Lamotrigine in pregnancy: clearance, therapeutic drug monitoring, and seizure frequency

UGT polymorphisms and epileptic seizure control in pregnant women treated with Lamotrigine

OBJECTIVE

We investigated whether polymorphisms of selected uridine-diphospho-glucuronosyl-tranferases (UGT) involved in Lamotrigine (LTG) metabolism are associated with seizure control during pregnancy and post-partum in women with epilepsy treated with LTG.

METHODS

Single nucleotide polymorphisms for UGT1A4 * 2 (P24T, c.70 C>A), UGT1A4 * 3 (L48V c.142 T > G) and UGT2B7 * 2 (H268Y, c.802 C>T), were determined in 47 pregnancies in 40 non-smoking women with LTG-treated epilepsy. Retrospectively collected data included seizure type and frequency, LTG dosage and LTG plasma level changes during pregnancy and PP. We evaluated the effect of UGT genotype on seizure control throughout pregnancy and post-partum (T1-PP).

RESULTS

In 47 pregnancies, seizure control was achieved in 60 % in T1-PP. Occurrence of seizures T1-PP was not directly associated with UGT genotype, but with having pre-pregnant seizures within the past 6 months (OR 8.33 (95 % CI 1.53-45.41, p = 0.01) and 12 months (OR 5.25, 95 % CI 1.47-18.77, p = 0.02) preceding pregnancy.

CONCLUSION

We did not observe any proximate effect of UGT genotypes on seizure control during pregnancy and post-partum in women treated with LTG, but seizures within the year preceding pregnancy had a significant impact.

Special Issues in Medical Management: Hormones and Pregnancy in Epilepsy

The relationship between sex hormones and epilepsy involves intricate interactions that influence seizure susceptibility, reproductive health, and treatment approaches. Estrogen generally exhibits proconvulsant effects, while progesterone and its metabolite allopregnanolone have anticonvulsant properties. Variability in hormone levels during the menstrual cycle can exacerbate seizures, a phenomenon known as catamenial epilepsy. Effective management often requires a tailored combination of antiseizure medications (ASMs) and hormonal therapies. Women and others of childbearing potential face unique challenges, including higher rates of menstrual dysfunction, potential exacerbation of seizures during pregnancy, and increased risks associated with hormonal contraception and menopause. Careful ASM selection is critical to ensure maternal and fetal safety, with lamotrigine, levetiracetam, and oxcarbazepine being preferred options. Postpartum ASM adjustments and breastfeeding considerations are also essential for optimizing outcomes. Emerging research highlights the impact of hormonal interactions in transgender individuals undergoing gender-affirming therapies. For transwomen, estrogen could heighten seizure risk. Close monitoring and collaboration between health care providers are crucial for personalized care. The complex interplay between hormones and epilepsy underscores the need for ongoing research and individualized approaches to optimize seizure control and address the unique reproductive health needs of people with epilepsy.

Association of seizure control during pregnancy with adverse offspring outcomes in women with epilepsy

BACKGROUND

Information on fetal risks with maternal seizures during pregnancy is scarce. This study investigates seizure control during pregnancy and fetal risks associated with maternal seizures in different stages of pregnancy among pregnant women with epilepsy (PWWE).

METHODS

The nested case-control study enrolled PWWE between 2009 and 2023 in China. Information was obtained on maternal seizures, antiseizure medication (ASM), folic acid supplementation and pregnancy outcomes. The primary outcome was composite including major congenital malformations (MCMs), neurodevelopmental delay, low birth weight (LBW) and fetal death. Univariate and multivariate logistic regression analyses were conducted to adjust for ASM effects and other confounders.

RESULTS

Among 1110 pregnancies from 934 PWWE included, 56.6% experienced seizures. Seizure deterioration during pregnancy compared with prepregnancy was observed in 25.9% of pregnancies, while 20.9% experienced worsening seizures from the first to second or third trimesters. Seizures (adjusted OR (aOR) 1.472, 95% CI 1.024 to 2.137), particularly status epilepticus (aOR 2.906, 95% CI 1.364 to 5.93), generalised tonic-clonic seizures (aOR 1.581, 95% CI 1.066 to 2.354) and seizure deterioration (aOR 1.829, 95% CI 1.233 to 2.69) were associated with composite adverse outcomes. Specifically, seizures occurring (aOR 2.324, 95% CI 1.320 to 4.084) or deteriorating (aOR 2.396, 95% CI 1.471 to 3.866) during second and third trimesters were associated with the risk of LBW. No significant association was found between seizures and MCMs.

CONCLUSIONS

While nearly half of PWWE remain seizure-free during pregnancy, those who do experience seizures face increased risks of adverse offspring outcomes. For PWWE, every effort should be made to optimise seizure control in order to minimise risks to both mother and child.

TRIAL REGISTRATION NUMBER

ChiCTR2100046318.

Seizure control and pregnancy outcomes in Chinese women with epilepsy: A prospective multicenter cohort study

OBJECTIVE

Data on seizure and pregnancy outcomes in Asian women with epilepsy are limited. We used a Chinese pregnancy registry to assess the impact of seizures and antiseizure medications (ASMs) on pregnant women with epilepsy and their children.

METHODS

This is an ongoing prospective multicenter study of pregnant women with epilepsy that has been running since 2012. Eligible participants were consecutively enrolled and had multiple follow-ups up to one year after delivery. We assessed ASM use and seizure frequency during pregnancy to establish potential effects on the mothers and infants and to identify relevant correlations. Descriptive analysis was used to estimate proportions. Logistic regression was used to identify the relevant risk factors and correlations.

RESULTS

Of 1907 potentially eligible pregnancies, we included 1763 in 1483 women with known outcomes from January 2012 to February 2022. There were 1278 completed pregnancies, resulting in 1270 live births. Tonic-clonic seizures occurred in fewer than one-third of pregnancies in each trimester. Compared with baseline, seizure frequency remained relatively stable throughout approximately two-thirds of the pregnancies. The majority were on ASM, with levetiracetam (39%), oxcarbazepine (19%), and lamotrigine (17.5%) being the most commonly used. In contrast, only 14.2% of pregnancies were exposed to valproate (VPA). There was a declining trend in treatment adjustments over the course of the pregnancy, with most changes occurring in the first trimester. The incidence of major congenital malformation (MCM) was 4.4%, with cardiogenic and orofacial anomalies being the most common. VPA use (p < .001), lack of folic acid use (p = .009), positive family history of MCM (p = .006), and topiramate (TPM) use (p = .04) were the most important predictors of MCM.

SIGNIFICANCE

Seizure control remained stable for the majority of women with epilepsy throughout pregnancy. Family history of MCM, VPA use, TPM use, and not taking folic acid were strong predictors of MCM in infants born to women with epilepsy.

Development of a PBPK Model for Lamotrigine which Incorporates Metabolism by UGT2B10: Impact of UGT2B10 Poor Metabolizer Phenotype and Pregnancy

An updated physiologically based pharmacokinetic (PBPK) model was developed for lamotrigine by incorporating a component of metabolism due to a UDP-glucuronyltransferase (UGT) 2B isozyme. This was assigned to UGT2B10 based on recent in vitro data in our laboratory demonstrating metabolism of lamotrigine by this isozyme (Tang et al. AAPS J 26:107, 2024). The PBPK model developed in this work was able to reasonably recapitulate the exposure of lamotrigine after single (IV and Oral) and multiple (Oral) doses. The predicted/observed maximal plasma concentration (Cmax) ratio ranged from 0.8 to 1.4 across all simulated studies and for 16 out of 18 simulated studies was between 0.8 and 1.25. Similarly, the predicted/observed area under the curve (AUC) ratio ranged from 0.6 to 1.44 across all simulated studies and for 18 out of 26 of the simulated studies the ratio was between 0.8 and 1.25. There was a slight tendency to overpredict the lamotrigine AUC on multiple dosing. The median predicted fraction metabolised (fm) by UGT2B10 in the model was 60%. With this fm value, the in vivo clinical DDI between lamotrigine and valproate was reasonably recapitulated considering only UGT2B10 inhibition (Predicted/Observed AUC ratios ranged from 0.65 - 1.2). Information on the prevalence of UGT2B10 poor metabolizer phenotypes and longitudinal changes in UGT1A4 and UGT2B10 expression during pregnancy were incorporated into the PBPK model and the plasma concentrations in subjects with different UGT2B10 phenotypes and in different trimesters of pregnancy were simulated. The simulated concentrations in pregnant subjects were in line with those reported during pregnancy.

Characterization of lamotrigine disposition changes during and after pregnancy in women with epilepsy

BACKGROUND

Lamotrigine clearance can change drastically in pregnant women with epilepsy (PWWE) making it difficult to assess the need for dosing adjustments. Our objective was to characterize lamotrigine pharmacokinetics in PWWE during pregnancy and postpartum along with a control group of nonpregnant women with epilepsy (NPWWE).

METHODS

The Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) study was a prospective, observational, 20 site, cohort study conducted in the United States (December 2012 and February 2016). Inclusion criteria included patients aged 14-45 years, gestational age <20 weeks at the time of recruitment, IQ >70 points, and receiving lamotrigine. PWWE participated throughout pregnancy and 18 months postpartum with NPWWE having matched visit intervals. Plasma drug and hormone concentrations were measured at each of the seven visits. A population mixed-effects modeling approach was used to describe lamotrigine clearance change.

