A comparison of four treatments for generalized convulsive status epilepticus. Veterans Affairs Status Epilepticus Cooperative Study Group

The Safety and Effectiveness of Intravenous Lacosamide for Refractory Status Epilepticus in the Critically Ill

BACKGROUND

Status epilepticus (SE) often does not respond to initial treatment. A second-line agent with a less established safety and efficacy profile is then required. This study examined the safety of intravenous (IV) lacosamide (LCM) in a critically ill population and obtained an estimate of effectiveness in patients with refractory SE on continuous video EEG monitoring (cEEG).

METHODS

Retrospective review of critically ill patients in SE on cEEG treated with IV LCM from June 2009 to April 2011.

RESULTS

Eighty-four patients in SE (43 F/41 M), mean age 59.6 years, were identified; and 59.5 % had nonconvulsive SE. The most common etiologies were ischemic and hemorrhagic strokes. There were no significant changes in serial blood pressure monitoring, PR prolongation, aspartate aminotransferase (AST), or creatinine pre- and post-LCM. There was a significant increase in alanine aminotransferase (ALT) from days 1-7 (p = 0.031). Fifty-one patients were LCM-naïve. In these patients, cessation of SE on cEEG after LCM occurred in 15.7, 25.5, 58.8, and 82.4 % by 4, 12, 24, and 48 h, respectively.

CONCLUSION

IV LCM appears safe short term in critically ill patients with SE. The retrospective estimate of effectiveness for LCM appears promising for management in SE. Prospective, randomized controlled studies are needed to better determine the role of LCM in treating SE.

Hidden in plain sight: Non-convulsive status epilepticus-Recognition and management

Non-convulsive status epilepticus (NCSE) is an electroclinical state associated with an altered level of consciousness but lacking convulsive motor activity. It can present in a multitude of ways, but classification based on the clinical presentation and electroencephalographic appearances assists in determining prognosis and planning treatment. The aggressiveness of treatment should be based on the likely prognosis and the underlying cause of the NCSE.

New Developments in Refractory Status Epilepticus

Status epilepticus (SE) is a medical emergency and presents with either a continuous prolonged seizure or multiple seizures without full recovery of consciousness in between them. The goals of treatment are prompt recognition, early seizure termination, and simultaneous evaluation for any potentially treatable cause. Improved understanding of the pathophysiology has led to a more practical definition. New data have emerged regarding the safety and efficacy of alternative agents, which are increasingly used in the management of these patients. Continuous electroencephalogram monitoring is more widely used and has revealed a higher incidence of subclinical seizures than was previously thought.

Impact of non-guideline-based treatment of status epilepticus

BACKGROUND

This retrospective study analyzed benzodiazepine usage patterns in relation to guideline recommendations for the treatment of generalized convulsive status epilepticus (GCSE) as practiced by emergency medical services (EMS) and the emergency department (ED) of an inner-city hospital. Secondary outcomes of interest were adverse events and admission/discharge outcomes.

METHODS

Records of all patients≥18years old diagnosed with GCSE between June 2012 and September 2015 and transported by EMS to our hospital ED were reviewed.

RESULTS

Of 44 patients analyzed, 43 (98%) had a history of epilepsy. Benzodiazepine utilization varied; EMS preferred midazolam (69% of cases) while the ED utilized lorazepam (91% of cases). Benzodiazepine dosages used were lower than guideline recommendations. Seizure activity was aborted with benzodiazepines alone in 22 (50%) patients. Twelve patients (27%) experienced seizure recurrence following SE treatment and achievement of seizure cessation. Twenty-three (52%) patients required intubation after arrival to ED. All 44 patients were admitted; 30 (68%) required admission to the intensive care unit.

CONCLUSIONS

There was consistent underdosing of benzodiazepines in treatment of GCSE in both EMS and ED settings likely resulting in underachievement of seizure cessation, while intubation rates were higher than reported when compared to previous studies. Prospective studies are needed to identify barriers to optimal benzodiazepine usage in GCSE patients.

An update on the recognition and treatment of non-convulsive status epilepticus in the intensive care unit

INTRODUCTION

Non-convulsive status epilepticus (NCSE) is a complex and diverse condition which is often an under-recognised entity in the intensive care unit. When NCSE is identified the optimal treatment strategy is not always clear. Areas covered: This review is based on a literature review of the key literature in the field over the last 5-10 years. The articles were selected based on their importance to the field by the authors. Expert commentary: This review discusses the complex situations when a neurological consultation may occur in a critical care setting and provides an update on the latest evidence regarding the recognition of NCSE and the decision making around determining the aggressiveness of treatment. It also considers the ictal-interictal continuum of conditions which may be met with, particularly in the era of continuous EEG, and provides an approach for dealing with these. Suggestions for how the field will develop are discussed.

Factors associated with occurrence and outcome of super-refractory status epilepticus

PURPOSE

Super-refractory status epilepticus (SRSE) represents a challenging medical condition with high morbidity and mortality. In this study, we aimed to establish variables related to SRSE development and outcome.

METHODS

We retrospectively screened our databases for refractory SE (RSE) and SRSE episodes between January 2001 and January 2015. Baseline demographics, SE characteristics, and variables reflecting the clinical course were compared in order to identify factors independently associated with SRSE occurrence. Within the SRSE cohort, predictors of in-hospital mortality as well as good functional outcome in survivors to discharge were established through univariate and multivariable analyses.

RESULTS

A total of 131 episodes were included, among those 46 (35.1%) meeting the criteria of SRSE. Comparison of RSE and SRSE episodes revealed a lower premorbid mRS score (odds ratio (OR) per mRS point, 0.769; p=0.039) and non-convulsive SE (NCSE) in coma (OR, 4.216; p=0.008) as independent predictors of SRSE. SRSE in-hospital mortality was associated with age (OR, 1.091 per increasing year; p=0.020) and worse premorbid functional status (OR, 1.938 per mRS point; p=0.044). Good functional outcome in survivors was independently related to shorter SRSE duration (OR, 0.714 per day; p=0.038).

