Tenofovir is one of the most commonly used NRTI's! The original formulation is tenofovir disoproxil fumarate (TDF), which had risks of nephrotoxicity and lowered bone mineral density. This was because TDF is a prodrug that is cleaved to active tenofovir in the plasma, and the active form can travel throughout the plasma to cause these effects. Tenofovir alafenamide (TAF) is a newer formulation. It is also a product but isn't cleaved until the lymphoid cells, so there is way less active tenofovir in the plasma, leaving a largely decreased risk of nephrotoxicity and osteopenia. Additionally TAF is able to be produced in a smaller tablet size.
TDF was still commonly used in the form of Truvada since this is the only FDA approved medication for HIV PrEP (pre-exposure prophylaxis). However, the newer version Descovy has been under review by the FDA for approval of HIV PrEP as well! While it's still not approved, an FDA advisory committee voted this week in favor of approving Descovy for HIV PrEP. However, the panel only voted for approval for use in men and transgender women. They did not vote in favor of approving Descovy for use in cisgendered women. This has been a controversial statement, but the FDA members stated that there is not enough clinical data for use in cisgendered women. This does not mean it will not be approved, this was just the vote of an advisory committee, but we will see if the FDA follows the decision of this advisory committee or instead votes to approve Descovy for HIV PrEP in ALL patients.
Jarred Prudencio, PharmD - https://www.instagram.com/ambcarerx
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