What Is Tamiflu?

Last Editorial Review: 1/11/2018

Ask the experts

I've heard there's a drug that can prevent flu. It's called something Tammyflu. What's the story?

Doctor's response

You're asking, I think, about Tamiflu.

Influenza immunization, that is the flu shot, is still the main means to prevent the flu. As an alternative, the antiviral agents amantadine (brand name: Symmetrel) and rimantadine (Flumadine) have been given to prevent the disease in high-risk situations but their usefulness has been limited by their side effects on the central nervous system, by the rapid emergence of resistant viruses during treatment, and by their ineffectiveness against influenza B infections.

Oseltamivir (Tamiflu) is the first oral agent in a new class of influenza drugs. It has been tested in the U.S. The drug acts by inhibiting the enzyme neuraminidase on the surface of the influenza A and B viruses. This enzyme is the key to unlocking virus from the surface of infected cells and liberating it so it can go to other cells. Inhibit the enzyme and the virus cannot spread.

The US Food and Drug Administration (the FDA) has given its approval to Tamiflu.

Tamiflu appears to have less potential than amantadine (Symmetrel) or rimantadine (Flumadine) for inducing resistance which is very good and to be associated with fewer major side effects which is also obviously to the good. However, the downside is that Tamiflu is likely to cost more.


The New England Journal of Medicine 1999;341:1336-1343, 1387-1388.