Zonisamide safety in pregnancy: Data from the UK and Ireland epilepsy and pregnancy register

Teratogenicity of zonisamide and other little-used antiseizure medications

PURPOSE

To investigate the risk of teratogenesis occurring in relation to intrauterine exposure to infrequently used antiseizure medications in Australia.

METHODS

Analysis of data contained in the Raoul Wallenberg Australian Pregnancy Register of Antiepileptic Drugs.

RESULTS

There was statistically significant evidence that zonisamide, but not any other of nine infrequently used antiseizure medications in Australia, was associated with a risk of teratogenesis related to the maternal dose of the drug taken in at least the earlier half of pregnancy.

CONCLUSIONS

The teratogenesis associated with zonisamide, like that associated with topiramate and possibly acetazolamide, may be an expression of a class effect shared among sulphonamide-derived carbonic anhydrase inhibitors that possess anti-seizure activity.

The evolution of antiseizure medication therapy selection in adults: Is artificial intelligence -assisted antiseizure medication selection ready for prime time?

Antiseizure medications (ASMs) are the mainstay of symptomatic epilepsy treatment. The primary goal of pharmacotherapy with ASMs in epilepsy is to achieve complete seizure remission while minimizing therapy-related adverse events. Over the years, more ASMs have been introduced, with approximately 30 now in everyday use. With such a wide variety, much guidance is needed in choosing ASMs for initial therapy, subsequent replacement monotherapy, or adjunctive therapy. The specific ASMs are typically tailored by the patient's related factors, including epilepsy syndrome, age, sex, comorbidities, and ASM characteristics, including the spectrum of efficacy, pharmacokinetic properties, safety, and tolerability. Weighing these key clinical variables requires experience and expertise that may be limited. Furthermore, with this approach, patients may endure multiple trials of ineffective treatments before the most appropriate ASM is found. A more reliable way to predict response to different ASMs is needed so that the most effective and tolerated ASM can be selected. Soon, alternative approaches, such as deep machine learning (ML), could aid the individualized selection of the first and subsequent ASMs. The recognition of epilepsy as a network disorder and the integration of personalized epilepsy networks in future ML platforms can also facilitate the prediction of ASM response. Augmenting the conventional approach with artificial intelligence (AI) opens the door to personalized pharmacotherapy in epilepsy. However, more work is needed before these models are ready for primetime clinical practice.

Monotherapy treatment of epilepsy in pregnancy: congenital malformation outcomes in the child

BACKGROUND

Prenatal exposure to certain anti-seizure medications (ASMs) is associated with an increased risk of major congenital malformations (MCM). The majority of women with epilepsy continue taking ASMs throughout pregnancy and, therefore, information on the potential risks associated with ASM treatment is required.

OBJECTIVES

To assess the effects of prenatal exposure to ASMs on the prevalence of MCM in the child.

SEARCH METHODS

For the latest update of this review, we searched the following databases on 17 February 2022: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid, 1946 to February 16, 2022), SCOPUS (1823 onwards), and ClinicalTrials.gov, WHO International Clinical Trials Registry Platform (ICTRP). No language restrictions were imposed.

SELECTION CRITERIA

We included prospective cohort controlled studies, cohort studies set within pregnancy registries, randomised controlled trials and epidemiological studies using routine health record data. Participants were women with epilepsy taking ASMs; the two control groups were women without epilepsy and untreated women with epilepsy.

DATA COLLECTION AND ANALYSIS

Five authors independently selected studies for inclusion. Eight authors completed data extraction and/or risk of bias assessments. The primary outcome was the presence of an MCM. Secondary outcomes included specific types of MCM. Where meta-analysis was not possible, we reviewed included studies narratively.

