Is breast-feeding of infants advisable for epileptic mothers taking antiepileptic drugs?

Adverse effects of prenatal and early postnatal exposure to antiepileptic drugs: Validation from clinical and basic researches

Epilepsy requires the long-term administration of antiepileptic drugs (AEDs), and thus, we must consider the effects of prenatal AED exposure on fetus when treating female patients of child bearing age. Large prospective clinical researches in humans have demonstrated the following: (1) prenatal exposure to valproic acid (VPA), carbamazepine, and phenobarbital increases the risk of congenital malformations in a dose-dependent manner and (2) prenatal exposure to VPA increases the risk of higher brain function impairments including intellectual disabilities and autistic spectrum disorders in the offspring. Furthermore, basic researches in animals have shown that prenatal exposure to specific AEDs causes microscopic structural abnormalities in the fetal brain. Specifically, prenatal exposure to VPA has been reported to inhibit the differentiation of neural progenitor cells during the early to middle phases of neuronogenesis, leading to increased number of projection neurons in the superficial layers of postnatal neocortices in mice. It is indispensable to prescribe AEDs that are associated with lower risk of congenital malformations and impairment of higher brain functions as well as to administer them at requisite minimum doses.

Mood stabilizers during breastfeeding: a systematic review of the recent literature

OBJECTIVE

This review examined the safety of mood stabilizers in exposed breastfed infants.

METHODS

PubMed was searched for English language reports between 1 January 1995 and 30 August 2015 by using combinations of key words breastfeeding, lactation, postpartum period, puerperium, mood stabilizers, lithium, lamotrigine, valproate, carbamazepine, and oxcarbazepine. Case reports, case series, and prospective or cross-sectional studies including relevant data such as relative infant dose, milk-to-plasma ratio, infant drug plasma levels, and adverse events were identified.

RESULTS

A total of 26 of 604 relevant reports in PubMed were included in the study. These reports included lamotrigine (122 cases in 12 reports), lithium (26 cases in five reports), carbamazepine (64 cases in five reports), valproate (nine cases in three reports), and oxcarbazepine (two cases in two reports). Of 26 reports, one report included both carbamazepine and valproate. The reports suggest that a considerable amount of lithium and lamotrigine are excreted into breast milk. There is a paucity of data on valproate and oxcarbazepine; however, the infant/maternal ratio of serum drug concentration seems to be lower in valproate exposure compared to other mood stabilizers. The incidence of adverse events in infants exposed to mood stabilizers is reported to be very low.

CONCLUSIONS

The current data suggest that mood stabilizers can be prescribed without any adverse events in most infants in lactating women. The available reports also suggest a low prevalence rate of laboratory abnormalities including hepatic, kidney, and thyroid functions in the infants. Additional studies examining short-term and especially long-term effects of mood stabilizers on breastfed infants are required.

Lactation studies of anticonvulsants: a quality review

AIM

The aim of this review was to investigate the quality of the current literature on the transfer of anticonvulsants to breast milk to provide an overview of which anticonvulsants are in need of further research.

METHODS

We reviewed the quality of the available lactation studies for 19 anticonvulsants against the guidelines of the Food and Drug Administration (FDA) and the International Lactation Consultant Association (ILCA).

RESULTS

Except for one study on lamotrigine and one case report on gabapentin, no study on anticonvulsants had both the absolute infant dose (AID) and milk to plasma ratio (M : P) correctly assessed. Only one study on carbamazepine, phenytoin and vigabatrin was found that correctly assessed the AID. The main cause for this low number is the lack of essential details in published studies, since 25 of 62 studies were case reports, letters or abstracts. Other major shortcomings were the lack of information on sampling methods, the number of samples in a particular dose interval as well as the low number of study participants.

CONCLUSION

The quality of the current literature on the transfer of anticonvulsants to breast milk is low, except for lamotrigine, which makes it hard to draw conclusions about the safety of the use of anticonvulsants during the lactation period. Therefore, further research is needed.

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.

Effect of 7 days of phenytoin on the pharmacokinetics of and the development of resistance to single-dose nevirapine for perinatal HIV prevention: a randomized pilot trial

OBJECTIVES

To confirm whether 7 days of phenytoin, an enzyme inducer, would decrease the elimination half-life of single-dose nevirapine and to investigate its effect on the development of nevirapine resistance in pregnant, HIV-infected women.

