ANTIVIRAL AGENTS FOR THE PREVENTION AND

TREATMENT ON INFLUENZA

Preventing and reducing the impact of influenza

• Good personal hygiene: good etiquette when coughing and sneezing, hand washing

• Protecting others by reducing exposure: staying at home when ill, reducing workplace contact, etc.

• Annual vaccination • Antiviral agents for prevention and treatment

Antivirals for influenza: Principles of use

• Vaccination is the primary method for the prevention of influenza

• Antivirals are useful for treatment of influenza and as a secondary means of preventing influenza

• Antivirals should be used where they have the greatest benefit

• Antivirals should be used responsibly in order to minimise the risk of emergence of drug resistance

• It is important that there is adequate availability of antivirals when required, including stockpiling for pandemic use

Influenza surface proteins

Neuraminidase

Hemagglutinin

RNA

M2 protein(only on type A)

Antiviral agents for influenza:two classes of drugs

• Matrix protein (M2) inhibitors– amantadine and rimantadine

– inhibit virus coating

– influenza A only

• Neuraminidase inhibitors– oseltamivir and zanamivir

– inhibit release of virus from infected cells

– active against all known strains of influenza

Antiviral agents for influenza

Class Drug Administration

M2 Inhibitors Amantadine Oral

Rimantadine Oral

Neuraminidase Inhibitors

Zanamivir Inhaled

Oseltamivir Oral

• They may be used to treat influenza but they should be given within 48 hours of developing symptoms.

• They act by decreasing the severity of illness and decreasing the duration of illness.

• An adjunct to influenza vaccine for controlling and preventing influenza but not a substitute for vaccination.

• Not effective in preventing or treating serious influenza-related complications (e.g. bacterial or viral pneumonia or exacerbation of chronic diseases).

Antiviral drugs for influenza

M2 inhibitors: Mechanism

Neuraminidase

Hemagglutinin

RNA

M2 protein(only on type A)

H+H+

H+

H+

X

M2 inhibitors

• M2 channel allows acidification of virus• Initiates uncoating of viral RNA• Allows viral replication• M2 inhibitors block this action

By courtesy of APACIAsia-Pacific Advisory Committee on influenzawww.apaci-flu.com