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

Trends in maternal deaths from epilepsy in the United Kingdom: a 30-year retrospective review

OBJECTIVE

Neurological diseases remain the second most common cause of maternal mortality from indirect causes, according to the last United Kingdom confidential enquiry into maternal death. The maternal mortality rate from epilepsy is reported as 0.61 per 100,000 maternities. The aim of this study was to analyse the trends and causes of maternal death from epilepsy in the UK over the last 30 years. Information on sub-standard care associated with fatalities was also consolidated to inform guidance and clinical care by obstetricians and physicians caring for pregnant women with epilepsy.

STUDY DESIGN

A retrospective review of 10 triennial confidential enquiry into maternal death reports (1979-2008) was performed, encompassing 21,514,457 maternities. Late and coincidental deaths were not included in the analyses.

RESULTS

Between 1979 and 2008, there were 92 maternal deaths from epilepsy. The proportion of total maternal deaths from epilepsy over 30 years is 3.7% (95% CI 3.0-4.5), which showed an increasing trend. Sudden unexpected death in epilepsy remains the single greatest cause of maternal death from epilepsy followed by aspiration of gastric contents during seizures and drowning during bathing.

CONCLUSION

All women with epilepsy should be looked after by specialist combined obstetric and medical or neurological teams in pregnancy to improve maternal and fetal outcomes.

Transcriptional regulation of human UDP-glucuronosyltransferase genes

Glucuronidation is an important metabolic pathway for many small endogenous and exogenous lipophilic compounds, including bilirubin, steroid hormones, bile acids, carcinogens and therapeutic drugs. Glucuronidation is primarily catalyzed by the UDP-glucuronosyltransferase (UGT) 1A and two subfamilies, including nine functional UGT1A enzymes (1A1, 1A3-1A10) and 10 functional UGT2 enzymes (2A1, 2A2, 2A3, 2B4, 2B7, 2B10, 2B11, 2B15, 2B17 and 2B28). Most UGTs are expressed in the liver and this expression relates to the major role of hepatic glucuronidation in systemic clearance of toxic lipophilic compounds. Hepatic glucuronidation activity protects the body from chemical insults and governs the therapeutic efficacy of drugs that are inactivated by UGTs. UGT mRNAs have also been detected in over 20 extrahepatic tissues with a unique complement of UGT mRNAs seen in almost every tissue. This extrahepatic glucuronidation activity helps to maintain homeostasis and hence regulates biological activity of endogenous molecules that are primarily inactivated by UGTs. Deciphering the molecular mechanisms underlying tissue-specific UGT expression has been the subject of a large number of studies over the last two decades. These studies have shown that the constitutive and inducible expression of UGTs is primarily regulated by tissue-specific and ligand-activated transcription factors (TFs) via their binding to cis-regulatory elements (CREs) in UGT promoters and enhancers. This review first briefly summarizes published UGT gene transcriptional studies and the experimental models and tools utilized in these studies, and then describes in detail the TFs and their respective CREs that have been identified in the promoters and/or enhancers of individual UGT genes.

Pharmacogenetics and individualizing drug treatment during pregnancy

Pharmacogenetics as a tool to aid clinicians implement individualized pharmacotherapy is utilized in some areas of medicine. Pharmacogenetics in pregnancy is still a developing field. However, there are several areas of obstetric therapeutics where data are emerging that give glimpses into future therapeutic possibilities. These include opioid pain management, antihypertensive therapy, antidepressant medications, preterm labor tocolytics, antenatal corticosteroids and drugs for nausea and vomiting of pregnancy, to name a few. More data are needed to populate the therapeutic models and to truly determine if pharmacogenetics will aid in individualizing pharmacotherapy in pregnancy. The objective of this review is to summarize current data and highlight research needs.

Advances in anti-epileptic drug testing

In the past twenty-one years, 17 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are clobazam, ezogabine (retigabine), eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, perampanel, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. Therapeutic drug monitoring is often used in the clinical dosing of the newer anti-epileptic drugs. The drugs with the best justifications for drug monitoring are lamotrigine, levetiracetam, oxcarbazepine, stiripentol, and zonisamide. Perampanel, stiripentol and tiagabine are strongly bound to serum proteins and are candidates for monitoring of the free drug fractions. Alternative specimens for therapeutic drug monitoring are saliva and dried blood spots. Therapeutic drug monitoring of the new antiepileptic drugs is discussed here for managing patients with epilepsy.

