Safety and pharmacokinetics of intravenous levetiracetam infusion as add-on in status epilepticus

Intravenous push administration of anti-seizure medications

Intravenous push (IVP) administration of anti-seizure medications is becoming increasingly popular among emergency departments. IVP administration eliminates the need for compounding and preparation by the pharmacy department, as well as the need to gather infusion materials or set up a patient's tubing and pump, all of which translate to faster drug administration. This is important given the time-sensitive nature of status epilepticus treatment. This review will discuss several anti-seizure medications, including phenytoin, fosphenytoin, valproic acid, levetiracetam, brivaracetam and lacosamide, for which evidence supports the safe and efficacious use of IV push administration.

Successful use of Rectal Pregabalin for the Treatment of Chemotherapy-Induced Neuropathic Pain-a Case Report

INTRODUCTION

A 65-year-old female patient could no longer take oral food or medications due to a duodenal occlusion associated with metastatic urothelial carcinoma. Her pre-existing chemotherapy-induced polyneuropathy had been well treated with pregabalin orally.

METHODS

Since only preparations for oral use of pregabalin are available, pregabalin suppositories were compounded by the hospital pharmacy for rectal use in this patient.

RESULTS

With the rectal administration, the treatment was successfully continued; we measured a good increase in serum levels and the symptoms improved significantly.

DISCUSSION

Cancer patients often need to be treated with co-analgesics. At the end of life, treatment often cannot be continued due to lack of other than oral administration. Our case adds to the low evidence of pregabalin administered rectally.

Effects of acupuncture in the treatment of occipital neuralgia: A systematic review and meta-analysis

BACKGROUND

Acupuncture is used to treat subjects with occipital neuralgia, which is 1 of the main causes of occipital pain; however, its effect is conflicting. Hence, the current study aims to evaluate the effects of acupuncture in the treatment of occipital neuralgia.

METHODS

In a systematic search of PubMed, Embase, OVID, China National Knowledge Infrastructure, Cochrane Library, Chinese Biomedical Literature Database, Wanfang databases, and Google Scholar until July 2021, 15 studies aimed to evaluate the effects of acupuncture in the treatment of occipital neuralgia were included. Human-related trials were considered in different languages. The size of the study was not considered a limit for its inclusion and the study intervention should focus on comparing the impact of acupuncture in the intervention group compared with the control group.The odds ratio (OR) and the mean difference (MD) with 95% confidence intervals (CIs) were calculated with a random or fixed-effect model for different subgroup analyses. Publication bias was assessed using the Egger test, while the risk of bias was assessed using the Review manager software.

RESULTS

Acupuncture had a significantly higher effective rate of treatment (OR, 5.40; 95% CI, 2.48 to 11.77, P < .001) compared to control in the treatment of occipital neuralgia and lower visual analogue scale (MD, -2.45; 95% CI, -2.69 to -2.21, P < .001). Acupuncture plus medication had a significantly higher effective rate of treatment (OR, 3.96; 95% CI, 2.10 to 7.47, P < .001) compared to medication in the treatment of occipital neuralgia. Acupuncture analysis for safety issues showed a significant reduction of adverse events compared with the medication group.

CONCLUSION

Acupuncture alone or acupuncture plus medication had a significantly beneficial effect on the effective rate of treatment, safety and visual analog scale compared to medication in the treatment of occipital neuralgia. Further studies are required to validate these findings.

The Pharmacokinetics of Levetiracetam in Critically Ill Adult Patients: An Intensive Care Unit Clinical Study

The aim of this study was to investigate levetiracetam pharmacokinetics in critically ill adult intensive care patients and to identify pathophysiological factors affecting its kinetics. Fourteen critically ill patients in an intensive care unit were enrolled in the study and received intravenous levetiracetam. Blood samples were collected at specific time points to determine the levetiracetam pharmacokinetics. Patient characteristics such as renal function, demographics, disease severity, organ dysfunction, and biochemical laboratory tests were evaluated for their influence on the kinetics of levetiracetam. Estimated glomerular filtration rate (eGFR) had a statistically significant (p = 0.001) effect on levetiracetam clearance. None of the other patient characteristics had a statistically significant effect on the pharmacokinetics. Simulations of dosing regimens revealed that even typically administered doses of levetiracetam may result in significantly increased concentrations and risk of drug toxicity in patients with impaired renal function. The Acute Physiology and Chronic Health Evaluation II (APACHE II) score differed significantly among the three groups with different epileptic activity (p = 0.034). The same groups also differed in terms of renal function (p = 0.031). Renal dysfunction should be considered when designing levetiracetam dosage. Patients with a low APACHE II score had the lowest risk of experiencing epileptic seizures.

