Generic Atripla contains three active ingredients. Efavirenz is categorized under the family of drugs known as non-nucleoside reverse transcriptase inhibitors (NNRTIs). Emtricitabine and Tenofovir are classified under nucleoside reverse transcriptase inhibitors (NRTIs). These three drugs work to control and treat HIV infection. Generic Atripla works by reducing the viral load so that the immune system can start working better, preventing further secondary infections.