An anthranilamide derivative with multidrug resistance properties. Tariquidar non-competitively binds to the p-glycoprotein transporter, thereby inhibiting transmembrane transport of anticancer drugs. Inhibition of transmembrane transport may result in increased intracellular concentrations of an anticancer drug, thereby augmenting its cytotoxicity. Check for active clinical trials using this agent. (NCI Thesaurus)