First came ddI and ddC, followed by D4T and 3TC.    From Wordnik.com.  [Targeting A Deadly Scrap Of Genetic Code] Reference

1992 ddC (HIVID).    From Wordnik.com.  [The End Of Aids?] Reference

AZT (ZDV, zidovudine, Retrovir®) ddI (didanosine, Videx®) ddC (zalcitabine, Hivid®) d4T (stavudine, Zerit®) 3TC (lamivudine, Epivir®).    From Wordnik.com.  [Antiretroviral Medications] Reference

APV - amprenavir, SQV - saquinavir; NRTIs: 3TC - lamivudine, ddI - didanosine, ABC - abacavir, ddC - zalcitabine, ZDV - zidovudine, TDF - tenofovir, d4T - stavudine; NNRTIs: DLV - delavirdine, NVP - nevirapine, EFV - efavirenz).    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference