Emtricitabine and tenofovir alafenamide

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

Medically reviewed by Carmen Pope, BPharm. Last updated on Jan 17, 2025.

What is emtricitabine and tenofovir alafenamide?

Emtricitabine and tenofovir alafenamide (brand name Descovy) is a prescription antiviral medication containing 2 antiviral agents, emtricitabine and tenofovir alafenamide. It has two primary uses:

1. HIV-1 treatment in combination with other HIV medications in:
   • adults and children who weigh at least 77 pounds (35 kg)
   • children who weigh at least 31 pounds (14 kg) and less than 77 pounds (35 kg) together with specific other HIV-1 medicines.
2. HIV Prevention (PrEP) in adults and adolescents weighing at least 77 pounds (35 kg).
   • Emtricitabine and tenofovir alafenamide is taken daily by HIV-negative individuals to prevent HIV.

Important Note: emtricitabine and tenofovir alafenamide for PrEP is not approved for use in people assigned female at birth (cisgender females) who are at risk of HIV-1 infection from vaginal sex because clinical trials have not been conducted in this population.

• The combination of emtricitabine and tenofovir alafenamide is only approved for males and transgender women.

Critical safety information

Before starting emtricitabine and tenofovir alafenamide

You must:

• Confirm you are HIV-negative through testing
• Get tested for hepatitis B (HBV)
• Inform your healthcare provider about any flu-like symptoms within the last month
• Discuss all existing medical conditions and medications

For PrEP users

To use emtricitabine and tenofovir alafenamide safely for HIV prevention:

• Maintain regular HIV testing (at least every 3 months)
• Practice safer sex using latex or polyurethane condoms
• Get regular STI testing
• Never miss doses
• Know your partner's HIV status
• Report any potential HIV exposure immediately

Emtricitabine and tenofovir alafenamide side effects

The most common emtricitabine and tenofovir alafenamide side effects are:

• nausea (most common in HIV-1 treatment)
• diarrhea (most common in PrEP)
• headache, dizziness, feeling depressed or tired
• sleep problems (insomnia), strange dreams
• stomach pain
• weight loss
• rash.

Serious side effects and warnings

Critical side effects to watch for:

Worsening of hepatitis B virus (HBV) infection

• Your healthcare provider will test you for HBV infection before and when you start treatment with emtricitabine and tenofovir alafenamide
• HBV may worsen or flare up if you stop taking emtricitabine and tenofovir alafenamide
• Regular monitoring is required, and for several months after stopping emtricitabine and tenofovir alafenamide
• Do not run out of emtricitabine and tenofovir alafenamide and never stop your medication without a healthcare provider consultation.

Immune System Changes

• Changes in your immune system can happen when you start taking medicines to treat HIV-1 infection.
• Your immune system may become stronger and begin to fight infections that have been hidden in your body for a long time.
• Watch for signs of new infections.
• Report any unusual symptoms to your healthcare provider.

Kidney Problems

• New or worse kidney problems, including kidney failure, may develop after starting emtricitabine and tenofovir alafenamide.
• Regular blood and urine tests are needed.
• This may require dose adjustments.

Lactic Acidosis

Rarely, emtricitabine and tenofovir alafenamide may cause too much lactic acid to build up in your blood. Seek immediate medical attention for:

• Unusual muscle pain
• Breathing difficulties
• Severe fatigue
• Stomach pain with nausea
• Irregular heartbeat

Liver Problems

Rarely, emtricitabine and tenofovir alafenamide may cause severe liver problems that can lead to death. Watch for:

• Yellowing of skin or eyes
• Dark urine
• Light-colored stools
• Loss of appetite
• Stomach pain

Do not take emtricitabine and tenofovir alafenamide if you also take other medicines that contain emtricitabine, tenofovir, lamivudine, or adefovir. Get emergency medical help if you have signs of an allergic reaction to emtricitabine and tenofovir alafenamide: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking this medicine

For people taking emtricitabine and tenofovir alafenamide for HIV-1 PrEP:

Do not take emtricitabine and tenofovir alafenamide for HIV-1 PrEP if:

• you already have an HIV-1 infection. If you are HIV-1 positive, you need to take other medicines with emtricitabine and tenofovir alafenamide to treat HIV-1. Emtricitabine and tenofovir alafenamide by itself is not a complete treatment for HIV-1
• you do not know your HIV-1 infection status. You may already be HIV-1 positive. You need to take other HIV-1 medicines with emtricitabine and tenofovir alafenamide to treat HIV-1 infection.

Emtricitabine and tenofovir alafenamide can only help reduce your risk of getting HIV-1 infection before you are infected.

What should I tell my healthcare provider before taking emtricitabine and tenofovir alafenamide?

Before taking emtricitabine and tenofovir alafenamide, tell your healthcare provider about all of your medical conditions, including if you:

• have any flu-like symptoms
• have liver problems, including HBV infection
• have kidney problems
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

It is not known if emtricitabine and tenofovir alafenamide can harm your unborn baby. Tell your healthcare provider if you become pregnant during treatment with emtricitabine and tenofovir alafenamide.

