Reviewed by: HU Medical Review Board | Last reviewed: March 2023 | Last updated: June 2023
Descovy is a two-drug combination that contains emtricitabine (FTC) and tenofovir alafenamide (TAF), both HIV nucleoside analog reverse transcriptase inhibitors (NRTIs). Descovy is recommended as HIV-1 pre-exposure prophylaxis (PrEP) in adults and adolescents (weighing at least 35 kilograms) who are at risk of acquiring HIV-1 through sexual activities, except for those at risk from receptive vaginal sex.
Although Descovy is not a cure for HIV, when taken as directed, it allows for the virus to be suppressed. This prevents further transmission of HIV and allows an individual’s immune system to improve through increasing CD4 cell counts and decreasing the amount of active virus in the blood. This is also called viral load.
Descovy is not effective against HIV-2. It should only be used in people with
- An HIV-1 diagnosis
- No prior history of antiretroviral treatment
- No known resistance to the components of Descovy
What are the ingredients in Descovy?
The main ingredients in Descovy are emtricitabine and tenofovir alafenamide. Both ingredients are nucleoside reverse transcriptase inhibitors (NRTIs).
How does Descovy work?
Descovy is a combination of two NRTI medications. NRTIs stop the reverse transcription step of the HIV life cycle. Normally, HIV uses its reverse transcriptase enzyme to build a strand of DNA from its original RNA form. In order to do this, it uses genetic building blocks called nucleosides that come from the host cell. These nucleosides are strung together one at a time, like beads on a string, to create the final DNA product.
NRTIs act as nucleoside mimics that stop the DNA-building process. NRTIs look like normal nucleosides, except they’re missing a special chemical group on one side. Without this group, the reverse transcriptase enzyme is unable to attach more nucleosides to the chain after them. This prevents the full string of DNA from being formed, preventing HIV RNA from making it all the way through the reverse transcription process and into host DNA for further replication.
Possible side effects
The most common side effect of Descovy is nausea. You may also have a slight increase in cholesterol with use of Descovy.
These are not all the possible side effects of Descovy. Talk to your doctor about what to expect when taking Descovy. You also should call your doctor if you have any changes that concern you when taking Descovy.
Things to note
Descovy has a boxed warning, the strictest warning from the US Food and Drug Administration (FDA). It has this warning because of the possibility of serious side effects as described below.
As with any medication, there are several very rare but serious risks that need to be considered before taking Descovy. Your healthcare provider can help determine what issues you may be at risk for and help determine what treatment options are the safest for you. It’s also important to remember that the risk of one or more of these issues occurring is low, and the benefits of treating the virus often greatly outweigh the risks.
Several of these rare but serious side effects of Descovy include liver issues and an increase of lactic acid in the blood (lactic acidosis). Signs of liver issues include, but are not limited to:
- Dark-colored urine
- Loss of appetite
- Yellowing of the whites of the eyes or skin
- Light-colored bowel movements
- Pain or tenderness on the right side of your stomach
Signs of lactic acidosis include, but are not limited to:
- Trouble breathing
- Feeling cold, especially in the limbs
- Dizziness or lightheadedness
- Feeling tired or weak
- Muscle pain
- Nausea and vomiting
- Irregular or fast heartbeat
The TAF in Descovy can reactivate the hepatitis B virus (HBV). Before prescribing Descovy, your doctor will assess your HBV status. They will closely monitor you during treatment.
TAF can also reduce your bone strength. Contact your doctor if you experience abdominal pain or unusual bone pain.
Descovy may also cause new or worsening kidney issues. This includes an increased risk of kidney failure. Your healthcare provider will need to monitor your kidney function before you start and while taking Descovy.
Before starting Descovy, tell your doctor if you:
- Have or previously had HBV
- Have a history of liver or kidney problems
- Are pregnant or planning to become pregnant
- Are breastfeeding or planning to breastfeed
- Are taking any over-the-counter vitamins, supplements, medicines, or herbal remedies
- Are on any other medications or are about to start any other medications, including hormonal birth control or medications for hepatitis viruses
Descovy may cause a condition called IRIS (immune reconstitution inflammatory syndrome). IRIS occurs when an individual’s immune system gets stronger after being weak and responds aggressively to previously hidden infections. This heightened response may make the person fighting the infection feel worse. Alert your healthcare provider immediately if you begin to have new symptoms after taking Descovy. These are not all the possible side effects of Descovy. Patients should talk to their doctor about what to expect with treatment with Descovy.