Small molecule · Antiviral

Nirmatrelvir

Paxlovid
Small moleculeSARS-CoV-2 main protease (3CLpro) inhibitor

PubChem CID 155903259 · 3D model

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Blocks a key enzyme the COVID-19 virus needs to cut its own proteins into working pieces, stopping the virus from multiplying in the body.

How it works

The COVID-19 virus makes one long chain of proteins that has to be cut into separate working parts before the virus can copy itself. Nirmatrelvir jams the scissors enzyme that does that cutting, so the virus gets stuck and can't reproduce. Paxlovid also contains a second drug, ritonavir, which doesn't fight the virus directly — its job is to slow down how fast the body breaks down nirmatrelvir, so enough of it stays active in the bloodstream.

What it’s used for

Used to treat COVID-19 that's already causing mild-to-moderate symptoms in people who are more likely to get seriously sick. It needs to be started quickly, within 5 days of symptoms starting. It is not meant to prevent infection before or after exposure, and it isn't used to start treatment in patients already hospitalized with severe illness.

Mechanism
SARS-CoV-2 main (3CLpro)
Drug class
Therapeutic area
Antiviral

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