doses. A total of 133 patients met inclusion criteria (65 supratherapeutic, 67 therapeutic). There was no statistically significant difference in terms of seizure control, health care utilization, or side effects between patients on supratherapeutic doses and those on therapeutic doses. This study lends further support to the safety and tolerability of supratherapuetic doses of clobazam.

Urine analysis of 28 designer benzodiazepines by liquid chromatography-high-resolution mass spectrometry

Hundreds of new psychoactive substances (NPS) covering most drugs-of-abuse classes have been introduced to the recreational drug market in recent years. One class of NPS drugs that has become more common recently is "designer" benzodiazepines. Due to a close structural resemblance with prescription benzodiazepines, some of these substances may elicit a positive response (i.e. cross react) in immunoassay screening. Consequently, it is increasingly important to include NPS benzodiazepines during method confirmation to ensure accurate identification of closely-related compounds as well as detection of the benzodiazepines themselves. Here, we present our efforts to develop a screening and confirmation method for detection of 28 NPS benzodiazepines in urine using reversed-phase liquid chromatographic separation in combination with high-resolution mass spectrometry (LC-HRMS). MS was performed in positive electrospray mode on a Thermo Fischer Scientific Q Exactive Orbitrap instrument using either full scan (for screening) or parallel reaction monitoring (for confirmation). We found the lower quantification limit of the method to range from 5 to 50 ng/mL. Analytical precision and accuracy were ≤15% for both screening and confirmation for all except one analyte. The method was used to analyze patient urine samples from routine drug testing and samples from acute intoxication cases presenting in emergency wards. Altogether, 16 of the 28 benzodiazepines (i.e., clobazam, clonazolam, deschloroetizolam, diclazepam, estazolam, etizolam, flubromazepam, flubromazolam, flunitrazolam, 3-hydroxyflubromazepam, 3-hydroxyphenazepam, ketazolam, meclonazepam, metizolam, nifoxipam, and pyrazolam) were detected in the urine samples. The results from patient sample analysis indicate a high prevalence of NPS benzodiazepine use, emphasizing the importance of including novel drugs of abuse in drug testing menus.

An evaluation of the effectiveness of annual health checks and quality of health care for adults with intellectual disability: an observational study using a primary care database

Background

People with intellectual disability (ID) have poorer health than the general population; however, there is a lack of comprehensive national data describing their health-care needs and utilisation. Annual health checks for adults with ID have been incentivised through primary care since 2009, but only half of those eligible for such a health check receive one. It is unclear what impact health checks have had on important health outcomes, such as emergency hospitalisation.

Objectives

To evaluate whether or not annual health checks for adults with ID have reduced emergency hospitalisation, and to describe health, health care and mortality for adults with ID.

Design

A retrospective matched cohort study using primary care data linked to national hospital admissions and mortality data sets.

Setting

A total of 451 English general practices contributing data to Clinical Practice Research Datalink (CPRD).

Participants

A total of 21,859 adults with ID compared with 152,846 age-, gender- and practice-matched controls without ID registered during 2009–13.

Interventions

None.

Main outcome measures

Emergency hospital admissions. Other outcomes – preventable admissions for ambulatory care sensitive conditions, and mortality.

Data sources

CPRD, Hospital Episodes Statistics and Office for National Statistics.

Results

Compared with the general population, adults with ID had higher levels of recorded comorbidity and were more likely to consult in primary care. However, they were less likely to have long doctor consultations, and had lower continuity of care. They had higher mortality rates [hazard ratio (HR) 3.6, 95% confidence interval (CI) 3.3 to 3.9], with 37.0% of deaths classified as being amenable to health-care intervention (HR 5.9, 95% CI 5.1 to 6.8). They were more likely to have emergency hospital admissions [incidence rate ratio (IRR) 2.82, 95% CI 2.66 to 2.98], with 33.7% deemed preventable compared with 17.3% in controls (IRR 5.62, 95% CI 5.14 to 6.13). Health checks for adults with ID had no effect on overall emergency admissions compared with controls (IRR 0.96, 95% CI 0.87 to 1.07), although there was a relative reduction in emergency admissions for ambulatory care-sensitive conditions (IRR 0.82, 95% CI 0.69 to 0.99). Practices with high health check participation also showed a relative fall in preventable emergency admissions for their patients with ID, compared with practices with minimal participation (IRR 0.73, 95% CI 0.57 to 0.95). There were large variations in the health check-related content that was recorded on electronic records.

Limitations

Patients with milder ID not known to health services were not identified. We could not comment on the quality of health checks.

Conclusions

Compared with the general population, adults with ID have more chronic diseases and greater primary and secondary care utilisation. With more than one-third of deaths potentially amenable to health-care interventions, improvements in access to, and quality of, health care are required. In primary care, better continuity of care and longer appointment times are important examples that we identified. Although annual health checks can also improve access, not every eligible adult with ID receives one, and health check content varies by practice. Health checks had no impact on overall emergency admissions, but they appeared influential in reducing preventable emergency admissions.

Future work

No formal cost-effectiveness analysis of annual health checks was performed, but this could be attempted in relation to our estimates of a reduction in preventable emergency admissions.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.