The abamectin derivative ivermectin is a potent P-glycoprotein inhibitor

Among the compounds endowed with the capacity to reverse the P-glycoprotein (Pgp)-mediated multidrug resistance of cancer cells, a powerful agent was found to be the cyclosporin D derivative SDZ PSC 833. After in vivo treatment with SDZ PSC 833, mice showed a decreased tolerability to cyclosporin A