Antivirals

Question 1

Zanamivir

Answer 1

Anti influenza
Inhibit neuramidase activity
This promotes virus aggregation (by preventing budding) and inhibits motility in the URT
Oseltamivir= prodrug

Question 2

Aciclovir

Answer 2

Anti herpes drug. Purine analogue
1) absorbed by cell. Phosphorylated by HSV thymidine kinase (confers specificity) -> cellular enzymes convert to aciclovir triphosphate -> competitively inhibits HSV DNA Pol
2) added to DNA instead of normal base. This makes DNA useless and inactivates DNA pol
Ganciclovir does the same but for CMV

Question 3

Nevirapine

Answer 3

Non nucleoside reverse transcriptase inhibitor (NNRTI)
Binds near catalytic site and denatures
Part of HAART therapy for AIDS

Question 4

Zidovudine (azidothymidine (AZT))

Answer 4

Nucleoside reverse transcriptase inhibitor (NRTI)
Activated by phosphorylation. Mimics thymidine.
This leads to direct inhibition of reverse transcriptase and incorporation of AZT into DNA (terminating DNA synthesis)
Often coadministered with hydroxyurea which potentiates by reducing the pool of other thymidines by inhibiting ribonucleotide Reductase

Question 5

Saquinivir

Answer 5

Blocks HIV protease
This enzyme is responsible for cleaving translated polypeptide to functional peptides.
Without this HIV units are not infectious

Question 6

Amantadine

Answer 6

Anti influenza A
Blocks M2 ion channel by stabilising closed state or blocking open state
Also interferes with haemagglutinin processing