ABCC1 and Hypertension: While research of CS agents has been mostly directed among P-gp substrates, whose CS may be determined by an ROS increase due to the ATP consumption responsible for the drug efflux, verapamil (L-type calcium channel antagonist, commonly used for the clinical treatment of hypertension) was found to be a CS agent also in MRP1-expressing cells, exploiting the MRP1 ability to efflux glutathione (GSH) [17].