May 27, 2009 -- Question:What is the difference between Tamiflu and Relenza?
Answer:They're both effective antivirals to both prevent infection with swine flu virus, and to actually treat infection with swine flu virus. The differences are in how they're administered. Tamiflu is taken orally as a pill. Zanamivir is taken as an inhaler. The nature of the inhaler is that it's more difficult to use, and there are some contraindications, for example, in younger children, in pregnant women, and in people who have reactive airways disease. As a result of that, about 80 percent of the stockpiles that we have are Tamiflu, and only about 20 percent Relenza.
There's one potential advantage in addition to Tamiflu. There've been worldwide about 20 cases now discovered of swine flu that is resistant to Tamiflu. So in the event that something like that were to happen on a wider spread basis, that is, more and more Tamiflu resistance, then zanamivir would become the preferred drug.