Use of intramuscular midazolam for status epilepticus

Midazolam - A diazepam replacement for the management of nerve agent-induced seizures

A benzodiazepine, diazepam, has been the leading antidote for seizures caused by nerve agents, the most toxic chemical weapons of mass destruction, since the 1960s. However, its limitations have often brought questions about its usefulness. Extensive effort has been devoted into exploring alternatives, such as other benzodiazepines, anticholinergics, or glutamate antagonists. However, only few showed clear clinical benefit. The only two options to ultimately reach clinical milestones are Avizafone, a water-soluble prodrug of diazepam adopted by the French and UK armed forces, and intramuscular midazolam, adopted by the US Army. The recently FDA-approved new intramuscular application of midazolam brought several advantages, such as rapid onset of action, short duration with predictable pharmacokinetics, increased water solubility for aqueous injectable solutions, and prolonged storage stability. Herein, we discuss the pitfalls and prospects of using midazolam as a substitute in anticonvulsant therapy with a particular focus on military purposes in combat casualty care. We have also considered and discussed several other alternatives that are currently at the experimental level. Recent studies have shown the superiority of midazolam over other benzodiazepines in the medical management of poisoned casualties. While its use in emergency care is straightforward, the proper dose for soldiers under battlefield conditions is questionable due to its sedative effects.

Challenges of status epilepticus management in a resource-limited setting: A review

Status epilepticus (SE) is a life-threatening neurological condition with significant mortality. Rapid management is essential to minimize the mortality and disability of SE. Two recent trials provided evidence to guide SE management in early and established stages. The Rapid Anticonvulsant Medication Prior To Arrival Trial (RAMPART, 2011) showed that intramuscular midazolam is a better alternative for early convulsive SE in prehospital settings. The Established Status Epilepticus Treatment Trial (ESETT, 2020) supported the use of sodium valproate and levetiracetam as second-line treatment for its efficacy and shorter administration time. However, there are challenges to revising the status epilepticus management in resource-limited settings, in pre-hospital, first- and second-line treatment, as well as management of refractory and super-refractory SE. These challenges included restrictions or lack of training in the administration of benzodiazepine in the prehospital setting, limited availability and accessibility of newer antiseizure medications (ASMs) in emergency departments and smaller hospitals, and low clinicians' awareness of the latest evidence. A collaborative effort to educate, improve awareness, and make certain ASMs more readily available is recommended to achieve a better clinical outcome in SE.

Transcranial Magnetic Stimulation for Reducing the Relative Reinforcing Value of Food in Adult Patients With Obesity Pursuing Metabolic and Bariatric Surgery: Protocol for a Pilot, Within-Participants, Sham-Controlled Trial

BACKGROUND

Metabolic and bariatric surgery (MBS) is the most effective and durable obesity treatment. However, there is heterogeneity in weight outcomes, which is partially attributed to variability in appetite and eating regulation. Patients with a strong desire to eat in response to the reward of palatable foods are more likely to overeat and experience suboptimal outcomes. This subgroup, classified as at risk, may benefit from repetitive transcranial magnetic stimulation (rTMS), a noninvasive brain stimulation technique that shows promise for reducing cravings and consumption of addictive drugs and food; no study has evaluated how rTMS affects the reinforcing value of food and brain reward processing in the context of MBS.

OBJECTIVE

The goal of the Transcranial Magnetic Stimulation to Reduce the Relative Reinforcing Value of Food (RESTRAIN) study is to perform an initial rTMS test on the relative reinforcing value (RRV) of food (the reinforcing value of palatable food compared with money) among adult patients who are pursuing MBS and report high food reinforcement. Using a within-participants sham-controlled crossover design, we will compare the active and sham rTMS conditions on pre- to posttest changes in the RRV of food (primary objective) and the neural modulation of reward, measured via electroencephalography (EEG; secondary objective). We hypothesize that participants will show larger decreases in food reinforcement and increases in brain reward processing after active versus sham rTMS.

METHODS

Participants (n=10) will attend 2 study sessions separated by a washout period. They will be randomized to active rTMS on 1 day and sham rTMS on the other day using a counterbalanced schedule. For both sessions, participants will arrive fasted in the morning and consume a standardized breakfast before being assessed on the RRV of food and reward tasks via EEG before and after rTMS of the left dorsolateral prefrontal cortex.

RESULTS

Recruitment and data collection began in December 2022. As of October 2023, overall, 52 patients have been screened; 36 (69%) screened eligible, and 17 (47%) were enrolled. Of these 17 patients, 3 (18%) were excluded before rTMS, 5 (29%) withdrew, 4 (24%) are in the process of completing the protocol, and 5 (29%) completed the protocol.

CONCLUSIONS

The RESTRAIN study is the first to test whether rTMS can target neural reward circuits to reduce behavioral (RRV) and neural (EEG) measures of food reward in patients who are pursuing MBS. If successful, the results would provide a rationale for a fully powered trial to examine whether rTMS-related changes in food reinforcement translate into healthier eating patterns and improved MBS outcomes. If the results do not support our hypotheses, we will continue this line of research to evaluate whether additional rTMS sessions and pulses as well as different stimulation locations produce clinically meaningful changes in food reinforcement.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05522803; https://clinicaltrials.gov/study/NCT05522803.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/50714.

Intramuscular Versus Intravenous Treatment of Status Epilepticus: A Systematic Review

Status epilepticus is a neurological emergency associated with high morbidity and mortality with fatal outcomes if not treated well. The goal of this study was to compare the intramuscular and intravenous treatment of individuals with status epilepticus. A search was performed on Scopus, PubMed, Embase, and Web of Science databases for articles published in the English language in peer-reviewed publications up to March 1, 2023. Studies were included if the treatment of status epileptics was compared either directly or indirectly between intramuscular and intravenous methods. In addition, relevant papers were manually screened for in the reference lists of the included studies. Non-duplicate articles were identified. Finally, five articles were included in the analysis, of which four were randomized controlled trials and one was a retrospective cohort study. The intramuscular midazolam group's time until the first seizure stopped was significantly shorter than the intravenous diazepam group's time (7.8 versus 11.2 minutes, respectively; p = 0.047). Moreover, the percentage of patients admitted was significantly lower in the intramuscular group than in the intravenous group (p = 0.01), but the lengths of stay in the intensive care unit and the hospital did not differ significantly between the groups. Regarding seizure recurrence, the intramuscular group had fewer incidences of recurrent seizures. Finally, there were no appreciable differences in safety outcomes between the two treatment arms. During the analysis, different outcomes reported after the use of intramuscular and intravenous treatments in managing patients with status epilepticus were categorized. This categorization led to a clear view of the efficacy and safety of intramuscular versus intravenous treatments in managing status epilepticus patients. The information at hand indicates that intramuscular therapy is just as successful as intravenous therapy in treating people with status epilepticus. The availability, adverse effect profile, logistics of administration, cost, and whether it is included in hospital formularies are some of the factors to be taken into consideration when choosing the drug administration technique.

