Health & Health Care

What Chloroquine Means for COVID-19

What chloroquine means for COVID-19 - image of coronavirus

Note: This post has not been updated since March and thus some of the information contained here may not reflect the current state of knowledge.  Please refer to the World Health Organization or your local public health agencies for the most up-to-date information on COVID-19.


All of a sudden, the medication chloroquine is in the news for its potential role in managing COVID-19.  This post will look at what’s known, and not known, about potential treatments for the novel coronavirus.

In the news

On March 19, U.S. President Donald Trump announced that the Food and Drug Administration (F.D.A.) had approved the medication chloroquine to treat COVID-19.  However, the F.D.A. hasn’t approved it for that particular indication.  It was already on the market, as it was approved for treating malaria.

On March 20, Dr. Anthony Fauci, the head of the National Institute of Allergy and Infectious Diseases, stated that there wasn’t clear evidence that chloroquine could treat the coronavirus, although at the same press briefing President Trump said that he was a “big fan” of the drug and he “comes from a very positive school” with regards to chloroquine.  Given that he has no public health training, take that with a grain of salt.

The research

Chloroquine has been around for years.  It has anti-malarial activity, but it’s seldom used now for malaria as resistance has developed in most parts of the world.  Like any medication, it has potential side effects, but given it’s been around for a while, its side effect profile is well known.  It can potentially cause psychosis, although the risk isn’t as high as with the related drug mefloquine (Lariam).

An expert consensus statement from a group of researchers in China that was published on March 12 indicated that chloroquine was used because of its antiviral properties and it “might improve” patient outcomes, so they were recommending that a 10-day course of chloroquine be given to patients with mild, moderate, or severe novel coronavirus pneumonia.

A paper by Colson et al. elaborated on the data used by the Chinese consensus group and stated that early findings from over 100 patients, chloroquine had positive clinical effects without any serious side effects.

A letter by a group of Chinese researchers to the editor of Cell Discovery, published March 18, reported some new research findings using chloroquine and a similar drug, hydroxychloroquine (Plaquenil), which is used to treat autoimmune conditions like rheumatoid arthritis.  In African green monkey cell cultures, both chloroquine and hydroxychloroquine were effective against the novel coronavirus.  That’s promising, but not enough to know if there will be clinical effectiveness in humans.

On March 17, an expert consensus group in Italy released a set of recommendations for managing COVID-19, which included a 10-day course of either chloroquine or hydroxychloroquine.

There is an experimental antiviral drug, remdesivir, that has also demonstrated activity against the novel coronavirus, but phase III clinical trials have just been started, so it’s unlikely to be widely available soon.  Several clinical trials are underway in China, and the National Institutes of Health are sponsoring a trial in the U.S.

A vaccine has been developed that is currently in phase I clinical trials at Kaiser Permanente Washington Health Research Institute in Seattle, Washington, funded by the National Institutes of Health.  If you happen to live in the Seattle area, they’re recruiting healthy volunteers.

Potential supply issues

Because chloroquine isn’t often used, there’s not a lot of it kicking around, so supply could be an issue.  Bayer announced on March 19 that it would be donating 3 million chloroquine to the U.S. government, which is a positive step.  If chloroquine and hydroxychloroquine do prove to be effective, governments need to play it right or prices could go through the roof.

We’ve already seen hoarding behaviour, so is everyone and their dog going to be rushing out to get a supply of these drugs if they turn out to be effective?  There’s a lot more hydroxychloroquine on the market than chloroquine, but regardless, there’s not enough for everyone, so there will need to be some type of system.

Where we are now

It’s good to know that there are some things coming down the pipe that might work.  But we’re still very much at the “might work” stage.  Since China got the virus first, they’re ahead of the rest of us in terms of research, so the findings of the clinical trials they have underway are going to be really important.

For now, though, we need to let the researchers and clinicians do their thing, and follow what our public health departments are directing in terms of social distancing and other precautions.


