Maternal Blood Concentration of Tadalafil and Uterine Blood Flow in Pregnancy

摘要

Tadalafil for treatment of fetal growth restriction (FGR) or preeclampsia is given once a day orally. The drug kinetics of tadalafil were investigated to determine the ideal dosage to promote uterine blood flow. We recruited five pregnant women with FGR or preeclampsia before administration of tadalafil, all of which were administered tadalafil (20 mg/day, once-daily dosing). The blood concentration of tadalafil was measured 1, 2, 4, 6, 8, and 24 h after administration, and uterine blood flow was measured before tadalafil administration and 2–4 and 20–24 h after. We then analyzed the correlation between tadalafil blood concentration and uterine artery blood flow. The blood concentration of tadalafil correlated with uterine artery blood flow in pregnant women. The blood concentration of tadalafil and uterine artery blood flow decreased 5 h after administration of tadalafil. The blood concentration of tadalafil and uterine artery blood flow fluctuate in parallel, the latter was decreased by reduced blood concentration. Thus, a study of tadalafil administered twice a day in pregnant women will be needed to stabilize uterine artery blood flow.