Perampanel in patients with refractory and super-refractory status epilepticus in a neurological intensive care unit: A single-center audit of 30 patients

Role of α-amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid receptors and the antagonist perampanel in geriatric epilepsy and status epilepticus

The α-amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) is an ionotropic glutamate receptor recognized for its active involvement in epilepsy. Through AMPAR functional alterations, multiple factors contribute to the increased susceptibility to seizures in the geriatric population. These factors include changes in the hippocampus, neuroinflammation, ischemic insults, amyloid deposition, previous seizures, alterations in the microenvironment, and neurovascular unit dysfunction. Perampanel, a noncompetitive AMPAR antagonist, has been approved for the treatment of focal and generalized epilepsy. However, a complete understanding of AMPAR's role in epileptogenesis and the pharmacotherapy of perampanel in the geriatric population remains elusive. To address this gap, we conducted a comprehensive literature review, screening 1557 articles and ultimately selecting 94 relevant ones. We provided insights into AMPAR functionality changes and perampanel's role in treating geriatric epilepsy. Various clinical trials and retrospective studies have demonstrated that the safety and efficacy of perampanel in the older population are comparable to those in the younger population, with overall good tolerability. It is also effective for treating focal and generalized onset seizures and possibly for managing status epilepticus. In conclusion, the existing body of evidence supports the safety and efficacy of perampanel in the geriatric population, indicating its potential as a valuable therapeutic option for focal and generalized epilepsy. Additional research is warranted to deepen our understanding of AMPAR's involvement in epileptogenesis and to refine the pharmacotherapeutic nuances in this specific demographic.

Use of perampanel oral suspension for the treatment of refractory and super-refractory status epilepticus

INTRODUCTION

Status epilepticus (SE) is a medical emergency associated with a significant risk of disability and death. The treatment of SE follows a step-wise approach, with limited data on ideal antiseizure medications (ASMs) for refractory and super refractory SE (RSE/SRSE). Perampanel (PER), an AMPA receptor antagonist, has shown promise in animal models but still has limited data in humans. This study tried to evaluate optimal dosage and safety of PER in RSE and SRSE patients.

MATERIALS AND METHODS

We retrospectively analysed 17 adult patients with RSE (1) or SRSE (16) treated with PER. Demographic and clinical data, including EEG patterns, ASMs administered, PER dosages, and PER plasma concentrations, were collected. For patients receiving a 24 mg PER loading dose (full dose group), the following treatment regimen was applied: 24 mg per day for 48 h following by 16 mg per day. The response to PER was assessed based on electroencephalographic (EEG) improvement from high to low epileptiform activity or from low to the absence of epileptiform activities. Safety was evaluated monitoring hepatic and renal function.

RESULTS

A response rate of 58.82 % was observed, with significantly higher responses in the full dose group (81.82 %) compared to those receiving PER doses below 24 mg (low dose group) (16.67 %) (p-value = 0.004; OR 0.044, 95 % CI 0.003 to 0.621, p = 0.021). No other clinical factors significantly influenced treatment response. Hepatic enzymes become elevated in most patients (70.59 %) but spontaneously decreased.

DISCUSSION

Our findings suggest that a 24 mg PER dose administered for 48 h may be more effective in managing RSE and SRSE compared to doses below 24 mg, potentially due to pharmacokinetic factors.

CONCLUSION

More robust data on PER in RSE and SRSE, including standardized dosing procedures and plasma level monitoring are needed. PER's potential benefits should be explored further, particularly in patients with RSE and SRSE.

Efficacy of Perampanel in Refractory and Super-Refractory Status Epilepticus with Suspected Inflammatory Etiology: A Case Series

(1) Background: Increasing evidence supports the anti-inflammatory and neuroprotective role of perampanel (PER), mediated by decreased expression of pro-inflammatory cytokines and by interference with apoptosis processes. Therefore, the use of PER to treat status epilepticus (SE) with suspected inflammatory etiology is appealing and deserves further investigation. (2) Methods: We retrospectively analyzed seven patients (five F, two M; median age: 62 years) with refractory and super-refractory SE due to a probable or defined inflammatory etiology and treated with PER. (3) Results: PER was administered as the third (4/7) or fourth drug (3/7), with a median loading dose of 32 mg/day (range: 16-36 mg/day) and a median maintenance dose of 10 mg/day (range: 4-12 mg/day). In five cases, SE was focal, while in two patients, it was generalized. SE was caused by systemic inflammation in three patients, while in the other four subjects, it was recognized to have an autoimmune etiology. SE resolution was observed after PER administration in all cases, particularly within 24 h in the majority of patients (4/7, 57.1%). (4) Conclusions: Our data support the efficacy of PER in treating SE when first- and second-line ASMs have failed and suggest a possible earlier use in SE cases that are due to inflammatory/autoimmune etiology.

