Teravir 300mg tablet tablet consists of the active substance called Tenofovir Disoproxil Fumarate, which belongs to the class of antiretroviral or antiviral medicine. This medicine treats HIV (human immunodeficiency virus) and HBV (hepatitis B virus) infections. It is a nucleotide reverse transcriptase inhibitor (NRTI) and works by inhibiting the enzymes (HIV reverse transcriptase; hepatitis B DNA polymerase) that are important for virus replication. It should always take in combination with other medicines to treat HIV infection. This tablet is suitable for the adult and adolescents aged from 12 to 18 years. For HIV, this medicine is given to adolescents who have already been medicated with other HIV medicines which are no longer fully effective due to resistance or have caused side effects. This tablet is not been studied in patients over 65 years of age.