Implications of obesity for drug administration and absorption from subcutaneous and intramuscular injections: A primer

DISCLAIMER

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

PURPOSE

To discuss the potential implications of obesity for drug administration and absorption from subcutaneous (SC) and intramuscular (IM) injection sites.

SUMMARY

The SC and IM routes are useful for the parenteral administration of medications to optimize pharmacokinetic properties such as time to onset and duration of effect, for cost considerations, or for ease of administration, such as when intravenous access is unavailable. The choice of SC or IM injection depends on the specific medication, with SC administration preferred for products such as insulin where a slower and more sustained response is desirable, while IM administration is usually preferred for products such as vaccines where more rapid absorption leads to a more rapid antibody response. Obesity has the potential to influence the rate and extent of absorption, as well as adverse effects, of medications administered by the SC or IM route through changes in SC tissue composition and depth or by inadvertent administration of IM medications into SC tissue because of improper needle length. Potential adverse effects associated with IM or SC injections in addition to pain, bruising, and hematoma formation include sciatic nerve injury, particularly with IM injection in the upper outer quadrant of the buttock; bone contusion or rarely osteonecrosis if the IM injection is excessively deep; and granulomas, fat necrosis, and calcification with SC injection.

CONCLUSION

Issues related to medication absorption in obese patients are likely to become more prominent in the future with increasing approvals of a wide range of biotherapeutic agents administered by SC injection. Studies should be directed toward these and other agents to assist with dosing decisions in this challenging population.

The Effectiveness of Intranasal Midazolam for the Treatment of Prehospital Pediatric Seizures: A Non-inferiority Study

Background: Intranasal (IN) midazolam allows for rapid, painless treatment of pediatric seizures in the prehospital setting and may be a preferred administration route if determined to be non-inferior to intravenous (IV) or intramuscular (IM) routes. We sought to evaluate the effectiveness of IN midazolam for terminating prehospital pediatric seizures compared to midazolam administered by alternate routes. Methods: We performed a retrospective, non-inferiority analysis using data from a regional Emergency Medical Services (EMS) database. We included pediatric patients ≤ 14 years treated with midazolam (0.1 mg/kg) by EMS for non-traumatic seizures. The primary outcome was the proportion of patients requiring redosing of midazolam after initial treatment with IN midazolam compared to those that received IV or IM midazolam. We established a priori a risk difference of 6.5% as the non-inferiority margin. Results: We evaluated outcomes from 2,034 patients (median age 6 years [interquartile range 3 - 10 years], 55% male). Initial administration routes were 461 (23%) IN, 547 (27%) IM, 1024 (50%) IV, and 2 (0.1%) intraosseous (IO). Midazolam redosing occurred in 116 patients (25%) who received IN midazolam versus 222 patients (14%) treated initially with midazolam via alternate routes (risk difference 11% [95%CI 7 - 15%]). The age-adjusted odds ratio for redosing midazolam after intranasal administration compared to alternate route administration was 2.0 (95% CI 1.6 - 2.6). Conclusion: Prehospital treatment of pediatric seizure with intranasal midazolam was associated with increased frequency of redosing compared to midazolam administered by other routes, suggesting that 0.1 mg/kg is a subtherapeutic dose for intranasal midazolam administration.

Treatment of acetylcholinesterase inhibitor-induced seizures with polytherapy targeting GABA and glutamate receptors

The initiation and maintenance of cholinergic-induced status epilepticus (SE) are associated with decreased synaptic gamma-aminobutyric acid A receptors (GABAAR) and increased N-methyl-d-aspartate receptors (NMDAR) and amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR). We hypothesized that trafficking of synaptic GABAAR and glutamate receptors is maladaptive and contributes to the pharmacoresistance to antiseizure drugs; targeting these components should ameliorate the pathophysiological consequences of refractory SE (RSE). We review studies of rodent models of cholinergic-induced SE, in which we used a benzodiazepine allosteric GABAAR modulator to correct loss of inhibition, concurrent with the NMDA antagonist ketamine to reduce excitation caused by increased synaptic localization of NMDAR and AMPAR, which are NMDAR-dependent. Models included lithium/pilocarpine-induced SE in rats and soman-induced SE in rats and in Es1-/- mice, which similar to humans lack plasma carboxylesterase, and may better model soman toxicity. These model human soman toxicity and are refractory to benzodiazepines administered at 40 min after seizure onset, when enough synaptic GABAAR may not be available to restore inhibition. Ketamine-midazolam combination reduces seizure severity, epileptogenesis, performance deficits and neuropathology following cholinergic-induced SE. Supplementing that treatment with valproate, which targets a non-benzodiazepine site, effectively terminates RSE, providing further benefit against cholinergic-induced SE. The therapeutic index of drug combinations is also reviewed and we show the improved efficacy of simultaneous administration of midazolam, ketamine and valproate compared to sequential drug administration. These data suggest that future clinical trials should treat both the lack of sufficient inhibition and the excess excitation that characterize RSE, and include early combination drug therapies. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.