Pregnancy and pharmacogenomics in the context of drug metabolism and response

It is well-known that profound physiological and biochemical changes occur throughout the course of pregnancy. At the same time, the role of pharmacogenomics in modulating the metabolism and response profile to numerous medications has been elucidated. Yet, the clinical impact of pharmacogenomics during pregnancy is less well understood. We present an overview of factors modulating the pharmacokinetics and pharmacodynamics of medications throughout the time span of pregnancy while providing insights on how pharmacogenomics may contribute to interindividual variability in drug metabolism and response amongst pregnant women.

Gender issues in antiepileptic drug treatment

The purpose of this review is to discuss gender-related aspects in the, pharmacokinetics, effects, selection and use of antiepileptic drugs (AED). In general, there are few known gender related differences in pharmacokinetics or efficacy of AEDs. Conversely, gender has a significant influence on the susceptibility to certain adverse effects, not the least those involving alterations in sex hormone metabolism. Particularly relevant are the teratogenic effects of AEDs, with important differences among AEDs in their potential to cause adverse effects on the fetus when used during pregnancy. Pregnancy can also markedly affect the pharmacokinetics of several AEDs, and dose adjustments are often needed during pregnancy to maintain seizure control. Some treatments that are used only by women, such as contraceptive steroids and hormone replacement therapy, can also interact with AEDs to an extent that may affect the utilization of both the AEDs and the other drug.

Carbamazepine clearance and seizure stability during pregnancy

The aims of this study were to characterize the alterations in total and free carbamazepine (CBZ) and in total and free carbamazepine-epoxide (CBZ-EPO) clearances during pregnancy, to calculate the change in free fractions of CBZ and CBZ-EPO during pregnancy, and to determine whether seizure worsening is associated with a low ratio to nonpregnant baseline concentration of total or free CBZ or CBZ-EPO. Women on CBZ were enrolled before conception or during pregnancy in this prospective, observational study. Concomitant medications and seizure frequency were recorded. Serum total and free CBZ and CBZ-EPO were collected at each visit. Changes in the clearance of all four compounds and free fractions of CBZ and CBZ-EPO were compared with nonpregnant baseline. During pregnancy, the ratios to baseline concentrations of total and free CBZ and CBZ-EPO were compared for months with and without increased seizure frequency. Total and free CBZ and CBZ-EPO clearances were calculated in 15 pregnancies in 12 women. Clearances did not change for any of these compounds during pregnancy. The free fraction of CBZ increased from 0.23 at baseline to a maximum of 0.32 in the third trimester (p=0.008). In the six women on CBZ monotherapy with adequate seizure diaries and blood sampling, seizure worsening did not correspond to a ratio to baseline concentration of less than 0.65 for total or free CBZ or CBZ-EPO. In conclusion, total and free CBZ and CBZ-EPO clearances did not change substantially during pregnancy, and seizure frequency worsening was not associated with decreased concentrations of total or free CBZ; therefore, therapeutic drug monitoring may not be necessary for all women on CBZ during pregnancy. Further studies with larger sample sizes are needed before definitive recommendations can be made. Carbamazepine monotherapy may be a relatively safe and cost effective treatment option for women with focal epilepsy syndromes during pregnancy.

Pharmacotherapy for mood disorders in pregnancy: a review of pharmacokinetic changes and clinical recommendations for therapeutic drug monitoring

OBJECTIVE

Pharmacotherapy for mood disorders during pregnancy is often complicated by pregnancy-related pharmacokinetic changes and the need for dose adjustments. The objectives of this review are to summarize the evidence for change in perinatal pharmacokinetics of commonly used pharmacotherapies for mood disorders, discuss the implications for clinical and therapeutic drug monitoring (TDM), and make clinical recommendations.

METHODS

The English-language literature indexed on MEDLINE/PubMed was searched for original observational studies (controlled and uncontrolled, prospective and retrospective), case reports, and case series that evaluated or described pharmacokinetic changes or TDM during pregnancy or the postpartum period.

RESULTS

Pregnancy-associated changes in absorption, distribution, metabolism, and elimination may result in lowered psychotropic drug levels and possible treatment effects, particularly in late pregnancy. Mechanisms include changes in both phase 1 hepatic cytochrome P450 and phase 2 uridine diphosphate glucuronosyltransferase enzyme activities, changes in hepatic and renal blood flow, and glomerular filtration rate. Therapeutic drug monitoring, in combination with clinical monitoring, is indicated for tricyclic antidepressants and mood stabilizers during the perinatal period.

