Infection: Influenza

Question 1

The current antivirals on the market for influenza are most effective for treatment if started when?

Answer 1

Within a few hours of the onset of symptoms, they are licensed for use within 48 hours of the first symptoms.

Oseltamivir and zanamivir.

Question 2

What are the two drugs which are licensed for use within 48 hours of the first symptoms of influenza?

Answer 2

Oseltamivir and zanamivir are most effective for the treatment of influenza if started within a few hours of the onset of symptoms; they are licensed for use within 48 hours of the first symptoms.

Question 3

In otherwise healthy patients, oseltamivir or zanamivir can reduce the duration of symptoms by about how long?

Answer 3

1-1.5 days.

Question 4

Oseltamivir and zanamivir are licensed for post-exposure prophylaxis of influenza when influenza is circulating in the community.

Oseltamivir should be given within __ hours of exposure to influenza while Zanamivir should be given within __ hours of exposure to influenza.

Answer 4

Oseltamivir and zanamivir are licensed for post-exposure prophylaxis of influenza when influenza is circulating in the community. Oseltamivir should be given within 48 hours of exposure to influenza while zanamivir should be given within 36 hours of exposure to influenza.

Question 5

There is evidence that some strains of influenza A virus have reduced susceptibility to which antiviral?

Answer 5

Oseltamivir, but may retain susceptibility to Zanamivir.

Question 6

The use of Zanamivir should be reserved for when?

Answer 6

The use of Zanamivir should be reserved for patients who are severely immunocompromised, or when oseltamivir cannot be used, or when resistance to oseltamivir is suspected.

For those unable to use the dry powder for inhalation, zanamivir is availabe as a solution that can be administered by nebuliser or intravenously [unlicensed].

Question 7

What NMDA receptor antagonist is licensed for prophylaxis and treatment of influenza A but is no longer recommended?

Answer 7

Amantadine.

Question 8

Can oseltamivir be used in children under 1 years of age?

Answer 8

Data on the use of oseltamivir in children under 1 year of age is limited. Furthermore, oseltamivir may be ineffective in neonates because they may not be able to metabolise oseltamivir to its active form. However, oseltamivir can be used (under specialist supervision) for the treatment or post-exposure prophylaxis of influenza in children under 1 year of age. The Department of Health has advised (May 2009) that during a pandemic, treatment with oseltamivir can be overseen by healthcare professionals experienced in assessing children.