Antiepileptic drugs and seizures may harm a fetus, so it is important for physicians to plan an individualized treatment strategy for women with epilepsy.
During pregnancy, certain antiepileptic drugs can cause major congenital malformations, which could pose lifelong challenges for the child. It is also known that seizures can cause these malformations.
What can women with epilepsy and their physicians do to prevent antiepileptic drug-related events from happening while also preventing seizures? During the North American Symposium session Controversies in the Management of Epilepsy During Pregnancy, presenter Page Pennell, MD, spoke about the importance of continuing treatment on antiepileptic drugs, and how important lower doses can be.
There is increasing evidence that both the type and the level of antiepileptic drug affect the risk of teratogenic effects, she said during the session. A teratogen is a substance, including drugs, that can impact a developing fetus and cause malformations.
However, it is important that pregnant women with epilepsy continue on treatment to prevent seizures, which can also impact the fetus. Therefore, creating a dosing strategy approach prior to a patient becoming pregnant is an important step physicians need to take.
To do so, Dr Pennell said that she reviews the patient’s chart in detail, and talks with the patient to determine which target concentration is most beneficial for her seizure control. This information should be established significantly prior to pregnancy because many pregnancies are unplanned. By creating a strategy ahead of time, adverse events are less likely to be experienced.
Physicians should also take into account any other medications that a patient may be taking, such as hormonal contraceptives, which may alter antiepileptic drug concentrations, according to the session.
During the session, Dr Pennell discussed her personal treatment strategy for patients taking lamotrigine along with estrogen contraceptives. She suggests that physicians create a target concentration level while a patient is on a contraceptive, and reduce the dose by 50% once the patient stops taking the contraceptive. Then, physicians should test their levels 2 weeks later, and adjust the dose accordingly.
While reducing the dose of antiepileptic drugs is the best option for having a safe complication-free pregnancy, women with epilepsy should be informed about the risks involved in changing medication or adjusting the dose.
During pregnancy, if a woman with epilepsy experiences a seizure, it may cause miscarriage, stillbirth, developmental delay, low birth weight, preterm delivery, and small for gestational age. Mothers who are considered to have status epilepticus have a 30% and 50% chance of maternal and infant mortality, respectively. It is clear that maintaining an effective level of antiepileptic drugs is critical for the health of the mother and the fetus.
Due to physiological changes during pregnancy, such as increased water, fat storage, and cardiac output, physicians must account for multiple changes that alter a drug’s disposition to ensure that the mother is receiving proper care that will prevent harm to the fetus, according to the session. This is why Dr Pennell suggests that physicians monitor antiepileptic drug levels monthly and adjust the dose based on seizures, adverse effects, and target concentration.
After birth, the dose of antiepileptic drugs should be adjusted to slightly above the dose the woman was taking prior to pregnancy. This dose increase should be done over a 2-week to 3-month period depending on the drug. Women should also be educated about the signs and symptoms of medication toxicity to prevent adverse events, Dr Pennell said.
It is important for patients and their physicians to determine the best treatment strategy prior to conception so that the mother and the fetus can have the best outcomes.