Pregnancy Registry: There is a pregnancy registry for people who take emtricitabine and tenofovir alafenamide during pregnancy. The purpose of this registry is to collect information about the health of you and your baby. Talk with your healthcare provider about how you can take part in this registry.

Breastfeeding

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

One of the ingredients in emtricitabine and tenofovir alafenamide (emtricitabine) passes into your breast milk.

How should I take emtricitabine and tenofovir alafenamide?

Take emtricitabine and tenofovir alafenamide exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

• Take one dose daily
• Can be taken with or without food
• For dialysis patients: Take after dialysis
• Never skip doses or stop treatment without medical advice
• Maintain an adequate supply. Do not run out of emtricitabine and tenofovir alafenamide as it may increase your risk of infection from HIV and other viruses.

Emtricitabine and tenofovir alafenamide (PrEP) alone will not protect you from infection with HIV. You must also use safer sex practices and get tested for HIV before starting prophylaxis and at least once every 3 months.

How long does emtricitabine and tenofovir alafenamide take to work?

When taking emtricitabine and tenofovir alafenamide for PrEP, the time to reach maximum protection varies depending on your risk factors.

For receptive anal sex

• Takes 7 days of daily use before emtricitabine and tenofovir alafenamide protects against HIV-1
• Must take one pill every day
• Provides over 99% protection when used consistently

For receptive vaginal sex

• Takes 21 days of daily use before emtricitabine and tenofovir alafenamide protects against HIV-1
• Requires strict daily adherence
• Over 99% effective with daily use

For injection drug use

• Takes 21 days to reach maximum protection
• Reduces HIV risk by at least 74%
• Must be taken every day

Important notes:

• Effectiveness depends on taking emtricitabine and tenofovir alafenamide every day without missing doses
• Protection levels are based on consistent, daily use
• Starting PrEP requires a negative HIV test and ongoing monitoring
• Must be combined with other safer sex practices

Currently unknown factors:

The following is not known:

• Time to reach protection for insertive anal sex
• Time to reach protection for insertive vaginal sex
• How this timeline for emtricitabine and tenofovir alafenamide compares to injectable cabotegravir (Apretude). See Apretude vs Descovy: How do they compare?

Always consult your healthcare provider about your specific situation and risk factors.

What happens if I miss a dose?

Take the medicine as soon as you remember, and then go back to your regular schedule. Do not use two doses at one time.

Skipping doses could make the virus resistant to medication or increase your risk of becoming infected with HIV.

Get your prescription refilled before you run out of medicine completely.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking emtricitabine and tenofovir alafenamide?

Using this medicine will not prevent HIV from spreading.

Do not have unprotected sex or share razors or toothbrushes. Ask your doctor how to prevent HIV transmission during sex. Sharing needles is never safe.

What other drugs will affect emtricitabine and tenofovir alafenamide?

Sometimes it is not safe to use certain medicines at the same time. Some drugs can affect your blood levels of other drugs you use, which may increase side effects or make the medicines less effective.

Emtricitabine and tenofovir can harm your kidneys, especially if you also use certain medicines for infections, cancer, osteoporosis, organ transplant rejection, high blood pressure, or pain or arthritis (including Advil, Motrin, and Aleve).

Tell your doctor about all your other medicines, especially:

• seizure medicine - carbamazepine, oxcarbazepine, phenytoin, phenobarbital; or

• other antiviral medicine to treat hepatitis C or HIV.

This list is not complete and many other drugs may interact with emtricitabine and tenofovir. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Emtricitabine and tenofovir alafenamide ingredients

Active ingredient: emtricitabine and tenofovir alafenamide.
Inactive ingredients: croscarmellose sodium, magnesium stearate, and microcrystalline cellulose.

The 200 mg/25 mg tablets are film-coated with a coating material containing indigo carmine aluminum lake, polyethylene glycol, polyvinyl alcohol, talc, and titanium dioxide.

The 120 mg/15 mg tablets are film-coated with a coating material containing polyvinyl alcohol, titanium dioxide, polyethylene glycol, and talc.

Available as

• Descovy 120 mg/15 mg (emtricitabine 120 mg and tenofovir alafenamide 15 mg)
• Descovy 200 mg/25 mg (emtricitabine 200 mg and tenofovir alafenamide 25 mg).

Storage

• Store your emtricitabine and tenofovir alafenamide tablets at room temperature (68°F to 77°F)
• Keep them in their original container.

Who makes emtricitabine and tenofovir alafenamide?

Emtricitabine and tenofovir alafenamide (brand name Descovy) is manufactured by Gilead Sciences, Inc., a biopharmaceutical company based in Foster City, California. Some of Gilead's other notable HIV medications include:

• Truvada (another PrEP medication)
• Biktarvy
• Genvoya
• Atripla
• Complera
• Stribild.

Other treatments Gilead is known for include:

• Veklury (remdesivir) for COVID-19
• Harvoni and Sovaldi for hepatitis C
• Vemlidy for chronic hepatitis B
• Yescarta for certain types of lymphoma
• Tecartus for mantle cell lymphoma.

Frequently asked questions

• Descovy vs Truvada: 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