The broad-spectrum activity of perampanel: state of the art and future perspective of AMPA antagonism beyond epilepsy

Glutamate is the brain's main excitatory neurotransmitter. Glutamatergic neurons primarily compose basic neuronal networks, especially in the cortex. An imbalance of excitatory and inhibitory activities may result in epilepsy or other neurological and psychiatric conditions. Among glutamate receptors, AMPA receptors are the predominant mediator of glutamate-induced excitatory neurotransmission and dictate synaptic efficiency and plasticity by their numbers and/or properties. Therefore, they appear to be a major drug target for modulating several brain functions. Perampanel (PER) is a highly selective, noncompetitive AMPA antagonist approved in several countries worldwide for treating different types of seizures in various epileptic conditions. However, recent data show that PER can potentially address many other conditions within epilepsy and beyond. From this perspective, this review aims to examine the new preclinical and clinical studies-especially those produced from 2017 onwards-on AMPA antagonism and PER in conditions such as mesial temporal lobe epilepsy, idiopathic and genetic generalized epilepsy, brain tumor-related epilepsy, status epilepticus, rare epileptic syndromes, stroke, sleep, epilepsy-related migraine, cognitive impairment, autism, dementia, and other neurodegenerative diseases, as well as provide suggestions on future research agenda aimed at probing the possibility of treating these conditions with PER and/or other AMPA receptor antagonists.

The potential of intravenous topiramate for the treatment of status epilepticus

There is considerable clinical evidence that topiramate (TPM) has a high potential in the treatment of refractory and super-refractory status epilepticus (RSE, SRSE). Because TPM is only approved for oral administration, it is applied as suspension via a nasogastric tube for SE treatment. However, this route of administration is impractical in an emergency setting and leads to variable absorption with unpredictable plasma levels and time to peak concentration. Thus, the development of an intravenous (i.v.) solution for TPM is highly desirable. Here we present data on two parenteral formulations of TPM that are currently being developed. One of these solutions is using sulfobutylether-β-cyclodextrin (SBE-β-CD; Captisol®) as an excipient. A 1% solution of TPM in 10% Captisol® has been reported to be well tolerated in safety studies in healthy volunteers and patients with epilepsy or migraine, but efficacy data are not available. The other solution uses the FDA- and EMA-approved excipient amino sugar meglumine. Meglumine is much more effective to dissolve TPM in water than Captisol®. A 1% solution of TPM can be achieved with 0.5-1% of meglumine. While the use of Captisol®-containing solutions is restricted in children and patients with renal impairment, such restrictions do not apply to meglumine. Recently, first-in-human data were reported for a meglumine-based solution of TPM, indicating safety and efficacy when used as a replacement for oral administration in a woman with epilepsy. Based on the multiple mechanisms of action of TPM that directly target the molecular neuronal alterations that are thought to underlie the loss of efficacy of benzodiazepines and other anti-seizure medications during prolonged SE and its rapid brain penetration after i.v. administration, we suggest that parenteral (i.v.) TPM is ideally suited for the treatment of RSE and SRSE. This paper was presented at the 8th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures held in September 2022.

Perampanel in achieving status epilepticus cessation: A systematic review

BACKGROUND

Status epilepticus (SE) is a neurological emergency necessitating rapid seizure control to prevent long-term consequences. Perampanel (PER) is a novel selective, noncompetitive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA) receptor antagonist that demonstrated efficacy and safety in lithium-pilocarpine models of SE; however, data in humans are limited. This systematic review was performed to assess the efficacy and safety of PER in patients with SE, RSE, and SRSE.

METHODS

We searched MEDLINE (accessed through PubMed), Embase, Scopus, Cochrane Library, and ClinicalTrials.gov from inception until May 30, 2021 to identify all human studies on PER for the treatment of SE of any type and etiology. An additional search was performed on DANS Easy Archive, in which OpenGrey data were stored, from inception until January 10, 2022 and conference proceedings by the International League Against Epilepsy from 2011 onward. The GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach was used to assess the overall certainty of the body of evidence.

RESULTS

Twenty-one studies (7 case reports, 9 case series, and 5 retrospective cohort studies) were included with a total of 369 cases of SE in 368 patients aged 11 months to 99 years, of which 56.2% were female. Seizures of the majority were refractory (n = 220), super refractory SE (n = 70), or either (n = 81) with prominent motor symptoms (n = 284) and are associated with a structural etiology (n = 218). The number of antiseizure medications and/or anesthetics used prior to PER ranged from 1 to 13. PER was administered in 324 cases and was initiated at a dose of 2-36 mg between 30 min to 59 days from SE onset. SE cessation ranged from 1 h to 4 weeks from PER initiation. A total of 119 cases (36.6%) were considered PER responders. According to the GRADE approach, there is very low certainty of evidence for all outcomes.

CONCLUSIONS

The real-world data of PER as a possible therapeutic option in SE of any type are increasing. However, there is very low certainty of evidence for its use and this requires further clinical studies to establish the appropriate timing, dosing, and titration that are efficacious and safe for SE cessation.