Tailoring Midazolam-Loaded Chitosan Nanoparticulate Formulation for Enhanced Brain Delivery via Intranasal Route

In the present study, midazolam (MDZ)-loaded chitosan nanoparticle formulation was investigated for enhanced transport to the brain through the intranasal (IN) route. These days, IN MDZ is very much in demand for treating life-threatening seizure emergencies; therefore, its nanoparticle formulation was formulated in the present work because it could substantially improve its brain targeting via the IN route. MDZ-loaded chitosan nanoparticles (MDZ-CSNPs) were formulated and optimized by the ionic gelation method and then evaluated for particle size, particle size distribution (PDI), drug loading (DL), encapsulation efficiency (EE), and in vitro release as well as in vitro permeation. The concentration of MDZ in the brain after the intranasal administration of MDZ-CSNPs (C_max 423.41 ± 10.23 ng/mL, tmax 2 h, and area under the curve from 0 to 480 min (AUC_0-480) of 1920.87 ng.min/mL) was found to be comparatively higher to that achieved following intravenous (IV) administration of MDZ solution (C_max 245.44 ± 12.83 ng/mL, t_max 1 h, and AUC_0-480 1208.94 ng.min/mL) and IN administration of MDZ solution (C_max 211.67 ± 12.82, t_max 2 h, and AUC_0-480 1036.78 ng.min/mL). The brain–blood ratio of MDZ-CSNPs (IN) were significantly greater at all sampling time points when compared to that of MDZ solution (IV) and MDZ (IN), which indicate that direct nose-to-brain delivery by bypassing the blood–brain barrier demonstrates superiority in brain delivery. The drug-targeting efficiency (DTE%) as well as nose-to-brain direct transport percentage (DTP%) of MDZ-CSNPs (IN) was found to be comparatively higher than that for other formulations, suggesting better brain targeting potential. Thus, the obtained results demonstrated that IN MDZ-CSNP has come up as a promising approach, which exhibits tremendous potential to mark a new landscape for the treatment of status epilepticus.

Intramuscular Midazolam for treatment of Status Epilepticus

INTRODUCTION

Status epilepticus (SE) is a common neurological and medical emergency. It has high mortality and morbidity rates, which typically correlate with seizure semiology and duration; therefore, prompt and proper pharmacological intervention is paramount. In a pre-hospital setting, establishing venous access can be difficult, so other routes of drug administration should be considered.

AREAS COVERED

The paper summarizes the data from the literature and provides an evaluation of the efficacy and safety of intramuscular midazolam (IM MDZ) as it pertains to the management of acute seizures and SE.

EXPERT OPINION

The cascade of events involved in the genesis and sustenance of seizures, if not promptly stopped, lead to the perpetuation of the condition and may contribute to the refractoriness of pharmacological treatment. Hence, non-venous routes for drug administration were developed to allow untrained personnel to rapidly stop seizures. Among benzodiazepines (BDZs), IM MDZ is at least as effective and safe as other intravenously administered BDZs. Moreover, thanks to IM MDZ's favorable pharmacodynamic and pharmacokinetic profile, it is a promising alternative to other non-venous drugs such as intranasal-MDZ, buccal-MDZ, and rectal-diazepam in the pre-hospital management of SE cases with motor features.

Midazolam and isoflurane combination reduces late brain damage in the paraoxon-induced status epilepticus rat model

Organophosphates (OPs) are widely used as pesticides and have been employed as warfare agents. OPs inhibit acetylcholinesterase, leading to over-stimulation of cholinergic synapses and can cause status epilepticus (SE). OPs poisoning can result in irreversible brain damage and death. Despite termination of SE, recurrent seizures and abnormal brain activity remain common sequelae often associated with long-term neural damage and cognitive dysfunction. Therefore, early treatment for prevention of seizures is of high interest. Using a rat model of paraoxon poisoning, we tested the efficacy of different neuroprotective and anti-epileptic drugs (AEDs) in suppressing early seizures and preventing brain damage. Electrocorticographic recordings were performed prior, during and after injection of 4.5 LD₅₀ paraoxon, followed by injections of atropine and toxogonin (obidoxime) to prevent death. Thirty minutes later, rats were injected with midazolam alone or in combination with different AEDs (lorazepam, valproic acid, phenytoin) or neuroprotective drugs (losartan, isoflurane). Outcome measures included SE duration, early seizures frequency and epileptiform activity duration in the first 24 -hs after poisoning. To assess delayed brain damage, we performed T2-weighted magnetic resonance imaging one month after poisoning. SE duration and the number of recurrent seizures were not affected by the addition of any of the drugs tested. Delayed brain injury was most prominent in the septum, striatum, amygdala and piriform network. Only isoflurane anesthesia significantly reduced brain damage. We show that acute treatment with isoflurane, but not AEDs, reduces brain damage following SE. This may offer a new therapeutic approach for exposed individuals.

Midazolam: an essential palliative care drug

Midazolam is a commonly used benzodiazepine in palliative care and is considered one of the four essential drugs needed for the promotion of quality care in dying patients. Acting on the benzodiazepine receptor, it promotes the action of gamma-aminobutyric acid. Gamma-aminobutyric acid action promotes sedative, anxiolytic, and anticonvulsant properties. Midazolam has a faster onset and shorter duration of action than other benzodiazepines such as diazepam and lorazepam lending itself to greater flexibility in dosing than other benzodiazepines. The kidneys excrete midazolam and its active metabolite. Metabolism occurs in the liver by the P450 system. This article examines the pharmacology, pharmacodynamics, and clinical uses of midazolam in palliative care.

Prehospital Care for the Adult and Pediatric Seizure Patient: Current Evidence-based Recommendations

INTRODUCTION

We sought to develop evidence-based recommendations for the prehospital evaluation and treatment of adult and pediatric patients with a seizure and to compare these recommendations against the current protocol used by the 33 emergency medical services (EMS) agencies in California.

METHODS

We performed a review of the evidence in the prehospital treatment of patients with a seizure, and then compared the seizure protocols of each of the 33 EMS agencies for consistency with these recommendations. We analyzed the type and route of medication administered, number of additional rescue doses permitted, and requirements for glucose testing prior to medication. The treatment for eclampsia and seizures in pediatric patients were analyzed separately.

