In Vivo Activity of Intestinal P-Glycoprotein and Hepatic Organic Anion Transporters Polypeptide in Pregnancy and Postpartum

Pregnancy can alter the activity of drug transporters, potentially affecting the disposition of many medications, but data on intestinal P-glycoprotein and hepatic organic anion transporting polypeptide (OATP) activity during pregnancy are limited. This study used fexofenadine and rosuvastatin as probe drugs to assess P-glycoprotein and OATP/BCRP activity in 11 healthy participants during the third trimester of pregnancy and again postpartum, with pharmacokinetic parameters calculated using Phoenix WinNonlin. Rosuvastatin exposure was significantly higher during pregnancy than postpartum, indicating inhibition of hepatic OATP1B1/OATP1B3 transporters, while fexofenadine exposure did not differ significantly between phases, indicating unchanged intestinal P-glycoprotein activity. The results suggest that dosage adjustments may be needed during the third trimester for drugs with a low therapeutic index that are OATP1B1/OATP1B3 substrates.