CONCLUSION

Better premorbid functional status and NCSE in coma as worst seizure type indicate a role of acute underlying etiologies in the development of SRSE. In-hospital mortality in SRSE is determined by nonmodifiable factors, while functional outcome in survivors depends on seizure duration underscoring the need of achieving rapid seizure termination.

Seizing Control of KCC2: A New Therapeutic Target for Epilepsy

Deficits in GABAergic inhibition result in the abnormal neuronal activation and synchronization that underlies seizures. However, the molecular mechanisms responsible for transforming a normal brain into an epileptic one remain largely unknown. Hyperpolarizing inhibition mediated by type A GABA (GABAA) receptors is dependent on chloride extrusion by the neuron-specific type 2K+-Cl- cotransporter (KCC2). Loss-of-function mutations in KCC2 are a known cause of infantile epilepsy in humans and KCC2 dysfunction is present in patients with both idiopathic and acquired epilepsy. Here we discuss the growing evidence that KCC2 dysfunction has a central role in the development and severity of the epilepsies.

Curriculum in Psychiatry and Neurology for Pharmacy Programs

Objective. To describe pharmacy curricula in psychiatry and neurology and to report on neuropsychiatric pharmacy specialists' views on optimal curriculum. Methods. Design and administer one electronic survey to accredited pharmacy programs asking them to report information on curricula in psychiatry and neurology for the 2014-2015 academic year. Design and administer a separate electronic survey to board certified pharmacists with an academic affiliation who are members of the College of Psychiatric and Neurologic Pharmacists (CPNP) asking about their teaching activities and their opinion on optimal curricula. Results. Fifty-six percent of pharmacy programs and 65% of CPNP members responded to the surveys. The program survey revealed greater than 80% of topics were taught by full-time faculty. Didactic lecturing, team-based learning, and case studies were the most common teaching methods. Programs dedicated the most didactics (3 to 5+ hours) to epilepsy, depression, schizophrenia, substance use disorders, and pain. Autism, traumatic brain injury, personality, and eating disorders were either not taught or given ≤ 1 hour of didactics in most programs. Inpatient psychiatry had the most APPE placements with a mean of 19.6, range 0-83. APPE electives in psychiatry outnumbered those in neurology 5 to 1. CPNP member survey results showed 2 out of 3 members agreed that curriculum could be improved with additional APPEs in psychiatry and neurology. Conclusion. Didactic hour distribution in psychiatry and neurology could be improved to better align with board certification in psychiatric pharmacy (BCPP) recommendations and disorder prevalence and complexity. Specialists recommend an experiential component in neurology and psychiatry to combat stigma and improve pharmacist knowledge and skills.

Enhanced AMPA receptor-mediated neurotransmission on CA1 pyramidal neurons during status epilepticus

Status epilepticus (SE) is a common neurological emergency that results from the failure of the mechanisms responsible for seizure termination or the initiation of mechanisms that lead to abnormally prolonged seizures. Although the failure of inhibitory mechanisms during SE is well understood, the seizure-initiating mechanisms are poorly understood. We tested whether hippocampal α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated transmission was enhanced during SE and assessed the underlying molecular mechanism. In animals in self-sustaining limbic SE the amplitudes of the miniature, spontaneous, and AMPA-evoked excitatory currents recorded from the CA1 pyramidal neurons were larger than those recorded in the controls. The evoked EPSCs rectified inwardly. In these animals, the surface expression of GluA1 subunit-containing AMPARs was increased in the CA1 pyramidal neurons. The phosphorylation of the GluA1 subunit on S831 and S845 residues was reduced in animals in SE. In contrast, the GluA1 subunit surface expression and AMPAR-mediated neurotransmission of dentate granule cells (DGCs) was not altered. Treating animals in SE with the NMDAR antagonist MK-801 or with diazaepam blocked the increased surface expression of the GluA1 subunits. NMDAR blockade also prevented the dephosphorylation of the S845 residue but not that of S831. Targeting NMDARs and AMPARs may provide novel strategies to treat benzodiazepine-refractory SE.

Acute and long-term effects of brivaracetam and brivaracetam-diazepam combinations in an experimental model of status epilepticus

Objective

To evaluate acute and long‐term effects of intravenous brivaracetam (BRV) and BRV + diazepam (DZP) combination treatment in a rat model of self‐sustaining status epilepticus (SSSE).

Methods

Rats were treated with BRV (10 mg/kg) 10 min after initiation of perforant path stimulation (PPS) as early treatment; or BRV (10–300 mg/kg), DZP (1 mg/kg), or BRV (0.3–10 mg/kg) + DZP (1 mg/kg) 10 min after the end of PPS (established SSSE). Seizure activity was recorded electrographically for 24 h posttreatment (acute effects), and for 1 week at 6–8 weeks or 12 months' posttreatment (long‐term effects). All treatments were compared with control rats using one‐way analysis of variance (ANOVA) and Bonferroni's test, or Kruskal‐–Wallis and Dunn's multiple comparison tests, when appropriate.

Results

Treatment of established SSSE with BRV (10–300 mg/kg) resulted in dose‐dependent reduction in SSSE duration and cumulative seizure time, achieving statistical significance at doses ≥100 mg/kg. Lower doses of BRV (0.3–10 mg/kg) + low‐dose DZP (1 mg/kg) significantly reduced SSSE duration and number of seizures. All control rats developed spontaneous recurrent seizures (SRS) 6–8 weeks after SSSE, whereas seizure freedom was noted in 2/10, 5/10, and 6/10 rats treated with BRV 200 mg/kg, 300 mg/kg, and BRV 10 mg/kg + DZP, respectively. BRV (10–300 mg/kg) showed a dose‐dependent trend toward reduction of SRS frequency, cumulative seizure time, and spike frequency, achieving statistical significance at 300 mg/kg. Combination of BRV (10 mg/kg) + DZP significantly reduced SRS frequency, cumulative seizure time, and spike frequency. In the 12‐month follow‐up study, BRV (0.3–10 mg/kg) + low‐dose DZP markedly reduced SRS frequency, cumulative seizure time, and spike frequency, achieving statistical significance at some doses. Early treatment of SSSE with BRV 10 mg/kg significantly reduced long‐term SRS frequency.

