<prompt> All of the following drugs are protease inhibitors except-NelfinavirSaquinavirAbacavirRitonavir  <response>: Ans. is c i.e., Abacavir Antiretroviral drugs a Nucleoside reverse transcriptase inhibitors NIs - Zidovudin, Didanosine, Zalcitabine, Stavudine, Larnivudine, Abacavir. b Nucleotide reverse transcriptase inhibitor Tenofovir Katzung I Othe c Nonucleoside reverse transcriptase inhibitors NNIS - Nevirapine, Eirenz, Delavirdine, Etravirine Rilpivirine. d Protease inhibitors - Ritonavir, Indinavir, Nelfinavir, Saquinavir, amprenavir, Lopinavir, Fosamprenavir, Atazanavir, Darunavir, Tipranavir. e Fusion inhibitor - Enfuviide, Maraviroc. f Integrase inhibitors - Roltegravir, Elvitegravir. 