How does PrEP work (MOA)?

Oral form PrEP Medications:

There are 2 oral forms that are FDA-approved : Truvada and Descovy.

  1. Truvada is an oral tablet containing 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate taken once daily

  2. Descovy is an oral tablet containing  200 mg emtricitabine and 25mg tenofovir alafenamide

  • These are antiviral medications that block the replication of HIV. These medications inhibit reverse transcription by causing chain termination after they have been incorporated into viral DNA

  • The NRTI class of antiretroviral medications comprises chemical compounds acting as nucleotide base analogs. PrEP’s FTC and TDF compounds are examples of NRTI’s. These compounds serve to halt the elongation of the DNA chain in the course of reverse transcription, a process facilitated by the HIV reverse transcriptase enzyme. While these NRTI compounds allow accurate base-pairing and incorporation into the DNA strand, a crucial hydroxyl group needed for the addition of the subsequent nucleotide has been substituted with an inert chemical group.

Alternative Non-Daily Dosing:

Alternative dosing (AKA “on-demand” or “event-driven”) can be used for biologic men and transgender women using a 2-1-1 dosing:

  • 2 pills in the 2-24 hours before sex (closer to 24 hours is preferred)

  • 1 pill 24 hours after the initial 2-pill dose

  • 1 pill 48 hours after the initial 2-pill dose

Injection form PrEP Medication:

The FDA has approved two injectable forms of PrEP:

  1. Apretude also known as cabotegravir or CAB 600mg administered every 2 months

  2. Yeztugo ® (lenacapavir, AKA LEN) 463.5 mg/1.5 mL is given every 6 months

Did you know: It is harder to reach and maintain a therapeutic level of PrEP within vaginal secretions. This makes daily dosing key for folks at risk for HIV due to vaginal sex.