A computer‑based study looked at existing FDA‑approved drugs and found that a few, including the peptide bremelanotide (also known as PT‑141), might stick to key COVID‑19 proteins and block the virus in theory. The work is purely virtual and needs lab and clinical testing before any real‑world use.

The COVID-19 pandemic caused by SARS-CoV-2 necessitated rapid development of effective therapeutics, prompting this study to identify potential inhibitors targeting key viral and host proteins: RNA-dependent RNA polymerase (RdRp), main protease (Mpro), transmembrane serine protease 2 (TMPRSS2), and angiotensin-converting enzyme 2 (ACE2). We used covalent docking and molecular dynamics (MD) simulations to screen FDA-approved compounds against these targets using diverse covalent reaction mechanisms. Top-ranking compounds underwent further evaluation through MD simulations to assess binding stability and conformational dynamics. Several promising drug repurposing candidates were identified: bremelanotide, lanreotide, histrelin, and leuprolide as potential RdRp inhibitors; azlocillin, cefiderocol, and sultamicillin for Mpro inhibition; tenapanor, isavuconazonium, and ivosidenib targeting TMPRSS2; and cefiderocol, cefoperazone, and ceftolozane as potential ACE2 inhibitors. This study provides valuable insights into repurposing existing drugs as potential COVID-19 therapeutics by targeting crucial viral proteins. However, further experimental validation and preclinical studies are necessary to confirm the efficacy and safety of these compounds before consideration for clinical application.