RESULTS

221 (170 PWWE, 51 NPWWE) women were included. Baseline apparent clearance (clearance for NPWWE and when not pregnant for PWWE) was identical between the two groups (2.79 L/hour. with 36% between-subject variability). Two subpopulations were identified in PWWE: ~91% of PWWE had a maximum increase to 275% of baseline clearance with 50% of the maximum increase reached at 12 weeks gestational age and ~9% had no significant change in clearance during gestation. Following delivery, a first-order mono-exponential decline (1.27 weeks-1) in clearance as a function of postpartum week described a return of clearance to baseline. The use of estrogen-based medication and enzyme-inducing antiseizure medications increased nonpregnant clearance by a further 0.33-fold and 0.84-fold, respectively.

DISCUSSION

During pregnancy, 91% of PWWE experience a 275% change from nonpregnant baseline in lamotrigine clearance whereas the remaining PWWE experience little to no change. Nonpregnant baseline lamotrigine clearance was higher in both PWWE and NPWWE with the administration of oral estrogen-containing medications. Our results are of clinical importance as they indicate a subpopulation without the need for substantial dose changes during pregnancy and a source of potential difference across nonpregnant individuals.

Development and internal validation of a prognostic model for predicting tonic-clonic seizures during pregnancy in women with epilepsy

BACKGROUND

We aim to develop a model to predict the probability of tonic-clonic seizures in women with epilepsy (WWE) at any point during pregnancy until six weeks postpartum.

METHODS

We conducted a screening of patients diagnosed with epilepsy and who were pregnant, at a tertiary hospital in China, during the period of 1 January 2010 to 31 December 2020. We then followed up with these patients for at least one year postpartum. A total of 271 eligible patients were included in the cohort. The outcome was the occurrence of a tonic-clonic seizure during pregnancy or within six weeks postpartum. Predictors were screened through univariate analysis, and models were fitted through multivariate logistic regression analysis. Further, we compared the WMU model with the AntiEpileptic drug Monitoring in PREgnancy (EMPiRE) model in terms of discrimination (the area under receiver operating characteristic curve [AUC]), accuracy (GiViTI calibration belt), decision curve analysis (DCA), net reclassification index (NRI), and integrated discrimination improvement (IDI). Finally, we plotted a nomogram of the WMU model.

RESULTS

Of the 271 pregnant WWE, 62 patients (22.9%) had the outcome. The WMU model included three predictors: age at the time of pregnancy, admission to hospital for seizures in previous pregnancy, and seizures in the 12 months before pregnancy. Compared to the EMPiRE model, the AUC value of the WMU model was higher (0.76 vs. 0.639, P < 0.05). GiViTI calibration belt showed that the predicted risks of the WMU model were mostly consistent with the observed risks. In terms of DCA, the WMU model revealed the highest net proportional benefit for predicted probability thresholds between 10% and 90%. Additionally, our model exhibited better reclassification performance than the EMPiRE model (NRI: 0.331, P < 0.01 and IDI: 0.129, P < 0.01).

CONCLUSION

We attempted to develop a prognostic model for predicting the risk of tonic-clonic seizures in pregnant WWE. The WMU model showed good performance, but without external validation, it is unclear whether WMU model could be generalized.

Peripartum seizures in women with epilepsy and multidisciplinary considerations as to how they can be prevented

OBJECTIVE

Seizures during labor are reported in 3.5% of women with epilepsy (WWE) and can result in both maternal and fetal morbidity. In response to an anecdotal increase in WWE developing seizures in labor or peripartum (up to 24 h post-partum), a review of patients managed in our service was undertaken to define the incidence of peripartum seizures and determine learning points.

METHODS

A retrospective review of all cases of WWE having peripartum seizures from 2017 to 2022 in our institution was undertaken. Each case was reviewed by the multidisciplinary team (MDT) and common themes identified.

RESULTS

In total, 106 WWE received pregnancy care in the study period, of whom 8/106 (7.5%) had a seizure in the peripartum period. The MDT-agreed learning points included importance of pre-pregnancy counseling, prompt up-titration of antiepileptic drugs where indicated and recommendations for the management in the peripartum period.

SIGNIFICANCE

We concluded that the peripartum period remains a high-risk time for seizures in WWE. There is little evidence to support guidelines for the management of WWE in the peripartum period. In the absence of this evidence, sharing experience may help those managing such women to improve care and reduce risk during this vulnerable time.

Adverse events associated with carbamazepine: a pharmacovigilance study using the FDA Adverse Event Reporting System

INTRODUCTION

Carbamazepine (CBZ) is a commonly used antiseizures medications (ASM), but its adverse drug reactions (ADRs) can impact the successful management of epilepsy. There are currently limited systematic studies on ADRs related to CBZ, necessitating further investigation.

AREAS COVERED

Using the FDA Adverse Event Reporting System (FAERS) database , we extracted reports where CBZ was the primary suspect, conducting subgroup analyses stratified by sex and age. Four risk signal detection methods ROR, PRR, BCPNN, and EGBM were employed to systematically analyze the ADRs associated with CBZ.

EXPERT OPINION

In the epilepsy population, ADRs related to CBZ often involve examinations, hereditary disorders, and infections. Subgroup analysis showed differences in ADR signals among male, female, elderly, and young patients. Human Herpesvirus 6 Infection and Dermatitis Exfoliative were consistent CBZ-induced ADRs, unaffected by age or sex. The study also identified previously overlooked ADRs such as bone metabolism abnormalities, ocular toxicity, and ototoxicity. Many ADRs linked to CBZ remain underreported. It is crucial to enhance monitoring and information dissemination about CBZ use in epileptic patients. Adjusting medication regimens for high-risk individuals, potentially incorporating acupuncture, traditional Chinese medicine, or alternative anti-seizure medications, should be considered when necessary.

PBPK Modeling of Lamotrigine and Efavirenz during Pregnancy: Implications for Personalized Dosing and Drug-Drug Interaction Management

This study aimed to model the pharmacokinetics of lamotrigine (LTG) and efavirenz (EFV) in pregnant women using physiologically based pharmacokinetic (PBPK) and pregnancy-specific PBPK (p-PBPK) models. For lamotrigine, the adult PBPK model demonstrated accurate predictions for pharmacokinetic parameters. Predictions for the area under the curve (AUC) and peak plasma concentration (Cmax) generally agreed well with observed values. During pregnancy, the PBPK model accurately predicted AUC and Cmax with a prediction error (%PE) of less than 25%. The evaluation of the EFV PBPK model revealed mixed results. While the model accurately predicted certain parameters for non-pregnant adults, significant discrepancies were observed in predictions for higher doses (600 vs. 400 mg) and pregnant individuals. The model's performance during pregnancy was poor, indicating the need for further refinement to account for genetic polymorphism. Gender differences also influenced EFV pharmacokinetics, with lower exposure levels in females compared to males. These findings highlight the complexity of modeling EFV, in general, but specifically in pregnant populations, and the importance of validating such models for accurate clinical application. The study highlights the importance of tailoring dosing regimens for pregnant individuals to ensure both safety and efficacy, particularly when using combination therapies with UGT substrate drugs. Although drug-drug interactions between LTG and EFV appear minimal, further research is needed to improve predictive models and enhance their accuracy.

The impact of pregnancy-related hormonal and physiological changes on antiseizure medications: expert perspective

INTRODUCTION

Epilepsy is a disorder of recurrent, unprovoked seizures affecting approximately 15 million individuals of childbearing potential worldwide. Patients with epilepsy rely on regular daily therapy with antiseizure medications (ASMs). Furthermore, ASMs are also prescribed for other neuropsychiatric indications (e.g. bipolar disorder, pain, migraines) with over 2% of the pregnancies in the United States involving prenatal exposure to ASMs.

AREAS COVERED

ASM concentrations are affected by hormonal and physiological changes in pregnancy, including increases in renal and hepatic blood flow, decreased protein binding, and changes in enzyme activity. Clearance changes typically reverse within a few weeks after delivery. During pregnancy, many ASMs, such as lamotrigine, levetiracetam, and oxcarbazepine, should have serum concentrations monitored and doses increased to maintain the individualized target range for seizure control. ASMs metabolized via glucuronidation, primarily lamotrigine, undergo marked increases in clearance throughout pregnancy, requiring about 3-fold the pre-pregnancy daily dose by delivery. Postpartum, ASM doses are usually decreased over several weeks to prevent drug toxicity.

EXPERT OPINION

In the future, the development of a physiologically-based pharmacokinetic model for various ASMs may enable empiric dose adjustments in pregnancy without the difficulties of frequent therapeutic drug monitoring.

Safe delivery, perinatal outcomes and breastfeeding in women with epilepsy

Safe delivery and optimal peripartum and postpartum care in women with epilepsy (WWE) is a major concern which has received limited attention in recent years. A diagnosis of epilepsy per se is not an indication for a planned cesarean section or induction of labor, even though epidemiological studies indicate that cesarean delivery is more common among WWE compared to the general population. Pregnancy in WWE is associated with an increased risk of obstetrical complications and increased perinatal morbidity and mortality, and these risks may be greater among WWE taking ASMs. Wherever feasible, pregnant WWE should be directed to specialist care. Risk minimization includes, when appropriate, dose adjustment to compensate for pregnancy-related changes in the pharmacokinetics of some ASMs. With respect to postpartum management, WWE should be advised that the benefits of breastfeeding outweigh the small risk of adverse drug reactions in the infant.

