S9.1 Old And New Antivrials

Question 1

What are the stages of viral replication which antivirals can intervene?

Answer 1

Attachment to host
Penetration 
Uncoating - frees viral nucleic acid 
Replication - viral RNA formed 
Assembly of new virions
Release from cell

Question 2

What is the mechanism of aciclovir?

Answer 2

In HSV, DNA bases are phosphorylated by viral thymidine kinase (activates it) this inhibits viral DNA synthesis.
Aciclovir inhibits thymidine kinase allowing DNA synthesis

Question 3

What are the other types of anti-herpes drugs?

Answer 3

Valaciclovir - HSV
Cidofovir - CMV
Ganciclovir - EBV

Question 4

What are the ADRs of anti-herpes drugs?

Answer 4

Nephrotoxicity, possible CNS symptoms e.g confusion, headaches

Question 5

What is the mechanism and ADRs of neuraminidase inhibitors?

Answer 5

Eg oseltamivir, zanamivir
Neuraminidase needed for viral replication, these anti-influenza drugs block release of influenza virions from the host cell.
ADRs: H5N1 infection (bird flu)

Question 6

What is the mechanism and ADRs of amantadines?

Answer 6

Eg amantadine, rimantadine
Block M2 ion channel on influenza A virus inhibiting viral uncoating
ADRs: renal problems

Question 7

Summarise the HIV lifecycle

Answer 7

Virus binds and fuses to CD4+, penetrates cell inserts contents.
Reverse transcription: ss RNA to ds DNA.
Integrase combines virus and cell’s DNA in nucleus.
Transcription: proteins of viral DNA are made.
Virus pushes out of cell