Tenohep 300 is a prescription-only antiretroviral drug. It belongs to the class of Nucleoside Reverse Transcriptase Inhibitors (NRTIs). By inhibiting specific enzymes (like HIV reverse transcriptase and hepatitis B DNA polymerase), the medication blocks DNA synthesis, effectively decreasing the viral load in the blood while allowing the immune system to recover. It is not a cure for HIV or HBV, but limits the spread and damage of these viruses.