[Epilepsy and pregnancy]

BACKGROUND

Regarding treatment of women of childbearing potential with epilepsy, several aspects of family planning and desire to have children have to be taken into account.

OBJECTIVE

Overview of current data on mutual implications of epileptic seizures, antiseizure medication (ASM), pregnancy and child development.

METHOD

Review of the current literature, discussion and presentation of resulting treatment recommendations.

RESULTS

Many ASMs bear the potential for clinically relevant interactions with both contraceptives and altered concentrations of sexual hormones and modified pharmacokinetics during pregnancy. All ASMs show an increased risk for congenital malformations; however, due to seizure-related risks for the mother and child effective ASM treatment during pregnancy is crucial.

CONCLUSION

When considering the special aspects of consultation and treatment of women of childbearing potential with epilepsy most pregnancies are uncomplicated.

Dose Monitoring of Lamotrigine Monotherapy in Pregnancy: Are Pregnant Women with Epilepsy Currently Optimally Managed? A Systematic Review

BACKGROUND

Lamotrigine monotherapy is the first-line treatment for epilepsy in pregnant women. However, altered pharmacokinetics during pregnancy can lead to suboptimal drug levels and increased seizure risk. This systematic review aimed to evaluate current therapeutic drug monitoring (TDM) strategies for lamotrigine monotherapy in pregnant women with epilepsy and provide guidance for monitoring and dose adjustments.

METHODS

A systematic search was performed using the Ovid-MEDLINE, Ovid-EMBASE, and Ovid-Cochrane Central Register of Controlled Trials databases. Studies were included if data on lamotrigine dosing, concentration, TDM strategies, efficacy, or safety were available.

RESULTS

Eleven studies were analyzed, revealing heterogeneity in outcomes with selective reporting of TDM strategies; however, clear similarities were observed. Blood samples were collected every 1-3 months during pregnancy to maintain prepregnancy baseline drug levels. Lamotrigine's apparent and relative clearance increased across trimesters, particularly in the second and third trimesters, coinciding with a period of increased seizure frequency and required dose adjustments. Details on dose adjustments were limited. Some studies have proposed using the threshold of the ratio to the target concentration to predict increased seizure risk. No distinct association was observed between adverse newborn outcomes and lamotrigine dose or serum concentration. Few maternal adverse effects have been reported after delivery, confirming the necessity of empirical postpartum tapering.

CONCLUSIONS

Further studies are required to establish evidence-based standardized protocols encompassing all aspects of TDM. Early interventions, such as empirical dose increases during pregnancy and postpartum tapering, and routine monitoring from preconception to the postpartum period may enhance seizure control, reducing the risk of breakthrough seizures for the mother and unborn child.

Physiologically based pharmacokinetic modeling to predict maternal pharmacokinetics and fetal carbamazepine exposure during pregnancy

Carbamazepine is an antiepileptic drug commonly used in pregnant women, during which the physiological changes may affect its efficacy. The aim of this study was to establish a physiologically based pharmacokinetic (PBPK) model of carbamazepine and its active metabolite carbamazepine-10,11-epoxide, and simulate maternal and fetal pharmacokinetic changes of carbamazepine and carbamazepine-10,11-epoxide in different trimesters and propose dose adjustment. We established pregnancy PBPK models for carbamazepine and carbamazepine-10,11-epoxide in PK-Sim® and Mobi® and validated the models with observed data from clinical reports. The placental transfer parameters obtained using different methods were also imported into the model and compared with the observed data to establish and validate fetal pharmacokinetic curves. The simulated results showed that mean steady-state trough plasma concentration of carbamazepine decreased by 27, 43.1, and 52 % during the first, second, and third trimesters, respectively. Therefore, to achieve an optimum therapeutic concentration, administering at least 1.4, 1.8, and 2.1 times the baseline dose of carbamazepine in the first, second, and third trimesters, respectively can be used as a dose reference. In conclusion, this study established and validated a pregnancy PBPK model of carbamazepine and carbamazepine-10,11-epoxide to assess exposure in pregnant women and fetuses, which provided a reference for the dosage adjustment of carbamazepine during pregnancy.

UHPLC-MS/MS for plasma lamotrigine analysis and comparison with a homogenous enzyme immunoassay

Aims: To develop and validate a UHPLC-MS/MS method for lamotrigine (LTG) analysis in human plasma and evaluate its agreement with a homogenous enzyme immunoassay (HEIA). Materials & methods: The UHPLC-MS/MS method was developed and validated according to the USFDA/EMA guidelines. A Bland-Altman plot was used to evaluate the agreement between UHPLC-MS/MS and HEIA. Results: Samples were pretreated with one-step protein precipitation and separated in 2.6 min. The intra- and inter-day bias and imprecisions were -15.8 to 15.0% and less than 11.17%, respectively. The recovery and matrix factor were 98.30 to 111.97%. The mean overestimation of UHPLC-MS/MS compared with HEIA was 21.57%. Conclusion: A rapid, sensitive and robust UHPLC-MS/MS method for plasma LTG analysis was developed and validated and was a 21.57% overestimation compared with HEIA.

Association of oxcarbazepine concentration with seizure frequency in pregnant women with epilepsy

The management of epilepsy during pregnancy presents particular challenges for neurologists worldwide. Currently, there are no clear recommendations for oxcarbazepine (OXC) specific target concentration during pregnancy. We conducted this retrospective observational cohort study on pregnant women with epilepsy (WWE) who received OXC monotherapy or polytherapy, at the epilepsy outpatient clinic of a tertiary hospital in eastern China. Sixteen pregnancies of 16 WWE were split into the seizure-free group or the non-seizure-free group, according to whether they had been seizure free for more than one year prior to conception or not. There was a significantly decrease in OXC concentration throughout pregnancy, as indicated by the concentration/dose ratio and the ratio of target concentration (RTC). The second trimester of pregnancy was the period when seizure deterioration occurred the most, particularly in the non-seizure-free group. Lower RTC_OXC was identified to be a risk factor for increasing seizure frequency in both the total group and the non-seizure-free group in both univariate and multivariate analysis, with a threshold of 0.575 for differentiating patients at high-risk and low-risk for seizure deterioration. In conclusion, this study suggested an OXC concentration threshold of 0.575 during pregnancy for assisting neurologists in OXC drug monitoring and dose adaptation.

Lamotrigine and exogenous estrogen among females with epilepsy: A retrospective analysis of administrative claims data

OBJECTIVE

Exogenous estrogen reduces lamotrigine serum concentrations. Little is known about whether providers adjust lamotrigine doses for addition of exogenous estrogen among people with epilepsy, despite expert recommendations. We determined the incidence of dose increases in lamotrigine following incident prescription of estrogen among females with epilepsy (FWE) in claims data.

METHODS

We used Optum's de-identified Clinformatics® Data Mart Database to create a cohort of U.S. FWE prescribed lamotrigine at a stable dose, with a subsequent prescription for estrogen from 2011 to 2021. We calculated cumulative incidence functions of dose increases in lamotrigine following prescription of exogenous estrogen. We performed a Cox proportional hazards model for multiple candidate predictors of a lamotrigine dose increase.

RESULTS

The cohort included 643 FWE, with median age of 31 (interquartile ratio [IQR] 20-42). The cumulative incidence of any lamotrigine increase was 28% (95% confidence interval [CI] 25%-32%). The median number of days after the first estrogen fill until the first lamotrigine adjustment was 118 (IQR 48-188). In unadjusted Cox models, older age, use of estrogen in hormone replacement therapy as opposed to contraception, and annual household income of $50,000-$99,999 (compared with <$50,000) were significant negative predictors of a dose adjustment in lamotrigine with hazard ratios (HRs) of 0.82 (95% CI 0.72-0.92), 0.63 (95% CI 0.42-0.95), and 0.62 (95% CI 0.40-0.95). In the adjusted Cox model, age and income remained significant predictors with HRs of 0.79 (95% CI 0.66-0.94) and 0.59 (95% CI 0.36-0.95).

CONCLUSION

Dose increase of lamotrigine following addition of exogenous estrogen is rare among U.S. FWE, with potential disparities based on age and income level. More guidance may be needed for providers on this topic.

Assisted reproductive technology outcomes and management considerations for people with epilepsy

PURPOSE OF REVIEW

Epilepsy is a common neurologic condition amongst people with reproductive capacity, and assisted reproductive technology (ART) is being increasingly utilized. A recent population-based study described favorable outcomes of ART in this population, but other work shows how fluctuating sex hormones may influence medication concentrations and seizures.

RECENT FINDINGS

This review discusses hormonal influences on epilepsy and catamenial epilepsy, considerations regarding fertility in women with epilepsy, emerging ART outcomes, and management considerations for people with epilepsy undergoing ART.

SUMMARY

Utilizing ART is an effective treatment for people with epilepsy desiring pregnancy, but closer monitoring and antiseizure medication adjustments may be needed to ensure the best outcomes. More research is needed to better guide epilepsy care during ART.

Empiric dosing strategies to predict lamotrigine concentrations during pregnancy

INTRODUCTION

Maintaining seizure control with lamotrigine is complicated by altered pharmacokinetics and existence of subpopulations in whom clearance increases or remains constant during pregnancy.

OBJECTIVE

Our objective was to characterize the potential for particular dosing scenarios to lead to increased seizure risk or toxicity.

