Descovy (emtricitabine/tenofovir alafenamide) is a prescription brand-name medication. It’s approved by the Food and Drug Administration (FDA) for use as pre-exposure prophylaxis (PrEP) for certain adults and adolescents at high risk for HIV. For details, see the “PrEP explained” section below.

With PrEP, people who don’t have HIV use HIV medication to prevent themselves from contracting the virus.

Here are the basics on Descovy:

Read on for more information on Descovy and its use as PrEP. You can also refer to this article for a comprehensive look at Descovy, which is also used to treat HIV.

Pre-exposure prophylaxis (PrEP) refers to taking an HIV drug, such as Descovy, before you might have contact with HIV. This treatment helps prevent you from contracting the virus.

PrEP is used for people at high risk for HIV. This includes people who:

  • have sex without using a condom with a partner who has HIV
  • have sex without using a condom with a partner whose HIV status isn’t known
  • share needles
  • are sexually active in a region where HIV is common and have other risk factors, such as:
    • a refusal to use condoms during sex
    • a tendency to trade sex for drugs, food, money, or shelter

Symptoms of HIV

HIV is a virus that transmits through bodily fluids, such as blood, semen, or vaginal fluids. Once HIV is inside your body, it attacks certain immune system cells. Your immune system acts as your body’s defense mechanism against infection.

Specifically, HIV attacks CD4 cells, which are also called T cells. CD4 cells are a type of white blood cell. They help direct how your immune system responds to an infection. Without treatment, HIV can cause your CD4 cell count to decrease. This negatively affects the immune system’s ability to fight infections.

Symptoms of HIV can vary depending on how much the condition has progressed and other factors. Early symptoms may include flu-like symptoms, such as fever, fatigue (lack of energy), weakness, and unintended weight loss.

Left untreated, HIV can cause your CD4 counts to drop to levels low enough to be dangerous. If this happens, you may be at risk for opportunistic infections. These are infections that usually aren’t likely to affect someone unless the person has a weakened immune system. In people with HIV, opportunistic infections can be life threatening.

Who can use Descovy for PrEP?

Descovy is approved for use as PrEP for certain people at high risk for HIV. This includes certain adults as well as certain adolescents who weigh at least 77 pounds (lb) (35 kilograms [kg]). Descovy isn’t approved for PrEP use in females* at risk for contracting HIV through vaginal sex. The drug’s effectiveness for HIV PrEP hasn’t been tested in this group of people.

Before using Descovy for PrEP, you must have a negative HIV test result immediately before you start treatment. Your doctor will order and interpret this test. You’ll also need to take an HIV test and have a negative result every 3 months while using Descovy for PrEP.

* Sex and gender exist on spectrums. This article uses the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

Descovy and children

Descovy is approved for use as HIV PrEP in certain adolescents weighing at least 77 lb (35 kg), as well as in certain adults. See “Who can use Descovy for PrEP?” just above for details.

Descovy is approved for use as pre-exposure prophylaxis (PrEP) for HIV in certain adults and adolescents. If your doctor has prescribed the drug, you may be wondering how Descovy works as PrEP.

Descovy contains two active drugs: emtricitabine and tenofovir alafenamide. Both drugs prevent HIV from multiplying (making copies of itself). To do this, the drugs work to block a certain enzyme that HIV needs to multiply. An enzyme is a type of protein.

When used for PrEP, Descovy works by preventing the virus from starting an attack against your immune system. If HIV enters your body, it wouldn’t be able to multiply. This means that it couldn’t grow or spread.

Descovy has been shown to be effective for pre-exposure prophylaxis (PrEP) for HIV in a clinical study. People in the study took either Descovy or Truvada, which is another medication used for PrEP. At the end of the study, nearly all of the people taking either Descovy or Truvada didn’t contract HIV.

The Centers for Disease Control and Prevention (CDC) recommends using the combination drugs emtricitabine/tenofovir alafenamide (Descovy) or emtricitabine/tenofovir disoproxil fumarate (Truvada) for HIV PrEP.

For more information about how Descovy compares with Truvada, see this article.

