PrEP on Demand
On-demand PrEP is sometimes known as PrEP 2-1-1 or event-based PrEP. It entails taking two pills 2 to 24 hours prior to intercourse, one tablet 24 hours after the first two, and another pill 24 hours after that.
In the French IPERGAY research, on-demand PrEP utilizing daily Truvada was demonstrated to be very effective for homosexual and bisexual men. In the United States, a newer tablet called Descovy (tenofovir alafenamide/emtricitabine) has been licensed for daily PrEP, but it has not yet been assessed for event-based PrEP.
PEP is a method of preventing HIV transmission among HIV-negative people who have recently been exposed to the virus. It entails starting antiretroviral therapy as soon as feasible following a probable HIV infection. Anyone who suspects they have been exposed to HIV should immediately contact their doctor, a hospital emergency department, or a sexual health clinic to determine if PEP is available.
PEP is quite successful, but it will not prevent 100 percent of HIV transmissions. It must be begun within 72 hours following HIV exposure. To be successful, PEP requires a high level of adherence to the whole course of PEP medicines, as well as no further HIV exposures while on PEP.
Created by Kate Underwood, RN and Mia Biondi, NP-PHC, adapted from: Canadian guideline on HIV pre-exposure prophylaxis and non-occupational postexposure prophylaxis (2017)