A pharmacokinetic simulation study to assess the performance of a sparse blood sampling approach to quantify early drug exposure

Estimating early exposure of drugs used for the treatment of emergent conditions is challenging because blood sampling to measure concentrations is difficult. The objective of this work was to evaluate predictive performance of two early concentrations and prior pharmacokinetic (PK) information for estimating early exposure. The performance of a modeling approach was compared with a noncompartmental analysis (NCA). A simulation study was performed using literature‐based models for phenytoin (PHT), levetiracetam (LEV), and valproic acid (VPA). These models were used to simulate rich concentration‐time profiles from 0 to 2 h. Profiles without residual unexplained variability (RUV) were used to obtain the true partial area under the curve (pAUC) until 2 h after the start of drug infusion. From the profiles with the RUV, two concentrations per patient were randomly selected. These concentrations were analyzed under a population model to obtain individual population PK (PopPK) pAUCs. The NCA pAUCs were calculated using a linear trapezoidal rule. Percent prediction errors (PPEs) for the PopPK pAUCs and NCA pAUCs were calculated. A PPE within ±20% of the true value was considered a success and the number of successes was obtained for 100 simulated datasets. For PHT, LEV, and VPA, respectively, the median value of the success statistics obtained using the PopPK approach of 81%, 92%, and 88% were significantly higher than the 72%, 80%, and 67% using the NCA approach (p < 0.05; Mann–Whitney U test). This study provides a means by which early exposure can be estimated with good precision from two concentrations and a PopPK approach. It can be applied to other settings in which early exposures are of interest.

Population Pharmacokinetics of Levetiracetam in Patients with Traumatic Brain Injury and Subarachnoid Hemorrhage Exhibiting Augmented Renal Clearance

BACKGROUND AND OBJECTIVE

Patients with severe trauma exhibit augmented renal clearance, which can alter the dosing requirement of renally eliminated drugs. This study aimed to develop a population pharmacokinetic model for levetiracetam in patients with severe traumatic brain injury and aneurysmal subarachnoid hemorrhage, and use it to describe optimal dosing regimens.

METHODS

This was a prospective open-label observational study. Critically ill adult patients with severe traumatic brain injury or aneurysmal subarachnoid hemorrhage without renal dysfunction and receiving levetiracetam were eligible. Serial levetiracetam plasma concentrations were analyzed to develop a population pharmacokinetic model and perform dosing simulations.

RESULTS

A two-compartment model best described the concentration-time data from 30 patients. The mean ± standard deviation parameter estimates were bioavailability (F) of 0.8 ± 0.2, absorption rate constant of 2.4 ± 2 h^-1, clearance 2.5 ± 1.1 L/h, central volume of distribution 8.9 ± 3.0 L/h, and transfer rate constraints of 1.8 ± 1.1 h^-1 from central to peripheral compartments and 0.7 ± 0.3 h^-1 from peripheral to central compartments. For the simulated intermittent dosing regimens, on average, the median trough concentration reduced by 50% for every 40-mL/min/1.73 m² increase in urinary creatinine clearance. Simulated doses of at least 6 g/day were required for some levels of augmented renal clearance.

CONCLUSIONS

Patients with severe traumatic brain injury and aneurysmal subarachnoid hemorrhage with augmented renal clearance are at risk of not achieving target levetiracetam plasma concentrations. We suggest dose titration guided by measured creatinine clearance, and/or, therapeutic drug monitoring if available, to minimize the risk of seizures.

Levetiracetam vs. Fosphenytoin for Second-Line Treatment of Status Epilepticus: Propensity Score Matching Analysis Using a Nationwide Inpatient Database

Objective: Status epilepticus is a major emergency condition. The choice of antiepileptic drugs for second-line treatment after benzodiazepine remains controversial, including levetiracetam vs. fosphenytoin. We compare the safety of intravenous levetiracetam and fosphenytoin as a second-line treatment in patients with status epilepticus using a nationwide database.

Methods: An observational study conducted with the Japanese Diagnosis Procedure Combination inpatient database identified adult patients who had been admitted for status epilepticus and who had received intravenous diazepam on the day of admission from March 1, 2011 to March 31, 2018. Patients who received intravenous levetiracetam on the day of admission were defined as the levetiracetam group and those who received intravenous fosphenytoin on the day of admission were defined as the fosphenytoin group. Propensity score matching was performed to compare outcomes obtained for the levetiracetam and fosphenytoin groups.