Significance

These findings support clinical evaluation of BRV for treatment of status epilepticus or acute repetitive seizures.

Efficacy of levetiracetam versus fosphenytoin for the recurrence of seizures after status epilepticus

Benzodiazepines are used as first-line treatments for status epilepticus. Fosphenytoin (FPHT) is recommended for second-line therapy; however, intravenous injection of levetiracetam (LEV) may also be effective against status epilepticus. Herein, we compared the efficacy and safety of LEV as a second-line treatment for status epilepticus with FPHT in Japanese patients.Patients with status epilepticus were selected from the database of the Emergency and Critical Care Center of Hitachi General Hospital. The subjects were patients whose status epilepticus was successfully stopped by diazepam, and in whom FPHT or LEV was administered after diazepam. As LEV injections recently became clinically available in Japan, the choice of drug was determined by the treatment period. Thus, 21 patients who were intravenously injected with LEV as a second-line therapy and 42 matched patients (historical controls) who were treated with FPHT (1:2) were selected.The subjects had a mean age of 64.0 ± 2.2 years, and included 48 males and 15 females. The status epilepticus control rates of the FPHT and LEV groups did not differ significantly (81.0% [34/42] vs 85.1% [18/21], respectively; P  =  .69). As for serious adverse events, a reduction in blood pressure was observed in the FPHT group, but not in the LEV group. The oral anticonvulsant switching rates of the 2 groups were similar, but the same-drug switching rates of the FPHT and LEV groups were 8.1% and 77.8%, respectively.The efficacy of intravenous LEV injections after status epilepticus was equivalent to that of FPHT, and the incidence of adverse events was lower in the LEV group. LEV is effective and safe at preventing recurrent seizures after status epilepticus following benzodiazepine treatment.

The efficacy of different kinds of intravenously applied antiepileptic drugs in the treatment of status epilepticus. How can it be determined?

We explored the influence of four different efficacy criteria on the results of observational studies concerning the treatment of status epilepticus (SE) and its subtypes. We compared and contrasted the results of four different efficacy criteria for the effectiveness of phenytoin, valproate, levetiracetam, and lacosamide. Criterion 1=the last antiepileptic drug (AED) administered before SE termination. Criterion 2=the last drug introduced into the antiepileptic therapy within 72h before the cessation of SE and without changes in dosage or number of the co-medication. Criterion 3=the last drug introduced into the antiepileptic therapy or increased in dose within 24h before termination of the SE without changes in the co-medication. Criterion 4=the last drug introduced into the antiepileptic therapy within 72h before the cessation of SE even allowing changes in the co-medication. We used two-tailed χ²-tests with the Yates adjustment for small samples to evaluate statistical differences between efficacy rates of different AEDs in the entire group and in subgroups of SE according to the second level of subdivisions in axis 1 and according to axis 2 of the new ILAE classification. A total of 145 treatment episodes in 124 patients (47 male, 77 female) were evaluated. There were 23 significant differences in efficacy according to the different criteria. Only criteria 1 and 3 led to significant results in our analysis. When incorporating theoretical considerations and the results of this study, criterion 3 seems to be the most appropriate measure for the evaluation of efficacy of an AED in the treatment of SE, because it seems to be more reasonable than criterion 1.

Lacosamide in Pediatric Status Epilepticus

Investigators from Baylor College of Medicine studied the efficacy of lacosamide in pediatric status epilepticus (SE).

[Acute focal neurological deficits in the emergency room]

A focal neurological deficit with sudden onset or rapid progression is an alarming symptom indicating a neurological disorder with often urgent need for treatment. Particularly in the emergency room, where time and resources are limited, it is necessary to rapidly assign such a focal neurological deficit to a certain syndrome and to define a suspected diagnosis in order to execute the correct diagnostics and emergency therapy. In this article, we highlight frequent and typical neurological disorders presenting in the emergency room and their corresponding focal neurological deficits. The article and a suggested algorithm are to guide less-experienced colleagues to find quick steps from acute symptoms to diagnosis and emergency treatment of frequent and relevant neurological disorders in the emergency room.

Status Epilepticus and Beyond: A Clinical Review of Status Epilepticus and an Update on Current Management Strategies in Super-refractory Status Epilepticus

Status epilepticus and refractory status epilepticus represent some of the most complex conditions encountered in the neurological intensive care unit. Challenges in management are common as treatment options become limited and prolonged hospital courses are accompanied by complications and worsening patient outcomes. Antiepileptic drug treatments have become increasingly complex. Rational polytherapy should consider the pharmacodynamics and kinetics of medications. When seizures cannot be controlled with medical therapy, alternative treatments, including early surgical evaluation can be considered; however, evidence is limited. This review provides a brief overview of status epilepticus, and a recent update on the management of refractory status epilepticus based on evidence from the literature, evidence-based guidelines, and experiences at our institution.

Simultaneous triple therapy for the treatment of status epilepticus

Early maladaptive internalization of synaptic GABA_A receptors (GABA_AR) and externalization of NMDA receptors (NMDAR) may explain the time-dependent loss of potency of standard anti-epileptic drugs (AED) in refractory status epilepticus (SE). We hypothesized that correcting the effects of changes in GABA_AR and NMDAR would terminate SE, even when treatment is delayed 40 minutes. SE was induced in adult Sprague-Dawley rats with a high dose of lithium and pilocarpine. The GABA_AR agonist midazolam, the NMDAR antagonist ketamine and the AED valproate were injected 40 min after SE onset in combination or as monotherapy. The midazolam-ketamine-valproate combination was more efficient than triple-dose midazolam, ketamine or valproate monotherapy or higher-dose dual therapy in reducing several parameters of SE severity. Triple therapy also reduced SE-induced acute neuronal injury and spatial memory deficits. In addition, simultaneous triple therapy was more efficient than sequential triple therapy: giving the three drugs simultaneously was more efficient at stopping seizures than the standard practice of giving them sequentially. Furthermore, midazolam-ketamine-valproate therapy suppressed seizures far better than the midazolam-fosphenytoin-valproate therapy, which follows evidence-based AES guidelines. These results show that a treatment aimed at correcting maladaptive GABA_AR and NMDAR trafficking can reduce the severity of SE and its long-term consequences.