CONCLUSIONS

Substantial pharmacokinetic changes can occur during pregnancy in a number of commonly used antidepressants and mood stabilizers. Dose increases may be indicated for antidepressants including citalopram, clomipramine, imipramine, fluoxetine, fluvoxamine, nortriptyline, paroxetine, and sertraline, especially late in pregnancy. Antenatal dose increases may also be needed for lithium, lamotrigine, and valproic acid because of perinatal changes in metabolism. Close clinical monitoring of perinatal mood disorders and TDM of tricyclic antidepressants and mood stabilizers are recommended.

MODEL-BASED LAMOTRIGINE CLEARANCE CHANGES DURING PREGNANCY: CLINICAL IMPLICATION

Objective

The objective of the study was to characterize changes in the oral clearance (CL/F) of lamotrigine (LTG) over the course of pregnancy and the postpartum period through a model-based approach incorporating clinical characteristics that may influence CL/F, in support of developing clinical management guidelines.

Methods

Women receiving LTG therapy who were pregnant or planning pregnancy were enrolled. Maternal blood samples were collected at each visit. A pharmacokinetic analysis was performed using a population-based, nonlinear, mixed-effects model.

Results

A total of 600 LTG concentrations from 60 women (64 pregnancies) were included. The baseline LTG CL/F was 2.16 L/h with a between-subject variability of 40.6%. The influence of pregnancy on CL/F was described by gestational week. Two subpopulations of women emerged based on the rate of increase in LTG CL/F during pregnancy. The gestational age-associated increase in CL/F displayed a 10-fold higher rate in 77% of the women (0.118 L/h per week) compared to 23% (0.0115 L/h per week). The between-subject variability in these slopes was 43.0%. The increased CL/F at delivery declined to baseline values with a half-life of 0.55 weeks.

Interpretation

The majority of women had a substantial increase in CL/F from 2.16 to 6.88 L/h by the end of pregnancy, whereas 23% of women had a minimal increase. An increase in CL/F may correspond to decreases in LTG blood concentrations necessitating the need for more frequent dosage adjustments and closer monitoring in some pregnant women with epilepsy. Postpartum doses should be tapered to preconception dose ranges within 3 weeks of delivery.

Antiepileptic drug clearance and seizure frequency during pregnancy in women with epilepsy

The aims of the study were to characterize the magnitude of clearance changes during pregnancy for multiple antiepileptic drugs (AEDs) and to assess seizure frequency and factors increasing seizure risk in pregnant women with epilepsy. A retrospective analysis was performed for 115 pregnancies in 95 women with epilepsy followed at the Emory Epilepsy Center between 1999 and 2012. Antiepileptic drug blood levels (ABLs) obtained during routine clinical practice were used to calculate AED clearance at multiple points during pregnancy. Antiepileptic drug doses and seizure activity were also recorded. The data were analyzed for changes in clearance and dose across pregnancy and for an association between ABL and changes in seizure frequency. Significant changes in clearance during pregnancy were observed for lamotrigine (p<0.001) and levetiracetam (p<0.006). Average peak clearance increased by 191% for lamotrigine and 207% for levetiracetam from nonpregnant baseline. Marked variance was present across individual women and also across repeat pregnancies in individual women. Despite increased AED dose across most AEDs, seizures increased in 38.4% of patients during pregnancy. Seizure deterioration was significantly more likely in patients with seizures in the 12 months prior to conception (p<0.001) and those with localization-related epilepsy (p=0.005). When ABL fell >35% from preconception baseline, seizures worsened significantly during the second trimester when controlling for seizure occurrence in the year prior to conception. Substantial pharmacokinetic changes during pregnancy occur with multiple AEDs and may increase seizure risk. Monitoring of AED serum concentrations with dose adjustment is recommended in pregnant women with epilepsy. Further studies are needed for many AEDs.

Oh baby! A review of mood stabilizers for bipolar disorder in the child-bearing woman

Background: Bipolar disorder is a brain disorder that can cause abnormal changes in a person's mood, cognitive function, and quality of life. Patients who are diagnosed with bipolar disorder often have intense emotional states that are characterized by either manic or depressive episodes. There is a strong correlation between women of child bearing age and the initial age of onset of the disease. Mood stabilizing drugs have been the mainstay of treatment for many decades; however, there is strong data supporting the teratogenic effects of these drugs on the fetus in pregnant and lactating women.

