The advances that have been made in the management of the COVID-19 disease have been remarkable. There are multiple vaccines available that are among the most effective and the safest in medical history. There are also monoclonal antibody combination products that are effective for both the treatment and prevention of coronavirus infection. However, the continual emergence of mutant strains of the virus, that we refer to as variants, challenge the protection offered by vaccines and monoclonal antibody therapeutics.
Ideally, we should have antiviral drugs that can be taken as pills or tablets while at home to treat the infection or even prevent it. The one drug that is currently available, Remdesivir, is administered intravenously and is not a particularly potent treatment.
At the end of 2021, The Food and Drug Administration granted emergency use for two new drugs against the Sar-Cov-2 coronavirus, which is the cause of COVID-19.
Paxlovid is used as a combination of two drugs; nirmaltrevir and ritonavir. Nirmaltrevir, which does all the work in the combination, inhibits a critical protein of the coronavirus, the protease enzyme.
By inhibiting the protease, the drug prevents the replicating viruses from being able to assemble into new viruses (virions). This makes it impossible for the infection to spread throughout the body.
RELATED: What Do I Do IF…COVID Decision Guide
Ritonavir is an interesting part of this combination because it happens to be an HIV protease inhibitor. So why is it being used to treat a COVID-19 infection? In this case, a low dose of ritonavir slows the rate at which our bodies break down the nirmaltrevir.
This keeps the concentration of the nirmaltrevir higher for a longer period so that it is more effective in fighting coronavirus. This is the same way it is used in HIV and Hepatitis C treatment.
Indeed, when this drug combo is administered to a person infected with COVID-19, the amount of coronavirus detected in nasal swabs falls dramatically and rapidly and can no longer be detected within a few days. In Phase II/Phase III clinical trials, when paxlovid was