Descovy (emtricitabine/tenofovir alafenamide) is a prescription brand-name medication. It’s approved by the Food and Drug Administration (FDA) to treat HIV. It’s also approved for HIV pre-exposure prophylaxis (PrEP). PrEP is treatment to decrease the risk of contracting the virus.

Descovy can be used in certain adults and adolescents who weigh at least 35 kilograms (about 77 pounds). The drug is typically meant to be a long-term treatment.

Here are some fast facts on Descovy:

Like other drugs, Descovy can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Descovy, including details about its uses, see this article.

Descovy can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days or weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Descovy in clinical trials:

  • abdominal (belly) pain
  • fatigue (lack of energy)
  • diarrhea
  • headache
  • nausea (see “Side effect specifics” below)

Mild side effects can occur with Descovy use. This list doesn’t include all possible mild side effects reported with the drug. For more information, you can refer to Descovy’s prescribing information.

Mild side effects of Descovy can include:

  • abdominal (belly) pain
  • fatigue (lack of energy)
  • diarrhea
  • headache
  • nausea (see “Side effect specifics” below)

These side effects may be temporary, lasting a few days or weeks. But if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Descovy and want to tell the FDA about it, visit MedWatch.

Descovy may cause serious side effects, some of which may be long term. The list below may not include all possible reported serious side effects of the drug. For more information, you can refer to Descovy’s medication guide.

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

Serious side effects and their symptoms can include:

  • Liver damage. Symptoms can include:
    • abdominal (belly) pain
    • dark-colored urine
    • jaundice (yellowing of your skin or the whites of your eyes)
  • Kidney problems. Symptoms can include:
    • nausea and vomiting
    • urinating less often than normal
  • Lactic acidosis.*
  • Immune reconstitution syndrome.*†
  • Worsening of hepatitis B.*‡
  • Resistance to Descovy treatment.*‡
  • Allergic reaction.*§

* For more information about this side effect, see “Side effect specifics” below.
† This side effect was reported in clinical trials only when Descovy was used to treat HIV.
Descovy has a boxed warning for this side effect. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effect specifics” section below.
§ An allergic reaction is possible after using Descovy. But this side effect wasn’t reported in clinical trials.

Descovy may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Is weight loss a side effect of Descovy?

No. Weight loss wasn’t reported as a side effect in clinical trials of Descovy.

But weight loss has been associated with HIV, which Descovy is used to treat. If you’re having trouble with weight loss, talk with your doctor. They can work with you to help you manage your weight.

Can Descovy cause vomiting?

Possibly.

In clinical trials, people who took Descovy didn’t report vomiting as a side effect. However, vomiting can be a symptom of serious side effects of Descovy, including:

See the “Serious side effects” section above for more details on these side effects.

If you’re taking Descovy for PrEP, vomiting may also be a symptom of recently contracted HIV.

Call your doctor right away if you develop vomiting while taking Descovy. Your doctor can work to determine the cause and recommend the best treatment for you. This may include using an HIV medication other than Descovy.

Is depression a side effect of Descovy?

No. Depression wasn’t reported as a side effect of Descovy in clinical trials.

But mental health conditions have been associated with HIV. And depression is one of the most common mental health conditions that people with HIV experience.

Other drugs used to treat HIV, such as emtricitabine/tenofovir disoproxil fumarate (Truvada), can cause depression as a side effect.

If you have questions or concerns about your mental health, talk with your doctor. They can help connect you with mental health resources, such as counseling.

Learn more about some of the side effects that Descovy may cause.

Nausea

Nausea was one of the most common side effects reported in clinical trials of Descovy.

Usually, nausea caused by Descovy isn’t severe. But nausea can be a symptom of more serious side effects of Descovy. These side effects include liver damage and lactic acidosis (lactic acid buildup in the body). See the “Serious side effects” section above for more details on these side effects.

What you can do

Call your doctor if you experience nausea while taking Descovy. Your doctor may examine you to see if your nausea is a sign of a more serious side effect.

