The FDA recently authorized two pills for treating COVID-19 and preventing severe disease, one from Pfizer and another from Merck. Here's what you need to know.
This week, the Food and Drug Administration authorized the use of two COVID-19 treatment pills, one from Pfizer and one from Merck, for recommended use in people at a high risk of developing severe disease from the coronavirus.
How Do the COVID pills work?
The first COVID pill given emergency use authorization by the FDA comes from Pfizer and is called Paxlovid. It includes two antiviral components called Nirmtrelvir and Ritonavir.
Nirmatrelvir blocks the activity of a protease enzyme that helps the virus replicate, thereby stopping the virus from being able to replicate in the body. Ritonavir is an antiviral that has been used in the past to treat HIV. In this case, it helps the Nirmatrelvir work more effectively by preventing it from being broken down in the body
The pill from Merck, authorized earlier today, is called Molnupiravir, which inhibits replication of the virus once in the body by acting like a “Trojan horse,” causing mutations to be integrated into the virus’s genetic material that prevent it from further replicating in the body.
While it was only recently authorized for use in the US, the Merck pill was authorized for use in the UK in early November.
The names are a mouthful, so it’s easier to just refer to them as the Merck pill and the Pfizer pill.
How Effective Are the COVID Pills?
The Merck pill’s authorization is based on a clinical trial of 1400 patients with mild to moderate COVID symptoms and at least one risk factor for severe disease.
The medication from Merck reduced the risk of hospitalization or death by 30% in COVID patients: 6.8% in the treatment group vs 9.7% in the placebo group. Of the 10 people who passed away during the study, 9 of them were in the placebo group (meaning they did not receive the medication).
The Pfizer pill’s authorization is based on a clinical trial of 1219 patients with at least one risk factor for severe disease.
The medication from Pfizer reduced the risk of hospitalization or death by 89% in the COVID patients: 0.9% in the treatment group vs 7% in the placebo group. Of the 10 people who passed away during this study, all 10 of them were in the placebo group (meaning they did not receive the medication).
The COVID pills don’t confer any immunity, so they should not be used or relied on as a substitute for a vaccine. What the pills are good for is treating mild to moderate illness brought on by the coronavirus and preventing it from becoming severe or leading to death
The Merck pill was studied when taken within 5 days of symptom onset and the Pfizer pill was studied when taken within 3 to 5 days of symptom onset (the clinical data was comparable for both), so it will be important when this medication is in use to test for COVID quickly and start treatment within the tested time frame.
This is similar to the idea that taking Tamiflu for the flu tends to work better the earlier it is started. It’s best used typically within the first 48 hours of symptom onset.
The studies that have been done so far largely took place during the Delta wave, so we don’t know the full story on effectiveness against the Omicron variant. However, there is little reason to believe that the pills won’t be just as effective against the Omicron variant as the mutations the make up Omicron are more related to its outer spike protein, as opposed to the way the variant replicates in the body.
How Safe Are the COVID Pills?
In the studies that have been done so far, there was no increase in the rate of side effects in the group that got the medication versus the group that got the placebo.
There is some concern that Merck’s pill may be associated with an increased risk of toxicity and birth defects since it has the ability to introduce genetic mutations, for this reason pregnant women were excluded from the study and some still feel that this may be a safety issue
As it will be approved under emergency use authorization it is possible that other side effects may emerge once it is used on a much broader scale - however other antiviral medications tend to be well tolerated with few side effects overall
How Do I Get a COVID Pill?
The medications will only be available as a prescription by your doctor and will not be available over the counter (OTC).
Both medications were approved this week and the US has already ordered millions of doses of each medication. However, availability at local pharmacies could lag behind that by weeks or months as more supply is produced.
If you are symptomatic and concerned you may have COVID-19, we encourage you to isolate yourself at home and get in touch with our providers through a telehealth visit, where we will discuss all available treatment options.