Methods: Review articles, clinical trials, and practice guidelines were located using online databases PubMed, CINAHL, IDIS, and Medline. Search terms included at least one of the following: “bipolar disorder”, “breast-feeding”, “carbamazepine”, “epilepsy”, “lactation”, “lamotrigine”, “lithium”, “mood stabilizers”, “pregnancy”, “valproate”, and “valproic acid”. Online clinical databases Clinical Pharmacology and Lexi-Comp were also used in the study.

Results: All mood stabilizer drugs are found to cause malformations in fetal development if given during the first trimester of pregnancy, thus use should be avoided if possible. Lamotrigine was found to cause lowest risk of adverse effects in both the mother and fetus during pregnancy; however, it should be avoided in breastfeeding women as it readily passes into breast milk. Lithium use during pregnancy and lactation has been associated with severe malformations and should only be used if maternal benefit outweighs fetal risk. Valproate is considered harmful to both the mother and fetus during pregnancy, but may be a compatible option for breastfeeding. Carbamazepine is found to cause serious malformations with the developing fetus as well as metabolic effects with the mother; however, it is found to cause little effects in breastfed infants as it does not readily pass through breast milk.

Conclusion: The use of medications in pregnant and breastfeeding women suffering from bipolar disorder must be carefully considered for impacts on fetal development as well as risks to the mother. Mood stabilizers are readily marketed as first line treatment options for bipolar disorder; however, their use in pregnant and lactating women may cause limitations as preferred therapy. Studies show that though lamotrigine has not been as well studied as the other agents, it may be the best recommendation during pregnancy, for both fetal and maternal health concerns. For breastfeeding women, carbamazepine has been shown to be the better option, as it carries the lowest risk of adverse events to the infant.

Seizures in pregnancy: epilepsy, eclampsia, and stroke

Seizures during pregnancy complicate <1% of all gestations; however, they are associated with increased adverse maternal and perinatal outcomes (acute and long term). The differential diagnosis of seizures in pregnancy is extensive. Determining the underlying etiology is crucial in the management of these patients. Medical providers caring for pregnant women should be educated about possible etiologies of seizures during pregnancy and the importance of prompt management of these women in a timely fashion. Evaluation and management should be performed in a stepwise fashion and may require a multidisciplinary approach with other specialties such as neurology. The objective of this review is to increase awareness and to provide a stepwise approach toward the diagnosis and management of pregnancies complicated by seizures.

Seizure control and treatment changes in pregnancy: observations from the EURAP epilepsy pregnancy registry

PURPOSE

To analyze seizure control, dose adjustments, and other changes of antiepileptic drug (AED) treatment during pregnancy in a large cohort of women with epilepsy entering pregnancy on monotherapy with carbamazepine, lamotrigine, phenobarbital, or valproate.

METHODS

Seizure control and AED treatment were recorded prospectively in 3,806 pregnancies of 3,451 women with epilepsy taking part in European and International Registry of Antiepileptic Drugs and Pregnancy (EURAP), an international AED and pregnancy registry.

KEY FINDINGS

Of all cases, 66.6% remained seizure-free throughout pregnancy. Generalized tonic-clonic seizures (GTCS) occurred in 15.2% of the pregnancies. Women with idiopathic generalized epilepsies were more likely to remain seizure-free (73.6%) than women with localization-related epilepsy (59.5%; p < 0.0001). Worsening in seizure control from the first to second or third trimesters occurred in 15.8% of pregnancies. The AED dose was increased during pregnancy in 26.0% and a second AED added to the initial monotherapy in 2.6% of all pregnancies. Seizures were more likely to occur in the first trimester in pregnancies with an increased drug load (35%; increased dose and/or addition of another AED) than in pregnancies without an increased drug load (15.3%) (p < 0.0001). Compared with other monotherapies, pregnancies exposed to lamotrigine were less likely to be seizure-free, 58.2% (p < 0.0001); had more GTCS, 21.1% (p < 0.0001); had a greater likelihood of deterioration in seizure control from first to second or third trimesters, 19.9% (p < 0.01), and were more likely to require an increase in drug load, 47.7% (p < 0.0001). The mean dose increases from the first to third trimesters were 26% for lamotrigine, 5% for carbamazepine, 11% for phenobarbital, and 6% for valproate. There were 21 cases of status epilepticus (10 convulsive): none with maternal mortality and only one with a subsequent stillbirth.

