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.
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 administered within 3 days of COVID-19 symptoms, the risk of hospitalization or death was reduced by almost 90%! If the drug was administered up to 5 days after the onset of COVID-19 symptoms, the benefit from the drug was reduced but still rather significant.
Molnupiravir is another oral treatment for COVID-19. When the coronavirus is copying its genetic material during replication, this drug forces lots of errors to be made, resulting in mutations.
This means the virus’s proteins are totally screwed up and are useless, so no new viruses can be produced. The latest results of molnupiravir were less encouraging than the early results from clinical trials, but in the final results, the drug reduced the risk of hospitalization and death by 30%. The benefit from this drug also depended on getting treatment early. While not the “slam-dunk” we were hoping for, this drug could have a benefit in improving COVID-19 outcomes.
One of the advantages of both these drugs is that, unlike the drug remdesivir, they are oral and do not have to be administered in a hospital or clinic. Your medical provider could call in a prescription to your pharmacy and you can start taking the drugs from home. Both are taken twice a day for five days.
Another advantage is that, unlike the monoclonal antibodies, these drugs should work against any of the variants, including Delta and Omicron. The Regeneron monoclonal antibody combo is effective against Delta but in laboratory studies, it has reduced activity against Omicron.
However, if you think these drugs are your escape from getting vaccinated, think again! Remember, just like with the monoclonal antibodies, both of these COVID-19 medications must be taken soon after the onset of symptoms to provide maximum benefit. You will need a medical provider to prescribe them and that may depend on the results of a COVID-19 test.
It may not be as simple to get the prescription as it may seem. The next question is, are the drugs available in the local pharmacies? And who will pay for the medication; your medical insurance? Another consideration that is important is the potential for a drug-drug interaction with Paxlovid, if you are taking other medications, mainly due to the use of Ritonavir.
While these drugs could be game-changers in fighting the pandemic, the most practical and cost-effective way to combat COVID-19 is to prevent it with vaccination (vaccines are free for everyone). The prevention of diseases is always superior to treating them after they occur.
(January 4, 2022 by Dr. Keith Crawford for Blackdoctor.org/Dr. Keith Crawford has over 25 years of experience in treatment of chronic infectious diseases, clinical and translational research.)