Nirmatrelvir is an orally active antiviral drug developed for the treatment of COVID-19. It functions as a SARS-CoV-2 main protease (Mpro) inhibitor, blocking viral replication by preventing the processing of viral polyproteins. Nirmatrelvir is commonly co-administered with ritonavir, which acts as a pharmacokinetic enhancer by slowing its metabolism and increasing plasma concentrations. The combination therapy, often referred to as Paxlovid, has been shown to reduce the risk of hospitalization and severe disease in high-risk COVID-19 patients. It is effective against multiple SARS-CoV-2 variants due to the conserved nature of the main protease. Nirmatrelvir has a favorable safety profile, with most adverse effects being mild to moderate. Its oral administration makes it convenient for outpatient treatment, helping to prevent disease progression early in infection. The drug was developed using structure-based drug design, targeting the active site of the viral protease with high specificity. It represents a significant advancement in antiviral therapy by enabling rapid intervention against SARS-CoV-2. Ongoing research is exploring its use in combination with other antivirals and in different patient populations to further enhance COVID-19 management.
