Antiviral drugs for influenza are available in some countries and effectively prevent and treat the illness. There are three classes of such medicines:

  1. The adamantanes, amantadine and rimantadine, act by binding to the M2 proton channel and blocking proton transport across the membrane. (Erhard van der Vries. et al Advances in Pharmacology, Volume 67, 2013, Pages 217-246)
  2. The neuraminidase inhibitors, oseltamivir and zanamivir, that frees viruses from the infected cells surface. (What is the difference between Xofluza and Tamiflu? )
  3. Baloxavir marboxil that inhibits the endonuclease activity of the polymerase acidic protein found in influenza virus to ultimately inhibit virus replication. (Ng KE. P T. 2019;44(1):9-11. )

When should antiviral treatments be used?

Treatment with antiviral medication for seasonal influenza should only be considered where there is a reasonable probability that a person has been exposed to the influenza virus. People who are at high risk of serious complications from influenza, especially elderly patients and people with underlying chronic medical conditions and their close contacts, may benefit most from antiviral medications. Antiviral treatments have been shown to reduce the severity and duration of illness of seasonal influenza in otherwise healthy adults if given early in the course of the illness (within 48 hours of developing symptoms)

Resistance

Some influenza viruses develop resistance to the antiviral medicines, limiting the effectiveness of treatment. The World Health Organization (WHO) monitors antiviral susceptibility in the circulating influenza viruses.

WHO Antiviral use and the risk of drug resistance (English)
WHO Antiviral use and the risk of drug resistance (Chinese)

 

(Updated 13 August 2020)