Used in the treatment of HIV and chronic hepatitis B infections. It is an antiviral prodrug that, once metabolized in the body, inhibits reverse transcriptase—an enzyme essential for viral replication. By blocking this enzyme, it reduces the amount of virus in the body, helping to slow disease progression and improve immune function. Commonly prescribed as part of combination antiretroviral therapy (ART), it offers improved oral bioavailability compared to tenofovir alone, allowing for lower doses and reduced kidney toxicity. Also used in pre-exposure prophylaxis (PrEP) to prevent HIV infection in high-risk individuals and to prevent mother-to-child transmission.