Abstract
Drug efflux transporters, such as P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP), are expressed not only in resistant tumor cells, but also in many normal tissues, including the epithelial apical membrane of the intestine. Thus, efflux transporters may play an important role in the barrier function of the intestine against xenobiotic drugs. On the other hand, several researchers have suggested that the influence of P-gp on intestinal absorption of drugs is relatively limited, since the absorption rates of various P-gp substrates after oral administration are quite high in humans. The controversy remains to be resolved.
Here, we review the effects of intestinal efflux transporters on drug absorption, and discuss the evaluation and prevention of such effects.