RESULTS

Protocols across EMS Agencies in California varied widely. We identified multiple drugs, dosages, routes of administration, re-dosing instructions, and requirement for blood glucose testing prior to medication delivery. Blood glucose testing prior to benzodiazepine administration is required by 61% (20/33) of agencies for adult patients and 76% (25/33) for pediatric patients. All agencies have protocols for giving intramuscular benzodiazepines and 76% (25/33) have protocols for intranasal benzodiazepines. Intramuscular midazolam dosages ranged from 2 to 10 mg per single adult dose, 2 to 8 mg per single pediatric dose, and 0.1 to 0.2 mg/kg as a weight-based dose. Intranasal midazolam dosages ranged from 2 to 10 mg per single adult or pediatric dose, and 0.1 to 0.2 mg/kg as a weight-based dose. Intravenous/intrasosseous midazolam dosages ranged from 1 to 6 mg per single adult dose, 1 to 5 mg per single pediatric dose, and 0.05 to 0.1 mg/kg as a weight-based dose. Eclampsia is specifically addressed by 85% (28/33) of agencies. Forty-two percent (14/33) have a protocol for administering magnesium sulfate, with intravenous dosages ranging from 2 to 6 mg, and 58% (19/33) allow benzodiazepines to be administered.

CONCLUSION

Protocols for a patient with a seizure, including eclampsia and febrile seizures, vary widely across California. These recommendations for the prehospital diagnosis and treatment of seizures may be useful for EMS medical directors tasked with creating and revising these protocols.

Status Epilepticus: What's New?

The emergent evaluation and treatment of generalized convulsive status epilepticus presents challenges for emergency physicians. This disease is one of the few in which minutes can mean the difference between life and significant morbidity and mortality. It is imperative to use parallel processing and have multiple treatment options planned in advance, in case the current treatment is not successful. There is also benefit to exploring, or initiating, treatment algorithms to standardize the care for these critically ill patients.

Pharmacotherapy Overview of Seizure Management in the Adult Emergency Department

Seizures are a common cause of emergency department visits, and approximately 28% of epilepsy patients present to an emergency department annually for treatment. This article will provide an overview of the pharmacotherapeutic management of seizures and anticonvulsant therapy for patients who present to the adult emergency department, including practical information for pharmacists covering or cross-covering this practice area. The benzodiazepines are reviewed as a class, including dosing strategies, pharmacodynamic considerations, and advantages and disadvantages of lorazepam, diazepam, and midazolam. Indications for the use of phenytoin and fosphenytoin will be reviewed, as well as dosing, adverse effects, and cost-effectiveness data. In addition, dosing, administration, pharmacokinetics, and adverse effects of phenobarbital, carbamazepine, and valproate will be discussed. Clinical indications for serum anticonvulsant concentration monitoring and subsequent calculation of loading doses from serum concentrations are reviewed. Since status epilepticus is a life-threatening emergency, its therapeutic management is reviewed, including the use of continuous infusion midazolam, pentobarbital, and propofol. There are many opportunities for clinical pharmacists to collaborate with other members of the health care team to optimize efficacy and minimize adverse effects of anticonvulsant agents in the emergency department setting.

Comparison of short-term effects of midazolam and lorazepam in the intra-amygdala kainic acid model of status epilepticus in mice

Benzodiazepines remain as the first-line treatment for status epilepticus (SE), but debate continues as to the choice and delivery route of pharmacotherapy. Lorazepam is currently the preferred anticonvulsant for clinical use, but midazolam has become a popular alternative, particularly as it can be given by nonintravenous routes. Anticonvulsants are also commonly used to terminate SE in animal models. Here, we aimed to compare the efficacy of midazolam with that of lorazepam in an experimental model of focal-onset SE. Status epilepticus was induced by intra-amygdala microinjection of kainic acid in 8week old C57Bl/6 mice. Forty minutes later, mice were treated with an intraperitoneal injection of either lorazepam or midazolam (8mg/kg). Electroencephalogram (EEG) activity, histology, and behavioral tests assessing recovery of function were evaluated and compared between groups. Intraperitoneal injection of either lorazepam or midazolam resulted in similar patterns of reduced EEG epileptiform activity during 1-hour recordings. Damage to the hippocampus and presentation of postinsult anxiety-related behavior did not significantly differ between treatment groups at 72h. However, return of normal behaviors such as grooming, levels of activity, and the evaluation of overall recovery of SE mice were all superior at 24h in animals given midazolam compared with lorazepam. Our results indicate that midazolam is as effective as lorazepam as an anticonvulsant in this model while also providing improved animal recovery after SE. These data suggest that midazolam might be considered by researchers as an anticonvulsant in animal models of SE, particularly as it appears to satisfy the requirements of refining procedures involving experimental animals at early time-points after SE.

Efficacy and safety of intramuscular midazolam versus rectal diazepam in controlling status epilepticus in children

OBJECTIVE

The aim of this study was to evaluate the efficacy and safety of intramuscular midazolam in controlling convulsive status epilepticus in children, by comparing it with rectal diazepam.

METHODS

In this randomized trial, 100 children (50 in each group) with convulsive status epilepticus aged 1 month to 16 years were enrolled and randomly assigned into two groups to receive either 0.3 mg/kg intramuscular midazolam or 0.5 mg/kg rectal diazepam. Main outcome measure was stopping of all motor activity after drug administration. Another measures were times between patient's arrival to emergency department till drug administration, between drug administration to seizure cessation, and between patient's arrival to seizure cessation.

RESULTS

Both medication were effective for seizure control and no significant difference was found between successful treatments after administering the medication (P = 0.061). In the midazolam group, in 96% (48/50) of cases treatment was successful and in the diazepam group, in 94% (47/50) of cases treatment was successful. Time from arrival to administering the medication was significantly shorter in midazolam group (P = 0.017). The majority of seizures in midazolam group were stopped in less than 66 s (median) compared to 130 s (median) for diazepam group, (P < 0.001). No serious adverse effects were seen in both groups.

CONCLUSION

IM midazolam is not superior but may be at least as effective as rectal diazepam for controlling of status epilepticus in children. Midazolam via IM route could be one of the choices in children with convulsive status seizures who have difficult IV access.

Intramuscular midazolam versus intravenous lorazepam for the prehospital treatment of status epilepticus in the pediatric population

OBJECTIVE

To examine the effectiveness of intramuscular (IM) midazolam versus intravenous (IV) lorazepam for the treatment of pediatric patients with status epilepticus (SE) in the prehospital care setting.

