TENOF 300MG contains tenofovir disoproxil fumarate which is an antiretroviral or antiviral medicine. It is a nucleotide reverse transcriptase inhibitor, generally known as an NRTI and works by interfering with the normal working of enzymes (in HIV reverse transcriptase; in hepatitis B DNA polymerase) that are essential for the viruses to reproduce themselves. It is used with other antiviral medicines to manage Human Immunodeficiency Virus (HIV) in adults and children 2 years of age and older. HIV is the virus that causes the AIDS (Acquired Immune Deficiency Syndrome).