Vigabatrin: placental transfer in vivo and excretion into breast milk of the enantiomers.
OBJECTIVE
Vigabatrin is a new antiepileptic medication consisting of a racemic mixture of 50% active S enantiomer and 50% inactive R enantiomer. Since patients suffering from epilepsy may become pregnant, it is important to understand the extent of placental transfer of such medication.


METHODS
During steady-state, vigabatrin enantiomer concentrations were measured in maternal and umbilical blood and in breast milk of two patients.


RESULTS
The concentration ratios from the umbilical vein to maternal plasma were R:0.068, S:0.16; 4h25 min after drug administration (case 1) and R: 1.39, S: 0.91; 9h after drug administration (case 2). The milk: plasma concentration ratio was lower than 1 at pre dose sampling in both cases, as well as 3 and 6 h post dose in one case. An estimate of the maximum amount of R and S enantiomers of vigabatrin that a suckling infant would ingest in a day is 3.6% and 1% of the weight-adjusted daily dose respectively.


CONCLUSIONS
These results would suggest a slow placental transfer of the vigabatrin enantiomers and that the quantity ingested through milk is small.
Tran
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A
Department de pharmacologie Périnatale et Pédiatrique, Hôpital St Vincent de Paul, Paris, France.
O'Mahoney
T
T
Rey
E
E
Mai
J
J
Mumford
J P
JP
Olive
G
G
D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002490:Central Nervous System / Q000187:drug effects / Q000196:embryology; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D008431:Maternal-Fetal Exchange; D008895:Milk, Human / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000188:drug therapy*; D012640:Seizures / Q000188:drug therapy; D020888:Vigabatrin; D005680:gamma-Aminobutyric Acid / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use
D000927:Anticonvulsants; D005680:gamma-Aminobutyric Acid; D020888:Vigabatrin