Immune reconstitution syndrome

Immune reconstitution syndrome (IRS) is a possible side effect of Descovy when the drug is taken to treat HIV. This may also be called immune reconstitution inflammatory syndrome.

HIV weakens the immune system over time. With IRS, your immune system gets stronger after starting HIV treatment. This can reduce HIV symptoms. But it can also lead to:

  • Symptoms caused by your immune system reacting to infections that may already be present in your body. These symptoms may develop unexpectedly due to a previously undiagnosed infection. Or they may be from a previously treated infection.
  • Certain autoimmune diseases, such as Graves’ disease. With autoimmune diseases, your body’s immune system mistakenly attacks your own cells and organs.

IRS wasn’t reported in clinical trials of Descovy. But it has been reported in people with HIV who took medications that contain emtricitabine. Emtricitabine is one of the active drugs in Descovy. (Tenofovir alafenamide is the other active drug.)

Keep in mind that Descovy may cause IRS only when used to treat HIV. People taking Descovy for HIV pre-exposure prophylaxis (PrEP) aren’t likely to develop IRS, because they don’t have a weakened immune system caused by HIV. PrEP treatment refers to taking an HIV medication to decrease the risk of contracting the virus.

What you can do

While taking Descovy to treat HIV, watch for symptoms of IRS. This side effect is most likely to occur when you first start treatment with Descovy. Symptoms vary depending on the condition that develops, such as:

Call your doctor right away if you notice any new symptoms when you start taking Descovy.

Lactic acidosis

Lactic acidosis is a very rare but serious side effect of Descovy. With this condition, there’s a buildup of lactic acid in your body. This is a medical emergency that could lead to hospitalization or, if untreated, death.

Lactic acidosis may develop very quickly, within minutes or hours. Or it may develop gradually over a few days. Symptoms may include:

  • abnormal or fast heart rate
  • trouble breathing
  • breath that smells fruity
  • muscle pain
  • nausea and vomiting

Certain HIV medications, such as emtricitabine, can make it harder for your body to get rid of lactic acid. This increases your risk for lactic acidosis. Emtricitabine is one of the active drugs in Descovy. (Tenofovir alafenamide is the other active drug.)

What you can do

If you notice symptoms of lactic acidosis, stop taking Descovy right away. If your symptoms are mild, talk with your doctor as soon as possible. If your symptoms develop rapidly or are severe, call 911 or your local emergency number immediately. Or go to your nearest emergency room.

If you develop lactic acidosis while taking Descovy, your doctor will have you stop taking the drug until they can determine what exactly caused this side effect. They may have you switch to a medication other than Descovy, even after your lactic acidosis is treated.

Worsening of hepatitis B

Descovy has a boxed warning about worsening of hepatitis B. This is a serious warning from the Food and Drug Administration (FDA).

This side effect is possible if you have hepatitis B and you stop taking Descovy. Hepatitis B that gets worse can cause severe symptoms, such as liver failure.

Worsening of hepatitis B has been reported in people who stop taking drugs that contain emtricitabine, tenofovir disoproxil fumarate, or both. Descovy contains the active drug emtricitabine and a form of tenofovir called tenofovir alafenamide.

What you can do

Before you start treatment with Descovy, your doctor will order a test to see if you have hepatitis B. If you have hepatitis B, your doctor may treat it before having you start Descovy.

It’s important to avoid running out of Descovy tablets. You also shouldn’t stop taking Descovy unless your doctor tells you to do so. Stopping Descovy could cause serious side effects in people with hepatitis B.

If you have hepatitis and your doctor decides to have you stop taking Descovy, they’ll monitor you for several months. This will include ordering liver function tests to help make sure your hepatitis B doesn’t get worse. If your hepatitis B does get worse, your doctor may have you take medications to treat it.

If you don’t have hepatitis B, your doctor may recommend getting the hepatitis B vaccine before you start taking Descovy.