Results: The analysis examined data of 5,667 patients. Overall, 1,403 (25%) patients received levetiracetam; 4,264 (75%) received fosphenytoin. One-to-one propensity score matching created 1,363 matched pairs. No significant difference was found in in-hospital mortality (5.2 vs. 5.1%; odds ratio, 1.03; 95% confidence interval, 0.73–1.46). The proportion of vasopressor use on the day of admission was significantly lower for the levetiracetam group than for the fosphenytoin group (3.2 vs. 4.9%; odds ratio, 0.63; 95% confidence interval, 0.43–0.92). No significant difference was found in other secondary outcomes including total hospitalization cost.

Conclusion: Levetiracetam was related to significantly reduced vasopressor use on the day of admission than that found for fosphenytoin, in adult status epilepticus.

The effects of acupuncture on occipital neuralgia: a systematic review and meta-analysis

Background

Occipital neuralgia is one of the main causes of occipital pain. This systematic review aims to assess the level of evidence in randomized controlled trials (RCTs) on the effects of acupuncture on occipital neuralgia.

Methods

We searched 11 databases and a journal archive from their inception up to December 2019 for relevant RCTs. We did not place any specific restrictions on patients diagnosed with occipital neuralgia, such as age or gender. We included studies that used an acupuncture intervention group, with or without the control group treatment, and that set a control group receiving active, interventional treatment such as medication. For outcomes, we used visual analogue scale (VAS) and effective rate.

Results

We included a total of 11 RCTs. All VAS scores (mean difference [MD] –2.35, 95% confidence interval [CI] –2.84, − 1.86) and effective rate values (odds ratio [OR] 4.96, 95% CI 2.24, 10.96) showed significant differences in effect between acupuncture treatment alone and the control group treatment. Similarly, combined acupuncture treatment with control group treatment also showed significant effects in effective rate (OR 6.68, 95% CI 1.11, 40.37). We performed a subgroup analysis on studies that used acupuncture only as the intervention and reported the effective rate, and found that all acupuncture subgroups showed significant effects compared to the control group treatments. None of the studies reported severe adverse effects.

Conclusions

Although acupuncture only and combined acupuncture treatments showed significant effects compared to medication, the results of this study are inconclusive. Studies with rigorous study design and larger sample sizes are needed to confirm the role of acupuncture in this field.

Trial registration

International prospective register for systematic review (PROSPERO) number CRD42019128050.

The association of patient weight and dose of fosphenytoin, levetiracetam, and valproic acid with treatment success in status epilepticus

The Established Status Epilepticus Treatment Trial was a blinded, comparative-effectiveness study of fosphenytoin, levetiracetam, and valproic acid in benzodiazepine-refractory status epilepticus. The primary outcome was clinical seizure cessation and increased responsiveness without additional anticonvulsant medications. Weight-based dosing was capped at 75 kg. Hence, patients weighing >75 kg received a lower mg/kg dose. Logistic regression models were developed in 235 adults to determine the association of weight (≤ or >75 kg, ≤ or >90 kg), sex, treatment, and weight-normalized dose with the primary outcome and solely seizure cessation. The primary outcome was achieved in 45.1% and 42.5% of those ≤75 kg and >75 kg, respectively. Using univariate analyses, the likelihood of success for those >75 kg (odds ratio [OR] = 0.9, 95% confidence interval [CI] = 0.54-1.51) or >90 kg (OR = 0.85, 95% CI = 0.42-1.66) was not statistically different compared with those ≤75 kg or ≤90 kg, respectively. Similarly, other predictors were not significantly associated with primary outcome or clinical seizure cessation. Our findings suggest that doses, capped at 75 kg, likely resulted in concentrations greater than those needed for outcome. Studies that include drug concentrations and heavier individuals are needed to confirm these findings.

Rapidity of CNS Effect on Photoparoxysmal Response for Brivaracetam vs. Levetiracetam: A Randomized, Double-blind, Crossover Trial in Photosensitive Epilepsy Patients

INTRODUCTION

Both levetiracetam (LEV) and brivaracetam (BRV) eliminate the electroencephalogram photoparoxysmal response (PPR) in the human phase IIa photosensitivity model of epilepsy. The physiochemical properties of BRV differ from those of LEV, having higher potency and lipophilicity plus 10- to 15-fold greater affinity for synaptic vesicle glycoprotein 2A.

