Emtricitabine/Tenofovir Alafenamide

Pronunciation: em-try-SITE-a-been and ten-NO-foe-vir al-a-FEN-a-mide
Generic name: emtricitabine/tenofovir alafenamide
Brand name: Descovy
Dosage form: oral tablet
Drug class: Antiviral combinations

Medically reviewed by Carmen Pope, BPharm. Last updated on May 9, 2024.

What is emtricitabine/tenofovir alafenamide?

Emtricitabine/tenofovir alafenamide is an oral 2-drug combination tablet that may be used in adults and children who weigh at least 77 pounds (35 kg) to treat HIV-1 infection OR as a preventive medicine to reduce the risk of getting HIV-1 infection (this is called HIV-1 PrEP).

• When used to treat HIV infection it is used in combination with other HIV-1 medicines.
• It can also be used to treat children with HIV-1 who weigh at least 31 pounds (14 kg), but less than 77 pounds (35 kg) in combination with specific types of other HIV-1 medicines
• When used for HIV-1 PrEP it is not known if emtricitabine/tenofovir alafenamide is effective in reducing the risk of getting HIV-1 from certain types of sex.

Emtricitabine/tenofovir alafenamide for HIV-1 PrEP is only prescribed to cisgender men and transgender women who have sex with men because it has not been studied in people assigned female at birth who are at risk of getting HIV from vaginal sex.

Emtricitabine and tenofovir alafenamide both belong to the class of medicines known as nucleoside reverse transcriptase inhibitors (NRTIs). These work by blocking an HIV enzyme called reverse transcriptase that converts HIV RNA into HIV DNA. By blocking this enzyme emtricitabine/tenofovir alafenamide prevents HIV from replicating or making copies of itself, reducing levels of HIV in the body and slowing its spread. Although emtricitabine/tenofovir alafenamide will not cure HIV, these medications may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer.

Emtricitabine/tenofovir alafenamide was FDA approved on April 4, 2016 under the brand Descovy. There is no Descovy generic.

Emtricitabine/tenofovir alafenamide side effects

Emtricitabine/tenofovir alafenamide may cause serious side effects, including a worsening of hepatitis B infection (HBV), risk of drug resistance in undiagnosed HIV-1 infection, immune reconstitution syndrome kidney damage, lactic acidosis or liver disease. See warnings below.

The most common side effects of emtricitabine/tenofovir alafenamide for:

• HIV-1 treatment reported in 10% or more people is nausea
• HIV-1 prevention (HIV-1 PrEP) reported in 5% or more people is diarrhea.

These are not all the possible side effects of emtricitabine/tenofovir alafenamide. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Warnings

Emtricitabine/tenofovir alafenamide can cause the following serious side effects.

Worsening of hepatitis B virus (HBV) infection. Your healthcare provider will test you for HBV infection before or when you start treatment with emtricitabine/tenofovir alafenamide. If you have an HBV infection and take emtricitabine/tenofovir alafenamide, your HBV may get worse (flare-up) when you discontinue treatment.

• Do not run out of emtricitabine/tenofovir. Refill your prescription or talk to your healthcare provider before it is all gone. Do not stop taking emtricitabine/tenofovir without first talking to your healthcare provider. If you stop taking emtricitabine/tenofovir, your healthcare provider will need to check your health often and do blood tests regularly for several months to check your liver, and may give you a medicine to treat hepatitis B. Tell your healthcare provider about any new or unusual symptoms you may have after you stop taking emtricitabine/tenofovir.

Changes in your immune system (Immune Reconstitution Syndrome) can happen when you start taking medicines to treat HIV-1 infection. Your immune system may get stronger and fight infections hidden in your body for a long time. Tell your healthcare provider right away if you start having any new symptoms after starting your HIV-1 medicine.

New or worse kidney problems, including kidney failure. Your healthcare provider should do blood and urine tests to check your kidneys before you start and while taking emtricitabine/tenofovir alafenamide. Your healthcare provider may tell you to stop treatment if you develop new or worse kidney problems.

Too much lactic acid in your blood (lactic acidosis). This is a serious but rare medical emergency that can lead to death. Tell your healthcare provider right away if you get these symptoms: weakness or being more tired than usual, unusual muscle pain, being short of breath or fast breathing, stomach pain with nausea and vomiting, cold or blue hands and feet, feeling dizzy or lightheaded, or a fast or abnormal heartbeat.