METHODS

This multicenter clinical trial randomized patients diagnosed with SE to receive either IM midazolam or IV lorazepam administered by paramedics in the prehospital care setting. Included in this secondary analysis were only patients younger than 18 years of age. Evaluated were the associations of the treatment group (IM vs. IV) with the primary outcome, defined as seizure cessation prior to emergency department (ED) arrival, and with patient characteristics, time to important events, and adverse events. Descriptive statistics and 99% confidence intervals (CIs) were used for the analysis.

RESULTS

Of 893 primary study subjects, 120 met criteria for this study (60 in each treatment group). There were no differences in important baseline characteristics or seizure etiologies between groups. The primary outcome was met in 41 (68.3%) and 43 (71.7%) of subjects in the IM and IV groups, respectively (risk difference [RD] -3.3%, 99% CI -24.9% to 18.2%). Similar results were noted for those younger than 11 years (RD -1.3%, 99% CI -25.7% to 23.1%). Time from initiating the treatment protocol was shorter for children who received IM midazolam, mainly due to the shorter time to administer the active treatment. Safety profiles were similar.

SIGNIFICANCE

IM midazolam can be rapidly administered and appears to be safe and effective for the management of children with SE treated in the prehospital setting. The results must be interpreted in the context of the secondary analysis design and sample size of the study.

Comparative pharmacokinetics and bioavailability of intranasal and rectal midazolam formulations relative to buccal administration in rabbits

The rectal and intranasal formulations under current development demonstrated comparative potential for administering midazolam in treating seizures in a medical emergency service.

Intramuscular midazolam versus intravenous diazepam for treatment of seizures in the pediatric emergency department: a randomized clinical trial

AIM

To compare the therapeutic efficacy of intramuscular midazolam (MDZ-IM) with that of intravenous diazepam (DZP-IV) for seizures in children.

DESIGN

Randomized clinical trial.

SETTING

Pediatric emergency department.

PATIENTS

Children aged 2 months to 14 years admitted to the study facility with seizures.

INTERVENTION

Patients were randomized to receive DZP-IV or MDZ-IM.

MAIN MEASUREMENTS

Groups were compared with respect to time to treatment start (min), time from drug administration to seizure cessation (min), time to seizure cessation (min), and rate of treatment failure. Treatment was considered successful when seizure cessation was achieved within 5min of drug administration.

RESULTS

Overall, 32 children (16 per group) completed the study. Intravenous access could not be obtained within 5min in four patients (25%) in the DZP-IV group. Time from admission to active treatment and time to seizure cessation was shorter in the MDZ-IM group (2.8 versus 7.4min; p<0.001 and 7.3 versus 10.6min; p=0.006, respectively). In two children per group (12.5%), seizures continued after 10min of treatment, and additional medications were required. There were no between-group differences in physiological parameters or adverse events (p=0.171); one child (6.3%) developed hypotension in the MDZ-IM group and five (31%) developed hyperactivity or vomiting in the DZP-IV group.

CONCLUSION

Given its efficacy and ease and speed of administration, intramuscular midazolam is an excellent option for treatment of childhood seizures, enabling earlier treatment and shortening overall seizure duration. There were no differences in complications when applying MDZ-IM or DZP-IV.

Bioavailability of a novel midazolam gel after intranasal administration in dogs

OBJECTIVE

To compare the pharmacokinetics of a novel bioadhesive gel formulation of midazolam after intranasal (IN) administration with that of midazolam solution after IN, IV, and rectal administration to dogs.

ANIMALS

10 (5 males and 5 females) healthy adult Beagles.

PROCEDURES

Dogs were assigned to 4 treatment groups for a crossover study design. Initially, midazolam solution (5 mg/mL) was administered (0.2 mg/kg) IV to group 1, rectally to group 2, and IN to group 3; a 0.4% hydroxypropyl methylcellulose midazolam gel formulation (50 mg/mL) was administered (0.2 mg/kg, IN) to group 4. Each dog received all 4 treatments; there was a 7-day washout period between subsequent treatments. Blood samples were collected before and after midazolam administration. Plasma concentration of midazolam was determined by use of high-performance liquid chromatography.

RESULTS

The peak plasma concentration after IN administration of the gel formulation was significantly higher than that after IN and rectal administration of the solution. Mean ± SD time to peak concentration was 11.70 ± 2.63 minutes (gel IN), 17.50 ± 2.64 minutes (solution IN), and 39 ± 14.49 minutes (solution rectally). Mean bioavailability of midazolam was 70.4% (gel IN), 52.0% (solution IN), and 49.0% (solution rectally). Bioavailability after IN administration of the gel formulation was significantly higher than that after IN and rectal administration of the solution.

CONCLUSIONS AND CLINICAL RELEVANCE

IN administration of midazolam gel was superior to both IN and rectal administration of midazolam solution with respect to peak plasma concentration and bioavailability.

Anaesthesia and epilepsy

Epilepsy is the most common serious neurological disorder, with a prevalence of 0.5-1% of the population. While the traditional antiepileptic drugs (AEDs) still play a significant role in treatment of seizures, there has been an influx of newer agents over the last 20 yr, which are now in common usage. Anaesthetists are frequently faced with patients with epilepsy undergoing emergency or elective surgery and patients suffering seizures and status epilepticus in the intensive care unit (ICU). This review examines perioperative epilepsy management, the mode of action of AEDs and their interaction with anaesthetic agents, potential adverse effects of anaesthetic agents, and the acute management of seizures and refractory status epilepticus on the ICU. Relevant literature was identified by a Pubmed search of epilepsy and status epilepticus in conjunction with individual anaesthetic agents.

Pharmacological management of seizures and status epilepticus in critically ill patients

Seizures are serious complications seen in critically ill patients and can lead to significant morbidity and mortality if the cause is not identified and treated quickly. Uncontrolled seizures can lead to status epilepticus (SE), which is considered a medical emergency. The first-line treatment of seizures is an intravenous (IV) benzodiazepine followed by anticonvulsant therapy. Refractory SE can evolve into a nonconvulsive state requiring IV anesthetics or induction of pharmacological coma. To prevent seizures and further complications in critically ill patients with acute neurological disease or injury, short-term seizure prophylaxis should be considered in certain patients.

A pharmacokinetic and pharmacodynamic study, in healthy volunteers, of a rapidly absorbed intranasal midazolam formulation

PURPOSE

To compare 2.5 mg and 5.0 mg single-dose pharmacokinetics (PK), pharmacodynamics (PD) and tolerability of an intranasal (i.n.) midazolam formulation, to a 2.5-mg intravenous (i.v.) dose.

