Skip to Content
Coronavirus

The antimalarial drug Trump took for covid might actually be dangerous

A blister pack of chloroquine antimalarial tablets.
A blister pack of chloroquine antimalarial tablets.
A blister pack of chloroquine antimalarial tablets.Wellcome Collection / Lauren Holden

Editor's note: On June 4, the study was retracted by three of its authors, after they were unable to complete an independent audit of the data.

Chloroquine and hydroxychloroquine are two of the most hyped drugs being studied as treatments for covid-19, thanks in large part to President Donald Trump’s repeated promotion during his public appearances. Trump told reporters this week he had been taking hydroxychloroquine as a preventive measure. But a new study published Friday in The Lancet suggests not just that the drugs don’t offer any real benefit to infected patients, but that they can increase the risk of heart problems or even death.  

What are these drugs again? Chloroquine and its less toxic alternative, hydroxychloroquine, are widely used antimalarial drugs Since chloroquine was discovered over 85 years ago, it’s been studied pretty extensively. It’s now very cheap to manufacture, and we know its side effects. Some previous research indicates that it can prevent a virus from replicating inside a host cell. We still don’t know exactly how effective these drugs are when it comes to treating covid-19.

The new study: A team of American researchers looked at the records of 14,888 hospitalized covid-19 patients who received one of four treatments: chloroquine alone, chloroquine with a macrolide (a class of antibiotics), hydroxychloroquine alone, or hydroxychloroquine with a macrolide. Those records were compared with those of another 81,144 patients who did not receive any of these drug regimens. 

After controlling for confounding factors (including underlying health conditions), the authors were “unable to confirm a benefit of hydroxychloroquine or chloroquine” when used alone or in one of the other regimens. Moreover, treatment with any of the four drug regimens was actually associated with a higher risk of death and heart ailments. The biggest risk increase was observed in the group treated with hydroxychloroquine and a macrolide—8% of those patients developed a heart arrhythmia, compared with just with 0.3% in the group who received none of the drug treatments. 

Caveats: The study is solely an observational look at previous medical records—it’s not a clinical study that can really prove anything about the drugs’ safety or efficacy. You cannot draw any strong conclusions from it. It's another notch in a larger body of research looking at chloroquine and hydroxychloroquine.

Deep Dive

Biotechnology

He Jiankui
He Jiankui

The creator of the CRISPR babies has been released from a Chinese prison

He Jiankui created the first gene-edited children. The price was his career. And his freedom.

Aging Clocks concept
Aging Clocks concept

Aging clocks aim to predict how long you’ll live

These clocks promise to measure biological age and help identify anti-aging drugs, but there are lingering questions over their accuracy.

transplant surgery
transplant surgery

The gene-edited pig heart given to a dying patient was infected with a pig virus

The first transplant of a genetically-modified pig heart into a human may have ended prematurely because of a well-known—and avoidable—risk.

individual aging affects covid outcomes concept
individual aging affects covid outcomes concept

Anti-aging drugs are being tested as a way to treat covid

Drugs that rejuvenate our immune systems and make us biologically younger could help protect us from the disease’s worst effects.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.