MAIN RESULTS

From 12,296 abstracts, we reviewed 283 full-text publications which identified 49 studies with 128 publications between them. Data from ASM-exposed pregnancies were more numerous for prospective cohort studies (n = 17,963), than data currently available for epidemiological health record studies (n = 7913). The MCM risk for children of women without epilepsy was 2.1% (95% CI 1.5 to 3.0) in cohort studies and 3.3% (95% CI 1.5 to 7.1) in health record studies. The known risk associated with sodium valproate exposure was clear across comparisons with a pooled prevalence of 9.8% (95% CI 8.1 to 11.9) from cohort data and 9.7% (95% CI 7.1 to 13.4) from routine health record studies. This was elevated across almost all comparisons to other monotherapy ASMs, with the absolute risk differences ranging from 5% to 9%. Multiple studies found that the MCM risk is dose-dependent. Children exposed to carbamazepine had an increased MCM prevalence in both cohort studies (4.7%, 95% CI 3.7 to 5.9) and routine health record studies (4.0%, 95% CI 2.9 to 5.4) which was significantly higher than that for the children born to women without epilepsy for both cohort (RR 2.30, 95% CI 1.47 to 3.59) and routine health record studies (RR 1.14, 95% CI 0.80 to 1.64); with similar significant results in comparison to the children of women with untreated epilepsy for both cohort studies (RR 1.44, 95% CI 1.05 to 1.96) and routine health record studies (RR 1.42, 95% CI 1.10 to 1.83). For phenobarbital exposure, the prevalence was 6.3% (95% CI 4.8 to 8.3) and 8.8% (95% CI 0.0 to 9277.0) from cohort and routine health record data, respectively. This increased risk was significant in comparison to the children of women without epilepsy (RR 3.22, 95% CI 1.84 to 5.65) and those born to women with untreated epilepsy (RR 1.64, 95% CI 0.94 to 2.83) in cohort studies; data from routine health record studies was limited. For phenytoin exposure, the prevalence of MCM was elevated for cohort study data (5.4%, 95% CI 3.6 to 8.1) and routine health record data (6.8%, 95% CI 0.1 to 701.2). The prevalence of MCM was higher for phenytoin-exposed children in comparison to children of women without epilepsy (RR 3.81, 95% CI 1.91 to 7.57) and the children of women with untreated epilepsy (RR 2.01. 95% CI 1.29 to 3.12); there were no data from routine health record studies. Pooled data from cohort studies indicated a significantly increased MCM risk for children exposed to lamotrigine in comparison to children born to women without epilepsy (RR 1.99, 95% CI 1.16 to 3.39); with a risk difference (RD) indicating a 1% increased risk of MCM (RD 0.01. 95% CI 0.00 to 0.03). This was not replicated in the comparison to the children of women with untreated epilepsy (RR 1.04, 95% CI 0.66 to 1.63), which contained the largest group of lamotrigine-exposed children (> 2700). Further, a non-significant difference was also found both in comparison to the children of women without epilepsy (RR 1.19, 95% CI 0.86 to 1.64) and children born to women with untreated epilepsy (RR 1.00, 95% CI 0.79 to 1.28) from routine data studies. For levetiracetam exposure, pooled data provided similar risk ratios to women without epilepsy in cohort (RR 2.20, 95% CI 0.98 to 4.93) and routine health record studies (RR 0.67, 95% CI 0.17 to 2.66). This was supported by the pooled results from both cohort (RR 0.71, 95% CI 0.39 to 1.28) and routine health record studies (RR 0.82, 95% CI 0.39 to 1.71) when comparisons were made to the offspring of women with untreated epilepsy. For topiramate, the prevalence of MCM was 3.9% (95% CI 2.3 to 6.5) from cohort study data and 4.1% (0.0 to 27,050.1) from routine health record studies. Risk ratios were significantly higher for children exposed to topiramate in comparison to the children of women without epilepsy in cohort studies (RR 4.07, 95% CI 1.64 to 10.14) but not in a smaller comparison to the children of women with untreated epilepsy (RR 1.37, 95% CI 0.57 to 3.27); few data are currently available from routine health record studies. Exposure in utero to topiramate was also associated with significantly higher RRs in comparison to other ASMs for oro-facial clefts. Data for all other ASMs were extremely limited. Given the observational designs, all studies were at high risk of certain biases, but the biases observed across primary data collection studies and secondary use of routine health records were different and were, in part, complementary. Biases were balanced across the ASMs investigated, and it is unlikely that the differential results observed across the ASMs are solely explained by these biases.