Spectrum and Predictors of Refractory Status Epilepticus in a Developing Country

OBJECTIVE

Refractory status epilepticus (RSE) can influence the outcome of status epilepticus (SE). In the present study, we report the aetiology and predictors of outcomes of RSE in a developing country.

METHODS

This is a prospective hospital-based study of SE patients (continuous seizures for five minutes or more). Those who had SE persisting after two antiepileptic drugs were defined as having RSE. We present the demographic information, duration, and type of SE, and we note its severity using the status epilepticus severity score (STESS), its aetiology, comorbidities and imaging findings. The outcome of RSE was defined as cessation of seizures and the condition upon discharge, as assessed by the modified Rankin Scale.

RESULTS

A total of 35 (42.5%) of our 81 patients had RSE. The median duration of SE before starting treatment was 2 hours (range=0.008-160 h). The most common causes of RSE were stroke in 5 (14.3%), central nervous system (CNS) infections in 12 (34.3%) and metabolic encephalopathies in 13 (37.1%) patients. Some 21 (60%) patients had comorbidities, and the STESS was favourable in 7 (20%) patients. A total of 14 (20%) patients died, but death was directly related to SE in only one of these. Some 10 patients had super-refractory status epilepticus, which was due to CNS infection in 5 (50%) and metabolic encephalopathy in 3 (30%). On multivariate analysis, an unfavourable STESS (p=0.05) and duration of SE before treatment (p=0.01) predicted RSE. Metabolic aetiology (p=0.05), mechanical ventilation (p60 years (p=0.003) were predictors of poor outcomes.

CONCLUSIONS

RSE was common (42.5%) among patients with SE in a tertiary care center in India. It was associated with high mortality and poor outcomes. Age above 60 years and metabolic aetiology were found to be predictors of poor outcomes.

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.

Seizures and the Role of Anticonvulsants After Traumatic Brain Injury

Posttraumatic seizures are a common complication of traumatic brain injury. Posttraumatic epilepsy accounts for 20% of symptomatic epilepsy in the general population and 5% of all epilepsy. Early posttraumatic seizures occur in more than 20% of patients in the intensive care unit and are associated with secondary brain injury and worse patient outcomes. Most posttraumatic seizures are nonconvulsive and therefore continuous electroencephalography monitoring should be the standard of care for patients with moderate or severe brain injury. The literature shows that posttraumatic seizures result in secondary brain injury caused by increased intracranial pressure, cerebral edema and metabolic crisis.

A randomized controlled trial of lacosamide versus sodium valproate in status epilepticus

OBJECTIVE

To compare the efficacy and safety of lacosamide (LCM) and sodium valproate (SVA) in lorazepam (LOR)-resistant status epilepticus (SE).

METHODS

Patients with LOR-resistant SE were randomized to intravenous LCM 400 mg at a rate of 60 mg/kg/min or SVA 30 mg/kg at a rate of 100 mg/min. The SE severity score (STESS), duration of SE and its etiology, and magnetic resonance imaging (MRI) findings were noted. Primary outcome was seizure cessation for 1 h, and secondary outcomes were 24 h seizure remission, in hospital death and severe adverse events (SAEs).

RESULTS

Sixty-six patients were included, and their median age was 40 (range 18-90) years. Thirty-three patients each received LCM and SVA. Their demographic, clinical, STESS, etiology, and MRI findings were not significantly different. One hour seizure remission was not significantly different between LCM and SVA groups (66.7% vs. 69.7%; p = 0.79). Twenty-four hour seizure freedom was higher in SVA (20, 66.6%) compared with LCM group (15, 45.5%), but this difference was not statistically significant. Death (10 vs. 12) and composite side effects (4 vs. 6) were also not significantly different in LCM and SVA groups. LCM was associated with hypotension and bradycardia (one patient), and SVA with liver dysfunction (six patients).

SIGNIFICANCE

In LOR-resistant SE patients, both LCM and SVA have comparable efficacy and safety. SVA resulted in slightly better 24 h seizure remission.

Propofol versus thiopental sodium for the treatment of refractory status epilepticus

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews (Issue 6, 2015).Failure to respond to antiepileptic drugs in patients with uncontrolled seizure activity such as refractory status epilepticus (RSE) has led to the use of anaesthetic drugs. Coma is induced with anaesthetic drugs to achieve complete control of seizure activity. Thiopental sodium and propofol are popularly used for this purpose. Both agents have been found to be effective. However, there is a substantial lack of evidence as to which of the two drugs is better in terms of clinical outcomes.

OBJECTIVES

To compare the efficacy, adverse effects, and short- and long-term outcomes of refractory status epilepticus (RSE) treated with one of the two anaesthetic agents, thiopental sodium or propofol.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialized Register (16 August 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Register of Studies Online (CRSO, 16 August 2016), MEDLINE (Ovid, 1946 to 16 August 2016), ClinicalTrials.gov (16 August 2016), and the South Asian Database of Controlled Clinical Trials (16 August 2016). Previously we searched IndMED, but this was not accessible at the time of the latest update.

SELECTION CRITERIA

All randomised controlled trials (RCTs) or quasi-RCTs (regardless of blinding) assessing the control of RSE using either thiopental sodium or propofol in patients of any age and gender.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results and reviewed the abstracts of relevant and eligible trials before retrieving the full-text publications.

