<prompt> Which of the following is not an antiretroviral drug: March 2009LamivudineZidovudineGanciclovirNevirapine  <response>: Ans. C: Ganciclovir Antiretroviral ARV drugs are broadly classified by the phase of the retrovirus life-cycle that the drug inhibits. Nucleoside and nucleotide reverse transcriptase inhibitors NI inhibit reverse transcription by being incorporated into the newly synthesized viral DNA and preventing its fuher elongation Zidovudine, Didanosine, Zalcitabine, Stavudine, Lamivudine, Abacavir Non-nucleoside reverse transcriptase inhibitors NNI inhibit reverse transcriptase directly by binding to the enzyme and interfering with its function Nevirapine, Eirenz, Delavirdine Retroviral Protease inhibitors PIs target viral assembly by inhibiting the activity of protease, an enzyme used by HIV to cleave nascent proteins for final assembly of new virons Ritonavir, indinavir, Nelfinavir, Saquinavir, Amprenavir, Lopinavir Entry inhibitors or fusion inhibitors interfere with binding, fusion and entry of HIV-1 to the host cell by blocking one of several targets. Maraviroc and enfuviide are the two currently available agents in this class. Ganciclovir is an anti-herpes drugs. 