Emivirine (also known as MKC-442) is an investigational non-nucleoside reverse transcriptase inhibitor (NNRTI) developed for the treatment of HIV infections. It targets the reverse transcriptase enzyme of the virus to inhibit replication, thereby reducing viral load and slowing disease progression. Although clinical development was discontinued in the early 2000s due to efficacy and safety concerns, it has been studied in combination therapy regimens to improve outcomes and reduce drug resistance. Emivirine remains of interest in research for managing HIV/AIDS, especially in cases resistant to other NNRTIs, and is available as a research chemical for laboratory use.