What Are Tamiflu And Relenza?

May 27, 2009 -- Question:What are Tamiflu and Relenza?

Answer:There are two different antiviral medications that can be used to treat swine influenza. One is called oseltamivir, or also known as Tamiflu, and the other is known as zanamivir, also known as Relenza. Both of those are what are called neuraminidase inhibitor medications. They work by preventing the release of infectious influenza virus from the cells, effectively stopping the infection. It is given primarily for swine influenza when and if the symptoms are severe enough to warrant hospitalization or medical care. In part that recognizes a reality and that is we don't want to use all of the stockpiles of these antivirals up for what is otherwise going to be very mild symptoms or very mild illness.

Hence reserving them based on CDC's recommendation to save it for people who have more severe infections or who have complications from that infection or are hospitalized. The difference is primarily in administration of the two drugs. Tamiflu is taken as a tablet orally and zanamivir is taken as an inhaled medication making it a little more difficult for some people to use that medication.

There is an important piece though that I think needs to be discussed and that's the fact that the circulating seasonal H1N1 viruses are resistant to Tamiflu but still susceptible to zanamivir. And that's likely to cause some confusion as we come to this fall and winter and have all of these viruses co-circulating.