PROVE: retrospective, non-interventional, Phase IV study of perampanel in real-world clinical care of patients with epilepsy

Objective

To assess retention, dosing, efficacy, and safety of perampanel in a large cohort of patients with epilepsy during routine clinical care.

Methods

PROVE was a retrospective, non‐interventional Phase IV study (NCT03208660). Data were obtained retrospectively from the medical records of patients in the United States initiating perampanel after January 1, 2014, according to treating clinicians' recommendation. Retention rate was the primary efficacy endpoint. Secondary efficacy endpoints included median percent changes in seizure frequency per 28 days from baseline, seizure‐freedom rate, and overall investigator impression of seizure effect. Safety endpoints included incidence of treatment‐emergent adverse events (TEAEs). Efficacy and safety were also assessed according to baseline use of enzyme‐inducing antiseizure medications (EIASMs).

Results

Overall, 1703 patients were enrolled and included in the Safety Analysis Set (SAS; ≥1 baseline EIASMs, n = 358 [21.0%]; no baseline EIASMs, n = 1345 [79.0%]). Mean (standard deviation [SD]) cumulative duration of exposure to perampanel was 17.4 (15.7) months; mean (SD) daily perampanel dose was 5.6 (2.7) mg. The most frequent perampanel titration intervals were weekly (23.4%) and every 2 weeks (24.7%). Across the SAS, 24‐month retention rate was 48.1% (n = 501/1042). Based on overall investigator impression at the end of treatment, 51.9%, 35.8%, and 12.3% of patients in the SAS experienced improvement, no change, or worsening of seizures, respectively. TEAEs occurred in 704 (41.3%) patients; 79 (4.6%) had serious TEAEs. The most common TEAE was dizziness (7.3%). There was some variation in efficacy according to EIASM use, while retention rates and safety were generally consistent.

Significance

In this final analysis of >1700 patients with epilepsy receiving perampanel in routine clinical care, favorable retention and sustained efficacy were demonstrated for ≥12 months.

Diagnosis and Management of Status Epilepticus

Seizures are among the most common neurological presentations to the emergency room. They present on a spectrum of severity from isolated new-onset seizures to acute repetitive seizures and, in severe cases, status epilepticus. The latter is the most serious, as it is associated with high morbidity and mortality. Prompt recognition and treatment of both seizure activity and associated acute systemic complications are essential to improve the overall outcome of these patients. The purpose of this review is to provide the current viewpoint on the diagnostic evaluation and pharmacological management of patients presenting with status epilepticus, and the common associated systemic complications.

Inpatient medical cost of status epilepticus in children: A national-wide, multicenter study from China

OBJECTIVES

To describe the inpatient medical cost during hospitalization in children with status epilepticus (SE) and identify factors associated with the cost by a nationwide, multicenter study in China.

MATERIALS & METHODS

We retrospectively identified pediatric inpatients with SE form Hospital Information System (HIS) of 44 hospitals in 27 provinces in China between 2013 and 2015. Inpatient medical cost and factors associated with the cost were analyzed.

RESULTS

A total of 4041 children diagnosed with SE with inpatient medical cost were enrolled in the present study. The median age at admission was 2.9 (range 0.1-18) years, and 2271 patients were male (56.2%). The median inpatient medical cost of children with SE was $1175.5 (665.1-2320.6). The median inpatient medical cost was $3865.6 (1837.4-8210.4) in children with SRSE and $1048.6 (619.8-1865.4) in those with N-SRSE (p < 0.0001). Children with length of hospital stay (LOS) > 7 showed a much higher inpatient medical cost than those with LOS ≤ 7 day ($2300.7 vs. $767.2, p < 0.0001). Regarding different etiologies, children with acute symptomatic etiology showed the highest median inpatient medical cost of $1681.1 (901.0-3699.6), in which children with central nervous system (CNS) infection reported $2606.0 (1380.0-5016.1) and prolonged febrile seizures (PFS) reported $909.8 (649.3-1322.0). Additionally, children with idiopathic/cryptogenic etiology reported a medical cost of $923.2 (548.9-1534.5). Multiple linear regression analysis of cost-driving factors revealed LOS > 7, examinations, treatment equipment and procedures, and treatment medicines were independently associated with a higher inpatient medical cost (R² = 60.91). In addition, PFS and idiopathic/cryptogenic epilepsy etiology were independently associated with a lower cost.

CONCLUSIONS

SE in children was a cost intensive disease in China with a median inpatient medical cost of $1175.5. LOS, etiology and examinations, treatment equipment and procedures, and treatment medicines were significantly associated with inpatient medical cost.

Determination of Impurities in Perampanel Bulk Drugs by High- Performance Liquid Chromatography and Gas Chromatography

Background:

High-performance liquid chromatography (HPLC) method has been used to detect related impurities of perampanel. However, the detection of impurities is incomplete, and the limits of quantification and detection are high. A sensitive, reliable method is in badly to be developed and applied for impurity detection of perampanel bulk drug.