AUTHORS' CONCLUSIONS

Exposure in the womb to certain ASMs was associated with an increased risk of certain MCMs which, for many, is dose-dependent.

Specific fetal malformations following intrauterine exposure to antiseizure medication

OBJECTIVE

To investigate in the Australian Pregnancy Register of Antiepileptic Drugs patterns of fetal malformation associated with intrauterine exposure to particular currently available antiseizure medications taken by women with epilepsy.

RESULTS

There was statistically significant evidence (P < 0.05) of an increased hazard of fetal malformation associated with exposure to valproate, carbamazepine, topiramate, zonisamide, and with conception after assisted fertilization, but a reduced hazard in the offspring of women who continued to smoke during pregnancy. Valproate exposure was associated with malformations in a wide range of organs and organ systems, carbamazepine and topiramate with hydronephrosis, topiramate also with hypospadias, zonisamide with spina bifida and assisted fertilization with heart and great vessel maldevelopment.

CONCLUSIONS

Prenatal valproate exposure appears to interfere with the development of many if not all, fetal tissues. It seems likely that prenatal exposure to carbamazepine and topiramate, and possibly exposure to zonisamide, but also some process related to in vitro fertilization, may more selectively affect the normal development of particular fetal tissues or organs.

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.

Increasing use of newer antiseizure medication during pregnancy: An observational study with special focus on lacosamide

INTRODUCTION

Epilepsy is a common neurological disease requiring long-term therapy also during pregnancy. Most studies on pregnancy outcomes in women with epilepsy are based on antiseizure medication (ASM) in monotherapy. However, about 20-30% of epilepsy patients require polytherapy and newer ASMs are an option, when seizure control is not achieved with first line ASMs.

METHODS

Observational study evaluating the use of newer ASMs with marketing authorization since 2005 reported to the Embryotox Center of Clinical Teratology and Drug Safety in Pregnancy between 2004 and 2019. In addition, course and outcome of lacosamide exposed pregnancies were analysed.

RESULTS

Our study confirms the increasing use of newer ASMs also in pregnant women. This is especially true for lacosamide, eslicarbazepine and brivaracetam with rising numbers of exposed pregnancies soon after marketing authorization. Analysis of 55 prospectively and 10 retrospectively ascertained lacosamide exposed pregnancies does not indicate increased risks of major birth defects or spontaneous abortion. However, bradycardia observed in 3 neonates might be related to prenatal lacosamide exposure.

CONCLUSION

Available data do not support the assumption of lacosamide being a major teratogen. The increasing use of newer ASMs during pregnancy underscores the need for more studies to guide preconception counselling, especially for lacosamide, eslicarbazepine and brivaracetam.

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.

Current safety concerns about the use of antiseizure medications in pregnancy

INTRODUCTION

Given the high prevalence of epilepsy in women of childbearing potential (15 million out of 50 million people worldwide), antiseizure medication (ASM) use in pregnancy is common. Identifying the safest and most effective ASM to use during pregnancy is often difficult, but also crucially important. The challenge is to balance two needs: maintaining seizure control while minimizing teratogenicity.

AREAS COVERED

This review looks at seizure- and treatment-related risks to mother and fetus during pregnancy, existing healthcare information programmes, strengths and pitfalls of the main pregnancy registries, known and supposed pharmacokinetic changes during gestation, the utility of therapeutic drug monitoring, and safety concerns. Articles and related content were screened on available publications after January 2000.