MAIN RESULTS

One study with a total of 24 participants was available for review. This study was a small, single-blind, multicentre trial studying adults with RSE receiving either propofol or thiopental sodium for the control of seizure activity. This study was terminated early due to recruitment problems. For our primary outcome of total control of seizures after the first course of study drug, there were 6/14 patients versus 2/7 patients in the propofol and thiopental sodium groups, respectively (risk ratio (RR) 1.50, 95% confidence interval (CI) 0.40 to 5.61, low quality evidence). Mortality was seen in 3/14 patients versus 1/7 patients in the propofol and thiopental sodium groups, respectively (RR 1.50, 95% CI 0.19 to 11.93, low quality evidence). Our third primary outcome of length of ICU stay was not reported. For our secondary outcomes of adverse events, infection was seen in 7/14 patients versus 5/7 patients in the propofol and thiopental sodium groups, respectively (RR 0.70; 95% CI 0.35 to 1.41). Hypotension during administration of study drugs and requiring use of vasopressors was seen in 7/14 patients versus 4/7 patients in the propofol and thiopental sodium groups, respectively (RR 0.87; 95% CI 0.38 to 2.00). The other severe complication noted was non-fatal propofol infusion syndrome in one patient. Patients receiving thiopental sodium required more days of mechanical ventilation when compared with patients receiving propofol: (median (range) 17 days (5 to 70 days) with thiopental sodium versus four days (2 to 28 days) with propofol). At three months there was no evidence of a difference between the drugs with respect to outcome measures such as control of seizure activity and functional outcome.

AUTHORS' CONCLUSIONS

Since the last version of this review we have found no new studies.There is a lack of robust, randomised, controlled evidence to clarify the efficacy of propofol and thiopental sodium compared to each other in the treatment of RSE. There is a need for large RCTs for this serious condition.

[Not Available]

Zusammenfassung. Der Status epilepticus, vor allem der konvulsive tonisch-klonische (Grand mal) Status epilepticus, ist ein Notfall, der zu einer sofortigen Behandlung führen muss. Die frühe Behandlung ist effektiver als der spätere Beginn, ebenso wie der Einsatz standardisierter Therapieprotokolle. Nach der Gabe von Benzodiazepinen muss die Aufdosierung eines Antikonvulsivums (Levetiracetam, Valproat oder Phenytoin) erfolgen, um das Wiederauftreten von Anfällen zu verhindern. Beim refraktären Status epilepticus werden die Anästhetika Propofol oder Midazolam (oder Thiopental) vorzugsweise unter EEG-Ableitung mit einem Burst-Suppressions-Muster eingesetzt. Neben der raschen Therapie sollte die Diagnostik nach der Ursache des Status epilepticus nicht vergessen werden. Insbesondere bei Persistenz sollte immer auch die Überprüfung der Diagnose erfolgen, um das Vorliegen eines Pseudostatus nicht-epileptischer Anfälle nicht zu übersehen.

Recent advances in epilepsy

This paper reviews advances in epilepsy in recent years with an emphasis on therapeutics and underlying mechanisms, including status epilepticus, drug and surgical treatments. Lessons from rarer epilepsies regarding the relationship between epilepsy type, mechanisms and choice of antiepileptic drugs (AED) are explored and data regarding AED use in pregnancy are reviewed. Concepts evolving towards a move from treating seizures to treating epilepsy are discussed, both in terms of the mechanisms of epileptogenesis, and in terms of epilepsy's broader comorbidity, especially depression.

Management of status epilepticus

Status epilepticus is a neurologic and medical emergency manifested by prolonged seizure activity or multiple seizures without return to baseline. It is associated with substantial medical cost, morbidity, and mortality. There is a spectrum of severity dependent on the type of seizure, underlying pathology, comorbidities, and appropriate and timely medical management. This chapter discusses the evolving definitions of status epilepticus and multiple patient and clinical factors which influence outcome. The pathophysiology of status epilepticus is reviewed to provide a better understanding of the mechanisms which contribute to status epilepticus, as well as the potential long-term effects. The clinical presentations of different types of status epilepticus in adults are discussed, with emphasis on the hospital course and management of the most dangerous type, generalized convulsive status epilepticus. Strategies for the evaluation and management of status epilepticus are provided based on available evidence from clinical trials and recommendations from the Neurocritical Care Society and the European Federation of Neurological Societies.

Anesthetics and Outcome in Status Epilepticus: A Matched Two-Center Cohort Study

BACKGROUND

The use of anesthetics has been linked to poor outcome in patients with status epilepticus (SE). This association, however, may be confounded, as anesthetics are mostly administered in patients with more severe SE and critical illnesses.

OBJECTIVE

To minimize treatment-selection bias, we assessed the association between continuously administered intravenous anesthetic drugs (IVADs) and outcome in SE patients by a matched two-center study design.

METHODS

This cohort study was performed at the Johns Hopkins Bayview Medical Center, Baltimore, MD, USA and the University Hospital Basel, Basel, Switzerland. All consecutive adult SE patients from 2005 to 2013 were included. Odds ratios (ORs) for death and unfavorable outcome (Glasgow Outcome Score [GOS] 1-3) associated with administration of IVADs were calculated. To account for confounding by known outcome determinants (age, level of consciousness, worst seizure type, acute/fatal etiology, mechanical ventilation, and SE duration), propensity score matching and coarsened exact matching were performed in addition to multivariable regression models.

RESULTS

Among 406 consecutive patients, 139 (34.2%) were treated with IVADs. Logistic regression analyses of the unmatched and matched cohorts revealed increased odds for death and unfavorable outcome in survivors who had received IVADs (unmatched: OR_death = 3.13, 95% confidence interval [CI] 1.47-6.60 and OR_GOS1-3 = 2.51, 95% CI 1.37-4.60; propensity score matched: OR_death = 3.29, 95% CI 1.35-8.05 and OR_GOS1-3 = 2.27, 95% CI 1.02-5.06; coarsened exact matched: OR_death = 2.19, 95% CI 1.27-3.78 and OR_GOS1-3 = 3.94, 95% CI 2.12-7.32).

CONCLUSION

The use of IVADs in SE is associated with death and unfavorable outcome in survivors independent of known confounders and using different statistical approaches. Randomized trials are needed to determine if these associations are biased by outcome predictors not yet identified and hence not accounted for in this study.