Severe liver problems. In rare cases, severe liver problems can happen that can lead to death. Tell your healthcare provider right away if you get these symptoms: skin or the white part of your eyes turns yellow, dark “tea-colored” urine, light-colored stools, loss of appetite for several days or longer, nausea, or stomach-area pain.

Emtricitabine/tenofovir alafenamide should not be used in people born female (assigned female at birth) who are at risk of getting HIV-1 infection from vaginal sex, because its effectiveness has not been studied.

It is not known:

• if treatment with emtricitabine/tenofovir alafenamide is safe and effective in children who weigh less than 31 pounds (14 kg).
• if emtricitabine/tenofovir alafenamide is effective at reducing the risk of HIV-1 infection in people who weigh less than 77 pounds (35 kg).

Before taking

Before taking emtricitabine/tenofovir alafenamide to reduce your risk of getting HIV-1 (HIV-1 PrEP) you must be HIV-1 negative to start treatment. You must get tested to make sure that you do not already have HIV-1 infection and wait to be confirmed to be HIV-1 negative.

Some HIV-1 tests can miss HIV-1 infection in a person who has recently become infected. If you have flu-like symptoms, you could have recently become infected with HIV-1. Tell your healthcare provider if you had a flu-like illness within the last month before starting emtricitabine/tenofovir alafenamide or at any time while taking the preventive medicine. Symptoms of new HIV-1 infection include:

• tiredness
• fever
• joint or muscle aches
• headache
• sore throat
• vomiting or diarrhea
• rash
• night sweats
• enlarged lymph nodes in the neck or groin.

Tell your healthcare provider about all of your medical conditions, including if you:

• have liver problems, including HBV infection
• have kidney problems
• are sexually active
• may have been exposed to HIV within the past month
• been recently tested for other sexually transmitted diseases (STIs) such as syphilis, chlamydia, and gonorrhea
• have bone problems or low bone mineral density
• kidney disease (or if you are on dialysis).
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

It is not known if emtricitabine/tenofovir alafenamide can harm your unborn baby. Tell your healthcare provider if you become pregnant during treatment. There is a pregnancy registry for people who take emtricitabine/tenofovir alafenamide during pregnancy. The purpose of this registry is to collect information about you and your baby's health. Talk with your healthcare provider about how you can take part in this registry.

Breastfeeding

Do not breastfeed if you take emtricitabine/tenofovir alafenamide for treatment of HIV-1 because of the risk of passing HIV-1 to your baby.

Emtricitabine also passes into your breast milk. It is unknown what effects it has on milk production or the breastfed child.

While taking emtricitabine/tenofovir alafenamide

Get tested for HIV-1 at least every 3 months or when your healthcare provider tells you.

Get tested regularly for other STIs such as syphilis, chlamydia, and gonorrhea. These infections make it easier for HIV-1 to infect you. Get information and support to help reduce sexual risk behaviors.

If you think you have been exposed to HIV-1, tell your healthcare provider right away. They may want to do more tests to be sure you are still HIV-1 negative. If you do become HIV-1 positive, you need more medicine than emtricitabine/tenofovir alafenamide alone to treat HIV-1. Emtricitabine/tenofovir alafenamide by itself is not a complete treatment for HIV-1.

• If you have HIV-1 and take only emtricitabine/tenofovir alafenamide, over time your HIV-1 may become harder to treat.

How should I take emtricitabine/tenofovir alafenamide?

Take emtricitabine/tenofovir alafenamide exactly as your healthcare provider tells you to take it.

• Emtricitabine/tenofovir alafenamide tablets are taken 1 time each day.
• The usual dosage in adults is one 200 mg/25 mg tablet once daily.
• May be taken with or without food.

If you take emtricitabine/tenofovir alafenamide to treat HIV-1 infection, you need to take it with other HIV-1 medicines. Your healthcare provider will tell you what medicines to take and how to take them.

If you are on dialysis, take your daily dose of emtricitabine/tenofovir alafenamide following dialysis.

Do not change your dose or stop taking emtricitabine/tenofovir alafenamide without first talking with your healthcare provider. Stay under a healthcare provider’s care when taking emtricitabine/tenofovir alafenamide. Do not miss a dose.

What happens if I miss a dose?

If you miss a dose, take the dose as soon as you remember. If it is almost time for your next dose, skip the dose. Talk to your healthcare provider if you miss more than 2 doses in a row. Missing doses means:

• The amount of virus in your blood may increase, resistance to the virus may develop, and the virus may become harder to treat.
• You are at greater risk for acquiring HIV-1 if you are taking emtricitabine/tenofovir alafenamide as HIV-1 PrEP.

