Descovy is an FDA-approved medication used for two purposes: treating HIV-1 infection and preventing HIV-1 infection in people who don’t yet have the virus. It combines two antiviral drugs into a single tablet taken once daily, with or without food.
HIV-1 Treatment
Descovy is approved for treating HIV-1 in adults and children weighing at least 25 kg (about 55 pounds). It is not a standalone treatment. It’s always prescribed alongside other antiretroviral medications as part of a combination regimen that suppresses the virus to undetectable levels.
The standard tablet for adults and older children (35 kg and above) contains 200 mg of emtricitabine and 25 mg of tenofovir alafenamide. A lower-dose tablet (120 mg/15 mg) is available for younger children weighing between 25 and 35 kg. In both cases, the dose is one tablet per day.
HIV Prevention (PrEP)
Descovy’s second use is pre-exposure prophylaxis, or PrEP, which means taking the medication daily to prevent HIV infection before any potential exposure. It’s approved for at-risk adults and adolescents weighing at least 35 kg. You must test negative for HIV immediately before starting Descovy for PrEP, and the medication should not be taken by anyone whose HIV status is unknown or positive.
There is one major limitation: Descovy is not approved for PrEP in people at risk of HIV through receptive vaginal sex. This is because it was not studied in that population during its pivotal clinical trial (called DISCOVER), which enrolled men and transgender women who have sex with men. The drug concentrations that build up in cervicovaginal tissue tend to be lower than those in rectal tissue at the same dose, which is why the FDA did not extend the approval. Truvada, the older PrEP option, remains approved for all populations including cisgender women.
That said, newer post-marketing data suggest oral PrEP with these drugs may work well in cisgender women who take it consistently. In a combined analysis of demonstration projects, none of the 498 cisgender women who took daily doses acquired HIV, and only one of 658 women taking four to six doses per week became infected. Still, the formal FDA indication for Descovy has not changed.
How Descovy Differs From Truvada
Descovy and Truvada share one active ingredient (emtricitabine) but differ in their version of tenofovir. Truvada uses an older formulation called TDF, while Descovy uses a newer one called TAF. TAF delivers higher concentrations of the active drug directly into immune cells while keeping blood levels lower, which reduces the amount of drug that reaches the kidneys and bones.
In the DISCOVER trial, which followed over 5,300 HIV-negative participants for a median of about 86 weeks, Descovy showed a more favorable profile for kidney function. Participants on Descovy had fewer drug-related kidney side effects (14 cases versus 26 with Truvada), and only one case of a serious kidney condition called Fanconi syndrome occurred, in the Truvada group. People who switched from Truvada to Descovy saw improvements in kidney function markers as early as four weeks after changing.
Bone density followed a similar pattern. In a sub-study of 383 participants, those taking Descovy experienced small increases in bone density at the hip and spine over 48 weeks, while those on Truvada saw declines. The differences were most pronounced in younger participants. People who switched from Truvada to Descovy showed significant improvements in hip and spine bone density compared to those who stayed on Truvada.
One trade-off worth knowing about: TAF-based regimens have been associated with modest weight gain and changes in cholesterol. In a 96-week study of people with suppressed HIV who switched to a TAF-containing regimen, the average weight increase was 0.7 kg (about 1.5 pounds), which is statistically significant but small in practical terms.
Common Side Effects
Descovy is generally well tolerated. In the DISCOVER trial, the most common side effect was diarrhea, reported by 5% of participants. Nausea occurred in 4%, headache in 2%, fatigue in 2%, and abdominal pain in 2%. These rates were similar to or slightly lower than those seen with Truvada in the same trial.
Hepatitis B Considerations
Descovy carries a boxed warning, the FDA’s most serious label alert, regarding hepatitis B. Both of the drugs in Descovy are active against hepatitis B virus, and stopping the medication can cause a severe flare of hepatitis B in people who are co-infected. Anyone starting Descovy should be tested for hepatitis B first, and liver function should be monitored closely if the medication is discontinued.
Who Descovy Is Best Suited For
For HIV treatment, Descovy is one component of a multi-drug regimen and is chosen based on a person’s overall treatment plan, other medications, and health profile. For PrEP specifically, Descovy is an option for men who have sex with men and transgender women who have sex with men. Its kidney and bone advantages over Truvada may make it a better fit for people with existing concerns in those areas, younger individuals whose bones are still developing peak density, or anyone planning to take PrEP long-term. Cisgender women at risk through receptive vaginal sex should discuss alternative PrEP options, including Truvada or injectable PrEP, with their provider.