Increased Levetiracetam Clearance Associated with a Breakthrough Seizure in a Pregnant Patient Receiving Once/Day Extended-Release Levetiracetam

Therapeutic Drug Monitoring of Antiepileptic Drugs in Women with Epilepsy Before, During, and After Pregnancy

During pregnancy, the pharmacokinetics of an antiepileptic drug is altered because of changes in the clearance capacity and volume of distribution. These changes may have consequences for the frequency of seizures during pregnancy and fetal exposure to antiepileptic drugs. In 2009, a review was published providing guidance for the dosing and therapeutic drug monitoring of antiepileptic drugs during pregnancy. Since that review, new drugs have been licensed and new information about existing drugs has been published. With this review, we aim to provide an updated narrative overview of changes in the pharmacokinetics of antiepileptic drugs in women during pregnancy. In addition, we aim to formulate advice for dose modification and therapeutic drug monitoring of antiepileptic drugs. We searched PubMed and the available literature on the pharmacokinetic changes of antiepileptic drugs and seizure frequency during pregnancy published between January 2007 and September 2018. During pregnancy, an increase in clearance and a decrease in the concentrations of lamotrigine, levetiracetam, oxcarbazepine's active metabolite licarbazepine, topiramate, and zonisamide were observed. Carbamazepine clearance remains unchanged during pregnancy. There is inadequate or no evidence for changes in the clearance or concentrations of clobazam and its active metabolite N-desmethylclobazam, gabapentin, lacosamide, perampanel, and valproate. Postpartum elimination rates of lamotrigine, levetiracetam, and licarbazepine resumed to pre-pregnancy values within the first few weeks after pregnancy. We advise monitoring of antiepileptic drug trough concentrations twice before pregnancy. This is the reference concentration. We also advise to consider dose adjustments guided by therapeutic drug monitoring during pregnancy if the antiepileptic drug concentration decreases 15-25% from the pre-pregnancy reference concentration, in the presence of risk factors for convulsions. If the antiepileptic drug concentration changes more than 25% compared with the reference concentration, dose adjustment is advised. Monitoring of levetiracetam, licarbazepine, lamotrigine, and topiramate is recommended during and after pregnancy. Monitoring of clobazam, N-desmethylclobazam, gabapentin, lacosamide, perampanel, and zonisamide during and after pregnancy should be considered. Because of the risk of teratogenic effects, valproate should be avoided during pregnancy. If that is impossible, monitoring of both total and unbound valproate is recommended. More research is needed on the large number of unclear pregnancy-related effects on the pharmacokinetics of antiepileptic drugs.

Population Pharmacokinetics of Levetiracetam: A Systematic Review

BACKGROUND

Levetiracetam has been widely used as a treatment option for different types of epilepsy in both adults and children. Because of its large between-subject variability, several population pharmacokinetic studies have been performed to identify its pharmacokinetic covariates, and thus facilitate individualised therapy.

OBJECTIVE

The aim of this review was to provide a synopsis for population pharmacokinetic studies of levetiracetam and explore the identified influencing covariates.

METHODS

We systematically searched the PubMed and Embase databases from inception to 30 June 2020. The information on study designs, target population, model characteristics, and identified covariates was summarised. Moreover, the pharmacokinetic profiles were compared among neonates, children, and adults.

RESULTS

Fourteen studies were included, among which two involved neonates, four involved children, two involved both children and adults, and six involved adults only. The median value of apparent clearance for children (0.074 L/h/kg [range 0.038-0.079]) was higher than that for adults (0.054 L/h/kg [range 0.039-0.061]). Body weight was found to significantly influence the apparent clearance and volume of distribution, whereas renal function influenced the clearance. Likewise, coadministration with enzyme-inducing antiepileptic drugs (such as carbamazepine and phenytoin) increased the drug clearance by 9-22%, whereas coadministration with valproate acid decreased it by 18.8%.

CONCLUSION

Levetiracetam dose regimen is dependent on the body size and renal function of patients. Further studies are needed to evaluate levetiracetam pharmacokinetics in neonates and pregnant women.

[Modern aspects of antiepileptic therapy during pregnancy]

This review of literature is devoted to contemporary issues of antiepileptic therapy in pregnancy, with identifying the most effective drug according to publications from 2006 to 2016 (PUBMED, MEDline, The Cochrane Lb.). The review presents the current published data on the incidence of seizures in pregnant women, specificity of therapy with antiepileptic drugs (AEDs), frequency of fetal malformations in pregnant women taking AEDs regularly and their dependence on the frequency, dosage and nature of therapy. The authors studied and analyzed the literature on antiepileptic therapy with AED for the last ten years and selected AED with the least teratogenic effect and less side-effects. Lamotrigine, phenytoin, carbamazepine, valproic acid, phenobarbital were studied. In addition to classic AEDs, new AEDs (vigabatrin, gabapentin, topiramate, tiagabine, oxcarbazepine, levetiracetam, pregabalin) were investigated. Over the past decade, the use of new-generation AEDs has increased. It has been found that the risk of birth defects in children is associated with high doses of drugs and polytherapy compared to monotherapy. New data of recent studies showed the effect of psychotropic drugs on the fetus allowing to assess the 'risk/benefit' ratio and develop recommendations on rational pharmacotherapy of epilepsy in pregnancy.

