Walsh & Hoyt: Therapy

Significant advances continue to occur in antiretroviral treatment and the prophylaxis and management of HIV-related opportunistic infections and malignancies. Several classes of antiretroviral medications target either the reverse transcriptase or protease enzymes of the virus. The nucleoside reverse transcriptase inhibitors (NRTI) include zidovudine (AZT), didanosine (ddI), zalcitabine (ddC), lamivudine (3TC), stavudine (d4T), and abacavir (ABC). These drugs are phosphorylated in infected cells to the active triphosphate form, which then inhibit HIV reverse transcriptase, thus preventing the formation of the double-stranded DNA that normally acts as the template for viral replication. There is one available nucleotide reverse transcriptase inhibitor, tenofovir (TDF). The nonnucleoside reverse transcriptase inhibitors (NNRTI) include nevirapine (NVP), delaviridine (DLV), and efavirenz (EFV). These drugs also act on the reverse transcriptase of HIV-1 (but not HIV-2). The protease inhibitors (PI) include saquinavir (SQV), indinavir, ritonavir (RTV), nelfinavir (NFV), and amprenavir (APV). These agents inhibit the enzymatic cleavage of the gag polyprotein required for the production of mature, infectious virions.