Addendum – March 21/20

President Trump announced on Twitter this morning:

HYDROXYCHLOROQUINE & AZITHROMYCIN, taken together, have a real chance to be one of the biggest game changers in the history of medicine. The FDA has moved mountains – Thank You! Hopefully they will BOTH (H works better with A, International Journal of Antimicrobial Agents)…..


This doesn’t actually have to do with the FDA.  A group of French researchers has submitted a paper to the International Journal of Antimicrobial Infections with early results of a trial that they’re running.  The trial compares COVID-19 patients treated with hydroxychloroquine to a control group with COVID-19 that did not receive the drug.  A segment of the hydroxychloroquine group also received azithromycin in an attempt to prevent bacterial infection on top of the viral infection.

The results that have just been released involved 16 control group patients, 14 patients receiving just hydroxychloroquine, and 6 patients receiving the combination of hydroxychloroquine and azithromycin.  The six patients receiving the combination did better, and got better faster, than the hydroxychloroquine alone patients, who in turn did better than the control group.

So, we’re talking about six patients.  It’s positive news, but a very small number.  And before we go handing them out in a Pez dispenser, it’s worth noting that there is a risk of serious heart rhythm abnormalities with the combination of the two drugs.   The patients in the French study were in hospital and had close cardiac monitoring.

The French trial is ongoing, and as the numbers grow the role of these drugs will start to become clearer.



There’s more on public health and COVID-19 in The Science Corner.

I’ve put together a COVID-19 coping toolkit with some resources to help with managing the stress of the current pandemic.



19 thoughts on “What Chloroquine Means for COVID-19”

  1. I think word has got around. We had a lot of patients enquiring about the medications you mentioned. In England (I don’t know drug classifications in the US) some are POM (prescription only medication). Patients were asking if they should go and but the over the counter P (pharmacy only) antimalarials. Pharmacies would be wondering why people wanted antimalarials when nobody is supposed to be travelling around.

  2. I’ve found it a very strange week on the medication front.

    First there was a bit of anxiety over the statement by the doctor from France regarding the use of Ibuprofen and NSAIDs which the WHO originally backed up but has since retracted saying there isn’t enough evidence that NSAIDs have any effect on the seriousness of the symptoms. Of course not everyone got the second memo and the shelves have been depleted of acetaminophen by all the panic buyers. If I could still take Advil, I’d have no problem finding it anywhere. Thankfully, I had a big bottle of Acetaminophen already.

    Now in the news it’s hyrdroxychloroquine. If you listen to Donald Trump (which I never do) it sounds like he’s about to hand it out like M&M’s. I know they’re doing studies on it and it would be great if it did work, but to create mass panic like this won’t help anyone. I’m a bit concerned that doctors are going to start prescribing it ‘just in case’ it works.

    As you know I have lupus. I take prescription strength NSAIDs daily and I also take hydroxychloroquine twice daily. I try not to follow too closely because it doesn’t do much for the anxiety but I would be lying if I weren’t worried that there might be a shortage if the hydroxychloroquine does in fact work…or if the Donald starts doing what he says he’s going to do. I have enough for about 2 months, but then who knows what will happen.

    This week has once again proven just a few other reasons that lupus can suck it!! But, I figure the NSAIDs (if they make things worse) will just be cancelled out by the hydroxychloroquine (if it makes things better). So I’m probably no better or worse than anyone else. :/

    1. It’s too bad nobody’s been able to put a leash on Trump. There’s already enough panic buying without getting medications drawn into it, I really hope it doesn’t end up impacting the availability of hydroxychloroquine or anything else for people that already need it.

  3. nicely written and very informative. I hope they find something official soon. I find so much info online that I do not know what to believe anymore. Thanks for sharing and keeping us informed.

  4. Perhaps Trumps love of this medication explains some of his behaviours Ashley? It will take at least 12months of testing before a vaccine it approved or medication I would imagine. Certainly that is what the Australian government is saying. Interesting article. It would not be the first medication that found a different use to what it was originally created and effective for.

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