EXPERT OPINION

The use of newer ASMs during pregnancy is still limited, as shown by the paucity of data collected by different pregnancy registries. Choosing these medications can be challenging, partly due to unknown pharmacokinetic modifications in pregnancy, an aspect that serum drug monitoring might help to clarify. The safest treatment is chosen also taking into account the woman's needs, concerns and wishes, but adequate pre-pregnancy counseling is necessary to properly inform her about personal and fetal risks related both to seizures and to medications.

Preventing Teratogenicity in Women with Epilepsy

Over the last 50 years there has been a significant increase in our understanding of the issues faced by women with epilepsy, in both planning and undertaking pregnancy. The risks of teratogenicity associated with antiseizure medications have emerged slowly. The major pregnancy registers have substantially contributed to our knowledge about teratogenic risk associated with the commonly used antiseizure medications. However, there are substantial gaps in our knowledge about the potential risks associated with many third-generation drugs. The remit of the pregnancy registers and the wider research focus has moved beyond anatomical major congenital malformations. Increasingly neurodevelopmental and behavioral abnormalities have been investigated after in utero exposure to antiseizure medications. Public health approaches can help reduce the risk of teratogenicity. However, neurologists still have a vital role in reducing the risk of teratogenicity at an individual level for women attending their clinic. They also have responsibility to ensure that women with epilepsy are aware of the rationale for the different available options.

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.

Treatment and care of women with epilepsy before, during, and after pregnancy: a practical guide

Women with epilepsy (WWE) wishing for a child represent a highly relevant subgroup of epilepsy patients. The treating epileptologist needs to delineate the epilepsy syndrome and choose the appropriate anti-seizure medication (ASM) considering the main goal of seizure freedom, teratogenic risks, changes in drug metabolism during pregnancy and postpartum, demanding for up-titration during and down-titration after pregnancy. Folic acid or vitamin K supplements and breastfeeding are also discussed in this review. Lamotrigine and levetiracetam have the lowest teratogenic potential. Data on teratogenic risks are also favorable for oxcarbazepine, whereas topiramate tends to have an unfavorable profile. Valproate needs special emphasis. It is most effective in generalized seizures but should be avoided whenever possible due to its teratogenic effects and the negative impact on neuropsychological development of in utero-exposed children. Valproate still has its justification in patients not achieving seizure freedom with other ASMs or if a woman decides to or cannot become pregnant for any reason. When valproate is the most appropriate treatment option, the patient and caregiver must be fully informed of the risks associated with its use during pregnancies. Folate supplementation is recommended to reduce the risk of major congenital malformations. However, there is insufficient information to address the optimal dose and it is unclear whether higher doses offer greater protection. There is currently no general recommendation for a peripartum vitamin K prophylaxis. During pregnancy most ASMs (e.g. lamotrigine, oxcarbazepine, and levetiracetam) need to be increased to compensate for the decline in serum levels; exceptions are valproate and carbamazepine. Postpartum, baseline levels are reached relatively fast, and down-titration is performed empirically. Many ASMs in monotherapy are (moderately) safe for breastfeeding and women should be encouraged to do so. This review provides a practically oriented overview of the complex management of WWE before, during, and after pregnancy.

Contraception, fecundity, and pregnancy in women with epilepsy: an update on recent literature

PURPOSE OF REVIEW

Caring for women with epilepsy requires specialized knowledge about potential teratogenicity of antiseizure medications, interactions with hormonal contraception, and pregnancy outcomes.

RECENT FINDINGS

There has been an improvement in understanding the cognitive outcomes of infants exposed in utero in recent years. Folic acid supplementation helps mitigate the cognitive teratogenicity of antiseizure medications. Recent updates provide reassurance that seizure frequency tends to remain stable throughout pregnancy. There is conflicting evidence about the fecundity impact of epilepsy and antiseizure medications in women with epilepsy.

SUMMARY

Recent research highlights the importance of early counseling about the risks and interactions of contraception, pregnancy, and antiseizure medications. More research is needed to understand fertility in women with epilepsy.