AW L2.3 Antivirals Flashcards
NA - neuraminidase (33 cards)
2 main types of antivirals
Adamantanes (M2 inhibitors)
Neuraminidase inhibitors
Adamantanes e.g. (2)
Amantadine
Rimantadine
Neuraminidase inhibitor examples
Oseltamivir
Zanamivir
Amantadine mode of action
interfere with the function of the transmembrane domain of M2 protein of flu A
- interferes with viral assembly
- decreased no. of flu particles release
What does M2 usually do
viral assembly during replication
What age can you use amantadine from?
1 year
Does amantadine work?
reduces the duration of illness by approximately 1 day
if administered within 2 days of onset
How is amantadine admined?
Orally
Does amantadine work for all flu?
No, only A - because it inhibits its replication
Can we use amantadine for prophylaxis?
Yes
Problems with amantadine:
- s/e and toxicity
- resistance (90% in the US)
What is the difference between amantadine and ramantadine
Rimantadine launched as less toxic alternative but still has problems with resistance (similar structure and action)
- neither recommended by NICE
What does NA do in a virus
catalyst to facilitate propagation/infection
How do NA inhibitors work?
Competitive inhibitors at NA active site - obvs.
Advantages of NA inhibitors
active against all strains of flu (A,B,C) and all serotypes
Zanamivir is admin by
dry powder diskhaler
Zanamivir is suitable from what age
7 years
does Zanamivir work?
reduces duration of illness by one day
reduces symptoms
decrease viral shedding
(if admin within 48 hours of onset)
BA of Zanamivir
10-20%
t1/2 Zanamivir
2.5-5 hours
Zanamivir excretion
unchanged by the kidney
Zanamivir dose adjustments in renal impairment?
Nein, danke
Oseltamivir also called
tamiflu
Oseltamivir administration
orally
