PrEP (pre-exposure prophylaxis) is medicine people at risk for HIV take to prevent getting HIV from sex or injection drug use. There are two medications approved for use as PrEP: Truvada and Descovy. Truvada is for all people at risk through sex or injection drug use. Descovy is for people at risk through sex, except for people assigned female at birth who are at risk of getting HIV from vaginal sex. PrEP is safe but some people experience side effects like diarrhea, nausea, headache, fatigue, and stomach pain. These side effects usually go away over time.

PrEP may be right for people that are tested negative for HIV, and meeting one of the following criteria:

Had anal or vaginal sex in the past 6 months and:

  • have a sexual partner with HIV (especially if the partner has an unknown or detectable viral load),
  • have not consistently used a condom, or
  • have been diagnosed with an STD in the past 6 months.

Inject drugs and:

  • have an injection partner with HIV, or
  • share needles, syringes, or other equipment to inject drugs (for example, cookers).

Have been prescribed PEP (post-exposure prophylaxis) and:

  • report continued risk behavior, or
  • have used multiple courses of PEP.

Woman that have a partner with HIV and are considering getting pregnant, should talk to doctor about PrEP. PrEP may be an option to help protect a person and a baby from getting HIV while trying to get pregnant, during pregnancy, or while breastfeeding.

PrEP is approved for use by adolescents without HIV who weigh at least 75 pounds (35 kg) and who are at risk for getting HIV from sex or injection drug use.

Taking PrEP 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.