Seizures in the critically ill

Critically ill patients with seizures are either admitted to the intensive care unit because of uncontrolled seizures requiring aggressive treatment or are admitted for other reasons and develop seizures secondarily. These patients may have multiorgan failure and severe metabolic and electrolyte disarrangements, and may require complex medication regimens and interventions. Seizures can be seen as a result of an acute systemic illness, a primary neurologic pathology, or a medication side-effect and can present in a wide array of symptoms from convulsive activity, subtle twitching, to lethargy. In this population, untreated isolated seizures can quickly escalate to generalized convulsive status epilepticus or, more frequently, nonconvulsive status epileptics, which is associated with a high morbidity and mortality. Status epilepticus (SE) arises from a failure of inhibitory mechanisms and an enhancement of excitatory pathways causing permanent neuronal injury and other systemic sequelae. Carrying a high 30-day mortality rate, SE can be very difficult to treat in this complex setting, and a portion of these patients will become refractory, requiring narcotics and anesthetic medications. The most significant factor in successfully treating status epilepticus is initiating antiepileptic drugs as soon as possible, thus attentiveness and recognition of this disease are critical.

Neurologic complications of cardiac and vascular surgery

This chapter will provide an overview of the major neurologic complications of common cardiac and vascular surgeries, such as coronary artery bypass grafting and carotid endarterectomy. Neurologic complications after cardiac and vascular surgeries can cause significant morbidity and mortality, which can negate the beneficial effects of the intervention. Some of the complications to be discussed include ischemic and hemorrhagic stroke, seizures, delirium, cognitive dysfunction, cerebral hyperperfusion syndrome, cranial nerve injuries, and peripheral neuropathies. The severity of these complications can range from mild to lethal. The etiology of complications can include a variety of mechanisms, which can differ based on the type of cardiac or vascular surgery that is performed. Our knowledge about neuropathology, prevention, and management of surgical complications is growing and will be discussed in this chapter. It is imperative for clinicians to be familiar with these complications in order to narrow the differential diagnosis, start early management, anticipate the natural history, and improve outcomes.

Hypothermia for Neuroprotection in Convulsive Status Epilepticus

BACKGROUND

Convulsive status epilepticus often results in permanent neurologic impairment. We evaluated the effect of induced hypothermia on neurologic outcomes in patients with convulsive status epilepticus.

METHODS

In a multicenter trial, we randomly assigned 270 critically ill patients with convulsive status epilepticus who were receiving mechanical ventilation to hypothermia (32 to 34°C for 24 hours) in addition to standard care or to standard care alone; 268 patients were included in the analysis. The primary outcome was a good functional outcome at 90 days, defined as a Glasgow Outcome Scale (GOS) score of 5 (range, 1 to 5, with 1 representing death and 5 representing no or minimal neurologic deficit). The main secondary outcomes were mortality at 90 days, progression to electroencephalographically (EEG) confirmed status epilepticus, refractory status epilepticus on day 1, "super-refractory" status epilepticus (resistant to general anesthesia), and functional sequelae on day 90.

RESULTS

A GOS score of 5 occurred in 67 of 138 patients (49%) in the hypothermia group and in 56 of 130 (43%) in the control group (adjusted common odds ratio, 1.22; 95% confidence interval [CI], 0.75 to 1.99; P=0.43). The rate of progression to EEG-confirmed status epilepticus on the first day was lower in the hypothermia group than in the control group (11% vs. 22%; odds ratio, 0.40; 95% CI, 0.20 to 0.79; P=0.009), but there were no significant differences between groups in the other secondary outcomes. Adverse events were more frequent in the hypothermia group than in the control group.

CONCLUSIONS

In this trial, induced hypothermia added to standard care was not associated with significantly better 90-day outcomes than standard care alone in patients with convulsive status epilepticus. (Funded by the French Ministry of Health; HYBERNATUS ClinicalTrials.gov number, NCT01359332 .).

Phenobarbital Versus Valproate for Generalized Convulsive Status Epilepticus in Adults: A Prospective Randomized Controlled Trial in China

OBJECTIVE

Although generalized convulsive status epilepticus (GCSE) is a life-threatening emergency, evidence-based data to guide initial drug treatment choices are lacking in the Chinese population. We conducted this prospective, randomized, controlled trial to evaluate the relative efficacy and safety of intravenous phenobarbital and valproate in patients with GCSE.

METHODS

After the failure of first-line diazepam treatment, Chinese adult patients with GCSE were randomized to receive either intravenous phenobarbital (standard doses, low rate) or valproate (standard). Successful treatment was considered when clinical and electroencephalographic seizure activity ceased. Adverse events following treatment, as well as the neurological outcomes at discharge and 3 months later, were also evaluated.

RESULTS

Overall, 73 cases were enrolled in the study. Intravenous phenobarbital was successful in 81.1% of patients, and intravenous valproate was successful in 44.4% of patients (p < 0.05). The relapse rate of status epilepticus within 24 h of receiving phenobarbital (6.7%) was significantly lower than that in patients receiving valproate (31.3%), and the total number of adverse events did not differ significantly between the two groups (p > 0.05). In the phenobarbital group, two patients (5.4%) required ventilation and two patients (5.4%) developed serious hypotension. The neurological outcomes of the phenobarbital group were generally better than those of the valproate group; however, no significant differences were observed between phenobarbital and valproate with respect to mortality (8.1 vs. 16.6%) at discharge, or mortality (16.2 vs. 30.5%) and post-symptomatic epilepsy (26.3 vs. 42.8%) at 3-month follow-up.

CONCLUSIONS

Intravenous phenobarbital appears to be more effective than intravenous valproate for Chinese adult patients with GCSE. The occurrence of serious respiratory depression and hypotension caused by phenobarbital was reduced by decreasing the intravenous infusion rate; however, even at a lower infusion rate than typically used in other institutions, intravenous phenobarbital resulted in more serious adverse events than intravenous valproate. The better outcomes in the phenobarbital group compared with the valproate group suggest that phenobarbital should be considered for the early successful treatment of GCSE.

The SAMUKeppra study in prehospital status epilepticus: lessons for future study

In the Lancet Neurology article "Prehospital treatment with levetiracetam plus clonazepam or placebo plus clonazepam in status epilepticus (SAMUKeppra): a randomised, double-blind, phase 3 trial" the authors conducted a prehospital, randomized controlled study to determine which treatment is more effective for status epilepticus (SE): benzodiazepine alone, or in combination with levetiracetam (LEV). Although the study had negative results, several aspects of the trial design likely masked any added effect that LEV may have had in controlling SE, including: higher doses of benzodiazepines, lower thresholds for determining cessation of SE, and a smaller sample size. Regardless, the study reaffirms the effectiveness and importance of early and adequate benzodiazepine dosing and helps guide us in designing future studies for treatment of SE.