METHODS

Design was an open-label, three-way crossover, randomized PK and PD study in seventeen healthy volunteers. Twelve-hour PK parameters were determined for each treatment arm. Subjects completed serial self-ratings for sedation and other drug effects. Nurse observers made serial observations for sedation and adverse effects. An otolaryngologist conducted a nasal endoscopy, pre-dose, 2-4 h, and at end of study, to examine the nasal cavity for formulation-induced changes in nasal anatomy.

RESULTS

Midazolam was rapidly absorbed following i.n. administration, with a median t(max) of 10 min; dose proportionate increases for C(max) and AUC; t(1/2) of 4 h; and, 60% (+/-23) nasal administration bioavailability compared to the i.v. dose. PD responses were rapid, paralleled the PK, and in magnitude was in a rank order of i.v. 2.5 mg > or = i.n. 5.0 mg > i.n. 2.5 mg doses. The formulation was well tolerated with no serious cardiovascular or respiratory complications. Fourteen subjects complained of at least one of the following: a brief and mild to moderate intensity facial flushing, nasal passage burning, sore throat or bad taste after drug administration. There were no adverse findings from the nasal endoscopic exam.

CONCLUSION

Dosages of an investigational i.n. midazolam formulation resulted in rapid absorption and attained plasma concentrations that correlated with pharmacodynamic effects.

Status epilepticus in a hospice inpatient setting

Although evidence-based guidelines on the management of status epilepticus in the general population are available, these cannot be readily applied to hospice inpatients. The treatment of status epilepticus in a hospice setting presents many challenges in terms of choice and availability of drugs, route of administration and availability of monitoring facilities. A case report is presented that illustrates the distinct challenges involved in the management of status epilepticus in this setting. Commonly used antiseizure medications are discussed, with emphasis on the potential benefits and drawbacks in a hospice population.

An alternative perspective on the management of status epilepticus

The definition of status epilepticus (SE) has been reduced from 30 minutes to 5 minutes and this article questions if treatment should not be offered before reaching that window. After provision of first aid, benzodiazepines (BDZ) are the initial form of intervention, with either nasal or buccal midazolam being favored for nonprofessionals. Proper patient supervision, including admission to an intensive care unit for more difficult patients, is endorsed, and the need to warn nonprofessionals of the potential risk of respiratory depression is imperative. The article criticizes the use of phenytoin as the antiepileptic medication (AEM) with which to load patients, as it is no longer a first-line AEM, and argues in favor of using a first-line AEM such as valproate or carbamazepine, or preferably the AEM that previously proved efficacious in a patient with known epilepsy who was noncompliant. Alternative routes of administration of AEMs are discussed, and the use of blood level monitoring, as an adjunct to management, to protect against further episodes of SE, is supported. Touched on in this article are the use of some of the newer AEMs in the management of SE and exploration of treatment strategies that acknowledge that treatment must also include patient education that incorporates techniques to enhance compliance.

Status epilepticus: evidence and controversy

Status Epilepticus (SE) is a potential and relatively common complication of epileptic seizures. Traditionally, SE was defined as 30 minutes of continuous seizure activity or a series of seizures without return to full consciousness between the seizures. As a practical rule, it is admitted that all patients arriving at the emergency room suffering from epileptic seizures could have SE and should be treated accordingly. It is well known that the longer an attack has lasted, the more difficult it is to control in the next 5 to 10 minutes. On the other hand, once an attack has lasted for over 5 to 10 minutes, it is unlikely to cease spontaneously. Ambulatory intervention should focus on this "therapeutic interval" in acute attacks with the use of first-line drugs such as the intramuscular, rectal, oral, and/or intranasal application of benzodiazepines (BZD). Treatment of SE is a medical emergency, which should include 3 priority objectives: (1) to stop the seizures; (2) to maintain internal homeostasis; and (3) to treat possible complications. Current consensus is that a BZD, notably lorazepam or diazepam, is the initial class of drug for the treatment of SE. Phenytoin, fosphenytoin, or valproate generally is agreed upon as the next drugs to be administered. Failure to respond to optimal BZD and phenytoin loading operationally defines refractory SE.

Treatment of convulsive status epilepticus in infants and young children in Japan

We review the types and causes of convulsive status epilepticus (CSE) in infants and young children in Japan, and discuss the current recommendations for the use of intravenous (IV) drugs in managing this condition, and report on our clinical experiences. There are prolonged or continuous CSE and clustered or intermittent CSE, and treatments are different between them. In Japan, fosphenytoin and IV preparation of lorazepam and phenobarbital are not available. Recently, midazolam and lidocaine (LDC) have been widely used, although neither of these drugs have official approval for the management of CSE. Febrile seizures and epilepsies are common causes of CSE in infants and young children in Japan, followed by benign infantile convulsions (BIC), convulsions with gastroenteritis (CwG), and acute encephalitis with refractory CSE and intractable epilepsy (AECSEE), which are familiar disorders in Japan. BIC and CwG frequently present with clustered CSE and do not respond to IV diazepam, but have an excellent response with oral carbamazepine or IV LDC. CSE in AECSEE requires control with barbiturate coma. The Research Committee on Clinical Evidence of Medical Treatment for Status Epilepticus in Childhood has developed a proposed guideline for the treatment of CSE in childhood in Japan by an evidence-based approach and consensus conference. Initial management of seizures should be attempted mainly with IV diazepam, the second-line treatment involves IV midazolam followed by IV phenytoin if seizures persist, and the third-line treatment requires barbiturate coma. However, our experience of 247 episodes of CSE in 77 patients, predominantly with chronic epilepsy, required different second-line treatments for prolonged CSE compared with clustered CSE: the former were treated with IV midazolam or pentobarbital, and the latter were given IV phenytoin or LDC. We propose modifications to the guideline for CSE that the second-line treatment is divided by prolonged CSE and clustered CSE, and that the procedures for brain protection and systemic management are added.

