AW L2.3 Antivirals

Question 1

2 main types of antivirals

Answer 1

Adamantanes (M2 inhibitors)

Neuraminidase inhibitors

Question 2

Adamantanes e.g. (2)

Answer 2

Amantadine

Rimantadine

Question 3

Neuraminidase inhibitor examples

Answer 3

Oseltamivir

Zanamivir

Question 4

Amantadine mode of action

Answer 4

interfere with the function of the transmembrane domain of M2 protein of flu A

• interferes with viral assembly
• decreased no. of flu particles release

Question 5

What does M2 usually do

Answer 5

viral assembly during replication

Question 6

What age can you use amantadine from?

Answer 6

1 year

Question 7

Does amantadine work?

Answer 7

reduces the duration of illness by approximately 1 day

if administered within 2 days of onset

Question 8

How is amantadine admined?

Answer 8

Orally

Question 9

Does amantadine work for all flu?

Answer 9

No, only A - because it inhibits its replication

Question 10

Can we use amantadine for prophylaxis?

Answer 10

Yes

Question 11

Problems with amantadine:

Answer 11

• s/e and toxicity

- resistance (90% in the US)

Question 12

What is the difference between amantadine and ramantadine

Answer 12

Rimantadine launched as less toxic alternative but still has problems with resistance (similar structure and action)
- neither recommended by NICE

Question 13

What does NA do in a virus

Answer 13

catalyst to facilitate propagation/infection

Question 14

How do NA inhibitors work?

Answer 14

Competitive inhibitors at NA active site - obvs.

Question 15

Advantages of NA inhibitors

Answer 15

active against all strains of flu (A,B,C) and all serotypes

Question 16

Zanamivir is admin by

Answer 16

dry powder diskhaler

Question 17

Zanamivir is suitable from what age

Answer 17

7 years

Question 18

does Zanamivir work?

Answer 18

reduces duration of illness by one day
reduces symptoms
decrease viral shedding
(if admin within 48 hours of onset)

Question 19

BA of Zanamivir

Answer 19

10-20%

Question 20

t1/2 Zanamivir

Answer 20

2.5-5 hours

Question 21

Zanamivir excretion

Answer 21

unchanged by the kidney

Question 22

Zanamivir dose adjustments in renal impairment?

Answer 22

Nein, danke

Question 23

Oseltamivir also called

Answer 23

tamiflu

Question 24

Oseltamivir administration

Answer 24

orally

Question 25

Oseltamivir from what age

Answer 25

1 year

13 years for chemoprophylaxis

Question 26

Oseltamivir BA

Answer 26

Prodrug BA high

De-esterification to the active (Ba-80%)

Question 27

Oseltamivir t1/2

Answer 27

active drug 8-10 hours

Question 28

Oseltamivir dose adjustment in renal impairment

Answer 28

Ja

Question 29

Oseltamivir s/e

Answer 29

Nausea/vomiting (10%)
Headache
hypersensitivity

Question 30

Use vaccines for….

Use antivirals for…

Answer 30

seasonal

epidemics

Question 31

Seasonal influenza is usually a variant on the previous strain, good because (2)

Answer 31

• can predict likely strains

- people have partial immunity from previous strain

Question 32

The use of anti-viral drugs in non-risk groups is for….

Answer 32

symptom relief

Question 33

1st line pandemic drugs

Answer 33

NA inhibitors
role is life-saving rather than symptom relief
widely administered for prophylaxis