METHODS

Lamotrigine pharmacokinetic parameters obtained from our previous study were applied to a one-compartment model structure with subpopulations (75:25%) exhibiting different clearance changes. A single-patient simulation was conducted with typical pharmacokinetic parameter values from each subpopulation. Population-level simulations (N = 48,000) included six dosing scenarios and considered four preconception doses using the R package mrgsolve (Metrum Research Group). Thresholds for efficacy and toxicity were selected as drug concentration that are 65% lower than preconception concentrations and doubling of preconception concentrations, respectively.

RESULTS

Individual simulation results demonstrated that without dose increases, concentrations fell below 0.65 at 6-8 weeks in the high clearance change (HC) subpopulation, depending on preconception clearance. While no simulated dosing regimen allowed all women in both subpopulations to maintain preconception concentrations, some regimens provided a more balanced risk profile than others. Predicted concentrations suggested potential increased seizure risk for 7%-100% of women in the HC group depending on preconception dose and subpopulation. Additionally, in 63% of dosing scenarios for women with low clearance change (LC), there was an increased risk of toxicity (34%-100% of women).

SIGNIFICANCE

A substantial percentage of simulated individuals had concentrations low enough to potentially increase seizure risk or high enough to create toxicity. Early clearance changes indicate possible subpopulation categorization if therapeutic drug monitoring is conducted in the first trimester. An arbitrary "one-size-fits-all" philosophy may not work well for lamotrigine dosing adjustments during pregnancy and reinforces the need for therapeutic drug monitoring until a patient is determined to be in the LC or HC group.

Management of epilepsy during pregnancy and lactation

Epilepsy is a group of neurological diseases characterized by susceptibility to recurrent seizures. Antiseizure medications (ASMs) are the mainstay of treatment, but many antiseizure medications with variable safety profiles have been approved for use. For women with epilepsy in their childbearing years, the safety profile is important for them and their unborn children, because treatment is often required to protect them from seizures during pregnancy and lactation. Since no large randomized controlled trials have investigated safety in this subgroup of people with epilepsy, pregnancy registries, cohort and case-control studies from population registries, and a few large prospective cohort studies have played an important role. Valproate, in monotherapy and polytherapy, has been associated with elevated risk of major congenital malformations and neurodevelopmental disorders in children born to mothers who took it. Topiramate and phenobarbital are also associated with elevated risks of congenital malformations and neurodevelopmental disorders, though the risks are lower than those of valproate. Lamotrigine and levetiracetam are relatively safe. Insufficient data exist to reach strong conclusions about the newest antiseizure medications such as eslicarbazepine, perampanel, brivaracetam, cannabidiol, and cenobamate. Besides antiseizure medications, other treatments such as vagal nerve stimulation, responsive neurostimulation, and deep brain stimulation are likely safe. In general, breastfeeding does not appear to add any additional long term risks to the child. Creative ways of optimizing registry enrollment and data collection are needed to enhance patient safety.

Managing Antiseizure Medications in Pregnancy: Is Earlier and More Frequent Monitoring Better?

Background and Objective

Medication management in pregnant women with epilepsy (PWWE) poses challenges, and understanding the effects of metabolic changes on antiseizure medications (ASMs) is important in planning care for PWWE. The possible teratogenic effects and risks of poorly controlled seizures have to be weighed. There are data in the literature on clinical management of ASMs including the effects of drug levels on seizures and factors that predict seizure frequency, but timing and frequency of monitoring and dose adjustment paradigms have not been well studied.

Methods

This retrospective study was approved by the Institutional Review Board at Johns Hopkins University. We retrospectively identified adult PWWE evaluated during pregnancy at the Johns Hopkins Bayview Medical Center epilepsy clinic, between January 1, 2007, and January 1, 2021. We reviewed charts for information regarding demographics, medical and epilepsy history, medications, serum drug levels, and dosing paradigms. We assessed risk factors for breakthrough seizures with a focus on frequency and timing of laboratory testing. We calculated the dose-normalized concentration (DNC) for analysis with levetiracetam and lamotrigine, assessing changes in DNC over time by half trimesters, and analyzed DNC and effects on seizures in pregnancy. We also compared preemptive vs clinically based lamotrigine dose adjustments in managing epilepsy in pregnancy.

Results

A total of 45 pregnancies in 39 patients were included in this study, 8 generalized, 28 focal epilepsy, and 3 unclassified. 31 PWWE (36 pregnancies) were on lamotrigine and/or levetiracetam, and 14 of these pregnancies experienced breakthrough seizures, 77% in the first trimester. Seizures led to the diagnosis of pregnancy in 5 patients. The DNC for levetiracetam decreased significantly compared with prepregnancy levels by the second half of the first trimester and demonstrated variable but frequently significant or near significant reduction throughout pregnancy. DNC for lamotrigine decreased significantly in the first half of the first trimester and remained significant throughout pregnancy. Age of mother at conception, week of first ASM serum level and number of levels obtained during pregnancy, and epilepsy type were not associated with breakthrough/increase in seizures. The history of drug resistance (p = 0.038) was associated with a higher odds of seizures. In those on lamotrigine, preemptive dose adjustments demonstrated similar results regarding seizure control when compared with clinical-based or laboratory-based dose management (p = 0.531).

Discussion

This study demonstrates that frequency and timing of ASM level monitoring may not affect overall seizure outcomes during pregnancy in those on lamotrigine or levetiracetam. Furthermore, one can consider preemptive dose adjustments or a laboratory-based/clinical-based approach in managing lamotrigine as both seem safe and feasible. However, in those with drug-resistant epilepsy before pregnancy, earlier and closer monitoring is warranted given the risk of seizures early during pregnancy. Larger prospective studies are needed to confirm these results.

External validation of the AntiEpileptic Drug Monitoring in PREgnancy (EMPiRE) model for predicting seizures in pregnant women with epilepsy

BACKGROUND

The AntiEpileptic Drug Monitoring in PREgnancy (EMPiRE) model is the only available tool for predicting seizures in pregnant women with epilepsy (WWE) using anti-seizure medications (ASMs); however, its predictive performance requires validation. This study aimed to evaluate the predictive ability of this model in pregnant Chinese WWE and its potential usefulness in clinical practice.

METHODS

Data of the EMPiRE model were derived from the EMPiRE study, a prospective multicenter cohort study that recruited women on ASM monotherapy (lamotrigine, carbamazepine, phenytoin or levetiracetam) or polytherapy (lamotrigine with either carbamazepine, phenytoin or levetiracetam). Based on the applicable population of the EMPiRE model, we evaluated 280 patients registered in the Wenzhou Epilepsy Follow-up Registry Database from January 1, 2010, to December 31, 2020. A total of 158 eligible patients were included in the validation cohort. We collected data on the baseline characteristics of patients, eight predictors of the EMPiRE model and outcome events. The outcome was the occurrence of tonic-clonic or non-tonic-clonic seizures at any time in pregnancy up to 6 weeks postpartum. We used the equation of the EMPiRE model to obtain the predicted probabilities of seizures. The predictive ability of the EMPiRE model was quantified by the C-statistic (scale 0-1, values > 0.5 show discrimination), GiViTI calibration test and decision curve analysis (DCA).

RESULTS

Of 158 eligible patients, 96 patients (60.8%, 96/158) experienced one or more seizures at any time between pregnancy and 6 weeks postpartum. The EMPiRE model showed good discrimination with a C-statistic of 0.76 (95% confidence interval [CI] 0.70-0.84). The GiViTI calibration belt showed that the predicted probabilities, which ranged from 16 to 96% (95% CI), were lower than the actual probabilities. DCA indicated that the highest net proportional benefit was obtained for predicted probability thresholds of 15-18% and 54-96%.

CONCLUSIONS

The EMPiRE model could discriminate well between WWE with and without seizures during pregnancy and 6 weeks postpartum, but the risk of seizures may be underestimated. The limitations of the model for specific medication regimens may limit its real-world application. If the model is further improved, it will be incredibly valuable.

Changes in seizure frequency and anti-seizure medication therapy during pregnancy and one year postpregnancy

Seizure control in women with epilepsy (WWE) during pregnancy is a vital concern. The aim of this study was to compare changes in seizure frequency and anti-seizure medication (ASM ) therapy in WWE in a real-world setting over three epochs (prepregnancy, pregnancy, and postpregnancy). We screened WWE who were pregnant between 1 January 2010 and 31 December 2020 from the epilepsy follow-up registry database of a tertiary hospital in China. We reviewed and collected follow-up data for the following time periods: 12 months before pregnancy (epoch 1), throughout pregnancy and the first 6 weeks postpartum (epoch 2), and from 6 weeks to 12 months postpartum (epoch 3). Seizures were classified into two categories: tonic‒clonic/focal to bilateral tonic‒clonic seizures and non-tonic‒clonic seizures. The main indicator was the seizure-free rate over the three epochs. Using epoch 1 as a reference, we also compared the percentage of women with an increased seizure frequency, as well as changes in ASM treatment, in epochs 2 and 3. Ultimately, 271 eligible pregnancies in 249 women were included. The seizure-free rates in epoch 1, epoch 2, and epoch 3 were 38.4%, 34.7%, and 43.9%, respectively (P = 0.09). The top three ASMs used in the three epochs were lamotrigine, levetiracetam, and oxcarbazepine. Using epoch 1 as a reference, the percentages of women with increased frequencies of tonic‒clonic/focal to bilateral tonic‒clonic seizures in epoch 2 and epoch 3 were 17.0% and 14.8%, respectively, while the percentages of women with an increased frequency of non-tonic‒clonic seizures in epoch 2 and epoch 3 were 31.0% and 21.8% (P = 0.02). The percentage of women whose ASM dosages were increased in epoch 2 was higher than that in epoch 3 (35.8% vs. 27.3%, P = 0.03). The seizure frequency during pregnancy may not differ significantly from that during prepregnancy and postpregnancy if WWE are treated according to the guidelines.

