Antiviral drugs-Other

Question 1

What are examples of other antiviral drugs?

Answer 1

Oseltamvir
Nirmatrelvir
Tenofovir
Efavirenz
Atazanavir

Question 2

What are common indications of antivirals

Answer 2

1. Flu/COVID to reduce illness duration and severity
2. PreP and PEP against HIV and flu if unvaccinated
3. Chronic treatment to suppress viral load in Hep B/C or HIV infection to reduce morbidity, mortality and onward transmission

Question 3

What is the mechanism of OSELTAMVIR and ZANAMIVIR?

Answer 3

Inhibits neuraminidase a viral surface enzyme needed for entry into and release from host cells

Question 4

What is the mechanism of action of molnupiravir and remdesivir?

Answer 4

Nucleotide analogues that block viral RNA synthesis

Question 5

What is the mechanism of action of NIRMATRELVIR?

Answer 5

A protease inhibitor that inhibits viral replication.

Question 6

What are mild and self limiting side effects?

Answer 6

GI upset
Skin reaction
dizziness
sleep problems

Question 7

What is a side effect specific to Zanamivir?

Answer 7

bronchospasm

Question 8

What are important Side effects?

Answer 8

immune-mediated;
hepatitis
blood dycrasias
severe skin reactions

long term- hyperglycaemia, weight gain, increased risk of CVD.

Question 9

Who should be prescribed with caution

Answer 9

patients with COPD or asthma w/ zanamivir inhaled.

NNRTIs and protease inhibitors are contraindicated in ✖ acute porphyria and should be used with caution in those at risk of ▲ QT prolongation.

Question 10

What are important positive interactions of ritonavir?

Answer 10

Ritonavir and cobicistat have a beneficial interaction with protease inhibitors.

By inhibiting enzymes that metabolise them, they smooth peaks and troughs in antiviral drug concentration

reduce dosing frequency (‘pharmacokinetic boosting’).

Question 11

What is dose for each indication?

Answer 11

Flu;
Oseltamvir= 75mg
zanamivir= 10mg inhaled

BD for treatment 5 days
OD for prevention 10 days

Question 12

What should be prescribed concurrently with zanamivir and why

Answer 12

A short-acting bronchodilator (e.g. β2 agonist) should be available in case of bronchospasm when inhaled

Question 13

How should the dosing be prescribed and why

Answer 13

at equal dosage intervals

to avoid periods of subtherapeutic drug concentration.

Question 14

Why is adherence particularly important for HIV treatment/ prophylaxis

Answer 14

As the virus can quickly change and become resistant to the drugs.

Ensures viral load stays low/ undetectable