| First generation |
Verapamil, cyclosporin A, reserpine, quinidine, yohimbine, tamoxifen and toremifena |
Non-selective and low binding affinities. |
They are substrates to other transporters and enzyme systems. They are pharmacologically active. They themselves are transported by P-gp. |
| Second generation |
Dexverapamil, dexniguldipine, valspodar (PSC 833), and Dofequidar fumarate (MS-209) |
Higher specificity then first generation inhibitors but interact with other systems. |
They are substrates to CYP 3A4 enzyme and other ABC transporters. |
| Third generation |
Cyclopropyldibenzosuberane zosuquidar (LY335979), laniquidar (R101933), mitotane (NSC-38721), biricodar (VX-710), elacridar (GF120918/GG918), ONT-093, tariquidar (XR9576), and HM30181 |
Highest specificity that specifically and potently inhibit P-gp function. |
No limitations like the first and the second generation inhibitors. |