Design Considerations for Pharmacokinetic Studies During Pregnancy

Most of the interventions performed by obstetric providers involve the administration of drugs. Pregnant patients are pharmacologically and physiologically different from nonpregnant young adults. Therefore, dosages that are effective and safe for the general public may be inadequate or unsafe for the pregnant patient and her fetus. Establishing dosing regimens appropriate for pregnancy requires evidence generated from pharmacokinetic studies performed in pregnant people. However, performing these studies during pregnancy often requires special design considerations, evaluations of both maternal and fetal exposures, and recognition that pregnancy is a dynamic process that changes as gestational age advances. In this article, we address design challenges unique to pregnancy and discuss options for investigators, including timing of drug sampling during pregnancy, appropriate selection of control groups, pros and cons of dedicated and nested pharmacokinetic studies, single-dose and multiple-dose analyses, dose selection strategies, and the importance of integrating pharmacodynamic changes into these protocols. Examples of completed pharmacokinetic studies in pregnancy are provided for illustration.

Antiseizure Medications in Pregnancy

Epilepsy affects up to 15 million of people assigned female at birth of childbearing age globally. Up to 65% of these people with epilepsy and gestational capacity have an unplanned pregnancy. Seizure control during pregnancy is important for both the childbearer's and fetus' safety. There are multiple antiseizure medications (ASMs) that can be used to control epilepsy; however, each medication has its own teratogenic risk profile, which must be considered. The majority of these ASMs will require frequent plasma concentration monitoring during pregnancy with corresponding dosage adjustments. Dosages can be reduced back to prepregnancy levels within 3 weeks postpartum. Breastfeeding on ASMs is recommended.

Association of Levetiracetam Concentration With Seizure Frequency in Pregnant Women With Epilepsy

BACKGROUND AND OBJECTIVES

Pharmacologic treatment of epilepsy in pregnant women is balancing between risks for the mother and fetus. Levetiracetam (LEV) is considered to be safe during pregnancy because of its low teratogenic potential and lack of drug-drug interaction with other antiseizure medications (ASMs). Recent studies have shown decline of ASM concentrations during pregnancy because of physiologically based pharmacokinetic changes. In this study, we established this decrease in LEV concentration during pregnancy. In addition, we aimed at investigating the effect of the low LEV levels during pregnancy and developing a target value for the level during pregnancy.

METHODS

Pregnant patients using levetiracetam were studied in this retrospective cohort study. Blood samples were monthly collected through venous puncture or the dried blood spot method. ASM serum concentrations were determined at least 6 months before conception and for each month of pregnancy. Seizure frequency and ASM dosages during pregnancy were obtained from patient records. Patients were divided into 2 groups: a seizure-free group and a non-seizure-free group, which contained pregnancies in which the mother had experienced an epileptic seizure more than 12 months and less than 12 months before pregnancy, respectively.

RESULTS

We found decreased concentration/dose ratios in 29 pregnancies throughout all months of pregnancy. In the non-seizure-free group, it was found that low LEV concentrations were associated with seizure increase frequency (p = 0.022). For this group, the cutoff value with the highest sum of sensitivity and specificity was 0.466.

DISCUSSION

All in all, we recommend therapeutic drug monitoring for all pregnant patients on LEV as the concentrations of LEV significantly decrease throughout most months of pregnancy. However, this decrease in LEV concentration was only significantly correlated with seizure deterioration in patients who had a seizure in the year preceding the pregnancy. Therefore, we suggest more careful monitoring of non-seizure-free patients as they are at higher risk for experiencing an increase of seizure frequency. For this group, we advise physicians to keep LEV concentration above 65% of the preconceptional concentration. For seizure-free patients, we recommend an LEV threshold value of approximately 46% of the preconceptional concentration.

Management of Anti-Seizure Medications during Pregnancy: Advancements in The Past Decade

Management of seizures often involves continuous medication use throughout a patient's life, including when a patient is pregnant. The physiological changes during pregnancy can lead to altered drug exposure to anti-seizure medications, increasing patient response variability. In addition, subtherapeutic anti-seizure medication concentrations in the mother may increase seizure frequency, raising the risk of miscarriage and preterm labor. On the other hand, drug exposure increases can lead to differences in neurodevelopmental outcomes in the developing fetus. Established pregnancy registries provide insight into the teratogenicity potential of anti-seizure medication use. In addition, some anti-seizure medications are associated with an increased risk of major congenital malformations, and their use has declined over the last decade. Although newer anti-seizure medications are thought to have more favorable pharmacokinetics in general, they are not without risk, as they may undergo significant pharmacokinetic changes when an individual becomes pregnant. With known changes in metabolism and kidney function during pregnancy, therapeutic monitoring of drug concentrations helps to determine if and when doses should be changed to maintain similar seizure control as observed pre-pregnancy. This review concentrates on the results from research in the past decade (2010-2022) regarding risks of major congenital malformations, changes in prescribing patterns, and pharmacokinetics of the anti-seizure medications that are prescribed to pregnant patients with epilepsy.

Monitoring of lamotrigine concentrations in mothers, colostrum, and breastfed newborns during the early postpartum period

OBJECTIVE

To analyse the concentrations of lamotrigine in maternal serum, colostrum, and serum of breastfed newborns, and to evaluate the effect of comedication with enzyme-inducing antiseizure medication and valproic acid.

METHODS

This cohort study collected data from 158 women and 143 breastfed newborns. Maternal serum, milk (i.e., colostrum), and newborn serum samples were collected between the 2nd and 5th postnatal days, and lamotrigine concentrations were measured by high-performance liquid chromatography.

RESULTS

The median lamotrigine concentrations were 2.7 mg/L in maternal serum, 1.4 mg/L in milk, and 1.7 mg/L in newborn serum. The median milk/maternal serum concentration ratio was 0.60, the median newborn/maternal serum concentration ratio was also 0.60, and the median newborn serum/milk concentration ratio was 1.00. A significant correlation was observed between milk and maternal serum concentrations and between newborn serum and milk concentrations, maternal serum concentrations, maternal daily dose, and dose related to maternal body weight.

CONCLUSIONS

Exposure to lamotrigine in breastfed newborns is lower than exposure during pregnancy. However, by the same dose by the same mother, lamotrigine concentrations in both maternal serum and milk increase significantly after delivery. This finding, together with the immature function of eliminating enzymes in newborns, may be the reason for reaching concentrations in the reference range used for the general epileptic population in breastfed newborns. Therapeutic monitoring of breastfed newborns serum concentrations of lamotrigine is not mandatory; however, if signs of possible adverse events are noted, newborn serum concentrations should be analysed.

Seizure medication and planned pregnancy: balancing the risks and outcomes

INTRODUCTION

The therapeutic management of women with epilepsy (WWE) of childbearing age can be complicated by the need to balance maternal/fetal risks related to seizure occurrence during gestation with the potential teratogenic risks related to the use of anti-seizure medications (ASMs).

AREAS COVERED

The authors review clinical evidence on seizure-related and ASM-related risks during pregnancy. Current regulatory indications are discussed, evaluating their impact on clinical practice, and ethical implications of pharmacological decisions are debated.

EXPERT OPINION

If properly informed about the maternal/fetal risks carried by different pharmacological choices, WWE can become the final decision makers regarding their care in every phase of their life. Over the coming years, analysis of aggregated pregnancy registry data on the structural impact, on the fetus, of low doses of valproate and of newer ASMs, together with analysis of the main population study data on functional (cognitive and behavioral) outcomes, could lead to huge advances, making choosing an ASM a less complex process for the clinician and a less painful decision for the woman. Future objectives should include identification of the potential role of the pharmacogenomic profile of WWE in determining the risk of fetal malformations.

Dosage Optimization of Lamotrigine in Pregnancy: A Pharmacometric Approach using Modeling and Simulation

Lamotrigine is the most widely used anti-epileptic drug in pregnancy due to its low teratogenicity. However, there is an increased metabolism & clearance of Lamotrigine in pregnancy contributing to suboptimal drug therapy and poor disease control, prompting the need for pro-active dosage adjustments. The present study aimed to develop a pharmacometric model-based framework for recommending optimal dosage regimen for Lamotrigine in pregnancy. A systematic review was performed to obtain the literature aggregate data on clearance of Lamotrigine in pregnancy. The data was incorporated into simulations using PUMAS software for estimating the plasma concentrations at preconception stage and three trimesters. Simulated drug-exposures for different doses were investigated to ascertain plasma concentrations similar to the pre-conception and above minimum effective concentration. The simulated mean steady state trough plasma concentrations (mg/L) of Lamotrigine in non-pregnant and pregnant women at 3 trimesters decreased significantly (p<0.001) viz. 4.31±1.14, 3.17± 0.93, 2.14±0.86, 1.51±0.65 respectively. The simulation studies revealed that 150mg, 175mg, 225mg and 250mg twice daily doses, in pre-conception stage and three trimesters respectively achieve the target concentrations. Thus, the model-informed dosage regimen of Lamotrigine proposed in this study shall be considered to initiate the dosing in pregnant women, however the safety and efficacy of the drug have to be assured through therapeutic drug monitoring, in order to avoid therapeutic failure of Lamotrigine in pregnancy. This article is protected by copyright. All rights reserved.

