In vivo constriction of the ductus arteriosus by nonsteroidal antiinflammatory drugs in near-term and preterm fetal XXXX .

@entity35 @entity3352 @entity8726
Herein we report age differences of in vivo constriction of the fetal ductus arteriosus by nonsteroidal antiinflammatory drugs in near-term and preterm @entity35 . Two potent nonsteroidal antiinflammatory drugs, @entity3352 and @entity8726 , were studied in preterm (19th and 20th day) and near-term (21st day) @entity35 , whose gestational period was 21.5 days. The time course of fetal ductus constriction was studied on the 20th (preterm fetus) and the 21st (near-term fetus) days of gestation with @entity3352 (1 mg/kg, 10 mg/kg) and @entity8726 (10 mg/kg). In addition, 5 mg/kg of @entity3352 was used on the 21st day. Maximal ductal constriction was noticed 8 h after administration. Constriction of the ductus was significantly weaker on the 20th day than on the 21st day in all three studies including @entity3352 1 mg/kg, 10 mg/kg, and @entity8726 , 10 mg/kg. Dose-response curves were studied at 4 h following administration of @entity3352 on the 19th, 20th, and 21st days, and @entity8726 on the 20th and 21st days. With both drugs, the ductus constricted more vigorously on the 21st day than on the 20th or 19th day. These studies showed a weaker constrictive response of the ductus to nonsteroidal antiinflammatory drugs in the preterm fetus than in the near-term fetus. Twenty-four h after administration of @entity3352 on the 20th day, the fetal ductus was dilated, although its plasma @entity3352 concentration was high and comparable with that obtained 4 h after administration. These results show that the response of the fetal ductus to @entity3352 decreased further at 24 h after administration to preterm @entity35 .
