Emtricitabine/tenofovir alafenamide (Descovy) is an oral medication your doctor might prescribe if you’re HIV positive. Adults and adolescents at risk of being exposed to the virus can also take it as pre-exposure prophylaxis (PrEP) to help protect them from getting HIV.
It’s an FDA-approved once-daily oral pill that’s made up of two active drugs: emtricitabine (200 milligrams) and tenofovir alafenamide (25 milligrams). But before you take it, here are some things to know.
Can I Take Emtricitabine/Tenofovir Alafenamide (Descovy)?
This drug helps in two major ways: treating HIV and preventing you from getting it. But it’s not for everyone.
Research shows it’s effective for men who have sex with men (gay, bisexual, and heterosexual men) and transgender women.
However, experts don’t recommend it for those assigned female at birth, who may be at risk for HIV through vaginal sex. That’s because its effectiveness of preventing HIV infection in this population hasn’t been studied much.
How Does Emtricitabine/Tenofovir Alafenamide (Descovy) Work to Prevent HIV?
It belongs to a class of drugs doctors call NRTIs. That’s short for nucleotide reverse transcriptase inhibitors.
NRTIs work by blocking an enzyme called “reverse transcriptase.” The HIV virus needs this enzyme to infect and attack specific cells (called CD4 cells or T cells) in your immune system in order to multiply. Taking this medication regularly will help to lower the overall viral load in your body and help control HIV infection.
This can also help prevent HIV infection.
Can I Take Emtricitabine/Tenofovir Alafenamide (Descovy) for PrEP?
If you’re likely to be exposed to HIV, your doctor may suggest this medication to prevent infection. But it’s not recommended for everyone.
You can take emtricitabine/tenofovir alafenamide for PrEP if you:
- Test negative for HIV before you start taking it.
- Test negative for HIV at least every 3 months while you’re taking it.
- Weigh over 77 pounds. This boosts your odds of avoiding infection.
- Can stick to taking it by mouth daily.
Don’t stop, skip, or change your dosage without talking to your doctor. Missing a dose can increase your risk for HIV infection.
Make sure to ask your partner about their HIV status, too. If they’re taking medications to prevent HIV infection, ask if they’re taking them as prescribed.
If you’re exposed to HIV, test positive for it, or notice signs and flu-like symptoms, tell your doctor immediately. If you test positive, you’ll need additional HIV medications to keep your infection under control.
HIV infection symptoms may include:
- Headache
- Sore throat
- Tiredness
- Fever
- Rashes
- Muscle or joint pain
- Vomiting
- Diarrhea
- Rash
- Night sweats
- Enlarged lymph nodes in the neck or groin
Your doctor will also have to regularly test you for STIs such as syphilis, chlamydia, or gonorrhea. HIV medications don’t protect you from other infectious diseases. STIs can increase your chances of HIV infection.
How Effective Is Emtricitabine/Tenofovir Alafenamide (Descovy) for PrEP?
Research has found it’s highly effective when you take it consistently.
A large-scale study that looked at over 5,000 men and trans women most at risk for HIV across 2 years found that over 99% tested negative for HIV by the end of the study. The results were similar across race and gender identity.
However, the study didn’t include women or trans men at risk for HIV through vaginal sex. It also didn’t include adolescents or people who inject substances into their veins.
Does Emtricitabine/Tenofovir Alafenamide (Descovy) Interact With Other Medications?
Taking it alone isn’t enough to prevent or control existing HIV infection. If you have HIV, for complete treatment, you’ll need to take other antiviral medications, too.
Plus, when you’re using this drug for PrEP, you need to use safe sex measures such as condoms, spermicides, and other barrier methods.
If you’re considering taking this drug to manage HIV infection or to prevent it, talk to your doctor. List any medications, vitamins, and herbal supplements you’re taking. That’s because the two active ingredients in this drug, along with other ingredients it contains, might interact with other prescription or over-the-counter medications.
In some cases, taking one drug can change the amount of other drugs in your bloodstream. That could cause the drugs to not work, or in severe cases, an overdose. Your doctor will know what drugs you can take together.
Avoid emtricitabine/tenofovir alafenamide (Descovy) for PrEP if you take:
- Carbamazepine
- Oxcarbazepine
- Phenobarbital
- Phenytoin
- Rifabutin
- Rifampin
- Rifapentine
- St. John's wort
- Tipranavir plus ritonavir
Warning and Safety Issues With Emtricitabine/Tenofovir Alafenamide (Descovy)
Like any drug, it can cause common side effects including nausea, headache, or upset stomach. But if you have certain health conditions, your doctor needs to closely monitor your health.
Before you start taking this medication, your doctor will test you for the hepatitis B virus (HBV). If you have an HBV infection, it’s important to follow your doctor’s directions and take your HIV medications exactly as prescribed.
If you stop or skip doses, your HBV is more likely to flare up. This means your symptoms could come back more severe than before. If this happens, you’ll need HBV treatment and your doctor will watch you for several months to keep your HBV in check.
If you have kidney problems in addition to being HIV positive, check with your doctor to see if emtricitabine/tenofovir alafenamide is right for you. They may have to run blood and urine tests, adjust your dosage, and monitor your kidney function.
If you develop new kidney problems or your existing issues worsen, your doctor may ask you to stop taking this HIV medication.
If you’re pregnant, plan to get pregnant, or you breastfeed, tell your doctor before you take this drug. That’s because there’s a risk of passing one or more of its ingredients to your fetus or breastmilk.