Abstracts

Rationale: Levetiracetam is used with increasing frequency in women with epilepsy during pregnancy. Reports of levetiracetam levels during pregnancy include 45 pregnancies to-date, including 24 prospectively followed women. Levels have been found to decrease during the last trimester. We report the results of a prospective study evaluating levetiracetam levels during pregnancy and post-partum period. Methods: 8 women with epilepsy were followed prospectively through pregnancy and post partum period. Plasma (am trough) levels of levetiracetam were measured monthly during pregnancy and for two months post-partum. Levetiracetam dose was adjusted during pregnancy as necessary on clinical grounds. Because of the dose adjustment and because of weight fluctuation during pregnancy, the ratio of levetiracetam level to levetiracetam dose/weight was calculated. Because the lowest plasma levels during pregnancy occurred during the last trimester, plasma levetiracetam levels and the ratios of levetiracetam level to levetiracetam dose/weight were compared between pre-pregnancy baseline and lowest levels at third trimester and between the that and post-partum period. Results: 8 women participated (age 23-36; 6 Caucasians, 1 African American, 1 Asian). 6/8 were treated with levetiracetam monotherapy, 2/8 had levetiracetam with another medication ( TPM/LM=1, CBZ=1).Mean levetiracetam levels declined from pre-pregnancy level of 22.46 g/ml to 15.8 g/ml lowest level during the last trimester , a change of [- 17.09%] (p 0.19) , with mean dose increasing from 37.2 mg/kg pre-pregnancy to 41.78 mg/kg during the last trimester, a mean change of + 20.82% The ratio of plasma levetiracetam level to levetiracetam dose/weight declined from mean of 0.6 at baseline to 0.375 during third trimester (p=0.075). Post-partum, mean LEV levels increased to 30.94 g/ml, a 46.9% change (p=0.03 when compared with third trimester lowest level) , while dose/kg also increased to 45.29, a 11.5% change. Plasma levetiracetam level to levetiracetam dose/weight ratio rose to 0.7 during the post-partum period. Conclusions: Levetiracetam plasma levels, both absolute and relative to levetiracetam dose/weight decline during pregnancy and rise during the post-partum period. The present study confirms previous findings.