Emtricitabine/tenofovir/efavirenz (INNs trade names Atripla ® Viraday ®) is a fixed-dose combination drug for the treatment of HIV infection. It combines Gilead Sciences’s tenofovir and emtricitabine (already available in the anti-HIV combination Truvada ®) with Merck & Co’s efavirenz into a fixed-dose pill.