Antiseizure Medication Concentrations During Pregnancy: Results From the Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD) Study

IMPORTANCE

During pregnancy in women with epilepsy, lower blood concentrations of antiseizure medications can have adverse clinical consequences.

OBJECTIVE

To characterize pregnancy-associated concentration changes for several antiseizure medications among women with epilepsy.

DESIGN, SETTING, AND PARTICIPANTS

Enrollment in this prospective, observational cohort study, Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs (MONEAD), occurred from December 19, 2012, to February 11, 2016, at 20 US sites. Enrolled cohorts included pregnant women with epilepsy and nonpregnant control participants with epilepsy. Inclusion criteria were women aged 14 to 45 years, an intelligence quotient greater than 70 points, and, for the cohort of pregnant women, a fetal gestational age younger than 20 weeks. A total of 1087 women were assessed for eligibility; 397 were excluded and 230 declined. Data were analyzed from May 1, 2014, to June 30, 2021.

EXPOSURE

Medication plasma concentrations in women taking monotherapy or in combination with noninteracting medications. The cohort of pregnant women was monitored through 9 months post partum, with similar time points for control participants.

MAIN OUTCOMES AND MEASURES

Dose-normalized concentrations were calculated as total or unbound plasma medication concentrations divided by total daily dose. Phlebotomy was performed during 4 pregnancy study visits and 3 postpartum visits for the pregnant women and 7 visits over 18 months for control participants. The primary hypothesis was to test pregnancy changes of dose-normalized concentrations from nonpregnant postpartum samples compared with those of control participants.

RESULTS

Of the 351 pregnant women and 109 control participants enrolled in MONEAD, 326 pregnant women (median [range] age, 29 [19-43] years) and 104 control participants (median [range] age, 29 [16-43] years) met eligibility criteria for this analysis. Compared with postpartum values, dose-normalized concentrations during pregnancy were decreased by up to 56.1% for lamotrigine (15.60 μg/L/mg to 6.85 μg/L/mg; P < .001), 36.8% for levetiracetam (11.33 μg/L/mg to 7.16 μg/L/mg; P < .001), 17.3% for carbamazepine (11.56 μg/L/mg to 7.97 μg/L/mg; P = .03), 32.6% for oxcarbazepine (11.55 μg/L/mg to 7.79 μg/L/mg; P < .001), 30.6% for unbound oxcarbazepine (6.15 μg/L/mg to 4.27 μg/L/mg; P < .001), 39.9% for lacosamide (26.14 μg/L/mg to 15.71 μg/L/mg; P < .001), and 29.8% for zonisamide (40.12 μg/L/mg to 28.15 μg/L/mg; P < .001). No significant changes occurred for unbound carbamazepine, carbamazepine-10,11-epoxide, and topiramate, although a decrease was observed for topiramate (29.83 μg/L/mg to 13.77 μg/L/mg; P = .18). Additionally, compared with dose-normalized concentrations from control participants, pregnancy dose-normalized median (SE) concentrations decreased significantly by week of gestational age: carbamazepine, -0.14 (0.06) μg/L/mg (P = .02); carbamazepine unbound, -0.04 (0.01) μg/L/mg (P = .01); lacosamide, -0.23 (0.07) μg/L/mg (P < .001); lamotrigine, -0.20 (0.02) μg/L/mg (P < .001); levetiracetam, -0.06 (0.03) μg/L/mg (P = .01); oxcarbazepine, -0.14 (0.04) μg/L/mg (P < .001); oxcarbazepine unbound, -0.11 (0.03) μg/L/mg (P < .001); and zonisamide, -0.53 (0.14) μg/L/mg (P < .001) except for topiramate (-0.35 [0.20] μg/L/mg per week) and carbamazepine-10,11-epoxide (0.02 [0.01] μg/L/mg).

CONCLUSIONS AND RELEVANCE

Study results suggest that therapeutic drug monitoring should begin early in pregnancy and that increasing doses of these anticonvulsants may be needed throughout the course of pregnancy.

Physiologically Based Pharmacokinetic Modeling in Pregnant Women Suggests Minor Decrease in Maternal Exposure to Olanzapine

Pregnancy is accompanied by significant physiological changes that might affect the in vivo drug disposition. Olanzapine is prescribed to pregnant women with schizophrenia, while its pharmacokinetics during pregnancy remains unclear. This study aimed to develop a physiologically based pharmacokinetic (PBPK) model of olanzapine in the pregnant population. With the contributions of each clearance pathway determined beforehand, a full PBPK model was developed and validated in the non-pregnant population. This model was then extrapolated to predict steady-state pharmacokinetics in the three trimesters of pregnancy by introducing gestation-related alterations. The model adequately simulated the reported time-concentration curves. The geometric mean fold error of Cmax and AUC was 1.14 and 1.09, respectively. The model predicted that under 10 mg daily dose, the systematic exposure of olanzapine had minor changes (less than 28%) throughout pregnancy. We proposed that the reduction in cytochrome P4501A2 activity is counteracted by the induction of other enzymes, especially glucuronyltransferase1A4. In conclusion, the PBPK model simulations suggest that, at least at the tested stages of pregnancy, dose adjustment of olanzapine can hardly be recommended for pregnant women if effective treatment was achieved before the onset of pregnancy and if fetal toxicity can be ruled out.

Pharmacokinetic changes for newer antiepileptic drugs and seizure control during pregnancy

Objective

To investigate pharmacokinetic changes in newer antiepileptic drugs (AEDs) and assess seizure frequencies and risk factors of increased seizures during pregnancy in women with epilepsy (WWE).

Methods

A total of 56 pregnancies in 53 WWE who received newer antiepileptic drugs (AEDs) were enrolled. Data on seizure activity and types, daily dose, and AEDs blood levels were derived from routine clinical follow‐up. Changes in AEDs clearance were compared between each trimester and nonpregnant baseline. The ratio of AED levels of each trimester to their targets (nonpregnant baseline) concentrations (RTC) was compared between patients with and without an increased seizure. A binary logistic regression was used to investigate the risk factors contributing to seizure worsening during pregnancy.

Results

Increased clearances of LTG, LEV, and OXC were observed in all trimesters versus nonpregnant baseline. The peak changes in the clearance of LTG (3.42‐fold baseline clearance) (p < 0.001) and LEV (2.78‐fold) (p < 0.001) occurred in the second trimester during pregnancy, followed by oxcarbazepine (2.11‐fold) in the third trimester (p < 0.03). Plasma concentrations of LTG and LEV during pregnancy were significantly decreased compared to baseline levels, except for OXC. However, no significant differences in RTC values were observed between patients with and without seizure worsening. Some risk factors as seizures for the prior nine months could significantly affect seizure frequency during pregnancy.

Conclusion

We found substantial changes in the pharmacokinetics of multiple newer AEDs in WWE, reinforcing the need for therapeutic drug monitoring (TDM) during pregnancy. We would encourage at least one monitoring every trimester and probably more frequently for women with poorly seizure control before pregnancy, and AEDs dose adjustment should keep up with clearance changes. In addition, a well‐controlled seizure nine months before pregnancy could lower the risks of seizure during pregnancy, highlighting the importance of pre‐pregnancy counseling and seizure management before pregnancy.

Current Concepts in the Management of Idiopathic Generalized Epilepsies

Idiopathic generalized epilepsies (IGEs) are a group of epilepsies characterized by an underlying genetic predisposition and a good response to antiseizure medicines (ASMs) in the majority of the patients. Of the various broad-spectrum ASMs, valproate is the most effective medicine for the control of seizures in IGEs. However, with the availability of many newer ASMs and evidence showing the high teratogenic potential of valproate, the choice of ASMs for IGEs has become increasingly difficult, especially in women of the child-bearing age group. In this article, we review the current evidence regarding the efficacy and safety of various ASMs in patients with IGEs and provide practical guidelines for choosing appropriate ASMs in various subgroups of patients with IGEs.

Pregnancy and the Control of Epileptic Seizures: A Review

Over the past 50 years, published studies have provided quantitative data on the control of epileptic seizures during pregnancy. The studies have varied in quality, and particularly in the ways in which seizure control has been assessed. However, most studies have shown that seizure occurrence rates are more likely to worsen than improve during pregnancy, though in most pregnancies the rates have been unaltered. Nearly all of the studies have involved women with antiseizure medication-treated epilepsy, but there is a little evidence that seizure control also tends to worsen in pregnancies of women with untreated epilepsy. The factors likely to contribute to the seizure worsening are (i) patient non-compliance, (ii) increased antiseizure medication clearance during pregnancy resulting in lower circulating drug concentrations relative to dose, (iii) the effects of the higher female sex hormone levels during pregnancy, oestrogens being pro-epileptogenic and progesterone anti-epileptogenic, and (iv) reluctance to use the potential teratogen valproate in women capable of pregnancy, depriving them of the most effective drug for certain types of epilepsy. Compliance can be encouraged, but at the present time only one other factor is readily correctable, i.e. the increased drug clearance. This can be compensated for by raising antiseizure medication dosage during pregnancy, guided by measurement of circulating drug concentrations. This course of action appears to reduce the chance of seizure disorder worsening during pregnancy, but so far it has not provided a complete solution to the issue.

