If you’re looking at treatment options for HIV, your doctor might suggest Descovy (emtricitabine and tenofovir alafenamide) for you. You may be wondering about the side effects that can occur with this drug.

Descovy is a prescription medication that’s used to treat and prevent HIV. (HIV is a virus that affects your immune system.) This drug is taken with other medications to treat HIV in adults and certain children. And it’s taken on its own to prevent HIV in certain adults and children at high risk for HIV. This is called preexposure prophylaxis (PrEP).

Descovy comes as a tablet that you take by mouth. You’ll typically take it once every day on a long-term basis.

For more information about Descovy (including details about its uses), see this in-depth article on the drug.

Like other drugs, Descovy can cause mild or serious side effects. Keep reading to learn more.

Some people may experience mild or serious side effects during their Descovy treatment. Examples of Descovy’s more commonly reported side effects include:

* To learn more about this side effect, see “Side effects explained” below.

Other side effects are also possible with Descovy. Read on to find out more.

Examples of mild side effects that have been reported with Descovy include:

* To learn more about this side effect, see “Side effects explained” below.

In most cases, these side effects should be temporary. And some may be easily managed, too. But if you have any symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. And don’t stop using Descovy unless your doctor recommends it.

Descovy may cause mild side effects other than the ones listed above. See the Descovy medication guide for more information.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Descovy, visit MedWatch.

Serious side effects aren’t common with Descovy, but they can occur and may sometimes be long term. Serious side effects that have been reported with Descovy include:

  • immune reconstitution syndrome (in which your immune system reacts to previously treated or undetected infections), a condition that can occur when Descovy is taken to treat HIV
  • new or worsening kidney problems
  • severe worsening of hepatitis B after stopping Descovy*
  • HIV resistance, which can occur when Descovy is taken to prevent HIV*
  • allergic reaction†‡
  • lactic acidosis
  • liver problems‡

* Descovy has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see “Side effects explained” below.
† An allergic reaction is possible after using Descovy. But this side effect wasn’t reported in studies.
‡ To learn more about this side effect, see “Side effects explained” below.

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.

Here are answers to some frequently asked questions about Descovy’s side effects.

Could I experience weight gain during my Descovy treatment?

Descovy isn’t known to cause weight gain. In studies, weight gain wasn’t reported by people who took Descovy to treat or prevent HIV.

People with HIV sometimes experience weight loss. And people who take a combination of different medications to treat HIV sometimes experience weight gain. It’s not known if this is caused by any particular medication or a result of the body recovering as HIV is controlled.

If you’re concerned about how Descovy may affect your weight, talk with your doctor.

Is rash a side effect of Descovy?

It might be. Rash wasn’t reported in studies of Descovy. But this side effect has been reported in some people taking Descovy after the studies were completed.

A rash may also be a symptom of an allergic reaction to Descovy. To read more about this, see “Side effects explained” below.

If you have a rash while taking Descovy, contact your doctor. They can tell you if it’s an allergic reaction and recommend ways to manage it.

It’s also worth noting that a widespread rash can sometimes be a symptom of early HIV. If you’re taking Descovy to prevent HIV and you get a widespread rash, contact your doctor. They may want you to have an HIV test.

If you have HIV and are taking Descovy, your doctor will need to evaluate your medications. This is to make sure you’re taking an appropriate combination. Taking Descovy alone to treat HIV could lead to HIV resistance. To read more about HIV resistance, see “Side effects explained” below.

Does Descovy cause vomiting?

It might. Descovy commonly causes nausea. Some people may also experience vomiting, but this isn’t as common. Vomiting can also be a symptom of a more serious side effect of Descovy, such as lactic acidosis or liver problems. See “Side effects explained” below to read more about these side effects.

If you vomit within 1 hour of taking Descovy, take another dose. If you frequently have vomiting with Descovy, talk with your doctor. They may recommend taking anti-nausea medication to help prevent this. To learn more about nausea with Descovy, including tips on how to manage this side effect, see “Side effects explained” below.

It’s worth noting that vomiting can sometimes be a symptom of early HIV. If you’re taking Descovy to prevent HIV and you experience vomiting, contact your doctor. They may want you to take an HIV test.

If you have HIV and are taking Descovy, your doctor will need to evaluate your medications. This is to make sure you’re taking an appropriate combination. Taking Descovy alone to treat HIV could lead to HIV resistance. To read more about HIV resistance, see “Side effects explained” below.

Is depression a side effect of Descovy?

It’s not known to be. In studies, depression wasn’t reported in people who took Descovy to treat or prevent HIV.

However, depression is very common in people who have HIV. If you have symptoms of depression, talk with your doctor. There are many effective treatments for this condition.

