TRUVADA (also called FTC/TDF)
The U.S. Food and Drug Administration (FDA) approved Truvada for PrEP use in 2012. This medication is taken as a once-daily oral pill, which combines two medicines in one: Emtriva (also called emtricitabine or FTC) and Viread (also called tenofovir disoproxil fumarate or TDF). Truvada works by blocking an enzyme called HIV reverse transcriptase. By blocking this enzyme, it prevents HIV from making more copies of itself in the body.

"Scientists have focused on these drugs because they are taken once a day, are potent, have relatively low rates of side effects"