Managing reproductive problems in women with epilepsy of childbearing age

Girls and women constitute nearly 50% of all epilepsy cases. Apart from the disease symptoms, epilepsy and antiseizure medications (ASMs) may also affect the reproductive function, pregnancy and even the health of their offspring. Therefore, it is very important to identify and summarize the problems and risks for women with epilepsy (WWE) of childbearing age, and offer internationally recognized methods through multidisciplinary collaboration. In this review, we summarize the reproduction-related problems with WWE and propose multidisciplinary management by epileptologists, gynecologists and obstetricians, as well as other experts, from preconception to delivery. Large, multicenter registries are needed to advance our knowledge on new ASMs and their effects on WWE and their offspring.

Lacosamide serum concentrations during pregnancy

Still considered a new ASD, teratogenicity from lacosamide (LCM) exposure during pregnancy is unknown. LCM metabolism through several cytochrome P450 enzymes and minor glucuronidation metabolism in the liver may increase during pregnancy and theoretically lead to lower LCM levels during pregnancy and the risk of increased seizures. Our objective was to determine the impact of pregnancy on serum LCM levels in a series of women with epilepsy (WWE). We identified seven pregnancies with exposure to LCM with at least one level drawn during pregnancy. Patient ages ranged from 18 to 38 years (mean 26.4 years) and total daily doses of LCM ranged from 200 to 600 mg/day. Two patients had increased dose adjustments in response to breakthrough seizures. Dose normalized concentrations (DNC) showed an overall decrease over time through each trimester (p = 0.002) and significantly lower during trimester 2 and 3 (p = 0.001 and p = 0.004, respectively) compared to pre-pregnancy levels. There were no significant changes in seizure frequency and none of the neonates had teratogenic findings at time of birth. We are the first to report a case series on the changes in LCM levels during pregnancy with significant decreased LCM DNC levels during the second and third trimesters in comparison to pre-pregnancy values.

Levetiracetam, lamotrigine and carbamazepine: which monotherapy during pregnancy?

OBJECTIVE

Epilepsy treatment during pregnancy is still challenging. The study is aimed at comparing the efficacy and safety of carbamazepine (CBZ), lamotrigine (LTG) and levetiracetam (LEV) monotherapies during pregnancy in women with focal (FE) or generalized (GE) epilepsy.

METHODS

A multicentre retrospective study was conducted to evaluate seizures frequency and seizure freedom (SF) rate during 3 months before pregnancy, each trimester of gestation and post-partum period in women on monotherapy with CBZ, LTG and LEV.

RESULTS

Fifty-seven pregnancies (45 FE, 12 GE) on monotherapy (29 CBZ, 11 LTG, 17 LEV) were included. A significant reduction of seizure frequency was found in the first trimester of pregnancy as compared with that one before pregnancy (p = 0.004), more evident in GE (p = 0.003) and in LEV group (p = 0.004). The SF rate significantly increased in the first trimester in comparison to that one before pregnancy and persisted in the post-partum period in the whole sample (p < 0.001) and in women on LEV (p = 0.004). Besides, 88.57% of SF women before pregnancy remained unchanged during gestation and the post-partum period. One major heart malformation in CBZ and no major malformations in LTG and LEV groups were found.

CONCLUSIONS

A better clinical outcome during pregnancy emerged since the first trimester in comparison to the before-pregnancy period, mostly evident in women with GE and LEV therapy, reinforcing the hypothesis of a protective role of pregnancy versus seizures. SF before pregnancy represents a significant predictive factor of good clinical outcome during gestation and the post-partum period. Compared to CBZ, LTG and LEV showed a better safety profile.

Seizure freedom and plasma levels of newer generation antiseizure medications

OBJECTIVES

Contrary to older antiseizure medications (ASM), correlation between plasma levels and seizure freedom is not well defined for newer generation ASM. We assessed correlations between efficacy and newer generation ASM plasma levels in patients with epilepsy.

MATERIALS AND METHODS

Plasma medication levels were measured over two years in consecutive patients taking lamotrigine, levetiracetam, oxcarbazepine, topiramate, zonisamide, lacosamide, perampanel or pregabalin. Seizure freedom was defined as three times the longest inter-seizure pre-treatment interval, or at least one year. Each medication level was stratified according to its position in relation to its proposed reference range (below or in lower half vs upper half or above).

RESULTS

168 patients on stable therapy were included. ASM plasma levels of seizure-free patients were lower than those with ongoing seizures; 45/48 (93.7%) were in the lower half or below the reference ranges, compared to 86/106 (81.1%; p = .004). Lamotrigine plasma levels were significantly lower in seizure-free patients (median 2.4 mg/L range 0.4-6.5 mg/L, none above 6.5 mg/L) compared with those with ongoing seizures (5 mg/L, 0.5-14.2 mg/L; p < .0001). Levetiracetam showed similar results (7.2 mg/L, 1.6-15.1 mg/L; none above 15.1 mg/L in seizure-free patients vs 16.4 mg/L, 0.6-47.7 mg/L; p = .005). Demographics, epilepsy type and polytherapy did not influence the results.

CONCLUSIONS

Efficacy of newer generation ASMs seems to be reached at the lower part or at times even below the reference ranges in drug responsive patients; this could inform regarding titrations of these treatments.

Neurological Emergencies During Pregnancy

This article serves as a comprehensive review of neurologic emergencies in pregnancy. Common initial presentations of neuroemergencies are reviewed with a clinical algorithm. Neurovascular disorders in pregnancy are reviewed, including acute ischemic strokes with data on tPA and thrombectomy; cerebral venous sinus thrombosis diagnosis and management; posterior reversible encephalopathy syndrome management; reversible cerebral vasoconstriction syndrome; and intracerebral hemorrhage. Attention is paid to management of cerebral edema and safety of osmotic therapies. A review of seizures in pregnancy is provided, including new-onset causes and decreased seizure thresholds. For status epilepticus, a low teratogenicity risk medication protocol in pregnancy is provided.

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.

Therapeutic Drug Monitoring in Pregnant Patients

During pregnancy, there are several physiological changes during each trimester that can affect the absorption, distribution, metabolism, and elimination of drugs. Although there is a potential need to understand the pharmacokinetics and pharmacodynamics of drugs in pregnant patients, therapeutic drug monitoring is not well established for various drug classes due to ethical and safety concerns regarding the neonate. Potential risks from in utero drug exposure to the fetus may impact growth and development and may cause malformations or teratogenesis. The clinician must consider the benefits of drug treatment for the pregnant mother versus the risk to the fetus, before prescribing medications during pregnancy. The objective of this review is to aid clinicians, pharmacists, and laboratorians in understanding the pharmacokinetic and pharmacodynamic changes during pregnancy, to provide drug class recommendations for monitoring therapy throughout pregnancy via therapeutic drug monitoring, and to highlight the recent directives of governing agencies on maternal and fetal health.

Estrogen profile- and pharmacogenetics-based lamotrigine dosing regimen optimization: Recommendations for pregnant women with epilepsy

During pregnancy, various physiological changes occur that can alter the pharmacokinetics of antiepileptic drugs, such as lamotrigine (LTG). Anticipating the change in LTG dose required to achieve a pre-pregnancy target concentration is challenging. This study aimed to develop a refined population pharmacokinetic (PopPK) model of LTG in pregnant women with epilepsy (WWE) to identify factors explaining the variability in pharmacokinetics and to establish a model-informed individualized dosing regimen. On that basis, a coarsened model containing only clinical variables was also developed to examine its predictive performance compared to the refined model. In total, 322 concentration-time points from 51 pregnant WWE treated with LTG were employed to establish a refined PopPK model that included endogenous estrogen profiles, variants of candidate genes encoding LTG-metabolizing enzymes and -transporter proteins, and other clinical variables and a coarsened model that included only clinical variables, respectively. Data from an additional 11 patients were used for external validation of these two models. A nonlinear mixed-effect modeling approach was used for PopPK analysis of LTG. The standard goodness-of-fit method, bootstrap, normalized prediction distribution errors and external evaluation were adopted to estimate the stability and predictive performance of the candidate models. Akaike information criterion (AIC) was used to compare the goodness of fit between these two models. A lower AIC indicates a better fit of the data and the preferred model. Recommended dosing regimens for pregnant WWE were selected using Monte Carlo simulation based on the established optimal model. In the refined PopPK model, the population mean of apparent LTG clearance (CL/F) in pregnant WWE was estimated to be 2.82 L/h, with an inter-individual variability of 23.6%. PopPK analysis indicated that changes in estrogen profile during pregnancy were the predominant reason for the significant variations in LTG-CL/F. Up to the 3rd trimester, the concentration accumulation effect of E2 increased LTG-CL/F by 5.109 L/h from baseline levels. Contrary to effect of E2, E3 as the main circulating estrogen in pregnancy with a peak value of 34.41 ng/mL is 1000-fold higher than that in non-pregnancy reduced LTG-CL/F by 1.413 L/h. In addition, the UGT2B7 rs4356975 C > T and ABCB1 rs1128503 A > G variants may contribute to a better understanding of the inter-individual variability in LTG-CL/F. LTG-CL/F was 1.66-fold higher in UGT2B7 rs4356975 CT or TT genotype carriers than in CC genotype carriers. In contrast, ABCB1 rs1128503 GG genotype carriers had only 71.9% of the LTG-CL/F of AA or AG genotype carriers. In the coarsened PopPK model, the gestational age was a promising predictor of changes in LTG-CL/F. When comparing these two models, the refined PopPK model was favored over the coarsened PopPK model (AIC = -30.899 vs. -20.017). Monte Carlo simulation based on optimal PopPK model revealed that the LTG dosage administered to carriers of the UGT2B7 rs4356975 CT or TT genotype required a 33-50% increase to reach the pre-pregnancy target concentration, and carriers of the ABCB1 rs1128503 GG genotype required a 33-66% lower dose of LTG than carriers of the ABCB1 rs1128503 AA or AG genotype. Changes in estrogen profile during pregnancy was a better predictor of variations in LTG-CL/F than gestational age. The developed model based on estrogen profile and pharmacogenetics can serve as a foundation for further optimization of dosing regimens of LTG in pregnant WWE.