Objective:

Methodologies utilising HPLC and gas chromatography (GC) were established and validated for quantitative determination of perampanel and its related impurities (a total of 10 impurities including 2 genotoxic impurities).

Methods:

The separation was achieved on a Dikma Diamonsil C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of 0.01 mol/L potassium dihydrogen phosphate solution (A) and acetonitrile (B) in gradient elution mode. The compound 2-bromopropane was determined on an Agilent DB-624 column (0.32 mm × 30 m, 1.8 μm) by electron capture detector (μ-ECD) with split injection ratio of 1:5 and proper gradient temperature program.

Result:

Both HPLC and GC methods were established and validated to be sensitive, accurate and robust according to the International Council for Harmonization (ICH) guidelines. The methods developed were linear in the selected concentration range (R2≥0.9944). The average recovery of all impurities was between 92.6% and 103.3%. The possible production mechanism of impurities during the synthesis and degradation processes of perampanel bulk drug was also discussed. Five impurities were analyzed by liquid chromatography–mass spectrometry (LC-MS). Moreover, two of them were simultaneously characterized by LC-MS, IR and NMR.

Conclusion:

The HPLC and GC methods were developed and optimized, which could be applied for quantitative detection of the impurities, and further stability study of perampanel.

Pharmacotherapy for Nonconvulsive Seizures and Nonconvulsive Status Epilepticus

Most seizures in critically ill patients are nonconvulsive. A significant number of neurological and medical conditions can be complicated by nonconvulsive seizures (NCSs) and nonconvulsive status epilepticus (NCSE), with brain infections, hemorrhages, global hypoxia, sepsis, and recent neurosurgery being the most prominent etiologies. Prolonged NCSs and NCSE can lead to adverse neurological outcomes. Early recognition requires a high degree of suspicion and rapid and appropriate duration of continuous electroencephalogram (cEEG) monitoring. Although high quality research evaluating treatment with antiseizure medications and long-term outcome is still lacking, it is probable that expeditious pharmacological management of NCSs and NCSE may prevent refractoriness and further neurological injury. There is limited evidence on pharmacotherapy for NCSs and NCSE, although a few clinical trials encompassing both convulsive and NCSE have demonstrated similar efficacy of different intravenous (IV) antiseizure medications (ASMs), including levetiracetam, valproate, lacosamide and fosphenytoin. The choice of specific ASMs lies on tolerability and safety since critically ill patients frequently have impaired renal and/or hepatic function as well as hematological/hemodynamic lability. Treatment frequently requires more than one ASM and occasionally escalation to IV anesthetic drugs. When multiple ASMs are required, combining different mechanisms of action should be considered. There are several enteral ASMs that could be used when IV ASM options have been exhausted. Refractory NCSE is not uncommon, and its treatment requires a very judicious selection of ASMs aiming at reducing seizure burden along with management of the underlying condition.

Efficacy and safety of perampanel in refractory and super-refractory status epilepticus: cohort study of 81 patients and literature review

BACKGROUND

The effective dose of perampanel in status epilepticus (SE), refractory SE (RSE), and super-refractory SE (SRSE) in humans is unknown, and the potential of perampanel in treating SE has not been evaluated in a large cohort.

METHODS

Data of intensive care patients with RSE and SRSE treated with perampanel were retrospectively reviewed and analyzed.

RESULTS

Eighty-one patients received perampanel, including 39 females with median age 64 [17-91] years, perampanel responders (n = 27), and non-responders (n = 54). The initial perampanel dose was positively associated with treatment response in patients with RSE or SRSE (OR = 1.27, 95% CI 1.03-1.57, p = 0.025), while the maximum dose was negatively associated with treatment response (OR = 0.74, 95% CI 0.58-0.96, p = 0.022). Hypoxia caused seizures in six patients; five died in hospital and one had severe disability. A statistically non-significant tendency toward better response was found in patients with unique SE type and cause, particularly in nonconvulsive status epilepticus (NCSE) without coma (NCSE without coma vs. generalized tonic-clonic seizure: OR = 4.14, 95% CI 0.98-17.47, p = 0.053). In the high-dose (≥ 16 mg/day) groups, although distributions of modified Rankin Scale (mRS) scores were similar between perampanel responders and non-responders at discharge, a greater proportion of perampanel responders had less change in mRS scores from baseline than did perampanel non-responders (median mRS: 0 vs 4, p = 0.064). No cardiorespiratory adverse events or laboratory abnormalities were noted with perampanel treatment.

CONCLUSIONS

Perampanel is effective and has a satisfactory safety profile in the emergency treatment of established RSE and SRSE.

