Lack of Clinically Relevant Differences in Safety and Pharmacokinetics After Second-Dose Administration of Intranasal Diazepam Within 4 Hours for Acute Treatment of Seizure Clusters: A Population Analysis

Benzodiazepines for the Treatment of Seizure Clusters

Patients with epilepsy may experience seizure clusters, which are described by the US Food and Drug Administration (FDA) as intermittent, stereotypic episodes of frequent seizure activity that are distinct from a patient's usual seizure pattern. Untreated seizure clusters may increase the risk for status epilepticus, as well as decrease quality of life and increase burden on patients and care partners. Benzodiazepine therapies are the mainstay for acute treatment of seizure clusters and are often administered by nonmedical care partners outside a healthcare facility. Three rescue therapies are currently FDA-approved for this indication, with diazepam rectal gel being the first in 1997, for patients aged ≥  2 years. Limitations of rectal administration (e.g., positioning and disrobing the patient, which may affect ease of use and social acceptability; interpatient variation in bioavailability) led to the investigation of the potential for nasal administration as an alternative. Midazolam nasal spray (MDS) was approved by the FDA in 2019 for patients aged ≥  12 years and diazepam nasal spray (DNS) in 2020 for patients aged ≥  6 years; these two intranasal therapies have differences in their formulations [e.g., organic solvents (MDS) vs. Intravail and vitamin E for absorption and solubility (DNS)], effectiveness (e.g., proportion of seizure clusters requiring only one dose), and safety profiles. In clinical studies, the proportion of seizure clusters for which only one dose of medication was used varied between the three approved rescue therapies with the highest single-dose rate for any time period for DNS; however, although studies for all three preparations enrolled patients with highly intractable epilepsy, inclusion and exclusion criteria varied, so the three cannot be directly compared. Treatments that have been used off-label for seizure clusters in the USA include midazolam for injection as an intranasal spray (indicated for sedation/anxiolysis/amnesia and anesthesia) and tablet forms of clonazepam (indicated for treatment for seizure disorders) and lorazepam (indicated for anxiety). In the European Union, buccal and intranasal midazolam are used for treating the indication of prolonged, acute convulsive seizures and rectal diazepam solution for the indication of epileptic and febrile convulsions; duration of effectiveness for these medications for the treatment of seizure clusters has not been established. This paper examines the literature context for understanding seizure clusters and their treatment and provides effectiveness, safety, and administration details for the three FDA-approved rescue therapies. Additionally, other medications that are used for rescue therapy in the USA and globally are discussed. Finally, the potential benefits of seizure action plans and candidates for their use are addressed. This paper is intended to provide details about the unique characteristics of rescue therapies for seizure clusters to help clarify appropriate treatment for individual patients.

Treatment of Seizure Clusters in Epilepsy: A Narrative Review on Rescue Therapies

Epilepsy is a common neurological disorder in the United States, affecting approximately 1.2% of the population. Some people with epilepsy may experience seizure clusters, which are acute repetitive seizures that differ from the person's usual seizure pattern. Seizure clusters are unpredictable, are emotionally burdensome to patients and caregivers (including care partners), and require prompt treatment to prevent progression to serious outcomes, including status epilepticus and associated morbidity (e.g., lacerations, fractures due to falls) and mortality. Rescue medications for community use can be administered to terminate a seizure cluster, and benzodiazepines are the cornerstone of rescue treatment. Despite the effectiveness of benzodiazepines and the importance of a rapid treatment approach, as many as 80% of adult patients do not use rescue medication to treat seizure clusters. This narrative review provides an update on rescue medications used for treatment of seizure clusters, with an emphasis on clinical development and study programs for diazepam rectal gel, midazolam nasal spray, and diazepam nasal spray. Results from long-term clinical trials have shown that treatments for seizure clusters are effective. Intranasal benzodiazepines provide ease of use and patient and caregiver satisfaction in pediatric and adult patients. Adverse events attributed to acute rescue treatments have been characterized as mild to moderate, and no reports of respiratory depression have been attributed to treatment in long-term safety studies. The implementation of an acute seizure action plan to facilitate optimal use of rescue medications provides an opportunity for improved management of seizure clusters, allowing those affected to resume normal daily activities more quickly.