Changes in Seizure Frequency and Antiepileptic Therapy during Pregnancy

BACKGROUND

Among women with epilepsy, studies regarding changes in seizure frequency during pregnancy have been limited by the lack of an appropriate nonpregnant comparator group to provide data on the natural course of seizure frequency in both groups.

METHODS

In this prospective, observational, multicenter cohort study, we compared the frequency of seizures during pregnancy through the peripartum period (the first 6 weeks after birth) (epoch 1) with the frequency during the postpartum period (the following 7.5 months after pregnancy) (epoch 2). Nonpregnant women with epilepsy were enrolled as controls and had similar follow-up during an 18-month period. The primary outcome was the percentage of women who had a higher frequency of seizures that impaired awareness during epoch 1 than during epoch 2. We also compared changes in the doses of antiepileptic drugs that were administered in the two groups during the first 9 months of epoch 1.

RESULTS

We enrolled 351 pregnant women and 109 controls with epilepsy. Among the 299 pregnant women and 93 controls who had a history of seizures that impaired awareness and who had available data for the two epochs, seizure frequency was higher during epoch 1 than during epoch 2 in 70 pregnant women (23%) and in 23 controls (25%) (odds ratio, 0.93; 95% confidence interval [CI], 0.54 to 1.60). During pregnancy, the dose of an antiepileptic drug was changed at least once in 74% of pregnant women and in 31% of controls (odds ratio, 6.36; 95% CI, 3.82 to 10.59).

CONCLUSIONS

Among women with epilepsy, the percentage who had a higher incidence of seizures during pregnancy than during the postpartum period was similar to that in women who were not pregnant during the corresponding epochs. Changes in doses of antiepileptic drugs occurred more frequently in pregnant women than in nonpregnant women during similar time periods. (Funded by the National Institutes of Health; MONEAD ClinicalTrials.gov number, NCT01730170.).

Simultaneous Determination of Lamotrigine, Topiramate, Oxcarbazepine, and 10,11-dihydro-10-hydroxycarbazepine in Human Blood Plasma by UHPLC-MS/MS

Background:

Lamotrigine (LTG), topiramate (TPM), and oxcarbazepine (OXC) are commonly used antiepileptic drugs. The bioactivity and toxicity of these drugs were related to their blood concentrations which varied greatly among individuals and required to be monitored for dose adjustment. However, the commercial method for monitoring of these drugs is not available in China.

Methods:

A UHPLC-MS/MS method for simultaneous determination of LTG, TPM, OXC, and OXC active metabolite (10,11-dihydro-10-hydroxycarbazepine, MHD) was developed and validated according to the guidelines and applied in clinical practice.

Results:

he separation was achieved by using methanol and water (both contain 0.1% formic acid) at 0.4 mL/min under gradient elution within 3 min. For all analytes, the isotope internal standard was used; the selectivity was good without significant carry over; LTG and TPM were linear between 0.06 to 12 mg/L while OXC and MHD were linear between 0.03 to 6 mg/L, the upper limit could be 10-fold higher because 10-fold dilution with water did not affect the results; the intra-day and interday bias and imprecision were -13.11% to 5.42% and < 13.32%; the internal standard normalized recovery and matrix factor were 90.95% to 111.94% and 95.57% to 109.91%; and all analytes were stable under tested conditions. LTG and OXC-D4 shared two ion pairs m/z 257.1 > 212.0 and 257.1 > 184.0, and m/z 257.1 > 240.0 was suggested for OXC-D4 quantitation. Lamotrigine and lamotrigine- 13C3 shared three ion pairs m/z 259.0 > 214.0, 259.0 > 168.0 and 259.0 > 159.0, and m/z 259.0 > 144.9 was suggested for LTG-13C3 quantitation. CBZ had a slight influence on OXC analysis only at 0.225 mg/L (bias, 20.24%) but did not affect MHD analysis. Optimization of chromatography conditions was useful to avoid the influence of isobaric mass transitions on analysis. This method has been successfully applied in 208 patients with epilepsy for dose adjustment.

Conclusions:

An accurate, robust, rapid, and simple method for simultaneous determination of LTG, TPM, OXC, and MHD by UHPLC-MS/MS was developed, validated, and successfully applied in patients with epilepsy for dose adjustment. The experiences during method development, validation, and application might be helpful for other researchers.

Contraceptive vaginal ring reduces lamotrigine levels

OBJECTIVE

The objective of the study was to describe the effect of the vaginal ring and transdermal patch on lamotrigine serum levels in women with epilepsy.

BACKGROUND

Previous studies demonstrate that oral hormonal contraceptives containing synthetic estrogen increase lamotrigine clearance through induction of glucuronidation. This leads to variable lamotrigine serum concentrations throughout monthly cycles in women who are on combined oral contraceptives (COCs). The effects of estrogen-containing nonoral hormonal contraceptive methods, including the vaginal ring and transdermal patch, on lamotrigine pharmacokinetics are not well described.

METHODS

Retrospective chart review was performed to identify serum lamotrigine levels drawn from women with epilepsy while on the active phase of vaginal ring or transdermal patch and while off contraception. Wilcoxon signed-rank tests for paired data were used to compare the difference in dose-corrected lamotrigine concentration in plasma between values while on hormonal contraception to those while off contraception in patients using a vaginal ring.

RESULTS

Six patients were using the vaginal ring, and one patient was using the transdermal patch. Lamotrigine dose-corrected concentrations were decreased during the active phase of the vaginal ring compared with concentrations during the period off contraception (p = .04). There was one patient without a decrease in concentration, but the other five patients on the vaginal ring had a decrease in dose-corrected lamotrigine concentration ranging from 36 to 70% while on the vaginal ring. Similarly, one patient using the transdermal patch had a decrease of 37% in dose-corrected lamotrigine concentration while on the patch.

CONCLUSIONS

The findings support that the vaginal ring contraceptive method decreases lamotrigine concentrations during the active phase of treatment. This has important implications for contraceptive counseling and maintaining therapeutic levels in women of childbearing age with epilepsy.

Antiepileptic Drug Exposure in Infants of Breastfeeding Mothers With Epilepsy

Importance

There is limited information on infant drug exposure via breastfeeding by mothers who are receiving antiepileptic drug therapy.

Objective

To provide direct, objective information on antiepileptic drug exposure through breast milk.

Design, Setting, and Participants

This prospective cohort study was conducted between December 2012 to October 2016, with follow-up in children until 6 years of age at 20 sites across the United States. Data were collected via an observational multicenter investigation (Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs [MONEAD]) of outcomes in pregnant mothers with epilepsy and their children. Pregnant women with epilepsy who were aged 14 to 45 years, had pregnancies that had progressed to less than 20 weeks' gestational age, and had measured IQ scores of more than 70 points were enrolled and followed up through pregnancy and 9 postpartum months. Their infants were enrolled at birth. Data were analyzed from May 2014 to August 2019.

Exposures

Antiepileptic drug exposure in infants who were breastfed.

Main Outcomes and Measures

The percentage of infant-to-mother concentration of antiepileptic drugs. Antiepileptic drug concentrations were quantified from blood samples collected from infants and mothers at the same visit, 5 to 20 weeks after birth. Concentrations of antiepileptic drugs in infants at less than the lower limit of quantification were assessed as half of the lower limit. Additional measures collected were the total duration of all daily breastfeeding sessions and/or the volume of pumped breast milk ingested from a bottle.

Results

A total of 351 women (of 865 screened and 503 eligible individuals) were enrolled, along with their 345 infants (179 female children [51.9%]; median [range] age, 13 [5-20] weeks). Of the 345 infants, 222 (64.3%) were breastfed; the data collection yielded 164 matching infant-mother concentration pairs from 138 infants. Approximately 49% of all antiepileptic drug concentrations in nursing infants were less than the lower limit of quantification. The median percentage of infant-to-mother concentration for all 7 antiepileptic drugs and 1 metabolite (carbamazepine, carbamazepine-10,11-epoxide, levetiracetam, lamotrigine, oxcarbazepine, topiramate, valproate, and zonisamide) ranged from 0.3% (range, 0.2%-0.9%) to 44.2% (range, 35.2%-125.3%). In multiple linear regression models, maternal concentration was a significant factor associated with lamotrigine concentration in infants (Pearson correlation coefficient, 0.58; P < .001) but not levetiracetam concentration in infants.

Conclusions and Relevance

Overall, antiepileptic drug concentrations in blood samples of infants who were breastfed were substantially lower than maternal blood concentrations. Given the well-known benefits of breastfeeding and the prior studies demonstrating no ill effects when the mother was receiving antiepileptic drugs, these findings support the breastfeeding of infants by mothers with epilepsy who are taking antiepileptic drug therapy.