Population pharmacokinetics of esomeprazole in patients with preterm preeclampsia

Esomeprazole is a proton pump inhibitor being investigated for treatment of preeclampsia. Esomeprazole pharmacokinetics during pregnancy is unknown. We used data from 10 pregnant patients with preterm preeclampsia, and 49 non-pregnant individuals to develop a population pharmacokinetic model of esomeprazole. A two-compartment model described the data well. In pregnant patients after single dose, clearance was 42.2% (14.9%– 61.6%) lower compared to non-pregnant, most likely due to downregulation of CYP2C19. In non-pregnant after repeated dosing, clearance was 54.9% (48.2% – 63.5%) lower in extensive metabolizers and bioavailability was 33% (10.0% – 52.0%) higher compared to single dosing, which could be due to autoinhibition of CYP2C19. Esomeprazole pharmacokinetics during pregnancy appears to be more dependent on CYP3A4.