ETHOSUXIMIDE ENANTIOMERS IN PREGNANCY AND LACTATION

A gas-chromatographic method was used to determine plasma concentratio ns of the ethosuximide enantiomers during three pregnancies in two epi leptic women, in samples from the umbilical cord in one, and in breast milk in two patients. The ratio of the two enantiomers of ethosuximid e ranged from 1.00 to 1.36 and was apparently unaffected by pregnancy, passage into breast milk, and transfer over the placenta. Hence, dete rmination of total ethosuximide concentrations appear to be sufficient for therapeutic drug monitoring during pregnancy and lactation.