OBJECTIVE

We compared the rapidity of the effects of both drugs in the central nervous system (CNS) of patients with photosensitive epilepsy using time to PPR elimination post-intravenous infusion as a pharmacodynamic endpoint.

METHODS

Using a randomized, double-blind, two-period, balanced, crossover design, we tested patients with photosensitive epilepsy with equipotent milligram doses of intravenous LEV 1500 mg versus BRV 100 mg post-15-min intravenous infusion (part 1) and post-5-min intravenous infusion (part 2, same doses). Eight patients per part were deemed sufficient with 80% power to determine a 70% reduction for intravenous BRV:LEV intrapatient time ratio to PPR elimination, with a 0.05 two-sided significance level. Plasma antiseizure medicine concentrations were measured using liquid chromatography/mass spectrometry.

RESULTS

Nine patients [six women; mean age 27.8 years (range 18-42)] completed the study; seven of these participated in both parts 1 and 2. In 31 of 32 instances, patients experienced PPR elimination. In mixed-effects model time analysis, BRV eliminated PPRs more quickly than did LEV (median 2 vs. 7.5 min, respectively). However, no statistically significant difference in BRV:LEV time ratio to PPR elimination was observed for two of our multiple primary outcomes: for the 15-min infusion alone (p = 0.22) or the 5-min infusion alone (p = 0.11). However, BRV was faster when we excluded an outlier patient in part 1 (p = 0.0016). For our remaining primary outcome, parts 1 and 2 data combined, the median intrapatient BRV:LEV time ratio was 0.39 [95% confidence interval (CI) 0.16-0.91], i.e., PPR elimination was 61% faster with BRV, p = 0.039. PPR was completely eliminated in ≤ 2 min in 11 patients with BRV and in four patients with LEV. No period or carryover effects were seen. No serious or severe adverse effects occurred. At PPR elimination (n = 16), median plasma [BRV] was 250 ng/mL (range 30-4100) and median plasma [LEV] was 28.35 μg/mL (range 1-86.7).

CONCLUSION

Outcome studies directly comparing LEV and BRV are needed to define the clinical utility of the response with BRV, which was several minutes faster than that with LEV.

CLINICAL TRIALS

ClinTrials.gov Identifier = NCT03580707; registered 07-09-18.

Pharmacokinetics of rectal levetiracetam as add-on treatment in dogs affected by cluster seizures or status epilepticus

Background

Levetiracetam can be used for seizure control alone or in combination with other antiepileptic medications. A previous study achieved the minimum targeted serum drug concentration after rectal administration of levetiracetam in healthy dogs. The purpose of the present study was to determine the pharmacokinetics of rectal LEV in dogs presented for cluster seizures or status epilepticus and potentially in treatment with other anti-epileptic drugs. Furthermore, preliminary information on response to this treatment as add-on to the standard treatment protocol is reported.

Results

Eight client-owned dogs were enrolled. Plasma levetiracetam concentrations (measured at 0, 30, 60, 90, 120, 180, 240, 360, 720, and 1440 min after drug administration) reached the minimum target concentration (5 μg/ml) at 30 min in all but one patient. At T1 (30 min) the mean concentration was 28.2 ± 15.5 μg/ml. Plasma concentrations remained above the targeted minimum concentration in all patients until 240 min and in 7/8 until 360 min. Six out of eight patients experienced no seizures in the 24-h period after hospitalization and were classified as “responders”.

Conclusions

Minimum plasma levetiracetam concentration can be reached after rectal administration of 40 mg/kg in dogs affected by cluster seizures and status epilepticus and concurrently receiving other antiepileptic drugs. These preliminary results may encourage the evaluation of rectal levetiracetam as an additional treatment option for cluster seizures and status epilepticus in a larger number of dogs.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1522-0) contains supplementary material, which is available to authorized users.

