emtricitabine + tenofovir disoproxil fumarate + third agent

This is a **combination regimen** consisting of two nucleoside/nucleotide reverse transcriptase inhibitors (**NRTIs**): emtricitabine and tenofovir disoproxil fumarate, paired with a third agent (frequently a non-nucleoside reverse transcriptase inhibitor, integrase inhibitor, or protease inhibitor). - **Emtricitabine** is a synthetic nucleoside analog of cytidine; it inhibits HIV-1 reverse transcriptase, terminating viral DNA chain elongation[1][4]. - **Tenofovir disoproxil fumarate** is a prodrug of tenofovir (an acyclic nucleotide analog of adenosine monophosphate), which also inhibits HIV-1 reverse transcriptase through DNA chain termination upon incorporation into viral DNA[1][4]. - The **third agent** serves as a complementary antiviral mechanism (such as integrase inhibition, protease inhibition, or further reverse transcriptase inhibition). This regimen forms the foundation of highly active antiretroviral therapy (**HAART**) for HIV-1 infection and is also used for **pre-exposure prophylaxis (PrEP)** when the third agent is omitted or present as part of combined therapy[2][3][4]. This regimen is not curative, but it suppresses viral replication, preserves immune function, and reduces transmission risk.

Other names

emtricitabine plus tenofovir disoproxil fumarate plus third agent