Descovy is approved for use as pre-exposure prophylaxis (PrEP) for HIV. Below are details on using Descovy for PrEP.


Descovy comes as a tablet that you swallow. It contains two active drugs: emtricitabine and tenofovir alafenamide. Descovy is available in one strength: 200 milligrams (mg) emtricitabine/25 mg tenofovir alafenamide.

The standard dosage for Descovy is one tablet daily.

Note: In addition to being used for PrEP, Descovy is also used to treat HIV. For this use, the drug’s dosage is the same as that for PrEP. To learn more, talk with your doctor.

How to use

Descovy may be taken either with or without food. You should take it at about the same time every day.

How often to use

Descovy is taken once a day.

Descovy may cause side effects that are mild or serious. The lists below include some of the main side effects that have been reported while using Descovy for pre-exposure prophylaxis (PrEP) for HIV.

To learn about other potential side effects of the drug, including side effects from taking Descovy to treat HIV infection, talk with your doctor or pharmacist. You can also see our comprehensive article on Descovy or refer to the drug’s prescribing information.

Note: The Food and Drug Administration (FDA) tracks and reviews side effects of drugs it has approved. If you’d like to notify the FDA about a side effect you’ve had with Descovy, you can do so through MedWatch.

Mild side effects

Like most drugs, Descovy can cause some mild side effects. The more common mild side effects of Descovy when used for PrEP in a clinical study included:

These side effects of Descovy may be temporary and last for a few days or weeks. But if they last for a longer time, or if they bother you or become severe, it’s important to talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Descovy are rare but can occur.

Talk with your doctor right away if you develop serious side effects while using Descovy. If the side effects seem life threatening or you think you’re having a medical emergency, call 911 (or your local emergency number) immediately.

Serious side effects from Descovy can include:

* An allergic reaction is possible after using Descovy. But this side effect wasn’t reported in clinical studies.
Descovy has a boxed warning for this side effect. A boxed warning is the most serious warning from the FDA. To learn more, see the “Before using Descovy” section below.

Before you use Descovy, there’s some important information to keep in mind. The drug may not be a safe option for you if you have certain medical conditions or other factors that affect your health. Some of these are mentioned below.

Boxed warnings

This drug has boxed warnings. These are the most serious warnings from the Food and Drug Administration (FDA). A boxed warning alerts doctors and patients about drug effects that may be dangerous.

  • Worsening of hepatitis B. There have been reports of worsening hepatitis B in people who stop taking drugs that contain emtricitabine or tenofovir disproxil fumarate. Because Descovy contains emtricitabine, this side effect may occur in someone with hepatitis B who stops taking Descovy. If you have hepatitis B, your doctor will test your liver function after you stop Descovy treatment. They may recommend a treatment other than Descovy, if needed.
  • Resistance to Descovy treatment. If you have HIV and use Descovy for pre-exposure prophylaxis (PrEP), the virus can become resistant to Descovy. Resistance means that the drug won’t be as effective at preventing HIV. Because of this, you’ll be tested for HIV immediately before your first dose of Descovy. You’ll need to have a negative test result to use the drug. You’ll also be tested every 3 months to confirm that you still have a negative HIV status.

Other warnings

In addition to boxed warnings, Descovy has other warnings.

If any of the following medical conditions or other health factors are relevant to you, talk with your doctor before using Descovy:

  • if you have liver problems, including hepatitis B
  • if you have kidney problems, such as chronic kidney disease
  • if you’re pregnant or breastfeeding
  • if you’ve had an allergic reaction to Descovy or any of its ingredients

How much Descovy costs depends on several factors. These can include your prescribed treatment regimen, the insurance plan you have, the pharmacy you use, and your location.

Now that you’ve learned about Descovy for pre-exposure prophylaxis (PrEP) of HIV, you may still have some questions. Talk with your doctor or pharmacist, who can advise you on whether Descovy might be right for you.

Here are some other helpful references:

  • More details. For details about other aspects of Descovy, refer to this article.
  • Drug comparison. To find out how Descovy compares with Truvada, read this article.
  • Information on HIV. For more information on HIV, see our list of HIV and AIDS articles.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.