Pharmacotherapy for Refractory and Super-Refractory Status Epilepticus in Adults

Patients with prolonged seizures that do not respond to intravenous benzodiazepines and a second-line anticonvulsant suffer from refractory status epilepticus and those with seizures that do not respond to continuous intravenous anesthetic anticonvulsants suffer from super-refractory status epilepticus. Both conditions are associated with significant morbidity and mortality. A strict pharmacological treatment regimen is urgently required, but the level of evidence for the available drugs is very low. Refractory complex focal status epilepticus generally does not require anesthetics, but all intravenous non-anesthetizing anticonvulsants may be used. Most descriptive data are available for levetiracetam, phenytoin and valproate. Refractory generalized convulsive status epilepticus is a life-threatening emergency, and long-term clinical consequences are eminent. Administration of intravenous anesthetics is mandatory, and drugs acting at the inhibitory gamma-aminobutyric acid (GABA)A receptor such as midazolam, propofol and thiopental/pentobarbital are recommended without preference for one of those. One in five patients with anesthetic treatment does not respond and has super-refractory status epilepticus. With sustained seizure activity, excitatory N-methyl-d-aspartate (NMDA) receptors are increasingly expressed post-synaptically. Ketamine is an antagonist at this receptor and may prove efficient in some patients at later stages. Neurosteroids such as allopregnanolone increase sensitivity at GABAA receptors; a Phase 1/2 trial demonstrated safety and tolerability, but randomized controlled data failed to demonstrate efficacy. Adjunct ketogenic diet may contribute to termination of difficult-to-treat status epilepticus. Randomized controlled trials are needed to increase evidence for treatment of refractory and super-refractory status epilepticus, but there are multiple obstacles for realization. Hitherto, prospective multicenter registries for pharmacological treatment may help to improve our knowledge.

Intravenous levetiracetam in Thai children and adolescents with status epilepticus and acute repetitive seizures

BACKGROUND

Intravenous levetiracetam is an option for treatment of status epilepticus (SE) and acute repetitive seizures (ARS). However, there have been relatively few studies with children and adolescents. Also, an appropriate dosage has yet to be determined.

AIM

This study investigated the safety and the efficacy of levetiracetam for intravenous treatment of convulsive status epilepticus and acute repetitive seizures in children and adolescents.

METHOD

Retrospectively, the study reviewed the medical records of 19 male and 31 female patients under 18 years of age who had received intravenous levetiracetam treatment either for acute repetitive seizures or for convulsive status epilepticus. The patients were admitted between April 1st, 2010 and December 31st, 2011 to the Department of Pediatrics, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. Data were collected on underlying illnesses, etiology of seizures, indication for levetiracetam therapy, initial dosage, rate of infusion, untoward effects during infusion and emerged complications. Efficacy of treatment was defined as the termination of seizure within 30 min of completing levetiracetam infusion and no seizure recurrence within 6 h of initial treatment.

RESULTS

The age range of the 50 patients was from one day to 18 years (mean 79.6 months). The analysis included 52 episodes of 34 acute repetitive seizures (63.4%) and 18 convulsive status epilepticus (34.6%). Infusion rates ranged from 2 to 66 mg/kg/min (mean 29.6). Cessation of seizure was obtained in 59.6% of 52 episodes. Patients with underlying drug resistant epilepsy did not respond to levetiracetam therapy as well as patients with other etiology of seizures. There were no adverse drug reactions or untoward effects observed during the therapy.

CONCLUSION

Intravenous administration of levetiracetam is safe and effective for treatment of acute repetitive seizures and convulsive status epilepticus in children and adolescents. Failure of treatment may be related to underlying drug resistant epilepsy. Further study of appropriate initial dosage and pharmacokinetic variations in the patients is needed as possible explanation of the unresponsiveness.

Intravenous levetiracetam treatment in status epilepticus: A prospective study

OBJECTIVE

To assess the efficacy of intravenous (IV) levetiracetam (LEV) in the treatment of status epilepticus (SE) and treatment outcomes.

METHODS

This study was conducted on patients, who were classified according to the clinical characteristics of their seizures, in the emergency department, neurology, and other services of our hospital. Patients were administrated IV LEV for the treatment of their SE after failing to respond to IV diazepam.

RESULTS

We prospectively investigated 30 patients, 16 females and 14 males whose ages ranged between 17 and 90 years (55.6 ± 19.6). Fourteen patients had convulsive SE (CSE), 11 had nonconvulsive SE (NCSE), and 5 had epilepsia partialis continua (EPC). The patients were given IV LEV with dosages ranging between 1000 and 4000 mg/day. Twenty-nine of the patients continued to receive LEV orally as maintenance treatment. The most common etiologies were cerebrovascular diseases (n = 7) and brain tumors (n = 6). SE was terminated in 23 (76.6%) patients. In the 12 months that followed SE, 9 of our patients (30%) died and 4 patients could not be contacted. Fifteen patients reported having no adverse effects, whereas three had mild adverse effects. No major adverse effects or complications causing disability were observed in twelve patients who were unconscious.