SIGNIFICANCE

Although the majority of women remain seizure-free throughout pregnancy, our data suggest that a more proactive approach to adjusting the dose of all AEDs in pregnancy should be considered, in particular for those pregnancies with seizures occurring in the first trimester and those exposed to lamotrigine, to reduce the risk of deterioration in seizure control.

Epilepsy in pregnancy: best evidence for care

Epilepsy is the most commonly encountered neurologic disorder during pregnancy. A majority of women with epilepsy continue antiepileptic drug regimens during pregnancy. To provide evidence-based care to women with epilepsy, it is critical that healthcare providers possess a basic knowledge of seizures, antiepileptic medications, and interventions specific to this patient population, as well as an understanding of the patient's basic needs and concerns. This article provides a discussion of seizure types, common antiepileptic medications, and provides evidence-based interventions related to the fetus and the mother during preconception, intrapartum, and postpartum periods.

The management of epilepsy in pregnancy at the Whittington Hospital: a retrospective audit 2004-2006 and 2007-2010

BACKGROUND

In the last maternal death enquiries report there were 14 indirect deaths due to epilepsy.

METHODS

Retrospective case-note analysis of epileptic women seen antenatally over two separate time periods were examined. Care in the routine antenatal clinic (ANC) was compared with that in the obstetric medicine clinic (OMC).

RESULTS

1st audit, 65 epileptic women seen. In OMC 14% had documented preconception counselling, 58% were on anti-epileptic drugs (AEDs). In ANC 0% had documented preconception counselling, 34% were on AEDs. 2nd audit, 88 epileptic women seen. In OMC 37.5% of women had preconception counselling, 84% were on AEDs. In ANC, 4.2% had preconception counselling, 31% were on AEDs.

CONCLUSIONS

Women seen in OMC received care more compliant with Scottish Obstetric Group and Audit Project recommendations. All women with epilepsy should be reviewed in an OMC.

Therapeutic drug monitoring in pregnancy

Therapeutic drug monitoring (TDM) is commonly recommended to optimize drug dosing regimens of various medications. It has been proposed to guide therapy in pregnant women, in whom physiological changes may lead to altered pharmacokinetics resulting in difficulty in predicting the appropriate drug dosage. Ideally, TDM may play a role in enhancing the effectiveness of treatment while minimizing toxicity of both the mother and fetus. Monitoring of drug levels may also be helpful in assessing adherence to prescribed therapy in selected cases. Limitations exist as therapeutic ranges have only been defined for a limited number of drugs and are based on data obtained in nonpregnant patients. TDM has been suggested for anticonvulsants, antidepressants, and antiretroviral drugs, based on pharmacokinetic studies that have shown reduced drug concentrations. However, there is only relatively limited (and sometimes inconsistent) information regarding the clinical impact of these pharmacokinetic changes during pregnancy and the effect of subsequent dose adjustments. Further studies are required to determine whether implementation of TDM during pregnancy improves outcome and is associated with any benefit beyond that achieved by clinical judgment alone. The cost effectiveness of TDM programs during pregnancy also remains to be examined.

Managing epilepsy during pregnancy: assessing risk and optimizing care

OPINION STATEMENT

Epilepsy is the most common neurologic condition found in pregnancy. As such, all neurologists, internists, and obstetricians should know how to counsel women with epilepsy as they are considering pregnancy. While all of the usual recommendations for women of childbearing potential apply, including preconceptual and ongoing use of folic acid, calcium, and vitamin D, additional consideration must be given to the need for adjustment or change of anticonvulsant therapy. Monotherapy with the lowest dose of medication needed to control seizures should be prescribed prior to conception. Most anticonvulsants have a favorable profile when used in pregnancy; older anticonvulsants such as valproate and carbamazepine should be avoided, as they are associated with higher rates of fetal malformation, and in the case of valproate, with proven cognitive deficits in children exposed to this medication in utero. With use of any anticonvulsant medication, dosing throughout pregnancy will need to be adjusted to maintain an appropriate serum concentration. Dosing of anticonvulsants needs to be decreased after delivery to avoid medication-related toxicity, although sleep deprivation and hormonal fluctuation can increase the risk of seizures in postpartum women. With proper management, the majority of women with epilepsy can have uneventful pregnancies and healthy babies.

