妊娠中における抗てんかん薬の血中濃度変化に関する検討

摘要

てんかん合併妊娠例の妊娠経過中における杭てんかん薬（AED ： antiepileptic drugs)の血中濃度変化は，母体の発作コントロールを左右し，胎児の生存にも係わる重大な問題であるにもかかわらず，その報告は少ない.また，各AEDごとの薬理学的特性の違いにより，妊娠中における薬物血中濃度の変化の仕方は一様ではなく，治療者側にもその点を踏まえた対策が求められるが，現時点で参照可能なェビデンスは僅かである.そこで，東京慈恵会医科大学附属病院（当院）にて経験したてんかん合併妊娠例について，妊娠中における各AED毎の血中濃度変化について後方視的に検討し，レべチラセタム（LEV ：levetiracetam)とラモトリギン（LTG ：lamotrigine)の両剤については，その血中濃度変化が生じる原因についても考察した.%This study retrospectively evaluated the changes in serum concentrations of antiepileptic drugs during pregnancy in 21 patients with epilepsy. Of these patients, 19 had levels of serum antiepileptic drugs that were lower in the third trimester of pregnancy than when they were not pregnant. The mean degree of decrease was 54.0%. Significant reductions of serum levels in the third trimester of pregnancy were shown by levetiracetam (51.5%,P=0.0024) and lamotrigine (69.6%, P=0.0019).On the other hand, significant changes in serum levels were not shown by phenytoin (p=0.12) and carbamazepine (p=0.29). We observed a significant correlation between the decrease of serum levels of levetiracetam and the increase of the estimated glomerular filtration rate. Therefore, we conclude that serum levetiracetam levels are reduced in the third trimester of pregnancy by the increased clearance of levetiracetam due to physiological changes in renal function.