Does Descovy cause any long-term side effects?

It might, though this is rare. Most side effects of Descovy are mild and short lived or get better with treatment or stopping the medication. In rare cases, Descovy might cause liver damage or kidney failure that could be long term.

If you’re concerned about long-term side effects from taking Descovy, talk with your doctor.

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

Nausea

You may have nausea with Descovy. Nausea was one of the most common side effects reported in people who took the drug.

Nausea is usually mild and short lived. But it can sometimes be a symptom of a more serious side effect of Descovy, such as lactic acidosis or liver problems. See below to read more about these side effects.

What might help

If you have nausea while taking Descovy, talk with your doctor. They may want to do tests to rule out a more serious side effect.

If your doctor feels that your nausea is a mild side effect of Descovy, they may suggest ways to manage this. Tips for reducing nausea include:

  • eating less but more often each day, rather than having three large meals
  • avoiding spicy or greasy foods
  • drinking fluids regularly throughout the day
  • eating or drinking something with fresh or ground ginger in it

If you have nausea that doesn’t go away, ask your doctor or pharmacist if an anti-nausea medication would be right for you.

Severe worsening of hepatitis B

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

The boxed warning notes that if you have hepatitis B, it could get worse when you stop taking Descovy.

When hepatitis B gets worse, it can lead to severe liver problems, such as liver failure.

What might help

Your doctor will test you for the hepatitis B virus (HBV) before you start taking Descovy. This is done with a blood test.

If you test negative for HBV, your doctor may recommend that you get a hepatitis B vaccine before you start taking Descovy.

If you test positive for HBV, your doctor may prescribe medication to treat hepatitis B before you start taking Descovy. When you’ve started Descovy treatment, it’s important that you don’t stop taking it without talking with your doctor first. Take care not to miss doses or run out of Descovy. It may help to set reminders to take your tablet every day. And be sure to order your repeat prescriptions in good time.

If you have hepatitis B and your doctor recommends that you stop taking Descovy, they’ll monitor you closely for several months afterward. You may need frequent blood tests to check your liver function. If your doctor feels that your hepatitis B is worsening, you may need medication to treat it.

HIV resistance

Descovy also has a boxed warning about HIV resistance. This is the mostserious warning from the FDA.

If a person who unknowingly has HIV takes Descovy to help prevent infection from the virus, they could develop HIV resistance to the drug.

With HIV resistance, the virus changes so that it becomes less treatable by a particular drug. If HIV develops resistance to Descovy, this medication won’t be effective against HIV in your body. Other HIV medications containing the same active drugs as Descovy also may not be effective.

You should only take Descovy to help prevent HIV if you don’t already have it. Descovy is used on its own to help prevent HIV. But if you contract HIV while you’re taking Descovy, you’ll also need to take other medications for treatment. You shouldn’t keep taking Descovy alone, as this could lead to HIV resistance.

When Descovy is used to treat HIV, it’s taken with other HIV drugs. Using a combination of drugs makes HIV less able to develop resistance to the drugs.

What might help

Before you take Descovy to help prevent HIV, you’ll have a blood test to check for HIV. While you’re taking Descovy to help prevent HIV, you should be tested for HIV at least every 3 months.

If you have symptoms of HIV, contact your doctor right away so that you can be tested. Early symptoms of HIV can include:

You should also contact your doctor if you have symptoms of other sexually transmitted infections (STIs). Some STIs can increase your risk for contracting HIV.

If you’re taking Descovy to prevent HIV, it’s important that you don’t miss doses of Descovy, as this will increase your risk for contracting HIV.

And if you’re taking Descovy in combination with other medications to treat HIV, it’s still important that you don’t miss doses of Descovy. This is because missing doses increases the likelihood of developing HIV resistance.

To remember to take Descovy, it may help to set reminders to do so every day. And be sure to order your repeat prescriptions in good time so that you don’t run out of tablets.

If you test positive for HIV while you’re taking Descovy, your doctor will discuss with you the best course of action. They may suggest continuing Descovy and taking other HIV medications as well. Or they may recommend treatments other than Descovy.

Lactic acidosis

Descovy can sometimes cause lactic acidosis, which is a buildup of lactic acid in your body. This side effect is rare with Descovy. But it’s a medical emergency that can be life threatening if not treated.

Symptoms of lactic acidosis can include:

What might help

If you have symptoms of lactic acidosis, stop taking Descovy and contact your doctor right away. But if your symptoms develop quickly or are severe, call 911 or your local emergency number.

If you have lactic acidosis, stopping Descovy can make it easier for your body to get rid of excess lactic acid. But you may also need treatment in a hospital for this side effect.