Continuous Infusion Antiepileptic Medications for Refractory Status Epilepticus: A Review for Nurses

Status epilepticus requires treatment with emergent initial therapy with a benzodiazepine and urgent control therapy with an additional antiepileptic drug (AED) to terminate clinical and/or electrographic seizure activity. However, nearly one-third of patients will prove refractory to the aforementioned therapies and are prone to a higher degree of neuronal injury, resistance to pharmacotherapy, and death. Current guidelines for refractory status epilepticus (RSE) recommend initiating a continuous intravenous (CIV) anesthetic over bolus dosing with a different AED. Continuous intravenous agents most commonly used for this indication include midazolam, propofol, and pentobarbital, but ketamine is an alternative option. Comparative studies illustrating the optimal agent are lacking, and selection is often based on adverse effect profiles and patient-specific factors. In addition, dosing and titration are largely based on small studies and expert opinion with continuous electroencephalogram monitoring used to guide intensity and duration of treatment. Nonetheless, the doses required to halt seizure activity are likely to produce profound adverse effects that clinicians should anticipate and combat. The purpose of this review was to summarize the available RSE literature focusing on CIV midazolam, pentobarbital, propofol, and ketamine, and to serve as a primer for nurses providing care to these patients.

25 years of advances in the definition, classification and treatment of status epilepticus

PURPOSE

Status epilepticus (SE) requires not only urgent symptomatic treatment with antiepileptic drugs but also rapid identification and treatment of its cause. This narrative review summarizes the most important advances in classification and treatment of SE.

METHOD

Data sources included MEDLINE, EMBASE, ClinicalTrials.gov, and back tracking of references in pertinent studies, reviews, and books.

RESULTS

SE is now defined as "a condition resulting either from the failure of the mechanisms responsible for seizure termination or from the initiation of mechanisms, which lead to abnormally, prolonged seizures (after time point t1). It is a condition, which can have long-term consequences (after time point t2), including neuronal death, neuronal injury, and alteration of neuronal networks, depending on the type and duration of seizures." A new diagnostic classification system of SE introduces four axes: semiology, aetiology, EEG correlates, and age. For the acute treatment intravenous benzodiazepines (lorazepam, diazepam, clonazepam) and intramuscular midazolam appear as most effective treatments for early SE. In children, buccal or intranasal midazolam are useful alternatives. In established SE intravenous antiepileptic drugs (phenytoin, valproate, levetiracetam, phenobarbital, and lacosamide) are in use. Treatment options in refractory SE are intravenous anaesthetics; ketamine, magnesium, steroids and other drugs have been used in super-refractory SE with variable outcomes.

CONCLUSION

Over the past 25 years major advances in definition, classification and understanding of its mechanisms have been achieved. Despite this up to 40% of patients in early status cannot be controlled with first line drugs. The treatment of super-refractory status is still an almost evidence free zone.

Is intravenous lorazepam really more effective and safe than intravenous diazepam as first-line treatment for convulsive status epilepticus? A systematic review with meta-analysis of randomized controlled trials

BACKGROUND

Some guidelines or expert consensus indicate that intravenous (IV) lorazepam (LZP) is preferable to IV diazepam (DZP) for initial treatment of convulsive status epilepticus (SE). We aimed to critically assess all the available data on efficacy and tolerability of IV LZP compared with IV DZP as first-line treatment of convulsive SE.

METHODS

Systematic search of the literature (MEDLINE, CENTRAL, EMBASE, ClinicalTrials.gov) to identify randomized controlled trials (RCTs) comparing IV LZP versus IV DZP used as first-line treatment for convulsive SE (generalized or focal). Inverse variance, Mantel-Haenszel meta-analysis to obtain risk ratio (RR) with 95% confidence intervals (CI) of following outcomes: seizure cessation after drug administration; continuation of SE requiring a different drug; seizure cessation after a single dose of medication; need for ventilator support; clinically relevant hypotension.

RESULTS

Five RCTs were included, with a total of 656 patients, 320 randomly allocated to IV LZP and 336 to IV DZP. No statistically significant differences were found between IV LZP and IV DZP for clinical seizure cessation (RR 1.09; 95% CI 1.00 to 1.20), continuation of SE requiring a different drug (RR 0.76; 95% CI 0.57 to 1.02), seizure cessation after a single dose of medication (RR 0.96; 95% CI 0.85 to 1.08), need for ventilator support RR 0.93; 95% CI 0.61 to 1.43, and clinically relevant hypotension.

CONCLUSION

Despite its favorable pharmacokinetic profile, a systematic appraisal of the literature does not provide evidence to strongly support the preferential use of IV LZP as first-line treatment of convulsive SE over IV DZP.

Epilepsy Emergencies

PURPOSE OF REVIEW

Epilepsy emergencies include acute repetitive seizures and status epilepticus. Their prognosis depends on the etiology of the seizures and the time spent in status epilepticus. This review discusses the current perspective on the diagnosis and treatment of status epilepticus and acute repetitive seizures in the intensive care unit.

RECENT FINDINGS

Current data on the treatment of status epilepticus emphasize early treatment over the choice of antiepileptic drug. The Rapid Anticonvulsant Medication Prior to Arrival Trial (RAMPART) data support the efficacy of prehospital treatment using faster routes of benzodiazepine administration. As additional antiepileptic drugs have become available in an IV formulation, their use in status epilepticus has increased, with little data to guide their administration. Recent publications have also stressed the changing epidemiology of status epilepticus in the United States, with a rise in incidence without much change in overall mortality. This rise is likely related to improved diagnostic capabilities with better availability and usage of continuous EEG in the intensive care unit and to the aging of the patient population.