Generalised convulsive status epilepticus: an overview

Generalised convulsive status epilepticus is one of the most common emergencies encountered in clinical practice. This review discusses the recent understanding of this life-threatening condition with reference to the definition, pathophysiology, evaluation, complications, refractory status and prognosis. Besides epilepsy, other neurological and medical illnesses could be associated with status epilepticus. The goals of management and pharmacological approach are outlined, considering the available evidence. Prompt recognition and timely intervention, including pre-hospital treatment, are therapeutically beneficial. Refractory status should be managed in intensive care units under close monitoring. More evidence is needed for evolving the optimal treatment. A suitable treatment protocol would guide in avoiding the pitfalls at various points along the management pathway.

Management of Seizures in the Critically Ill

Seizures in a critically ill patient are not infrequent phenomena. Physicians are perplexed by the wide range of possible cranial or extracranial etiologies, alerted by the risk for further crucial organ compromise if seizures recur, and confused about the treatment options in an environment rich in complex drug interactions and multiple organ dysfunction. The advent of an armamentarium containing multiple new antiepileptic medications complicates the situation further, since several of them have less known mechanisms of action, side effects, or interactions with other intensive care unit (ICU) medications. This review contains useful information regarding the most common etiologies and treatment options for intensivists, consulting neurologists, neurosurgeons, or other specialized physicians treating ICU patients with seizures.

Treatment of convulsive and nonconvulsive status epilepticus

Status epilepticus (SE) should be treated as quickly as possible with full doses of medications as detailed in a written hospital protocol. Lorazepam is the drug of choice for initial treatment. If intravenous access is not immediately available, then rectal diazepam or nasal or buccal midazolam should be given. Prehospital treatment of seizures by emergency personnel is effective and safe, and may prevent cases of refractory SE. Home treatment of prolonged seizures or clusters with buccal, nasal, or rectal benzodiazepines should be considered for all at-risk patients. Nonconvulsive SE is underdiagnosed. An electroencephalogram should be obtained immediately in anyone with unexplained alteration of behavior or mental status and after convulsive SE if the patient does not rapidly awaken. Delay in diagnosis of SE is associated with a worse outcome and a higher likelihood of poor response to treatment. For refractory SE, continuous intravenous midazolam and propofol (alone or in combination) are rapidly effective. Randomized trials are needed to determine the best treatment for SE after lorazepam.

Pharmacokinetic studies of intramuscular midazolam in guinea pigs challenged with soman

Studies have demonstrated that benzodiazepine compounds are effective at antagonizing seizure activity produced by the organophosphate (OP) cholinesterase inhibitor soman. In this present study we have investigated the pharmacokinetics of midazolam and its associated effects on electroencephalographic (EEG) activity following intramuscular (i.m.) injection to soman-exposed guinea pigs (Crl:(HA)BR). Prior to experiments, the animals were surgically implanted with EEG leads to monitor seizure activity. For the study, animals were administered the following pretreatment/OP/treatment regimen. Pyridostigmine bromide (0.026 mg/kg, i.m.) was given 30 min prior to soman (56 micrograms/kg, 2 x LD50; subcutaneously, s.c.), followed in one minute by atropine sulfate (2 mg/kg, i.m.) and pralidoxime chloride (25 mg/kg, i.m.). All animals receiving this regimen developed seizure activity. Midazolam 0.8 mg/kg, i.m., was administered 5 min after onset of seizure activity. Based on EEG data, animals were categorized as either seizure-terminated or seizure not-terminated at 30 min following anticonvulsant administration. Serial blood samples were collected for the plasma midazolam analysis; the assay was accomplished with a gas chromatograph/mass spectrometer. The mean time to seizure termination was 8.8 +/- 1.6 min. The mean time-plasma concentration data were fit to standard pharmacokinetic models. The following parameter estimates were determined from the model-fit for seizure terminated and not-terminated animals respectively: apparent volumes of distribution (Vd) were 1.4 and 1.7 l/kg; area under the time-concentration curves (AUC), 15,990 and 15,120 ng.min/ml; times to maximal plasma concentration (Tmax), 1.66 and 2.91 min and maximal plasma concentrations (Cmax) 535.1 and 436.6 ng/ml. These data indicate that i.m. injection of midazolam is effective at terminating ongoing soman-induced seizure activity. Additionally, the relatively short Tmax and latency to seizure termination demonstrate the rapidity of drug absorption and action respectively.

Management of seizures in critically ill patients

For many neurologists, seizures in critically ill patients represent a difficult problem. Etiology can be elusive because of the complexity of the environment, and treatment decisions can be compromised by the paucity of evidence-based guidelines. Emerging data support a higher than previously thought incidence of nonconvulsive epileptic activity in this patient population, which is another important consideration. Although a seizure in the intensive care unit should be treated aggressively, prophylactic antiepileptic drug administration is dependent on the specific etiology, time of onset, and ensuing complications. After ischemic stroke, prophylactic treatment is not generally recommended, and after intracerebral hemorrhage treatment is recommended only after a few weeks. After subarachnoid hemorrhage, prophylactic treatment beyond discharge is also not recommended. Although there is no reason to believe that late seizures after severe head trauma cannot be prevented with prophylactic treatment, such an approach may be useful during the first week after the injury. Physicians, however, have to individualize the treatment to the critical patient after stroke or trauma based on the presence of additional factors that increase the risk for seizures, including structural cortical injuries and medications used in critical illness with epileptogenic potential. A general therapeutic scheme for seizures in the intensive care unit and the role newer antiepileptic drugs can play are also presented in this review.

New management strategies in the treatment of status epilepticus

Status epilepticus is a neurologic emergency associated with high mortality and long-term disability. Recent advances in our understanding of the pathophysiological mechanisms involved in the initiation and perpetuation of seizure activity have revealed that status epilepticus is a dynamic and evolving process. Alterations at the cellular level parallel physiological, physical, and electrical changes at the bedside. Loss of cerebral autoregulation and neuronal damage begin after 30 minutes of continuous seizure activity. This understanding has led to changes in treatments of status epilepticus, which must be multidisciplinary and occur simultaneously in many different areas. The goals of pharmacological therapy are to terminate seizures early and prevent recurrence. Two recent large clinical studies have shown the benefit of early administration of benzodiazepines to control status epilepticus. Pharmacological algorithms designed to focus medical management have trended toward earlier and more aggressive treatment. The hope is that continued exploration into the basic mechanisms involved in status epilepticus and future controlled clinical trials defining optimal medical management will produce further advances.

