Coronavirus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus. Most people with COVID-19 experience mild to moderate symptoms and recover without the need for special treatments. The SARS‑CoV‑2 RNA‑dependent RNA polymerase (RdRp) plays a crucial role in the viral life cycle, and as the active site of the RdRp is the most conserved and accessible region, targeting this region for inhibition of viral replication may be an effective therapeutic approach. Scientists worldwide have proposed the use of preexisting drugs against the novel coronavirus. However, the efficacy of these drugs is somewhat limited. Others reported repurposing the use of existing antiviral agents in order to reduce time and cost compared to de novo drug discovery. For this reason, in this study has been selected a series of ligands used as SARS-CoV-2 virus inhibitors such as: Abacavir, Acyclovir, Amprenavir, Ascorbic acid Vitamin C, Azithromycin, Baloxavir, Boceprevir, Cholecalciferol Vitamin D, Cidofovir, Edoxudine, Emtricitabine, Hydroxychoroquine, Remdesivir. These ligands were analyzed using molecular docking, molecular quantum similarity, and chemical reactivity indices defined within Density Funtional Theory framework. These studies allow to identify the main stabilizing interactions using the crystal structure of SARS‑CoV‑2 RNA‑dependent RNA polymerase. The Molecular Quantum Similarity and Chemical reactivity shows new insights of these ligands that can be used in the COVID-19 treatments.