Antiviral mechanisms

Question 1

Aciclovir

Answer 1

Inhibits DNA polymerase (nucleoside analogue)

used in HSV, VZV

Causes crystalline nephropathy

As going up Herpesvirus 1-2-6-7-8 etc need higher doses to kill

Question 2

Ganciclovir

Answer 2

Inhibits DNA polymerase

used in CMV

Causes myelosupression/agranulocytosis

Question 3

Ribavirin

Answer 3

Guanosine analogue which inhibits inosine monophosphate dehydrogenase to interfere with capping of viral mRNA

Used in Hep C and Ribavirin

Causes haemolytic anaemia

Question 4

Oseltamivir

Answer 4

Neruaminidase inhibitor - prevent release/budding of new virions

used in Flu A and B

Question 5

Amantadine

Rimantadine

Answer 5

M2 inhibitor
Blocks uncoating

For Flu A only

Question 6

Interferon

Answer 6

blocks mRNA translation somehow

Not too well understood

Question 7

Why give valaciclovir over aciclovir?

Answer 7

Better bioavailability

Famciclovir even higher bioavaiability

Question 8

Foscarnet

Answer 8

Phosphorylate analogue- inhibits DNA polymerase

Use in CMV retinitis in HIV
HIV patients with aciclovir resistant HSV