NNRTIs (Non-Nucleoside Reverse Transcriptase Inhibitors) are a class of antiretroviral drugs used to treat HIV infections. Common members include nevirapine and efavirenz. These drugs inhibit viral replication by binding to the inactive site of HIV reverse transcriptase, blocking its catalytic activity. NNRTIs do not require phosphorylation for activation and directly interact with the enzyme. They primarily function within cells, inhibiting the transcription of viral RNA into DNA. Resistance to NNRTIs in HIV is mainly caused by point mutations in the reverse transcriptase gene.