Treatment of Super-Refractory Status Epilepticus: A Review

PURPOSE

Super-refractory status epilepticus (SRSE) presents management challenges due to the absence of randomized controlled trials and a plethora of potential medical therapies. The literature on treatment options for SRSE reports variable success and quality of evidence. This review is a sequel to the 2020 American Epilepsy Society (AES) comprehensive review of the treatment of convulsive refractory status epilepticus (RSE).

METHODS

We sought to determine the effectiveness of treatment options for SRSE. We performed a structured literature search (MEDLINE, Embase, CENTRAL, CINAHL) for studies on reported treatments of SRSE. We excluded antiseizure medications (ASMs) covered in the 2016 AES guideline on the treatment of established SE and the convulsive RSE comprehensive review of the 2020 AES. Literature was reviewed on the effectiveness of vagus nerve stimulation, ketogenic diet (KD), lidocaine, inhalation anesthetics, brain surgery, therapeutic hypothermia, perampanel, pregabalin (PGB), and topiramate in the treatment of SRSE. Two authors reviewed each therapeutic intervention. We graded the level of the evidence according to the 2017 classification scheme of the American Academy of Neurology.

RESULTS

For SRSE (level U; 39 class IV studies total), insufficient evidence exists to support that perampanel, PGB, lidocaine, or acute vagus nerve stimulation (VNS) is effective. For children and adults with SRSE, insufficient evidence exists to support that the KD is effective (level U; 5 class IV studies). For adults with SRSE, insufficient evidence exists that brain surgery is effective (level U, 7 class IV studies). For adults with SRSE insufficient, evidence exists that therapeutic hypothermia is effective (level C, 1 class II and 4 class IV studies). For neonates with hypoxic-ischemic encephalopathy, insufficient evidence exists that therapeutic hypothermia reduces seizure burden (level U; 1 class IV study). For adults with SRSE, insufficient evidence exists that inhalation anesthetics are effective (level U, 1 class IV study) and that there is a potential risk of neurotoxicity.

CONCLUSION

For patients with SRSE insufficient, evidence exists that any of the ASMs reviewed, inhalational anesthetics, ketogenic diet, acute VNS, brain surgery, and therapeutic hypothermia are effective treatments. Data supporting the use of these treatments for SRSE are scarce and limited mainly to small case series and case reports and are confounded by differences in patients' population, and comedications, among other factors.

Perampanel in real-world clinical care of patients with epilepsy: Interim analysis of a phase IV study

Objective

To assess the retention rate, efficacy, safety, and dosing of perampanel administered to patients with epilepsy during routine clinical care in the retrospective phase IV, PROVE Study (NCT03208660).

Methods

Exposure, efficacy, and safety data were obtained from the medical records of patients initiating perampanel after January 1, 2014, across 29 US study sites. The cutoff date for this interim analysis was October 10, 2018. The primary efficacy endpoint was retention rate. Secondary efficacy endpoints included median percent changes in seizure frequency, seizure-freedom rate, and overall investigator impression of seizure effect.

Results

All enrolled patients (N = 1121) received perampanel. Mean (standard deviation [SD]) cumulative duration of exposure to perampanel was 16.6 (14.7) months; overall mean (SD) daily perampanel dose was 5.7 (2.7) mg. Perampanel uptitration occurred weekly (21.1%), biweekly (23.8%), every 3 weeks (1.5%), other (43.3%), and unknown (10.3%). Across the Safety Analysis Set (N = 1121), retention rate on perampanel at 24 months was 49.5% (n = 319/645).At 12 months, the median reduction in seizure frequency per 28 days from baseline in the small number of patients for whom data were available was 75.0% (n = 85), and 30/85 (35.3%) patients were seizure free. Based on investigator impression at the end of treatment, improvement, no change (ie, stable), or worsening of seizures was reported in 54.3%, 33.7%, and 12.0% of patients, respectively.Treatment-emergent adverse events occurred in 500 (44.6%) patients; the most common were dizziness (9.2%), aggression (5.4%), and irritability (4.5%). Serious treatment-emergent adverse events occurred in 32 (2.9%) patients.

Significance

Favorable retention and sustained efficacy were demonstrated for ≥12 months following initiation of perampanel during routine clinical care in patients with epilepsy.

A retrospective, observational study of perampanel in refractory and super-refractory status epilepticus

INTRODUCTION

The outcomes of administration of Perampanel (PER) which is a β-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propionic acid (AMPA) receptor antagonist for the treatment of refractory status epilepticus (RSE) and Super-refractory (SRSE) were previously reported in small cohort studies and case reports. We report efficacy and side effect results of an observational cohort of 75 patients treated with PER for RSE and SRSE.

METHODS

This was a single-center, retrospective, observational study of patients with RSE admitted to the neurocritical care unit between April 2017 and September 2019 who received treatment with PER. The primary outcome was the occurrence of a definite response to PER, which was defined as clear resolution of the ictal pattern and/or seizures within 72 h of delivery of PER which was the last administered antiseizure medication (ASM). Secondary outcomes included the percentage of patients other response types (partial responder or non-responder), as well as the rate of adverse effects.