Lamotrigine use in pregnancy

Lamotrigine is a sodium-channel-modulating, antiepileptic drug (AED), which was approved in the USA in 1994 for use in partial-onset seizures. It was ultimately approved for monotherapy in 1998. Lamotrigine has gained widespread use in the USA as both an immediate and an extended-release agent. Lamotrigine is effective against a broad spectrum of seizure types and has a favorable metabolic profile, with few but significant drug interactions. Pregnancy registries in several countries have demonstrated that AED use in women with epilepsy is associated with an increased risk of fetal malformations, if the infant is exposed during the period of organogenesis. In addition, new evidence demonstrates that AEDs may affect the intellectual development of a child, as measured up until the age of 3 years. This information has made the choice of an anticonvulsant for a woman who might become pregnant significantly more important. Pregnancy registries have consistently demonstrated lamotrigine to be among the safest medications for a developing fetus, both in terms of fetal malformations and postpartum cognitive development. These findings make lamotrigine probably the first choice of AED for women wishing to become pregnant and for whom the medication is appropriate.

Algorithm for lamotrigine dose adjustment before, during, and after pregnancy

BACKGROUND

Treatment with lamotrigine (LTG) during pregnancy is associated with a pronounced risk of seizure deterioration, because pregnancy accelerates LTG elimination. The extent to which pregnancy affects LTG pharmacokinetics is unpredictable and varies considerably among patients.

AIM

We propose an algorithm for systematic LTG plasma concentration monitoring and dose adjustment to guide the clinician between the risk of seizure deterioration and LTG toxicity by maintaining a stable LTG concentration, using the optimal prepregnancy target concentration as a reference.

METHODS

The reference LTG plasma concentration (RC) should be determined before pregnancy or as early in pregnancy as possible. After conception, plasma concentration of LTG should be measured every 4 weeks throughout pregnancy. When the LTG plasma concentration falls below the RC, the dose of LTG should be increased by 20-25%. Post-partum, the plasma concentration of LTG should be measured within the first or second week, and if the LTG plasma concentration is higher than the RC, the LTG dose should be reduced by 20-25% and the procedure repeated until RC is re-established.

CONCLUSIONS

Seizure deterioration during pregnancy may be prevented or reduced by closely and systematically following our proposed algorithm.

AED Treatment Through Different Ages: As Our Brains Change, Should Our Drug Choices Also?

Patient age can impact selection of the optimal antiepileptic drug for a number of reasons. Changes in brain physiology from neonate to elderly, as well as changes in underlying etiologies of epilepsy, could potentially affect the ability of different drugs to control seizures. Unfortunately, much of this is speculative, as good studies demonstrating differences in efficacy across age ranges do not exist. Beyond the issue of efficacy, certain drugs may be more or less appropriate at different ages because of differing pharmacokinetics, including changes in hepatic metabolism, absorption, and elimination. Lack of appropriate drug formulations (such as liquid forms) may be a barrier to using drugs in the very young. Finally, some serious adverse events are seen either exclusively or preferentially at different ages.

Patient knowledge about issues related to pregnancy in epilepsy: a cross-sectional study

In 2009, new guidelines were established by the American Academy of Neurology regarding pregnancy in women with epilepsy. A questionnaire was developed to assess patient knowledge of current guidelines related to epilepsy and pregnancy. Patients were recruited from a single outpatient clinic in a large Canadian tertiary care center. Patients were eligible to participate if they were female, of reproductive age, had active epilepsy for at least 6 months and were not cognitively impaired. One hundred women completed the survey (response rate 87%) with a median score of 40%. A significant association was found between total score and years of education (p<0.001). Significant associations were not found between total score and epilepsy duration (p=0.37), previously being pregnant (p=0.22), and polytherapy (p=0.31). Patient knowledge of the impact of epilepsy on pregnancy is low. More knowledge translation efforts are required to increase knowledge of issues related to pregnancy for women with epilepsy.

Prenatal antiepileptic exposure associates with neonatal DNA methylation differences

