Ritonavir
NorvirPubChem CID 392622 · 3D model
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Blocks a key enzyme HIV needs to assemble new infectious virus particles, and also boosts the levels of other HIV medicines taken alongside it.
How it works
HIV needs a specific enzyme, called protease, to cut up long chains of viral protein into the working pieces it needs to build new copies of itself. Ritonavir jams this enzyme, so the virus ends up making faulty copies that can't infect new cells. Ritonavir also slows down the liver enzyme that normally breaks down other HIV drugs, so those drugs stay active in the body longer. Because of this, doctors often prescribe a small dose of ritonavir not to fight the virus itself, but to make another antiviral drug work better and last longer, which is why it's included in combinations like Paxlovid.
What it’s used for
Approved, in combination with other HIV medicines, to treat HIV-1 infection in both adults and children. In everyday use, it is more often given in small amounts alongside another HIV drug, or alongside the COVID-19 antiviral nirmatrelvir, simply to help that other medication stay effective in the body for longer.
- Mechanism
- HIV protease inhibitor
- Drug class
- Small molecule
- Therapeutic area
- Antiviral