Several 2′,3′-dideoxynucleosides and 2′,3′-didehydro-2′,3′-dideoxynucleosides have been used for the treatment of patients with human immunodeficiency virus (HIV). These nucleosides, in their 5′-triphosphate form, inhibit the polymerization of proviral DNA facilitated by HIV reverse transcriptase. 2′,3′-Dideoxynucleosides that are FDA-approved for clinical use include 2′,3′-dideoxycytidine (ddC), 2′,3′-dideoxyinosine (ddI) and ...