Controlling seizures in the prehospital setting: diazepam or midazolam?

OBJECTIVE

To determine which is the most effective and safe treatment for controlling seizures in children out-of-hospital: diazepam or midazolam.

METHODS

A retrospective review of the medical records of children presenting to the Emergency Department of the Children's Hospital at Westmead (CHW-ED) with seizures requiring treatment in the field by paramedics was carried out over a 4-year period (April 1996 to March 2000). In New South Wales, children with seizures in the prehospital setting received 0.5 mg/kg per rectum (p.r.) or 0.1 mg/kg i.v. diazepam until March 1998 and from March 1997 onwards they received 0.15 mg/kg i.m. or 0.1 mg/kg i.v. midazolam. The main outcome measured was cessation of seizure in the prehospital setting. Secondary outcomes were time taken to initiate treatment and the frequency of cardiorespiratory compromise.

RESULTS

Over the 4-year period, 2566 children presented to CHW-ED with a seizure; 107 children were eligible for entry into the present study. Of these 107 patients, 62 received diazepam and 45 received midazolam. Thirty-one (50.0%) in the diazepam group and 15 (33.3%) in the midazolam group were febrile seizures. Both groups were similar in terms of demographics and seizure type. A comparison of diazepam with midazolam showed that both drugs were effective in stopping seizures within 5 min of drug administration (37.1% cf. 51.1%). Fewer patients in the midazolam group suffered apnoea (20.0% cf. 29.0%; P < 0.05).

CONCLUSION

Midazolam controls seizures as effectively as diazepam in the prehospital setting. Furthermore, midazolam potentially reduces respiratory depression and time to treatment.

Progress in clinical neurosciences: Status epilepticus: a critical review of management options

Although generalized tonic-clonic status epilepticus (SE) is frequently seen, an evidence-based approach to management is limited by a lack of randomized clinical studies. Clinical practice, therefore, relies on a combination of expert recommendations, local hospital guidelines and dogma based on individual preference and past successes. This review explores selected and controversial aspects of SE in adults and provides a critical appraisal of currently recommended management strategies.

The current state of treatment of status epilepticus

There have been many important developments in the diagnosis and treatment of status epilepticus in the recent past. Earlier treatment, including at home by caregivers and in the field by paramedics, has been shown to be safe and effective. Rapid-acting anesthetic agents, such as midazolam and propofol, are being used more often for refractory status epilepticus, though clinical trials are lacking. Nonconvulsive status epilepticus is being considered and recognized more often, including in ambulatory patients with a confusional state, after convulsive status epilepticus, and in critically ill patients. Modern technology and continuous digital electroencephalogram (EEG) recordings have taught us many things, but have raised at least as many questions. Much work needs to be done regarding the significance of certain EEG patterns (particularly periodic discharges) and when and how to treat them. This article reviews these issues, concentrating on recent advances and practical issues related to the clinical care of patients with status epilepticus.

Status Epilepticus

Status epilepticus (SE) is a common neurologic emergency with a high mortality. Immediate recognition and rapid treatment are essential. After initial stabilization of airway and circulation, the patient should be treated as soon as possible with an intravenous (IV) benzodiazepine, followed immediately by IV fosphenytoin. If SE persists, general anesthesia should be initiated, with intubation and cardiac monitoring. Electroencephalogram must also be monitored to ensure suppression of all seizures. Etiology of SE should be assessed through history, examination, blood tests, and brain imaging.

The etiology and diagnosis of status epilepticus

Status epilepticus (SE) is a common, serious, potentially life-threatening, neurologic emergency characterized by prolonged seizure activity. Generalized convulsive status epilepticus (GCSE) is the most widely recognized form of SE. Direct consequences of convulsive movements from SE can result in injury to the body and brain. Nonconvulsive status epilepticus (NCSE) is underrecognized, with controversy surrounding the consequences and treatment. High mortality rates with GCSE have been noted in the past. New treatments for SE are emerging with new parenteral drug formulations as well as new agents for refractory SE, offering an opportunity to improve outcome. Special drug delivery systems, drug combinations, and neuroprotective agents that prevent the subsequent development of epilepsy may soon emerge as future options for treating SE.

Treatment of status epilepticus

The approach to treatment of status epilepticus has changed because of the demonstration of decreased mortality with rapid intervention, completion of a randomized, double-blind VA Cooperative study comparing first-line agents, and further understanding of the pathophysiologic changes discovered in experimental animal studies. This article reviews the treatments of generalized convulsive status epilepticus in the prehospital, emergency department, and intensive care unit settings.

[Epileptogenic drugs in anesthesia]

Most anaesthetics and analgesics have both pro- and anticonvulsant activity. The data in the literature should be analysed with respect to the patient population, the recording of epileptic activity and the method of EEG analysis. Among inhaled anaesthetics, isoflurane has strong anticonvulsant properties. In some circumstances, sevoflurane may induce an epileptic activity. With the exception of ketamine and etomidate, all intravenous hypnotics may be used for anesthesia of the epileptic patient. Midazolam is a potent anticonvulsant. Among narcotics, fentanyl and alfentanil may induce clinical or electroencephalographic seizures. Considering the large number of patients treated with these agents without any neurological adverse effect, the clinical relevance of these data is unclear. Neuromuscular blocking agents do not possess pro- or anticonvulsant properties.

[Anesthesia for epilepsy surgery]

Epilepsy is rather common, affecting 0.5 to 2% of the population. Numerous patients, particularly those resistant to the antiepileptic therapy, can be surgically treated after a thorough evaluation. Surgery for epilepsy can be carried out either under general or local anaesthesia with sedation. This second approach is reserved for the extirpation of foci localised in motor, sensory or language areas. During the preoperative anaesthetic evaluation, two specific points have to be taken into account: the psychological aspect and the antiepileptic medication. During the procedure, an electrocorticography with or without stimulation may be indicated, particularly when a perioperative stimulation is scheduled. Low doses of volatile agents are chosen, and no curare and large doses of benzodiazepines and barbiturates. Awakening takes place on the operation table for a rapid and reliable neurological evaluation. During procedures performed under local anaesthesia, the anaesthetist must be ready at any time to intubate the patient in order to secure the airway.