RESULTS

A total 75 patients were included in our analysis. PER was initiated as the median sixth ASM at a median initial dose of 12 mg. For the primary outcome, 31 (41.3%; 95% confidence interval 31.0%-53.0%) patients were classified as a definite responder. Seven patients (9.3%) experienced an adverse effect that was attributed to PER, with the most common being sedation in four patients.

CONCLUSIONS

In our retrospective cohort of RSE, we observed a definite response rate of 41.3% within 72 h of PER initiation. PER was well tolerated with few documented adverse effects. Further prospective studies are needed to confirm the role of PER in treating patients with RSE.

Principles of Pharmacotherapy of Seizures and Status Epilepticus

Status epilepticus is a neurological emergency with an outcome that is highly associated with the initial pharmacotherapy management that must be administered in a timely fashion. Beyond first-line therapy of status epilepticus, treatment is not guided by robust evidence. Optimal pharmacotherapy selection for individual patients is essential in the management of seizures and status epilepticus with careful evaluation of pharmacokinetic and pharmacodynamic factors. With the addition of newer antiseizure agents to the market, understanding their role in the management of status epilepticus is critical. Etiology-guided therapy should be considered in certain patients with drug-induced seizures, alcohol withdrawal, or autoimmune encephalitis. Some patient populations warrant special consideration, such as pediatric, pregnant, elderly, and the critically ill. Seizure prophylaxis is indicated in select patients with acute neurological injury and should be limited to the acute postinjury period.

Therapeutic Options for Patients with Refractory Status Epilepticus in Palliative Settings or with a Limitation of Life-Sustaining Therapies: A Systematic Review

BACKGROUND

Refractory status epilepticus (RSE) represents a serious medical condition requiring early and targeted therapy. Given the increasing number of elderly or multimorbid patients with a limitation of life-sustaining therapy (LOT) or within a palliative care setting (PCS), guidelines-oriented therapy escalation options for RSE have to be omitted frequently.

OBJECTIVES

This systematic review sought to summarize the evidence for fourth-line antiseizure drugs (ASDs) and other minimally or non-invasive therapeutic options beyond guideline recommendations in patients with RSE to elaborate on possible treatment options for patients undergoing LOT or in a PCS.

METHODS

A systematic review of the literature in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, focusing on fourth-line ASDs or other minimally or non-invasive therapeutic options was performed in February and June 2020 using the MEDLINE, EMBASE and Cochrane databases. The search terminology was constructed using the name of the specific ASD or therapy option and the term 'status epilepticus' with the use of Boolean operators, e.g. "(brivaracetam) AND (status epilepticus)". The respective Medical Subject Headings (MeSH) and Emtree terms were used, if available.

RESULTS

There is currently no level 1, grade A evidence for the use of ASDs in RSE. The best evidence was found for the use of lacosamide and topiramate (level 3, grade C), followed by brivaracetam, perampanel (each level 4, grade D) and stiripentol, oxcarbazepine and zonisamide (each level 5, grade D). Regarding non-medicinal options, there is little evidence for the use of the ketogenic diet (level 4, grade D) and magnesium sulfate (level 5, grade D) in RSE. The broad use of immunomodulatory or immunosuppressive treatment options in the absence of a presumed autoimmune etiology cannot be recommended; however, if an autoimmune etiology is assumed, steroid pulse, intravenous immunoglobulins and plasma exchange/plasmapheresis should be considered (level 4, grade D). Even if several studies suggested that the use of neurosteroids (level 5, grade D) is beneficial in RSE, the current data situation indicates that there is formal evidence against it.

CONCLUSIONS

RSE in patients undergoing LOT or in a PCS represents a challenge for modern clinicians and epileptologists. The evidence for the use of ASDs in RSE beyond that in current guidelines is low, but several effective and well-tolerated options are available that should be considered in this patient population. More so than in any other population, advance care planning, advance directives, and medical ethical aspects have to be considered carefully before and during therapy.

Treatment of status epilepticus with zonisamide: A multicenter cohort study of 34 patients and review of literature

INTRODUCTION

We present a summary of clinical cases of oral zonisamide (ZNS) used to treat refractory and super-refractory episodes of status epilepticus (SE).

METHODS

Zonisamide administration in SE was identified in the clinical records of patients treated in Frankfurt and Marburg between 2011 and 2017.

