Clinical Therapeutics in Pregnancy

Table 3

Major ABC drug efflux transporters, their placental localization, and substrates.

Transporter	Gene	Placental localization	Gestational-age-dependent regulation	Substrate	Inhibitor	Inducer
P-gp	ABCB1	Apical, syncytiotrophoblast	Yes	Digoxin, fexofenadine, indinavir, vincristine, colchicines, topotecan, paclitaxel, talinolol, loperamide	Ritonavir, cyclosporine, verapamil, erythromycin, ketoconazole, itraconazole, quinidine, elacridar, azithromycin, valspodar	Rifampin, St. John’s wort
MRP1	ABCC1	Basolateral, syncytiotrophoblast predominantly at fetal blood endothelia	Yes	Adriamycin, topotecan, cisplatinum, methotrexate, etoposide, vincristine	Probenecid, sulfinpyrazone, indomethacin, glibenclamide, agosterol A, verapamil, cyclosporin A, genistein, quercetin, RU486, budesonide, agosterol A
MRP2	ABCC2	Apical, syncytiotrophoblast	Yes	Vincristine, etoposide, doxorubicin, epirubicin, methotrexate, irinotecan, ampicillin, ceftriaxone, pravastatin, temocaprilat, grepafloxacin, BQ-12, saquinavir, ritonavir, indinavir, ^99mTc-Sestamibi	Probenecid, sulfinpyrazone, benzbromarone, MK571	Sulfinpyrazone
MRP3	ABCC3	Basolateral, syncytiotrophoblast predominantly at fetal blood endothelia	Unknown	Etoposide, methotrexate, tenoposide, acetaminophen	Probenecid, sulfinpyrazone, benzbromarone, MK571
MRP4	ABCC4	Unknown	Unknown	Azidothymidine monophosphate, lamivudine, ganciclovir, 6-mercaptopurine, 6-thioguanine, methotrexate	Probenecid, benzbromarone, sulfinpyrazone, MK571, dipyridamole
MRP5	ABCC5	Preferentially basolateral, syncytiotrophoblast, and fetal vessels	Yes		Benzbromarone, sulfinpyrazone, MK571, dipyridamole	Sildenafil
MRP6	ABCC6	Unknown	Unknown	Conjugated organic anions
MRP7	ABCC10	Uknown	Unknown	Organic anions
BCRP	ABCG2	Apical syncytiotrophoblast	Yes	Daunorubicin, doxorubicin, topotecan, rosuvastatin, AZT, lamivudine	Elacridar, acridone carboxamide, fumitremorgin C
OCT3	SLC22A3	Basal syncytiotrophoblast	Cimetidine	Desipramine, phenoxybenzamine, quinine
OCTN1	SLC22A4	Apical syncytiotrophoblast	Quinidine, verapamil

References: [67–69].