Efavirenz. Molecular model of the drug efavirenz (C14.H9.Cl.F3.N.O2). This drug, sold under the brand name Sustiva, is a non-nucleoside reverse transcriptase inhibitor (NNRTI). It is used as part of highly active antiretroviral therapy (HAART) for the treatment of a human immunodeficiency virus (HIV) type 1. Atoms are represented as spheres and are colour-coded: carbon (grey), hydrogen (white), nitrogen (dark blue), oxygen (red), chlorine (green) and fluorine (light blue).