DARUVIR 800-R Tablets DARUVIR 800-R is a fixed-dose co-formulation combining Darunavir (an HIV-1 protease inhibitor) and Ritonavir (a pharmacokinetic enhancer and CYP3A inhibitor). Darunavir binds to the active site of HIV-1 protease, preventing the cleavage of viral Gag-Pol polyproteins and halting the maturation of infectious virions. Ritonavir acts as a pharmacokinetic booster by potent CYP3A enzyme inhibition, substantially increasing plasma concentrations and half-life of darunavir to enable once-daily dosing. It is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection in adult and pediatric patients.