SUMMARY

Acute repetitive seizures and status epilepticus are neurologic emergencies that are being increasingly diagnosed and treated in the modern era. Rapid treatment may influence patient prognosis, future cognitive outcomes, and the long-term potential for developing epilepsy. However, little is known about the mechanisms that perpetuate seizure activity, and our ability to intervene and prevent this condition remains limited. Preventing complications during the treatment of status epilepticus plays a large role in prognosis and the chance of treatment success.

Should Barbiturates be Used in Refractory Status Epilepticus?

Status epilepticus (SE) is a frequent neurologic emergency, one third of patients do not respond to treatment with benzodiazepines followed by a second antiepileptic drug. While initial treatment of complex partial SE is accordant to that of generalized convulsive SE, further management of refractory SE depends on the risk for acute complications and long-term clinical consequences. These risks are low in complex partial SE; therefore, in this clinical form anesthetics commonly are not used. Generalized convulsive SE-even in its early course-is a potentially life-threatening condition; therefore, prompt use of anesthetics is urgently required. Drugs of choice are barbiturates, midazolam, and propofol, all of which exhibit specific advantages and disadvantages. Up to now, data from clinical studies do not allow to prefer or to discard one of these anesthetics, therefore also barbiturates still should be used in refractory SE. A widely accepted in-house protocol for the management of initial and refractory SE is highly recommended.

Treating epileptic emergencies - pharmacological advances

INTRODUCTION

Epileptic emergencies are frequently encountered and include ictal events as status epilepticus or seizure clusters, and non-ictal situations like postictal psychosis or acute drug side effects. The aim of this review was to describe recent pharmacological advances in the treatment of epileptic emergencies. Areas covered: Based on clinically relevant questions, a literature search was performed. The search showed that most pharmacological advances have been made in management of status epilepticus, where substantial literature has accumulated on several AEDs with potentially less side-effects than the traditional choices. The use of these drugs; valproate, levetiracetam, and lacosamide, was therefore made the main focus of this review. Pharmacological advances in treatment of other epileptic emergencies were scarce, and were therefore covered more briefly in the Expert Opinion section. Expert opinion: This section outlines our current practice in management of status epilepticus and seizures clusters. Our opinion is that valproate is an equal alternative as second line treatment to fosphenytoin, with levetiracetam considered a good choice in frail and elderly patients. Due to the lack of literature, lacosamide is used mainly as a 2^nd line drug after the failure of valproate, fosphenytoin and levetiracetam. Our review underlines the need for more research in management of epileptic emergencies.

Therapeutic coma for status epilepticus: Differing practices in a prospective multicenter study

OBJECTIVE

Our aim was to analyze and compare the use of therapeutic coma (TC) for refractory status epilepticus (SE) across different centers and its effect on outcome.

METHODS

Clinical data for all consecutive adults (>16 years) with SE of all etiologies (except postanoxic) admitted to 4 tertiary care centers belonging to Harvard Affiliated Hospitals (HAH) and the Centre Hospitalier Universitaire Vaudois (CHUV) were prospectively collected and analyzed for TC details, mortality, and duration of hospitalization.

RESULTS

Two hundred thirty-six SE episodes in the CHUV and 126 in the HAH were identified. Both groups were homogeneous in demographics, comorbidities, SE characteristics, and Status Epilepticus Severity Score (STESS); TC was used in 25.4% of cases in HAH vs 9.75% in CHUV. After adjustment, TC use was associated with younger age, lower Charlson Comorbidity Index, increasing SE severity, refractory SE, and center (odds ratio 11.3 for HAH vs CHUV, 95% confidence interval 2.47-51.7). Mortality was associated with increasing Charlson Comorbidity Index and STESS, etiology, and refractory SE. Length of stay correlated with STESS, etiology, refractory SE, and use of TC (incidence rate ratio 1.6, 95% confidence interval 1.22-2.11).

CONCLUSIONS

Use of TC for SE treatment seems markedly different between centers from the United States and Europe, and did not affect mortality considering the whole cohort. However, TC may increase length of hospital stay and related costs.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that for patients with SE, TC does not significantly affect mortality. The study lacked the precision to exclude an important effect of TC on mortality.

Emergency Neurological Life Support: Status Epilepticus

Patients with prolonged or rapidly recurring convulsions lasting more than 5 min are in status epilepticus (SE) and require immediate resuscitation. Although there are relatively few randomized clinical trials, available evidence and experience suggest that early and aggressive treatment of SE improves patient outcomes, for which reason this was chosen as an Emergency Neurological Life Support protocol. The current approach to the emergency treatment of SE emphasizes rapid initiation of adequate doses of first-line therapy, as well as accelerated second-line anticonvulsant drugs and induced coma when these fail, coupled with admission to a unit capable of neurological critical care and electroencephalography monitoring. This protocol will focus on the initial treatment of SE but also review subsequent steps in the protocol once the patient is hospitalized.

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.

Therapeutic Index Estimation of Antiepileptic Drugs: A Systematic Literature Review Approach

OBJECTIVES

Our study aimed to determine whether data obtained from the medical literature can be used to estimate the therapeutic index of 5 antiepileptic drugs (AEDs): carbamazepine, lamotrigine, phenobarbital, phenytoin, and valproate.

METHODS

We performed a literature search using PubMed and EMBASE to collect published safety, efficacy, and therapeutic monitoring data for 5 AEDs and extracted all relevant information into a drug- and study-specific drug database. For each AED, we summarized (1) type, severity, and incidence of toxicity-related adverse events and toxicity-associated range of drug doses or concentrations; (2) effective versus toxic concentration and dose (therapeutic range); and (3) therapeutic drug monitoring practices. We defined therapeutic index as the ratio of the minimum toxic concentration to the minimum effective concentration.

RESULTS

We reviewed a total of 810 full-text articles and extracted data from 163. The literature suggests that the therapeutic index of phenytoin is 2. The therapeutic indices of phenobarbital and valproate exceed 2. There were insufficient data to precisely quantify the therapeutic indices of carbamazepine and lamotrigine.

CONCLUSIONS

For some drugs, this approach offers a low-cost method of therapeutic index estimation. Our results can serve as preliminary data for future trials and as guidance for US Food and Drug Administration decision making regarding narrow therapeutic index classification.