Emtricitabine/Tenofovir Alafenamide
Sold as Descovy
Descovy is used two ways: as part of a combination regimen to treat HIV, and on its own as daily PrEP (pre-exposure prophylaxis) for certain HIV-negative people. It uses the newer tenofovir alafenamide (TAF), which is gentler on the kidneys and bones than the older tenofovir in Truvada.
Boxed warning
Boxed warning (class effect): lactic acidosis and severe hepatomegaly with steatosis have been reported with nucleoside analogs. Severe acute exacerbation of hepatitis B has occurred after stopping this product in patients coinfected with HIV and HBV — hepatitis B status must be checked before stopping.
What it treats
1) HIV treatment: used in combination with other antiretrovirals for HIV-1 infection. 2) PrEP: approved for HIV-negative adults and adolescents at risk through sex, EXCEPT people at risk from receptive vaginal sex — Descovy was not studied in that population and is not approved for it; Truvada is used instead for people who may have receptive vaginal sex. This distinction matters and should be discussed with a prescriber.
Typical dosing
One tablet (200 mg emtricitabine/25 mg tenofovir alafenamide) by mouth once daily, with food, for both the treatment and PrEP indications. HIV testing required before starting PrEP and at least every 3 months while continuing.
Monitoring
Kidney function before starting and periodically (TAF has less renal/bone impact than TDF, but monitoring still applies). Lipid panel — Descovy has been associated with modest increases in cholesterol/triglycerides in some studies, more so than Truvada; periodic lipid monitoring is reasonable. HIV testing before and every ~3 months during PrEP use. Hepatitis B screening before starting.
Side effects
Common: diarrhea, nausea, headache. Less bone density and kidney impact than tenofovir disoproxil (Truvada), but modestly higher effect on cholesterol/lipids in some studies. Serious (rare): lactic acidosis/severe liver problems (class effect), hepatitis B flare if stopped in a coinfected patient.
Interactions to know
Avoid combining with other tenofovir-containing products. Antacids/supplements with calcium, iron, magnesium, or aluminum can reduce absorption if taken simultaneously — space doses apart.
Cost assistance programs
Gilead Advancing Access offers copay assistance for eligible commercially insured patients (often $0 copay) and support pathways for the uninsured — enroll at https://www.gileadadvancingaccess.com/. For PrEP specifically, the HHS-funded Ready, Set, PrEP program provides PrEP medications at no cost to eligible people without prescription drug coverage — see https://readysetprep.hiv.gov/.
Pregnancy & breastfeeding
Data specific to Descovy in pregnancy are more limited than for Truvada. CDC guidance currently favors Truvada for PrEP during pregnancy given its larger safety database; discuss options with your prescriber if pregnancy is being considered or occurs while on Descovy.
Additional notes
Bone density and kidney safety: tenofovir alafenamide (TAF) results in lower drug levels in the blood and kidneys compared with tenofovir disoproxil fumarate (TDF, in Truvada), which translates to less impact on bone mineral density and kidney function — a meaningful consideration for patients with existing kidney or bone risk factors. Lipids: modest increases in LDL/triglycerides have been observed versus Truvada — discuss with your prescriber if you have cardiovascular risk factors. Resistance considerations: for PrEP, consistent daily use is required for protection; HIV testing before and during PrEP prevents starting the drug in someone with undiagnosed HIV, which could otherwise promote resistance.
Clinical content reviewed by the BetterBuyRx clinical team, on 2026-07-07.
Educational only. Not medical advice. Always confirm with your prescriber or pharmacist.