Tenofovir alafenamide (abbreviated TAF, common brand names Hepbest, Teravir) is an antiviral drug of the nucleotide reverse transcriptase inhibitor (NtRTI) group used to treat chronic hepatitis B virus infection in adults and children over 12 years old. TAF prevents the hepatitis virus from multiplying in the body, thereby helping to reduce liver damage and control the disease.