Therapeutic levetiracetam monitoring during pregnancy: "mind the gap"

Background

Epilepsy is one of the most common chronic neurological conditions and its treatment during pregnancy is challenging. Levetiracetam (LEV) is an antiepileptic medication frequently used during pregnancy. Only a few small studies have been published on LEV monitoring during pregnancy, demonstrating decreased serum LEV levels during the first and second trimester; however, the most significant decrease was observed during the third trimester of pregnancy. In this study we aimed to evaluate LEV pharmacokinetics during different stages of pregnancy.

Methods

We followed up and monitored serum levels of pregnant women treated with LEV for epilepsy.

Results

Fifty-nine women with 66 pregnancies during the study period were included. The lowest raw LEV serum concentrations were observed during the first trimester. Compared with the pre-pregnancy period, raw serum concentration was lower by 5.76 mg/L [95% confidence interval (CI) (2.78, 8.75), p = 0.039] during the first trimester. Comparing the decrease in the first trimester with either the second or the third, no significant changes were observed (p = 0.945, p = 0.866). Compared with pre-pregnancy measurements, apparent clearance was increased by 71.08 L/day [95%CI (16.34, 125.83), p = 0.011] during the first trimester. About 30% of LEV serum levels during pregnancy were below the laboratory quoted reference range.

Conclusions

Raw LEV serum levels tend to decrease during pregnancy, mainly during the first trimester contrary to previous reports. Monitoring of LEV serum levels is essential upon planning pregnancy and thereafter if pre-pregnancy LEV levels are to be maintained. However, more studies are needed to assess the correlation with clinical outcome.

Levetiracetam use during pregnancy in women with epilepsy: Preliminary observations from a tertiary care center in Northern India

INTRODUCTION

Data on efficacy and safety of levetiracetam (LEV) during pregnancy is still limited. We analyzed efficacy and safety of LEV during pregnancy in North Indian women with epilepsy (WWE) which is being presented here.

PATIENTS AND METHODS

This retrospective study included 99 WWE (on treatment with a single antiepileptic drug [AED]) who were evaluated in medical-surgical disorder antenatal clinic of the department of obstetrics and gynecology at a tertiary care teaching hospital and referral center in North India. All the obstetric and fetal data as well as data pertaining to epilepsy were noted meticulously.

RESULTS

In this study (n = 99), 35 women received carbamazepine, 28 received LEV, 15 received valproate (VPA), 13 received phenytoin (PHT), three each received oxcarbazepine and lamotrigine, respectively, and two received clobazam. Although the use of VPA was associated with significantly better control of seizures compared to LEV, its use was associated with higher risk of major congenital malformations (13.3%). The incidence of gestational hypertension was lower while incidence of fetal distress was significantly higher in WWE receiving PHT during pregnancy. None of the child born to pregnant women receiving LEV had any congenital malformation.

CONCLUSION

LEV is a first-line AED during pregnancy. Future prospective studies using therapeutic drug monitoring during pregnancy may further help in establishing its role during pregnancy.

A Systematic Appraisal of Neurosurgical Seizure Prophylaxis: Guidance for Critical Care Management

Clinical decisions are often made in the presence of some uncertainty. Health care should be based on a combination of scientific evidence, clinical experience, economics, patient value judgments, and preferences. Seizures are not uncommon following brain injury, surgical trauma, hemorrhage, altered brain metabolism, hypoxia, or ischemic events. The impact of seizures in the immediate aftermath of injury may be a prolonged intensive care stay or compounding of the primary injury. The aim of brain injury management is to limit the consequences of the secondary damage. The original intention of seizure prophylaxis was to limit the incidence of early-onset seizures. However, clinical trials have been equivocal on this point, and there is concern about the adverse effects of antiepileptic drug therapy. This review of the literature raises concerns regarding the arbitrary division of seizures into early onset (7 d) and late onset (8 d and beyond). In many cases it would appear that seizures present within 24 hours of the injury or after 7 days, which would be outside of the scope of current seizure prophylaxis guidance. There also does not appear to be a pathophysiological reason to divide brain injury-related seizures into these timeframes. Therefore, a solution to the conundrum is to reevaluate current practice. Prophylaxis could be offered to those receiving intensive care for the primary brain injury, where the impact of seizure would be detrimental to the management of the brain injury, or other clinical judgments where prophylaxis is prudent. Neurosurgical seizure management can then focus attention on which agent has the best adverse effect profile and the duration of therapy. The evidence seems to support levetiracetam as the most appropriate agent. Although previous reviews have identified an increase cost associated with the use of levetiracetam, current cost comparisons with phenytoin demonstrate a marginal price differential. The aim of this review is to assimilate the applicable literature regarding seizure prophylaxis. The final guidance is a forum upon which further clinical research could evaluate a new seizure prophylaxis paradigm.