CONCLUSION

Treatment with IV LEV is well-tolerated and effective both in focal and generalized SE. IV LEV has the combined advantage of efficacy, safety, and ease of use, which qualifies it to be the first choice after benzodiazepines (BZD) in the treatment of SE. This is the first prospective study of IV LEV treatment in status epilepticus and has the longest follow-up period, one year.

Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with seizures

This clinical policy from the American College of Emergency Physicians is the revision of a 2004 policy on critical issues in the evaluation and management of adult patients with seizures in the emergency department. A writing subcommittee reviewed the literature to derive evidence-based recommendations to help clinicians answer the following critical questions: (1) In patients with a first generalized convulsive seizure who have returned to their baseline clinical status, should antiepileptic therapy be initiated in the emergency department to prevent additional seizures? (2) In patients with a first unprovoked seizure who have returned to their baseline clinical status in the emergency department, should the patient be admitted to the hospital to prevent adverse events? (3) In patients with a known seizure disorder in which resuming their antiepileptic medication in the emergency department is deemed appropriate, does the route of administration impact recurrence of seizures? (4) In emergency department patients with generalized convulsive status epilepticus who continue to have seizures despite receiving optimal dosing of a benzodiazepine, which agent or agents should be administered next to terminate seizures? A literature search was performed, the evidence was graded, and recommendations were given based on the strength of the available data in the medical literature.

Status epilepticus: current treatment strategies

Status epilepticus is a neurological emergency that is commonly encountered by the neurohospitalist. Successful treatment depends upon the recognition of prolonged seizure activity and the acute mobilization of available resources. Pharmacologic treatment regimens have been shown to decrease the time needed for successful control of seizures and have provided for the rapid administration of anticonvulsant medications. Treatment strategies have evolved so that clinicians can administer effective doses of medication by whatever routes of administration are immediately available. Traditional algorithms for the treatment of status epilepticus have used a stepwise approach to the administration of first-, second-, and third-order medications. More recent options have included aggressive anesthetic doses of medications while second-line medications are being titrated.

Levetiracetam use in the critical care setting

Intravenous (IV) levetiracetam (LEV) is currently approved as an alternative or replacement therapy for patients unable to take the oral form of this antiepileptic drug (AED). The oral form has Food and Drug Administration (FDA) indications for adjunctive therapy in the treatment of partial onset epilepsy ages 1 month or more, myoclonic seizures associated with juvenile myoclonic epilepsy starting with the age of 12 and primary generalized tonic-clonic seizures in people 6 years and older. Since the initial introduction, oral and IV LEV has been evaluated in various studies conducted in the critical care setting for the treatment of status epilepticus, stroke-related seizures, seizures following subarachnoid or intracerebral hemorrhage, post-traumatic seizures, tumor-related seizures, and seizures in critically ill patients. Additionally, studies evaluating rapid infusion of IV LEV and therapeutic monitoring of serum LEV levels in different patient populations have been performed. In this review we present the current state of knowledge on LEV use in the critical care setting focusing on the IV uses and discuss future research needs.

Therapeutic drug monitoring in the neurocritical care unit

PURPOSE OF REVIEW

Various antiepileptics, sedative and anesthetic agents are used in the neurocritical care setting and therapeutic drug monitoring (TDM) has been proposed as a means to individualize dosing to ensure efficacy, avoid toxicity, and to account for drug-drug interactions. The purpose of this review is to highlight key articles relating to TDM published in the last 5 years with a focus on drug therapy for seizures, status epilepticus, and traumatic brain injury.

RECENT FINDINGS

Current evidence supports TDM of first-generation antiepileptics, and free-level monitoring for phenytoin and valproic acid is recommended in the neurocritical care population. There are insufficient data to recommend routine TDM of second-generation antiepileptics at this time. In traumatic brain injury, routine TDM of barbiturate infusions appears to be of little value in guiding or evaluating patient response to therapy except to differentiate between drug-induced coma and brain death. Although TDM of sedative agents has been studied, the use of clinical sedation scales is preferred over TDM in evaluating a patient's level of sedation.

SUMMARY

Therapeutic drug monitoring plays an important role in the care of patients in the neurocritical care setting but is applicable only to a limited number of drugs.

