A popular epilepsy drug taken by pregnant women with epilepsy because of its mild risk of birth defects has been linked to increased seizure activity in up to 75 percent of pregnancies.
Now, new research shows that monitoring the level of the drug in the blood helps to reduce the increased seizure activity associated with the drug lamotrigine and improve the overall health of pregnant women and their fetuses. The findings are published November 28, 2007, in the online edition of Neurology®, the medical journal of the American Academy of Neurology.
“This is important data considering current treatment guidelines do not address how to dose epilepsy drugs once women become pregnant,” said study author Page B. Pennell, MD, with Emory University School of Medicine in Atlanta, GA, and member of the American Academy of Neurology.
For the study, 53 women taking lamotrigine underwent therapeutic drug monitoring every one to three months throughout their pregnancies.
Researchers measured seizure activity and the amount of lamotrigine in the blood since past studies have shown lamotrigine levels significantly drop during pregnancy, causing seizures to worsen. In the current study, the clearance of lamotrigine increased by 89 percent in the third trimester compared to non-pregnant levels. Dosages were adjusted depending on the lamotrigine blood levels with the goal of maintaining each patient's target concentration determined by pre-pregnancy information.