What happens if I overdose?

If you take too much emtricitabine/tenofovir alafenamide, call your healthcare provider or go to the nearest hospital emergency room right away.

What should I avoid while taking emtricitabine/tenofovir alafenamide?

Avoid running out of emtricitabine/tenofovir alafenamide because if you are taking it for the treatment of HIV-1 it can increase your risk of the virus developing resistance to HIV-1 and becoming harder to treat.

• If you are taking emtricitabine/tenofovir alafenamide for HIV-1 PrEP, missing doses increases your risk of getting HIV-1 infection.
• When your emtricitabine/tenofovir alafenamide supplies start running low, get more from your healthcare provider or pharmacy.

Do not take emtricitabine/tenofovir alafenamide for HIV-1 PrEP if you already have HIV-1 infection, do not know your HIV-1 infection status, or do not know the HIV-1 status of your partners. If you are HIV-1 positive, you need to take other medicines with emtricitabine/tenofovir alafenamide to treat HIV-1. Emtricitabine/tenofovir alafenamide by itself is not a complete treatment for HIV-1.

• Emtricitabine/tenofovir alafenamide for HIV-1 PrEP can only help reduce your risk of getting HIV-1 infection before you are infected.
• Ask your partners with HIV-1 if they are taking HIV-1 medicines and have an undetectable viral load. An undetectable viral load is when the amount of virus in the blood is too low to be measured in a lab test. To maintain an undetectable viral load, your partners must keep taking HIV-1 medicines every day. Your risk of getting HIV-1 is lower if your partners with HIV-1 are taking effective treatment.

Do not have unprotected sex. Emtricitabine/tenofovir alafenamide does not prevent other sexually transmitted infections (STIs). Practice safer sex by using a latex or polyurethane condom to reduce the risk of getting STIs.

What is the difference between emtricitabine/tenofovir disoproxil fumarate (Truvada) and emtricitabine/tenofovir alafenamide (Descovy)

The difference between emtricitabine/tenofovir disoproxil fumarate (Truvada) and emtricitabine/tenofovir alafenamide (Descovy) is in the form of tenofovir contained in each product. Truvada contains the original form of tenofovir as tenofovir disoproxil fumarate (TDF) and Descovy contains a newer form of tenofovir called tenofovir alafenamide (TAF).

TAF is a prodrug of tenofovir that enters HIV-infected cells more efficiently than TDF, and it can therefore be given at a much lower dose (less than one-tenth) than TDF. TAF appears to be associated with less kidney toxicity and decreases in bone density compared to TDF.

What other drugs affect emtricitabine/tenofovir alafenamide?

Tell your healthcare provider about all your medicines, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Many other medicines interact with emtricitabine/tenofovir alafenamide. Keep a list of your medicines and show it to your healthcare provider and pharmacist when you get a new medicine. Examples of medicines that interact with emtricitabine/tenofovir alafenamide include:

• Other medicines that also affect your kidneys, including antibiotics, other antivirals, or medicines used to treat cancer, osteoporosis, organ transplant rejection, high blood pressure, pain, or arthritis (including Advil, Motrin, and Aleve)
• Seizure medications such as carbamazepine, oxcarbazepine, phenytoin, phenobarbital
• Other antivirals such as those used to treat hepatitis C or HIV.

You can ask your healthcare provider or pharmacist for a list of medicines that interact with emtricitabine/tenofovir alafenamide. Do not start a new medicine without telling your healthcare provider.

Storage

Store at room temperature 68°F to 77°F (20°C to 25°C). Keep it in its original bottle or blister pack. Keep the bottle tightly closed.

Keep out of reach of children.

Descovy ingredients

Active ingredients: emtricitabine and tenofovir alafenamide.

Inactive ingredients: croscarmellose sodium, magnesium stearate, and microcrystalline cellulose.

Film coating 120 mg/15 mg: polyvinyl alcohol, titanium dioxide, polyethylene glycol, and talc.

Film coating 200 mg/25 mg: indigo carmine aluminum lake, polyethylene glycol, polyvinyl alcohol, talc, and titanium dioxide.

Available in 2 strengths 120 mg/15 mg and 200 mg/25 mg.

Manufacturer

Descovy: Gilead Sciences Inc.

Frequently asked questions

• Truvada vs Descovy: How do they compare for HIV and PrEP?
• What is the difference between Biktarvy and Descovy?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer