Darunavir

Key facts

• Darunavir (sold as Prezista) is a protease inhibitor used with a low dose of ritonavir or cobicistat, plus other antiretroviral medicines, to treat HIV infection in adults and adolescents. It is never taken alone.
• Take it with food at the same times each day; missed or irregular doses let HIV develop resistance to the whole regimen.
• Darunavir can injure the liver, and the risk is higher in people with hepatitis B or C. Liver blood tests are checked before starting and periodically during treatment.
• Seek urgent care for yellowing of the skin or eyes, a spreading rash, or blistering, peeling skin.

What darunavir treats

Darunavir treats HIV-1 infection as part of combination antiretroviral therapy, lowering the amount of virus in the blood and helping the immune system recover, seen as a rising CD4 count. It is used in people starting treatment for the first time and in those switching regimens after earlier HIV medicines stop working. It does not cure HIV and does not treat other infections.

How darunavir works

HIV uses an enzyme called protease to cut long viral protein chains into the pieces it needs to build new, infectious virus particles. Darunavir blocks this enzyme, so the virus assembles defective, non-infectious particles instead. Ritonavir or cobicistat is added not to fight HIV directly but to block the liver enzyme that would otherwise clear darunavir too quickly, keeping its levels high enough to work.

Before you take it

• Tell your prescriber about liver disease, hepatitis B or C, or an allergy to sulfonamide (sulfa) drugs, since darunavir contains a sulfonamide group.
• Many medicines change darunavir levels or become unsafe alongside it, including some anticonvulsants, certain statins, some heart-rhythm drugs, and St John's wort. Check every new medicine, including over-the-counter and herbal products, against your regimen.
• Pregnancy is not a reason to stop treatment. Untreated HIV carries more risk to a pregnancy than continuing most antiretrovirals, but tell your prescriber so the regimen can be reviewed.

Side effects

Common effects include nausea, diarrhea, headache, fatigue and a mild rash.

Stop and seek urgent medical care for any of these:

• Yellowing of the skin or eyes, dark urine, or pale stools.
• A spreading rash, blistering or peeling skin, fever, or mouth sores.
• Extreme thirst or frequent urination, which can signal high blood sugar.

Safety essentials

• Never take darunavir without its booster (ritonavir or cobicistat). Without it, blood levels fall too low to control the virus, and resistance can develop quickly.
• Liver function is monitored throughout treatment, especially in people with hepatitis B or C co-infection, because drug-induced liver injury is a recognized risk.
• Take every dose as prescribed. Skipping doses or stopping early is the main way HIV becomes resistant to darunavir and the rest of the regimen.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.