Acute seizure therapies in people with epilepsy: Fact or fiction? A U.S. Perspective

Patients with epilepsy (PWE) may experience seizure emergencies including acute repetitive seizures despite chronic treatment with daily antiseizure medications. Seizures may adversely impact routine daily activities and/or healthcare utilization and may impair the quality of life of patients with epilepsy and their caregivers. Seizures often occur at home, school, or work in a community setting. Appropriate treatment that is readily accessible for patients with seizure urgencies and emergencies is essential outside the hospital setting. When determining the best acute antiseizure therapy for PWE, clinicians need to consider all of the available rescue medications and their routes of administration including the safety and efficacy profiles. Benzodiazepines are a standard of care as a rescue therapy, yet there are several misconceptions about their use and safety. Reevaluating potential misconceptions and formulating best practices are necessary to maximize usage for each available option of acute therapy. We examine common beliefs associated with traditional use of acute seizure therapies to refute or support them based on the current level of evidence in the published literature.

Acute Abortive Therapies for Seizure Clusters in Long-Term Care

OBJECTIVES

To describe acute seizure treatment for the long-term care setting, emphasizing rescue (acute abortive) medications for on-site management of acute unexpected seizures and seizure clusters.

DESIGN

Narrative review.

SETTING AND PARTICIPANTS

People with seizures in long-term care, including group residences.

METHODS

PubMed was searched using keywords that pertained to rescue medications, seizure emergencies/epilepsy, seizure action plans, and long-term care.

RESULTS

Seizure disorder, including epilepsy, is prevalent in long-term care residences, and rescue medications can be used for on-site treatment. Diazepam rectal gel, intranasal midazolam, and diazepam nasal spray are US Food and Drug Administration (FDA)-approved seizure-cluster rescue medications, and intravenous diazepam and lorazepam are approved for status epilepticus. Benzodiazepines differ by formulation, route of administration, absorption, and metabolism. Intranasal formulations are easy and ideal for public use and when rectal treatment is challenging (eg, wheelchair). Intranasal, intrabuccal, and rectal formulations do not require specialized training to administer and are easier for staff at all levels of training compared with intravenous treatment. Off-label rescue medications may have anecdotal support; however, potential disadvantages include variable absorption and onset of action as well as potential risks to patients and caregivers/care partners. Delivery of intravenous-administered rescue medications is delayed by the time needed to set up and deliver the medication and is subject to dosing errors. Seizure action plans that include management of acute seizures can optimize the quality and timing of treatment, which may reduce emergency service needs and prevent progression to status epilepticus.

CONCLUSIONS AND IMPLICATIONS

Seizure disorder is prevalent across all ages but is increased in older adults and in those with intellectual and developmental disabilities. Prompt intervention may reduce negative outcomes associated with acute unexpected seizures and seizure clusters. Seizure action plans that include acute seizures can improve the treatment response by detailing the necessary information for staff to provide immediate treatment.

Implications of Seizure-Cluster Treatment on Healthcare Utilization: Use of Approved Rescue Medications

PURPOSE

People with epilepsy may experience seizure clusters despite a stable regimen of antiseizure medications. Such clusters have the potential to last ≥24 hours, typically occur in the community setting, and may progress to medical emergencies, such as status epilepticus, if untreated. Thus, long-acting rescue therapy for seizure clusters is needed that can be administered by nonmedical individuals outside a hospital. Benzodiazepines are the foundation of rescue therapy for seizure clusters. The approved outpatient treatments (ie, diazepam, midazolam) have differing profiles that may affect multiple aspects of health-care utilization. The current labeling of these medications allows for a second dose if needed to control the cluster. Although no head-to-head studies directly comparing rescue treatments have been conducted, differences between studies with generally similar designs may provide context for the potential importance of second doses of rescue therapy on health-care utilization.

METHODS

For this analysis, large, long-term, open-label studies of approved seizure-cluster treatments designed for use by nonmedical caregivers were reviewed, and the percentage of seizure clusters for which a second dose was used or that were not controlled at 6, 12, and 24 hours was examined. Available data on hospitalizations were also collected.

RESULTS

The 3 identified studies meeting the inclusion criteria were for use of diazepam rectal gel, intranasal midazolam, and diazepam nasal spray. Across these studies, the use of a second dose ranged from <40% at 6 hours to <13% at 24 hours. Hospitalizations and serious treatment-emergent adverse events were reported variably across these studies.

CONCLUSION

These results demonstrate the importance of second doses of rescue therapy for seizure clusters for optimizing health-care utilization. Need for second doses should be included as one component. In turn, when second doses are needed, they have the potential to curtail emergency department use and hospitalization and to prevent further seizure clusters.