Anti-HIV agents to be used in drug combination regimens

Antiviral therapy and, particularly, anti-HIV therapy has definitely come of age [1]. There are now more than 30 compounds that have been formally approved for the therapy of virus infections. The nucleoside reverse transcriptase inhibitors (NRTIs) zidovudine, didanosine, zalcitabine, stavudine, lamivudine and abacavir are used in the treatment of human immunodeficiency virus (HIV) infections and lamivudine is also licensed for the treatment of hepatitis B virus (HBV) infections. The nucleotide reverse transcriptase inhibitor (NtRTI) tenofovir has been approved for the treatment of HIV infections and is also effective againstHBVinfections. The non-nucleoside reverse transcriptase inhibitors (NNRTIs) nevirapine, delavirdine and efavirenz are exclusively used in the treatment of HIV infections, and so are the HIV protease inhibitors (PIs) saquinavir, ritonavir, indinavir, nelfinavir, amprenavir and lopinavir.