Non-nucleoside reverse transcriptase inhibitors
(NNRTIs) - These drugs are direct, non-nucleoside inhibitors of HIV-1 reverse transcriptase. Combinations of an NNRTI with NRTIs tend to be at least additive in reducing HIV replication in vitro. HIV isolates that are resistant to NRTIs and protease inhibitors remain sensitive to NNRTIs, but cross-resistance is common within the NNRTI class. Resistance to NNRTIs develops rapidly if they are used alone or in combinations that do not completely suppress viral replication.