Guidelines for the evaluation and management of status epilepticus

Status epilepticus (SE) treatment strategies vary substantially from one institution to another due to the lack of data to support one treatment over another. To provide guidance for the acute treatment of SE in critically ill patients, the Neurocritical Care Society organized a writing committee to evaluate the literature and develop an evidence-based and expert consensus practice guideline. Literature searches were conducted using PubMed and studies meeting the criteria established by the writing committee were evaluated. Recommendations were developed based on the literature using standardized assessment methods from the American Heart Association and Grading of Recommendations Assessment, Development, and Evaluation systems, as well as expert opinion when sufficient data were lacking.

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.

Treatment strategies for refractory status epilepticus

PURPOSE OF REVIEW

Status epilepticus is one of the most common emergencies in neurology, and every third patient does not respond to adequate first-line treatment. Refractory status epilepticus may be associated with increased morbidity and mortality, and new treatment options are urgently required. This review critically discusses recently published data regarding the role of 'new' antiepileptic drugs, the efficacy and safety of anesthetic agents, and the overall clinical outcome that is an integral part of treatment decisions.

RECENT FINDINGS

In complex partial status epilepticus, levetiracetam may be administered after failure of first-line and/or second-line agents. Lacosamide may be an interesting new adjunct, but reliable data are pending. In the treatment of refractory generalized convulsive status epilepticus, propofol seems to be as efficient as barbiturates. The latter are associated with prolonged ventilation times due to redistribution kinetics, whereas the former bears the risk of propofol infusion syndrome if administered continuously. Even after prolonged treatment with anesthetics over weeks, survival with satisfactory functional outcome is possible.

SUMMARY

Unambiguous recommendations regarding treatment strategies for refractory status epilepticus are limited by a lack of reliable data. Therefore, randomized controlled trials or at least prospective observational studies based on strict protocols incorporating long-term outcome data are urgently required.

Levetiracetam for treatment of neonatal seizures

Neonatal seizures are often refractory to treatment with initial antiseizure medications. Consequently, clinicians turn to alternatives such as levetiracetam, despite the lack of published data regarding its safety, tolerability, or efficacy in the neonatal population. We report a retrospectively identified cohort of 23 neonates with electroencephalographically confirmed seizures who received levetiracetam. Levetiracetam was considered effective if administration was associated with a greater than 50% seizure reduction within 24 hours. Levetiracetam was initiated at a mean conceptional age of 41 weeks. The mean initial dose was 16 ± 6 mg/kg and the mean maximum dose was 45 ± 19 mg/kg/day. No respiratory or cardiovascular adverse effects were reported or detected. Levetiracetam was associated with a greater than 50% seizure reduction in 35% (8 of 23), including seizure termination in 7. Further study is warranted to determine optimal levetiracetam dosing in neonates and to compare efficacy with other antiseizure medications.

Safety of non-therapeutic levetiracetam ingestions--a poison center based study

BACKGROUND

Very limited data is available regarding the safety of levetiracetam in cases of unintentional or intentional ingestions.

METHODS

All cases of single agent ingestions of levetiracetam, excluding adverse drug reactions (ADRs), reported to 61 American poison control centers during 2000-2009 were identified. Demographics, dose, symptoms, and medical outcome were abstracted from each case record.

RESULTS

A total of 222 cases of single agent levetiracetam ingestions were reported during the study period. Median age was 14.0 years (IQR: 2.0 years, 39.0 years) and 51.8% were female. In 207 of 222 cases (93.2%) medical outcome was known. No deaths were reported and only 1 (0.5%) case resulted in a major outcome and 3 (1.4%) cases resulted in moderate outcomes. Minor, minimal, or no effects were reported in 198 (89.2%) cases. In 27 (12.2%) cases, ingestion was intentional and in 192 (86.5%) unintentional. There were no major outcomes and only one case (1.4%) of moderate outcome in 74 children aged 6 years or less. All ingestions in these children were unintentional.

CONCLUSIONS

In this study with a limited number of cases, intentional and unintentional ingestions of levetiracetam were safe in the majority of cases.

Analytical validation of microdialysis analyzer for monitoring glucose, lactate and pyruvate in cerebral microdialysates

BACKGROUND

Cerebral microdialysis is a valuable tool for neurochemical monitoring of acute brain injury. We performed an independent analytical validation of glucose, lactate and pyruvate methods on the new ISCUS(flex) new analyzer developed by CMA Microdialysis.

METHODS

Evaluation of analytical parameters included limit of detection, limit of quantification, linearity, intra- and inter-assay imprecision expressed as the coefficient of variation (CV), recovery, inter-sample and inter-reagent contamination, drug and bilirubin interferences, sample stability, method comparison.

