What Was Approved?
On May 29, 2026, the U.S. Food and Drug Administration approved Xocova (ensitrelvir) for post-exposure prophylaxis of COVID-19 in adults and adolescents 12 years of age and older after contact with someone who has COVID-19.
Xocova is intended to reduce the risk of developing COVID-19 after a known exposure. It is not the same as treatment for someone who is already being treated for symptomatic COVID-19.
How Does Xocova Work?
Xocova is an antiviral medicine that inhibits the SARS-CoV-2 main protease, an enzyme the virus needs to replicate.
By blocking this enzyme, ensitrelvir interferes with viral replication.
How Is Xocova Taken?
Treatment should begin as soon as possible and within 72 hours after exposure to a person with COVID-19.
The FDA-approved regimen is:
- Day 1: 375 mg by mouth
- Days 2 through 5: 125 mg once daily
It may be taken with or without food.
What Are the Main Safety Concerns?
Xocova can have important drug interactions because it affects the CYP3A enzyme system.
Some medications should not be taken with Xocova because drug concentrations may become dangerously high or Xocova may become less effective.
Patients should provide a complete medication list to a pharmacist or prescriber before starting treatment.
Are There Pregnancy Concerns?
Yes.
The FDA prescribing information warns that Xocova may cause fetal harm based on animal data.
Pregnancy status should be checked before treatment in patients who could become pregnant, and effective contraception is recommended during treatment and for 2 weeks after the final dose.
What Are the Common Side Effects?
The most commonly reported adverse events occurring more often than with placebo included:
- Headache
- Diarrhea
- Cough
Serious allergic reactions, including anaphylaxis and angioedema, have also been reported.
Bottom Line
Xocova (ensitrelvir) is a newly FDA-approved oral antiviral for post-exposure prevention of COVID-19 in adults and adolescents age 12 and older.
It must be started within 72 hours after exposure, and careful medication review is important because significant drug interactions can occur.
Sources
- U.S. Food and Drug Administration (FDA) — Novel Drug Approvals for 2026.
- U.S. Food and Drug Administration (FDA) — Xocova (ensitrelvir) Prescribing Information, revised May 2026.