Paxlovid vs. Molnupiravir: Patients Pick the Winner - And It's Not Close

By Josh Bloom — Jan 17, 2022
Patients and their doctors have voted with their scripts. Overwhelmingly, they are choosing Pfizer's Paxlovid and rejecting Merck's molnupiravir. So much so that when Paxlovid is unavailable (which is most of the time) many don't even bother to try the other option. Surprising?

Just for laughs (and what could possibly be more fun than this?), I called a bunch of local pharmacies to see whether any of them had a supply of the two newly-approved (1) antiviral COVID medications. After all, you never know when you may be in the mood to stay off a ventilator.

The good news is that every pharmacy I called (2) did, in fact, have a supply of COVID drugs in stock. Excellent!

Make that drug. But, before we get into that, here's some potentially helpful information about where to get COVID antiviral drugs should the need arise (3). The Department of Health and Human Services created a website where you can find out which pharmacies (there are very few of them) were issued a supply of antiviral drugs and the current supply in each store. It's more or less accurate. But HHS really doesn't want you to use it.

Needless to say, I did just that.

What I found was both surprising and not surprising. As I have written, there is no question that Pfizer's Paxlovid works a whole lot better than Merck's molnupiravir. But would doctors or their patients know or care about this, or would they just grab at whichever drug happens to be available? It is the former – by a lot

For example, there's a rumor of two old ladies engaged in a mixed martial arts match in front of a pharmacy, each trying to get their hands on a bottle of Paxlovid, while at the same time pharmacists were hurling cartons of molnupiravir at completely disinterested passers-by just to make room on the shelves. Am I exaggerating? Not so much. 

For some reason, Alto Pharmacy on Park Avenue in Manhattan received the most Paxlovid in the city, but it currently has none of the 1,360 doses of the drug allotted last week. But its shelves are bursting with molnupiravir: 5,813 of the 6,360 issued doses remain. Just so you don't think that this is some freaky outlier, if you looked at all of NYC (as of January 10th), 8,340 of the 9,640 courses of molnupiravir that was delivered about a week before were available, while of the 2,180 courses of Paxlovid, zero remained in the whole city.

Maybe this is just a neurotic New Yorker thing. Unlike Paxlovid, neurotic New Yorkers have never been in short supply, so perhaps they just hit the pharmacies hard. Perhaps a trip out of the city will reveal a different story? Nope. According to the HHS site, at that same time, there was a single CVS at Rocky Point on Long Island, about 80 miles from the city, that had four boxes (3) of Paxlovid (of the 20 that arrived on January 3rd) but 298/300 courses (!) of molnupiravir. Under other circumstances, I'd suggest that you'd better drive out there fast, but the route to Rocky Point includes considerable mileage on the Long Island Expressway (LIE), perhaps the most misnamed road ever. Driving fast on the LIE is little more than a fanciful dream.

The LIE. On a good day. Images: Facebook, Wikimedia Commons. That thing zooming by is a turtle.

Save the drive. I called them. The pharmacist told me that they were out of the drug and that there was no Paxlovid whatsoever on Long Island, where a mere 8 million people live.

(Left) A "drug map" of Long Island. The green dots represent pharmacies that have molnupiravir. Ignore the yellow dots. These represent Evusheld, a combination of two antibodies. Paxlovid is in purple. Can you find the "2?" Don't bother looking for it. It's really a zero. (Right) Meanwhile, 85% of allocated molnupiravir remains in stock. How bizarre.

Location, location, location

Things are different in other parts of the country. Here is a random sample of pharmacy supplies from different parts of the US (Figure 1). 

Figure 1. Supply of molnupiravir and Paxlovid in pharmacies in different cities. Although some pharmacies have a shortage of both molnupiravir and Paxlovid, this chart better represents reality in an "average" store – an ample supply of molnupiravir and shortage (or absence) of Paxlovid.

What's going on?

There are a number of possible explanations:

  • Doctors have decided that Paxlovid is the superior drug
  • Patients have decided that Paxlovid is the superior drug
  • The in vitro mutagenicity of molnupiravir may have caused a cancer scare (which is very unlikely)
  • The in vitro mutagenicity of molnupiravir prevents pregnant women and women who are breastfeeding from taking the drug

As I have written before, while molnupiravir is a breeze to synthesize, the opposite is true for Paxlovid, which is why the drug is in short supply. I find most interesting (and unexpected) that patients who don't have access to Paxlovid often choose to opt-out entirely rather than take a shot with the less effective molnupiravir. This cannot be making Merck executives happy.

Pfizer is cranking out as much Paxlovid as possible, but it will be months before there is an ample supply in the US. By then, omicron will merely be a bad dream. But perhaps not as bad as what's coming next. 

#Conflict of interest statement: My IRA contains both Pfizer and Merck stock


(1) Both drugs have been granted Emergency Use Authorization, not full approval.

(2) Average waiting time: at least 30 minutes

(3) I was hardly the first person to call these guys. The pharmacist told me that the four listed on the website was actually zero. And that there was no Paxlovid on all of Long Island.

Josh Bloom

Director of Chemical and Pharmaceutical Science

Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. He holds a Ph.D. in chemistry.

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