Antiepileptic drugs (AEDs) are used to treat a variety of neuropsychiatric illnesses commonly encountered in women during their reproductive years, including epilepsy and bipolar disorder. Despite their widespread use, the impact of prenatal exposure on fetal development remains obscure. To evaluate whether AEDs taken by pregnant mothers influence DNA methylation patterns in their neonates, DNA was extracted from the umbilical cord blood of 201 neonates whose mothers were treated for neuropsychiatric illness during pregnancy and interrogated across 27,578 CpG sites using the Illumina HumanMethylation27 BeadChip. The association of each methylation value with the cumulative duration of prenatal AED exposure was examined using a linear mixed model. The average methylation level across all CpG sites was calculated for each subject, and this global methylation measure was evaluated similarly. Neonates with a longer duration of AED exposure in pregnancy showed a decrease in average global methylation (p = 0.0045). Further, DNA methylation of CpG sites in 14 genes significantly decreased with the duration of prenatal AED exposure even after adjusting for multiple comparisons (FDR < 0.05). For a small subset (n = 19) of these neonates, a second tissue, placenta, was available in addition to cord blood. Methylation of 3 of these 14 CpG sites was also significantly decreased in placental tissue. These novel data suggest decreased DNA methylation in neonates of mothers who took AEDs during pregnancy. The long-term stability and potential impact of these changes warrant further attention, and caution may be warranted before prescribing AEDs to pregnant women.

Antiepileptic drugs in women with epilepsy during pregnancy

Prescribing antiepileptic drugs (AEDs) in pregnancy is a challenge to the clinician. A multitude of questions arise that must be addressed even prior to conception. In women with proven epilepsy, it may be dangerous to stop or even change the AED regimen during pregnancy. Changes could lead to injury or death in both the mother and the fetus. In the rare cases when discontinuing an AED is plausible, it should be done methodically in consultation with the physician prior to conception. Most women with epilepsy are consigned to continue their AEDs before, during and after pregnancy. The metabolism of AEDs may change drastically during pregnancy. These changes must be addressed by the clinician. Drug levels should be monitored consistently during pregnancy. The risks to the fetus must be delineated in terms of side effects from specific drugs as well as risks from the seizure disorder itself. Many AEDs have well known teratogenic effects, and these must be elucidated to the mother. There are risks (theoretical and evidence based) for obstetrical complications, poor neonatal outcomes, congenital malformations and even cognitive effects on the child later in life. These risks are addressed in this article with respect to individual AEDs. Recommendations include but are not limited to preconception counseling, taking folate pre and post conception, prescribing the most effective AED while minimizing risks, and avoiding polytherapy and valproate if possible.

Do lamotrigine and levetiracetam solve the problem of using sodium valproate in women with epilepsy?

Women with epilepsy, especially those of child-bearing age, are faced with difficult choices when it comes to choosing the most suitable antiepileptic drug (AED). This is particularly so for those with idiopathic generalized epilepsies, or those for whom seizure syndrome is not immediately apparent, where sodium valproate is still considered the drug of choice. While with treatment most might expect to become seizure free, without any adverse effects, other considerations for women mean that valproate is usually initially avoided, with other AEDs such as lamotrigine or levetiracetam being chosen in preference. Based on current information, this article attempts to provide an overview on whether or not the availability of these and other broad-spectrum AEDs have solved the difficulties of using valproate in women of child-bearing age.

The effect of age and comedication on lamotrigine clearance, tolerability, and efficacy

PURPOSE

To compare pharmacokinetics, tolerability, and efficacy of lamotrigine (LTG) in older versus younger adults.

METHODS

We studied 686 adult outpatients seen at our center over 5 years. We compared apparent clearance (CL) of LTG in the youngest (16-36 years; n = 247) and oldest (55-92 years; n = 155) tertiles. We analyzed one-year retention for younger and older adults newly started on LTG, frequency of adverse effects causing intolerability, and rates of specific adverse effects. We also investigated 6-month seizure freedom.

KEY FINDINGS

Median LTG CL of older adults taking LTG in monotherapy was approximately 22% lower compared to younger adults (28.8 vs. 36.5 ml/h/kg; p < 0.001). LTG CL in older adults was lower compared to younger adults in patients on polytherapy and on polytherapy without enzyme inducers or valproate. One-year retention for LTG was comparable in older (78.1%, 121/155) and younger (72.4%, 179/247) adults. Intolerability to LTG was higher in older (34.8%) versus younger adults (24.2%; p = 0.005). Imbalance, drowsiness, and dizziness were common intolerable side effects in both groups. Older patients had higher rates of intolerability due to imbalance (16% vs. 4%), drowsiness (13% vs. 7%), and tremor (5% vs. 2%) compared with younger patients. Rates of 6-month seizure freedom were comparable, and small numbers of each group benefited from very high levels of LTG (>15 μg/ml).