RESULTS

Linearity ranges were 0.1-25 mmol/L, 0.2-12 mmol/L and 19-1500 μmol/L for glucose, lactate and pyruvate respectively. For critical threshold, intra- and inter-assay CVs were 3.1/4.5% for glucose (1 mmol/L), 3.5/4% for lactate (4 mmol/L) and 3.3/4.3% for pyruvate (100 μmol/L). Inter-assay CVs for lactate/pyruvate (LPR) and lactate/glucose (LGR) ratios were 5.9% and 6.0% respectively. For glucose, lactate, pyruvate, LPR and LGR, the reference change values (RCV) were 20%, 26%, 20%, 27% and 28% respectively. Practically, variations below 27% between two successive LPR values could not be interpreted as significant.

CONCLUSION

These data prove that ISCUS(flex) has the qualities required for clinical application in neuro-intensive care. Correct clinical interpretation of data need the implementation of a strict quality control program and strong cooperation between clinicians and biologists.

Medical treatment of pediatric status epilepticus

Status epilepticus (SE) is a common pediatric neurologic emergency that refers to a prolonged seizure or recurrent seizures without a return to baseline mental status between seizures. Appropriate treatment strategies are necessary to prevent prolonged SE and its associated morbidity and mortality. This review discusses the importance of a rapid and organized management approach, reviews data related to commonly utilized medications including benzodiazepines, phenytoin, phenobarbital, valproate sodium, and levetiracetam, and then provides a sample SE management algorithm.

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.

Intravenous Levetiracetam as first-line treatment of status epilepticus in the elderly

BACKGROUND

Status epilepticus is a condition of prolonged/repetitive seizures that often occurs in the elderly. Treatment in the elderly can be complicated by serious side effects associated with traditional drugs.

OBJECTIVE

The aim of this pilot study was to evaluate the short-term efficacy/safety of intravenously administered LEV (IVLEV) as the treatment of choice for SE in the elderly.

METHODS

We enrolled nine elderly patients (five female/four male; median age 78 years) with SE. Two patients had a previous diagnosis of epilepsy; in the remaining seven, SE was symptomatic. SE was convulsive in five and non-convulsive in four. All the patients presented concomitant medical conditions (arrhythmias/respiratory distress/hepatic diseases). As the traditional therapy for SE was considered unsafe, IVLEV was used as first-line therapy (loading dose of 1500 mg/100 ml/15 min, mean maintenance daily dose of 2500 mg/24 h) administered during video-EEG monitoring.

RESULTS/CONCLUSIONS

In all the patients but one, IVLEV was effective in the treatment of SE and determined either the disappearance of (7/8), or significant reduction in (1/8), epileptic activity; no patient relapsed in the subsequent 24 h. No adverse events or changes in the ECG/laboratory parameters were observed. These data suggest that IVLEV may be an effective/safe treatment for SE in the elderly.

Management of refractory status epilepticus at a tertiary care centre in a developing country

BACKGROUND

Refractory status epilepticus (RSE) is a common Neurological Emergency with increased mortality and morbidity in developing countries where facilities of intubation, adequate ventilation, Intensive Care Units (ICUs) and general anaesthesia are not ubiquitously available. Treatment protocols use antiepileptic drugs (AEDs) and need ICU facilities after failure of standard AEDs. Our aim was to see the response to two additional drugs in the armamentarium against refractory status, that is, valproate and levetiracetam.

METHODS

Patients with generalized RSE admitted in neurology and neurosurgery services at AIIMS during December 2006 to June 2008 were included in the study. The patients were allotted to two groups based on certain criteria. Demographic details, reason for delay, etiology precipitating status, ongoing AEDs therapy, duration of status, the time taken for cessation along with clinical, EEG and MRI correlates were noted. Outcome parameters were analyzed by an independent blinded observer.

RESULTS

82 patients with RSE were studied out of which 41 patients were given IV valproate (Group A) and 41 patients were given IV levetiracetam (Group B). Cessation of status failed in 13 patients in valproate group and 11 patients in levetiracetam group. Majority of the patients did not require ICU settings despite being classified as refractory.

CONCLUSION

RSE can be controlled with intravenous loading and maintenance of valproate or levetiracetam which do not cause respiratory depression, hypotension, need of intubation and ICU care. These must always be considered in a developing country scenario where ICU facilities are not always available or while transporting to centres where these facilities are available.