After your lactic acidosis has been treated, your doctor may recommend that you switch to a different HIV medication.

Liver problems

Descovy can sometimes cause severe and even life threatening liver problems, but these side effects are rare.

Symptoms of a liver problem can include:

What might help

If you have symptoms of liver problems while taking Descovy, contact your doctor right away. They may order blood tests to check your liver function. If Descovy may be causing a problem with your liver, your doctor might recommend that you take a different HIV medication.

Allergic reaction

Like most drugs, Descovy can cause an allergic reaction in some people. But this side effect wasn’t reported in studies.

Symptoms of an allergic reaction can be mild or serious and can include:

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

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest an over-the-counter antihistamine that you take by mouth, such as Benadryl (diphenhydramine), or a product that you apply to your skin, such as hydrocortisone cream, to manage your symptoms.

If your doctor confirms that you had a mild allergic reaction to Descovy, they’ll decide if you should continue using it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms that you had a serious allergic reaction to Descovy, they may have you switch to a different treatment.

Keeping track of side effects

During your Descovy treatment, consider keeping notes on any side effects you’re having. Then, you can share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your side effect notes can include things like:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were from the side effect
  • how it affected your daily activities
  • what other medications you were also taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help your doctor learn more about how the drug affects you. And your doctor can use this information to adjust your treatment plan if needed.

Descovy has several warnings that may affect whether you can safely use it.

Boxed warnings

Descovy has two boxed warnings. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA). The boxed warnings for Descovy are:

  • Severe worsening of hepatitis B. If you have hepatitis B, it could get worse when you stop taking Descovy.
  • HIV resistance. You should only take Descovy to help prevent HIV if you don’t already have it. If you already have HIV, taking Descovy to prevent it could make the virus become resistant to Descovy.

To learn more about these boxed warnings, see “Side effects explained” above.

Other warnings

Descovy may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Descovy. Factors to consider include those listed below.

Allergic reaction. If you’ve had an allergic reaction to Descovy or any of its ingredients, you shouldn’t take Descovy. Ask your doctor which other medications are better options for you.

Kidney or liver problems. If you have a kidney or liver problem, taking Descovy could make this worse. Ask your doctor about whether Descovy is safe for you.

Infections. Taking Descovy to treat HIV can make your immune system more responsive. As a result, your immune system may react to previously undiagnosed or previously treated infections. This side effect is called immune reconstitution syndrome (IRS). IRS can cause symptoms of infection and inflammation that may need treatment. Tell your doctor about any infections you have now or have had in the past.

Alcohol use and Descovy

If you have certain side effects with Descovy, drinking alcohol might make them worse. For example, alcohol could worsen nausea, diarrhea, and headache. Drinking alcohol might also increase your risk for liver problems with Descovy.

If you drink alcohol, talk with your doctor about how much you can safely drink with Descovy.

Pregnancy and breastfeeding while taking Descovy

Pregnancy. Descovy hasn’t been specifically studied during pregnancy. Data from females* who’ve taken this medication during pregnancy don’t show an increased risk of birth irregularities.

If you’re pregnant or planning to become pregnant, talk with your doctor about the possible risks and benefits of taking Descovy. If you do take Descovy, you’re encouraged to enroll in the Antiretroviral Pregnancy Registry. This tracks the health of children born to those who took antiretroviral drugs, such as Descovy, during their pregnancy.

Breastfeeding. If you have HIV, you shouldn’t breastfeed your child, regardless of the treatment you’re taking. If your child doesn’t have HIV, breastfeeding can transmit the virus to your child. If your child does have HIV, breastfeeding them could make their HIV become resistant to any HIV drugs in your breast milk. This may make the child’s HIV harder to treat.

Emtricitabine, one of the active ingredients in Descovy, is known to pass into breast milk. But it’s not known if this occurs with tenofovir alafenamide, the other active ingredient in Descovy. It’s also not known if Descovy affects breast milk production or causes side effects in a child who’s breastfed.

If you’re taking Descovy to prevent HIV, talk with your doctor about the best way to feed your child.

* In this article, we use the term “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Most of Descovy’s side effects are mild and typically get better on their own within a couple of weeks. But as with all drugs, there is a small risk of rare but serious side effects.

If you’d like to know more about Descovy’s side effects, talk with your doctor or pharmacist. They can help you decide if this medication might be right for you. Here are some examples of questions you might like to ask:

  • I have diabetes. Am I at higher risk for side effects from Descovy?
  • Am I more likely to get side effects from Descovy the longer I take it?
  • If I take Descovy to prevent HIV, will it affect my immune system?
  • Is Descovy safer than Truvada?

Disclaimer: Healthline 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.