Dengue viruses (DENV) pose significant health threats, with no approved antiviral drugs currently available, creating an urgent need for new therapies. This study screened FDA-approved drugs for their antiviral ability against DENV and identified three promising candidates: darunavir (DRV), domperidone, and tetracycline. DRV demonstrated the highest efficacy against three DENV serotypes, with half-maximal effective concentrations (EC50) below 1 µM, surpassing the performance of tetracycline and domperidone. It effectively blocked DENV envelope (E) protein attachment to two type cells with EC50 values less than 0.2 μM. Domperidone reduced DENV-2 attachment to TE671 cells (EC50 = 3.08 μM) but was less effective in BHK-21 cells, while tetracycline inhibited NS3 protease (IC50 = 1.12 μM). Among DRV's structurally related drugs, fosamprenavir (FPV) significantly reduced DENV infectivity and virus yield, with EC50 values below 0.5 µM. In vivo, DRV at 1, 2, and 5 mg/kg achieved 100 % survival in suckling mice, compared to 83.5 % with FPV. Real-time RT-PCR showed DRV more effectively reduced DENV-2 RNA in mouse brains than FPV. Molecular docking showed DRV and FPV bind tightly to the DENV-2 E protein's N-octyl-β-D-glucoside (βOG) hydrophobic pocket, with DRV forming stronger interactions than FPV. Chimeric DENV-2 single-round infectious particle tests confirmed DRV's effective targeting of this pocket, though mutations at K128, L198, Q200, I270, and T280 reduced its efficacy. These findings highlight DRV as a potent antiviral agent against DENV, targeting the E protein's βOG hydrophobic pocket, with the potential for rapid deployment in treating and preventing infections.