Commonly Used Newer Antiepileptic Drugs
Data are available in the literature for the clinical pharmacologies of three newer antiepileptic drugs which have achieved a moderate amount of use in pregnant women, viz. lamotrigine, topiramate and levetiracetam. There is more information available for the first of these drugs than for the other two. The clearance value for lamotrigine, which is almost fully biotransformed to glucuronides, is considerably increased during pregnancy, with the clearances of topiramate (eliminated by a mix of metabolism and renal excretion unchanged) and levetiracetam (eliminated mainly by renal excretion without prior metabolism) being less increased. Relatively little information is available concerning the dispositions of the three drugs in the neonate, though there are published data for maternal plasma to breast milk concentration ratios.