Antivirals

Question 1

What is the mechanism of action of Aciclovir?

Answer 1

It is a guanosine analogue which gets inserted into viral DNA. It therefore inhibits DNA polymerase and inhibits viral DNA replication

Question 2

Aciclovir is used in what viral diseases?

Answer 2

• Herpes simplex virus
• Varicella zoster
• Can be used either as treatment or prophylaxis

Question 3

What are the toxic effects of aciclovir?

Answer 3

• Relativley minimal however when used in high doses for HSV encephalitis it can cause renal tubular crystalosis or seziures.

Question 4

What are neuroaminidase inhibitors?

Answer 4

Drugs which prevent the action of neuroaminidase in viral budding. They are able to shorten the duration of influenza symptoms if given early in infection and can be post exposure prophylaxis

Question 5

What neuraminudase inhibitors are used in the UK?

Answer 5

• Oseltamivir (tablet)
• Zanamivir (inhaled)

Question 6

What drug is used in influenza A?

Answer 6

Amantadine

Question 7

what is the toxicity associated with neuraminidase inhibitors?

Answer 7

Usually well tolerated by can cause GI upset.
Probably safe in pregnancy and can use zanamivir as alternative to oseltamivir