Distribution of bupivacaine enantiomers and lidocaine and its metabolite in the placental intervillous space and in the different maternal and fetal compartments in term pregnant women.
The aim of this study is to determine the concentrations of lidocaine and its metabolite, monoethylglycine xylidide (MEGX), and of the enantiomers of bupivacaine in maternal and fetal compartments. Ten healthy pregnant women were submitted to epidural anesthesia. Drug concentrations were determined in the maternal vein, fetal umbilical artery and vein, and the placental intervillous space. The highest concentrations of the bupivacaine enantiomers lidocaine and of lidocaine and of its MEGX metabolite were detected in maternal plasma and in the placental intervillous space. The placental transfer was 33% for the (+)-(R)-bupivacaine enantiomer and 31% for the (-)-(S)-bupivacaine enantiomer. For lidocaine and its MEGX metabolite, respective placental transfers were 60% and 43%. Lidocaine concentration in the fetal umbilical vein was 1.46 times higher than in the fetal umbilical artery. The highest concentrations of lidocaine and its metabolite and of the enantiomers of bupivacaine were detected in the placental intervillous space. The higher lidocaine concentrations in the fetal umbilical vein than in the fetal umbilical artery suggest that there was tissue uptake of the drug or drug metabolization by the fetus.
de Barros Duarte
Luciana
L
Departamento de Ginecologia and Obstetrícia-8° andar, Hospital das Clínicas-Faculdade de Medicina de Ribeirão Preto, Av Bandeirantes, 3900-Campus da USP, 14049-900 Ribeirão Preto, SP, Brasil. lbdmedi@msn.com
Dantas Móises
Elaine Cristine
EC
Cavalli
Ricardo Carvalho
RC
Lanchote
Vera Lucia
VL
Duarte
Geraldo
G
da Cunha
Sérgio Pereira
SP
D000328:Adult; D000767:Anesthesia, Epidural / Q000379:methods; D000773:Anesthesia, Obstetrical / Q000379:methods; D000779:Anesthetics, Local / Q000737:chemistry / Q000493:pharmacokinetics*; D002045:Bupivacaine / Q000737:chemistry / Q000493:pharmacokinetics*; D002824:Chorionic Villi / Q000378:metabolism; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D010920:Placenta / Q000378:metabolism; D011247:Pregnancy; D013237:Stereoisomerism; D014018:Tissue Distribution; D014469:Umbilical Arteries / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism; D055815:Young Adult
D000779:Anesthetics, Local; D008012:Lidocaine; C001173:monoethylglycinexylidide; D002045:Bupivacaine