RESULTS

Zonisamide was administered during a total of 37 SE episodes in 34 patients with a mean age of 58.7 ± 17.8 years, 21 of them were female (61.7%). The median latency from the onset of SE to administration of ZNS was 6.3 days. Patients had already undergone unsuccessful treatment with a median of three other antiseizure drugs (ASDs). The median initial dose of ZNS was 100 mg/d, titrated to a median maintenance dose of 400 mg/d. Patients underwent ZNS treatment for a median period of 7 days. Zonisamide was the final drug administered in 9 of 37 (24.3%) episodes, with a clinical effect attributed to ZNS observed in 6 of 37 (16.2%) episodes. An effect attributed to ZNS was observed in 5 out of 30 episodes of refractory SE (RSE) and in one out of 7 episodes of super-refractory SE (SRSE). Possible negative side effects of ZNS were observed in two patients (one patient each with ataxia and skin rash). The mortality rate in hospitalized patients was 10.4% (n = 4).

CONCLUSION

The rate of SE resolution attributed to ZNS treatment (16.2%) can be considered relevant, particularly since ZNS treatment tends to be administered only after several other options have been tried, and has a treatment latency of over six days. Zonisamide may therefore be considered as an alternative oral treatment option in RSE and SRSE.

Perampanel Treatment for Refractory Status Epilepticus in a Neurological Intensive Care Unit

BACKGROUND/OBJECTIVE

Perampanel is a novel anti-epileptic drug (AED) which acts as a non-competitive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist to reduce glutamate-mediated postsynaptic excitation. Previous animal studies and a few case reports/series have suggested that it may be effective to treat refractory status epilepticus (RSE).

METHODS

We retrospectively reviewed 67 consecutive patients with RSE, of whom 22 received perampanel. The clinical features, epidemiology-based mortality score in status epilepticus, status epilepticus severity score, seizure control, functional outcome, RSE etiology, and electroencephalogram findings were collected. Responder to perampanel was defined as seizure resolution within 4 days of therapy with perampanel being the last AED used plus no recurrence during hospitalization.

RESULTS

Eight of the 22 (36.4%) RSE patients fulfilled the definition of responder to perampanel. An additional 1 patient responded to perampanel after 4 days of treatment. In total, perampanel was the last AED in 9 (40.1%) patients. Among the 8 responders to perampanel, 5 had convulsive SE, 1 had non-convulsive SE, and 2 had focal motor SE. The responders accounted for both of the patients with focal motor SE (100%), 5 (33.3%) of the 15 patients with convulsive SE, and 1 (20%) of the 5 patients with non-convulsive SE. The ictal and inter-ictal activities also decreased after perampanel therapy, and three patients (13.6%) had preferable outcomes at last follow-up.

CONCLUSIONS

Perampanel may be an effective add-on treatment for RSE even in patients who failed multiple AEDs. Our study suggests that perampanel may be more effective for focal motor SE and convulsive SE than non-convulsive SE. As most previous studies have focused on non-convulsive SE, further studies are warranted to clarify the effectiveness of perampanel for different subtypes of SE.

Super-Refractory Status Epilepticus Treated with High Dose Perampanel: Case Series and Review of the Literature

Introduction

Acute symptomatic seizures are frequent in the critically ill patient and can be difficult to treat. The novel anticonvulsant perampanel may be effective in the treatment of status epilepticus considering its mechanism of action of being an AMPA antagonist. We present four cases of super refractory status epilepticus treated with high dose perampanel.

Method

Case report.

Cases

Four patients were treated with perampanel for their refractory status epilepticus. One patient had new onset refractory status epilepticus of unknown etiology. Three other patients had status epilepticus as a result of their cardiac arrest. Two of the cardiac arrest patients had myoclonus. In all patients, the additional of perampanel resulted in a reduction of seizure burden without affecting hemodynamics or hepatic or renal function.

Conclusion

Perampanel may be effective in the treatment of super-refractory status epilepticus of varying etiologies. A larger, prospective study is needed to further assess this therapy.

Antiseizure medications in critical care: an update

PURPOSE OF REVIEW

Seizures and status epilepticus are very common diagnoses in the critically ill patient and are associated with significant morbidity and mortality. There is an abundance of research on the utility of antiseizure medications in this setting, but limited randomized-controlled trials to guide the selection of medications in these patients. This review examines the current guidelines and treatment strategies for status epilepticus and provides an update on newer antiseizure medications in the critical care settings.

RECENT FINDINGS

Time is brain applies to status epilepticus, with delays in treatment corresponding with worsened outcomes. Establishing standardized treatment protocols within a health system, including prehospital treatment, may lead to improved outcomes. Once refractory status epilepticus is established, continuous deep sedation with intravenous anesthetic agents should be effective. In cases, which prove highly refractory, novel approaches should be considered, with recent data suggesting multiple recently approved antiseizure medications, appropriate therapeutic options, as well as novel approaches to upregulate extrasynaptic γ-aminobutyric acid channels with brexanolone.

SUMMARY

Although there are many new treatments to consider for seizures and status epilepticus in the critically ill patient, the most important predictor of outcome may be rapid diagnosis and treatment. There are multiple new and established medications that can be considered in the treatment of these patients once status epilepticus has become refractory, and a multidrug regimen will often be necessary.