METHODS

In a pharmacokinetic pilot trial (NCT01187719), HIV-infected, antiretroviral (ARV)-naive pregnant women ≥18 years old from Zambia and Tanzania and with CD4 cell counts >350 cells/mm(3) were randomized 1 : 1 to a control (zidovudine pre-delivery, single-dose nevirapine/zidovudine/lamivudine at delivery and zidovudine/lamivudine for 7 days post-delivery) or an intervention (control plus 184 mg of phenytoin once daily for 7 days post-delivery) group. Primary endpoints were the pharmacokinetics of and resistance to nevirapine.

RESULTS

Thirty-five and 37 women were allocated to the control and intervention groups, with median (IQR) ages of 27 (23-31) and 27 (23-33) years, respectively. Twenty-three and 23 women had detectable nevirapine levels at delivery and subsequent samples in the control and the intervention groups, respectively. Geometric mean (GM) (95% CI) plasma levels of nevirapine at delivery were 1.02 (0.58-1.78) mg/L and 1.14 (0.70-1.86) mg/L in the control and intervention groups, respectively (P = 0.76). One week after delivery, 0/23 (0%) and 15/22 (68%) control and intervention mothers, respectively, had undetectable levels of nevirapine (<0.05 mg/L; P<0.001). One week later, the figures were 10/21 (48%) and 18/19 (95%) mothers, respectively (P = 0.002). The GM (95% CI) half-life of nevirapine was 63.2 (52.8-75.7) versus 25.5 (21.6-30.1) h in the control group versus the intervention group (P < 0.001). New nevirapine mutations were found in 0/20 (0%) intervention-group mothers versus 1/21 (5%) control-group mothers. Overall, there was no difference in adverse events reported between the control and intervention arms (P > 0.28).

CONCLUSIONS

Adding 7 days of an enzyme inducer to single-dose nevirapine to prevent mother-to-child transmission of HIV significantly reduced subtherapeutic nevirapine levels by shortening the half-life of nevirapine. As prolonged subtherapeutic nevirapine dosage leads to the emergence of resistance, single-dose nevirapine could be used with phenytoin as an alternative if other ARVs were unavailable.

Developmental enamel defects in children prenatally exposed to anti-epileptic drugs

Objective

Some anti-epileptic drugs (AED) have well-known teratogenic effects. The aim of the present study was to elucidate the effect of prenatal exposure to AED and the risk of enamel defects in the primary and permanent dentition.

Methods

A total of 38 exposed and 129 non-exposed children, 6–10 years of age, were recruited from the Aarhus Birth Cohort and the Department of Neurology, Viborg Regional Hospital, Denmark. Medication during pregnancy was confirmed by the Danish Prescription Database. All children had their teeth examined and outcomes in terms of enamel opacities and enamel hypoplasia were recorded.

Results

Children prenatally exposed to AED have an increased prevalence of enamel hypoplasia (11% vs. 4%, odds ratio (OR) = 3.6 [95% confidence interval (CI): 0.9 to 15.4]), diffuse opacities (18% vs. 7%, OR = 3.0; [95% CI: 1.0 to 8.7, p<0.05]), and numerous (>3) white opacities (18% vs. 10%, OR = 2.2; [95% CI: 0.8 to 6.1]) in the primary dentition. In the permanent dentition, an increased risk of numerous (>3) white opacities (34% vs. 12%, OR = 3.3; [95% CI: 1.3 to 8.4]) was found.

Conclusions

The present study shows that children prenatally exposed to AED have an increased risk of developing numerous teeth with white opacities in their primary and permanent dentition. In addition, they also have an increased risk of developing diffuse opacities and enamel hypoplasia in their primary teeth.

[Family planning in women with epilepsy]

Epilepsy is a common neurological condition with gender-related management implications. Epilepsy and antiepileptic drug treatment affect aspects of contraception, fertility and pregnancy which are discussed in the article.

[Specificities of the epileptic women (oral contraceptives, pregnancy)]

The enzyme-inducing antiepileptic drugs such as carbamazepine, phenytoin, barbiturates, oxcarbazepine do not allow oral contraceptives. The pregnancy must be planned. Every patient in childbearing age should be informed by her practitioner. The rule is to optimize the antiepileptic treatment before the pregnancy: less drugs, less dosages. This optimization will depend on the epileptic syndrome and the nature of the treatment. Valproate of sodium should be avoided, if possible, during pregnancy. Preconceptional supplementation by folic acid should be considered. Antiepileptic drugs monitoring is required during pregnancy. Natural delivery with peridural anaesthesiology is mandatory. The breast feeding must be considered individually.