SIGNIFICANCE

LTG CL in monotherapy in older adults is approximately 20% lower than in younger adults. For a given serum LTG level, older adults are twice as likely to have significant adverse effects compared to younger adults. Older patients are more likely to experience imbalance, drowsiness, and tremor than younger patients. Younger adults tolerate LTG better than older adults, but one-year retention is comparable. Some patients may benefit from high serum levels of LTG.

Pharmacotherapeutics of epilepsy: use of lamotrigine and expectations for lamotrigine extended release

The goal in managing patients with epilepsy is complete seizure freedom. Pharmacotherapeutic management of epilepsy is complicated by multiple syndromes, inter-individual differences in drug sensitivities, inter-individual differences in drug disposition, and drug interactions. Most anti-epileptic drugs (AEDs) have a therapeutic window with only a 2- to 3-fold concentration range. Extended release formulations offer advantages over their immediate release counter parts with less fluctuation in the serum concentration vs time curve and improved compliance. However, missed doses are more likely to result in prolonged “sub-therapeutic serum concentrations”. Best clinical outcome may sometimes require twice daily dosing of extended release formulations even though approved for once daily dosing, as this optimally balances pharmacokinetics against compliance. Lamotrigine (LTG) is a broad spectrum AED with efficacy in partial and generalized epilepsy syndromes and good tolerability. Its metabolism is affected by co-medications which may be inducing, neutral or inhibiting of hepatic glucuronidation. Furthermore, though the average half-life in monotherapy is about 24 hours, there is a large inter-individual variation that may, including the extremes, approach a range of 10-fold. LTG-XR is expected to decrease fluctuation of serum concentration in the presence of hepatic inducing or neutral drugs. However, optimal clinical benefit in some patients may require twice daily dosing when metabolism is rapid.

Perinatal exposure to maternal lamotrigine: clinical considerations for the mother and child

QUESTION

The question of neonatal safety during breastfeeding when mothers are taking lamotrigine (LTG) has become more prevalent in my practice. There are some theoretical concerns about breastfeeding while taking LTG, which have been compounded by a published case report of toxicity in the breastfed neonate of a mother taking LTG. How should I advise my patients who wish to breastfeed while taking LTG?

ANSWER

Most neonates born to mothers taking LTG have already been exposed to the drug for 9 months in utero, given the chronic indications for which the drug is intended. Lamotrigine exposure via breast milk is considerably less than placental transfer, with serum LTG concentrations in neonates higher at birth than during lactation. While a single case of toxicity has been reported in a neonate exposed to LTG via breast milk, in most circumstances, breastfeeding can be initiated and maintained given the tremendous benefits of mothers' milk. On the other hand, toxicity during breastfeeding might occur more commonly in the mother, if sufficient and gradual dose readjustments are not undertaken in the weeks following delivery.

Advances in epilepsy: new perspectives on new-onset epilepsy, comorbidities, and pharmacotherapy

The purpose of this brief article is to review old concepts of the significance of acute symptomatic seizures, the impact of psychiatric comorbidities on the response of pharmacologic and surgical treatments of the seizure disorder, and the importance of factoring comorbid medical comorbidities into the choice of antiepileptic drugs (AEDs). In addition, this article provides an update on the latest data on the teratogenic effects of AEDs and reviews the most relevant results of a recent practice guideline on pregnancy issues in women with epilepsy. The article closes with a review of the latest advances in the therapeutic effects of first- and second-generation AEDs.

Therapeutic Drug Monitoring of the Newer Anti-Epilepsy Medications

In the past twenty years, 14 new antiepileptic drugs have been approved for use in the United States and/or Europe. These drugs are eslicarbazepine acetate, felbamate, gabapentin, lacosamide, lamotrigine, levetiracetam, oxcarbazepine, pregabalin, rufinamide, stiripentol, tiagabine, topiramate, vigabatrin and zonisamide. In general, the clinical utility of therapeutic drug monitoring has not been established in clinical trials for these new anticonvulsants, and clear guidelines for drug monitoring have yet to be defined. The antiepileptic drugs with the strongest justifications for drug monitoring are lamotrigine, oxcarbazepine, stiripentol, and zonisamide. Stiripentol and tiagabine are strongly protein bound and are candidates for free drug monitoring. Therapeutic drug monitoring has lower utility for gabapentin, pregabalin, and vigabatrin. Measurement of salivary drug concentrations has potential utility for therapeutic drug monitoring of lamotrigine, levetiracetam, and topiramate. Therapeutic drug monitoring of the new antiepileptic drugs will be discussed in managing patients with epilepsy.