Emtricitabine AIDS drug molecule. Computer model of a molecule of the AIDS (acquired immune deficiency syndrome) drug emtricitabine (marketed as Emtriva). Atoms are represented as spheres and are colour-coded; carbon (light blue), hydrogen (white), oxygen (red), nitrogen (dark blue), sulphur (yellow) and fluorine (green). Emtricitabine belongs to a class of drugs known as nucleoside reverse transcriptase inhibitors (NRTIs). It slows the spread of HIV (human immunodeficiency virus) in the body by inhibiting reverse transcriptase, the enzyme that converts HIV RNA (ribonucleic acid) into viral DNA (deoxyribonucleic acid) that can be incorporated into human cells. Emtricitabine is used in combination with other medications.