Mechanism of action<unk>  is a nucleotide analog reverse-transcriptase inhibitor (NtRTI). It selectively inhibits viral reverse transcriptase, a crucial enzyme in retroviruses such as human immunodeficiency virus (HIV), while showing limited inhibition of human enzymes, such as DNA polymerases α, β, and mitochondrial DNA polymerase γ. In vivo<unk>  fumarate is converted to<unk> , an acyclic analog of deoxyadenosine 5'-monophosphate (dAMP).<unk>  lacks a hydroxyl group in the position corresponding to the 3' carbon of the dAMP, preventing the formation of the 5′ to 3′ phosphodiester linkage essential for DNA chain elongation. Once incorporated into a growing DNA strand,<unk>  causes premature termination of DNA transcription, preventing viral replication. Pharmacokinetics<unk>  is a prodrug that is quickly absorbed from the gut and cleaved to release<unk> . Inside cells,<unk>  is phosphorylated to<unk>  diphosphate (which is analogous to a triphosphate, as<unk>  itself already has one phosphonate residue), the active compound that inhibits reverse transcriptase via chain termination. In fasting persons, bioavailability is 25%, and highest blood plasma concentrations are reached after one hour. When taken with fatty food, highest plasma concentrations are reached after two hours, and the area under the curve is increased by 40%. It is an inhibitor of cytochrome P450 1A2.<unk>  is mainly excreted via the kidneys, both by glomerular filtration and by tubular secretion using the transport proteins OAT1, OAT3 and ABCC4. Detection in body fluids<unk>  may be measured in plasma by liquid chromatography. Such testing is useful for monitoring therapy and to prevent drug accumulation and toxicity in people with kidney or liver problems.
Tenofovir disoproxil
Tenofovir alafenamide
Rilpivirine
Brincidofovir
Daclatasvir
Cidofovir
Telbivudine
Sorivudine