Perampanel for treatment of status epilepticus in Austria, Finland, Germany, and Spain

OBJECTIVE

Novel treatments are needed to control treatment-resistant status epilepticus (SE). We report a summary of clinical cases where perampanel was used in established SE, refractory SE (RSE), or super-refractory SE (SRSE).

METHODS

Medical records were retrospectively reviewed for perampanel administration in SE at five European hospitals between 2011 and 2015.

RESULTS

Of 1319 patients identified as experiencing SE, 52 (3.9%) received perampanel. Median latency from SE onset to perampanel initiation was 10 days. Patients with SE had previously failed benzodiazepines (when received) and a median of five other antiepileptic drugs (AEDs). Median initial perampanel dose was 6 mg/d, up-titrated to a median maximum dose of 10 mg/d. Perampanel was the last drug added in 32/52 (61.5%) patients, with response attributed to perampanel in 19/52 (36.5%) patients. A greater proportion of perampanel non-responders had SRSE (51.5%; 17/33) vs perampanel responders (31.6%; 6/19), and had failed a higher mean number of AEDs before initiating perampanel (5.9 vs 5.1, respectively). Most commonly reported adverse effects during perampanel treatment were dizziness (n = 1 [1.9%]) and somnolence (n = 1 [1.9%]). No serious adverse effects were documented, and none led to discontinuation of perampanel.

CONCLUSIONS

Perampanel was administered to patients with established SE, RSE, or SRSE at greater initial doses than those administered in clinical practice to patients with epilepsy. The SE cases reported here represent a refractory and heterogeneous population, and rate of seizure cessation attributed to perampanel treatment (36.5%) represents a notable response. These data should be confirmed in a larger patient population.

Use of Newer Anticonvulsants for the Treatment of Status Epilepticus

Status epilepticus (SE) has a high mortality rate and is one of the most common neurologic emergencies. Fast progression of this neurologic emergency and lack of response to traditional antiepileptic drugs (AEDs) in most cases has challenged clinicians to use new agents. This article evaluates the efficacy and safety of AEDs released to the market after 2000 for SE, refractory status epilepticus (RSE), and super-refractory status epilepticus (SRSE). The PubMed database was searched for clinical trials published between January 2000 and July 2018 using the search terms status epilepticus, refractory status epilepticus, super refractory status epilepticus, brivaracetam, clobazam, cannabidiol, eslicarbazepine, lacosamide, perampanel, rufinamide, stiripentol, and zonisamide. Trials that evaluated these agents in adults with SE, RSE, and SRSE were included. Brivaracetam use was identified in two retrospective reviews with success rates of 27% and 57%. One unsuccessful case report of cannabidiol use in SE was found. Four clobazam studies were identified in SE and RSE with success rates ranging from 25-100%. No evidence for the use of eslicarbazepine and zonisamide was found. Using the search terms for lacosamide identified 38 articles: 1 systematic review, 5 prospective studies, 15 retrospective reviews, and 17 case reports. Success rates and dosing varied, but studies that included focal or partial types of SE showed higher success rates. Five articles were identified regarding perampanel use in this setting. Three were retrospective reviews with success rates ranging from 17-60%, and two were case reports. Only one case report regarding the use of rufinamide was found; rufinamide titrated up to 4.4 mg/day allowed discontinuation of barbiturate and clobazam. One case report and two case series of stiripentol were found with reported efficacy between 60% and 100% in SRSE. Evidence is currently insufficient to support the use of these agents in this setting.

Perampanel in the treatment of status epilepticus: A systematic review of the literature

OBJECTIVE

Perampanel (PER) is a noncompetitive β-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propionic acid (AMPA) receptor antagonist with demonstrated efficacy in animal models of status epilepticus (SE). We performed a systematic review of the literature to assess the efficacy and tolerability of PER in the treatment of refractory and super-refractory SE.

METHODS

We searched Medline, Embase, and CENTRAL (accessed from inception to April 30, 2018) to identify studies evaluating oral PER as treatment of SE of any type. We also searched the OpenGrey repository and conference proceedings of international congresses by the International League Against Epilepsy and by the American Epilepsy Society from 2012 onwards.

RESULTS

Ten articles were included, with a total of 69 episodes of SE occurring in 68 patients (aged 18 to 91 years). The type and etiology of SE varied remarkably across studies. The number of drugs used prior to PER ranged from 1 to 9. The time from SE onset to PER administration ranged from 9.25 h to 35 days. The initial PER dose ranged from 2 to 32 mg. The proportion of patients achieving clinical SE cessation varied from 17% to 100%. The time from PER administration to SE cessation ranged from 1 h to 4 weeks.

CONCLUSIONS

The currently available evidence supporting the use of PER in SE is weak and hampered by several confounding factors. Further studies should be performed in more clinically homogeneous and larger cohorts to evaluate the efficacy and safety of PER administered in earlier stages of SE, at higher dosages, and at intervals shorter than 24 h.