Resistance to Descovy treatment

Descovy has a boxed warning about resistance to this drug when used as pre-exposure prophylaxis (PrEP) for HIV. A boxed warning is a serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Resistance means that Descovy will be less effective at treating HIV, or it may no longer be effective at all. And PrEP treatment refers to taking an HIV medication to decrease the risk of contracting the virus.

For this reason, only people who don’t have HIV should take Descovy for PrEP. If you take Descovy for PrEP and you already have HIV, the virus may become resistant to the drug.

What you can do

Before you start taking Descovy for HIV PrEP, your doctor will order a blood test to check for HIV. And while you’re taking Descovy, you’ll need to have this test at least every 3 months. If you have or develop HIV, your doctor will recommend a treatment other than Descovy for you.

Allergic reaction

As with most drugs, Descovy can cause an allergic reaction in some people. But this side effect wasn’t reported in clinical trials of the drug.

Symptoms can be mild or serious and can include:

  • rash
  • itching
  • flushing (warmth, swelling, redness, or discoloration in your skin)
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Descovy. But if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Boxed warnings

This drug has boxed warnings. These are 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. In people who have hepatitis B, stopping Descovy treatment may cause this condition to get worse.

Resistance to Descovy treatment. Descovy should only be used for pre-exposure prophylaxis (PrEP) in people who don’t have HIV. PrEP treatment refers to taking an HIV medication to lower the risk of contracting the virus. Taking Descovy for PrEP when you already have HIV can cause the virus to become resistant to the drug. This means that Descovy will no longer effectively treat your HIV.

For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you take Descovy. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Liver problems. Rarely, Descovy may cause severe liver problems that can be life threatening. Be sure to talk with your doctor about any liver problems you have before you begin treatment with Descovy. They can determine whether Descovy is safe for you, or if a different medication would be better for your condition.

Kidney problems. If you have kidney problems, taking Descovy can make these problems worse. Talk with your doctor about any kidney problems you may have before you take Descovy. They can recommend whether you should take Descovy or a different HIV medication.

Allergic reaction. You shouldn’t take Descovy if you’ve ever had an allergic reaction to Descovy or any of its ingredients. Talk with your doctor about which other treatments are better choices for you.

Alcohol use with Descovy

There aren’t any known interactions between Descovy and alcohol.

Treatment guidelines recommend that people who have HIV, or are at risk for contracting HIV, limit their alcohol intake to moderate amounts. Talk with your doctor about how much alcohol may be safe for you to drink while taking Descovy.

Pregnancy and breastfeeding while taking Descovy

Here’s some information on whether Descovy can be used while pregnant or breastfeeding.

Pregnancy

It isn’t known if Descovy is safe to take during pregnancy. Animal trials didn’t show any negative effects caused by Descovy use during pregnancy. But animal trials don’t always predict what will happen in humans.

Pregnancy registry

People who take antiretroviral HIV drugs such as Descovy are encouraged to sign up for the Antiretroviral Pregnancy Registry. This monitors and records the health of children born to people who took antiretroviral drugs during their pregnancy.

Pregnancy registries help healthcare professionals collect information about the safety of drugs such as Descovy. This can help people make informed decisions about the treatments they take when pregnant.

You can learn more on the registry’s website, and you can enroll by calling 800-258-4263. Your doctor may also be able to provide more information about enrolling.

Breastfeeding

You shouldn’t breastfeed while taking Descovy. Emtricitabine, one of the active drugs in Descovy, passes into breast milk. This could lead to side effects in children who are breastfed. And if you have HIV, the Centers for Disease Control and Prevention (CDC) recommend against breastfeeding your child. Talk with your doctor about healthy ways to feed your child.

Side effects from Descovy aren’t common. And when they do occur, they’re usually mild. Most mild side effects of the drug go away with time and don’t require medical attention.

Although rare, Descovy can cause serious side effects. You should talk with your doctor if you experience symptoms of:

You should also talk with your doctor if you become pregnant while taking Descovy.

If you’d like to learn more about Descovy, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from taking the drug.

Note: For more information on HIV, see our list of HIV 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.