Dofequidar fumarate is primarily used in the field of oncology as a chemosensitizing agent. It enhances the efficacy of certain chemotherapy drugs by inhibiting the efflux of these drugs from cancer cells, thereby increasing their intracellular concentration. This mechanism is particularly useful in overcoming multidrug resistance (MDR) in cancer treatment, which is a significant challenge in chemotherapy. By improving the retention of chemotherapeutic agents within cancer cells, it helps in achieving better therapeutic outcomes and potentially reducing the required dosage of toxic drugs, thereby minimizing side effects. Its application is mainly focused on improving the treatment of resistant cancers, offering a promising adjunct in complex chemotherapy regimens.