On-Demand PrEP

On-Demand PrEP
If I am not at ongoing risk for getting HIV, can I take PrEP only when I’m at risk?

Taking PrEP pills only when you are at risk for getting HIV is known as “on-demand” PrEP.

  • It is also known as “intermittent,” “non-daily,” “event-driven,” or “off-label” PrEP use.
  • The type of “on-demand” PrEP that has been studied is the “2-1-1” schedule. This means taking 2 pills 2-24 hours before sex, 1 pill 24 hours after the first dose, and 1 pill 24 hours after the second dose.
  • There is scientific evidence that the “2-1-1” schedule provides effective protection for gay and bisexual men* when having anal sex without a condom.
  • We don’t know how “on-demand” PrEP works for heterosexual men and women, people who inject drugs, and transgender persons.

Some health departments in the United States and some health organizations in Europe and Canada are offering guidance for “on-demand” PrEP as an alternative to daily PrEP for gay and bisexual men at risk for HIV.

Although the updated PrEP guideline provides information on how to correctly use the “2-1-1” schedule, this approach is not approved by the U.S. Food and Drug Administration (FDA) and is not recommended by CDC. Taking PrEP as prescribed is currently the only FDA-approved schedule for taking PrEP to prevent HIV. When taken as prescribed, PrEP is highly effective for preventing HIV.

Anyone considering PrEP should discuss the issue with their health care provider.

* The term “gay and bisexual men” is used to describe men who identify as gay or bisexual, as well as men who have sex with men who do not identify as gay or bisexual.