Abstract
Background: Transport proteins, for example the drug export pump P-glycoprotein, are important for the absorption, distribution and excretion of drugs. Inhibition and induction of P-glycoprotein efflux function is a well-established mechanism of drug–drug interactions. Alteration of transporter-mediated drug uptake by concomitantly administered drugs may also result in a change in drug pharmacokinetics. These uptake transporter-mediated drug–drug interactions are the focus of this review. Objective: To examine the current in vitro evidence on interactions mediated by OATPs (organic anion transporting polypeptides) and OCTs (organic cation transporters). Methods: Comparing data of in vivo observed drug–drug interactions with in vitro analysed alterations in drug transport mediated by the hepatic expressed uptake transporters OATP1B1, OATP1B3 and OCT1 and by the renal expressed OCT2 protein. Results/conclusions: Some of the previously in vivo described drug–drug interactions could be explained by alteration in uptake transporter function demonstrating that inhibition or induction of uptake transporters is a newly recognised mechanism of potential drug–drug interactions.
Acknowledgement
The authors' work on the relevance of drug transporters is supported by grants from the Deutsche Forschungsgemeinschaft (DFG Ko 2120/1-3 and DFG Fr 1298/5-1) as well as by a grant from the Deutsche Krebshilfe (107854).