Pharmacokinetic Changes of Antiseizure Medications and Coping Strategy During Pregnancy

Epilepsy is a chronic neurological condition characterized by lasting predisposition to generate spontaneous epileptic seizures, which often requires a management by lifelong intake of antiseizure medications(ASMs). The physiologic changes during pregnancy, such as the increase of distribution volume and renal blood flow, the induction of drug metabolism, the changes of hormone levels and the decrease of serum protein levels, can affect the pharmacokinetics of ASMs at any level from the absorption, distribution, metabolism, to elimination. These changes may have a direct consequence of decreased level of ASMs which leads to seizure deterioration during pregnancy. Moreover, together with many other factors, such as gene polymorphism, fetus and diet, the therapeutic effect of ASMs varies among individuals. How to achieve the balance of the benefit of achieving an adequate level of ASMs for seizure control versus minimal exposure to the fetus is an urgent question to be answered. Based on this background, this literature review summarizes the changes of level and/or clearance of commonly used ASMs during pregnancy, and strongly recommends that the monitoring of the ASMs concentrations during pregnancy is necessary, especially the newer generation ASMs such as lamotrigine, levetiracetam and oxcarbazepine. It is considerable to monitoring the level of topiramate and zonisamide and to monitoring the level of the traditional ASMs such as valproate and carbamazepine for safety. More research is needed to provide evidence for the management of women with epilepsy during pregnancy.