MOA - Antivirals Flashcards
What is the mechanism of Acyclovir?
an acyclic nucleoside analogue of deoxyguanosine that is selectively phosphorylated by the virus-encoded thymidine kinase to its monophosphate form. Cellular enzymes then convert the monophosphate to the active antiviral acyclovir triphosphate, which competitively inhibits viral DNA synthesis by inactivation of viral DNA polymerase and incorporation into and termination of viral DNA replication. Acyclovir has potent activity against HSV I and II and HZV (VZV).
What is the mechanism of Atazanavir?
binds to the site of HIV-1 protease activity and inhibits cleavage of viral Gag-Pol polyprotein precursors into individual functional proteins required for infectious HIV. This results in the formation of immature, noninfectious viral particles.
What do Elbasvir and Grazoprevir do?
inhibits HCV NS5B RNA-dependent RNA polymerase, essential for viral replication. Grazoprevir inhibits NS3/4 protease, which cleaves the HCV polyprotein into mature forms and is required for replication.
What is the function of Efavirenz?
binds to HIV reverse transcriptase, blocking the RNA-dependent and DNA-dependent DNA polymerase activities including HIV-1 replication.
What is the role of Emtricitabine/Tenofovir?
a cytidine analogue while tenofovir is an analogue of adenosine 5’-monophosphate. Each drug interferes with HIV viral RNA-dependent DNA polymerase resulting in inhibition of viral replication.
How does Entecavir work?
intracellularly phosphorylated to guanosine triphosphate which competes with natural substrates to effectively inhibit HBV polymerase; enzyme inhibition blocks reverse transcriptase activity thereby reducing viral DNA synthesis.
What do Glecaprevir and Pibrentasvir target?
inhibits hepatitis C virus NS5B RNA-dependent RNA polymerase, essential for virus replication. Glecaprevir inhibits NS3/4 protease, which cleaves the hepatitis C virus polyprotein into mature forms and is required for replication.
What is the mechanism of Maraviroc?
selectively and reversibly binds to chemokine CCR5 coreceptors on CD4 cells. CCR5 antagonism prevents interactions between human CCR5 coreceptor and gp120 subunit of viral envelope glycoprotein, inhibiting gp120 conformational change required for CCR5-tropic HIV-1 fusion with CD4 cell and subsequent cell entry.
What does Oseltamivir inhibit?
an inhibitor of influenza virus neuraminidase, which prevents viral progeny detaching from the cellular envelope.
How does Raltegravir function?
inhibits the catalytic activity of HIV-1 integrase, thus preventing integration of the viral DNA into the host strand.
What is the mechanism of Sofosbuvir?
a direct-acting antiviral agent against the hepatitis C virus. It inhibits HCV NS5B RNA-dependent RNA polymerase, essential for viral replication, and acts as a chain terminator.
What is Valacyclovir?
a prodrug of acyclovir. Acyclovir is an acyclic nucleoside analogue of deoxyguanosine that is selectively phosphorylated by the virus-encoded thymidine kinase to its monophosphate form. Cellular enzymes then convert the monophosphate to the active antiviral acyclovir triphosphate, which inhibits viral DNA synthesis by incorporation into viral DNA, resulting in chain termination. Acyclovir has potent activity against herpes simplex virus (HSV) 1 and 2 and varicella-zoster virus (VZV).
