Det aktive stof i Telzir, fosamprenavir, er et "prodrug" (et forstadium) for proteasehæmmeren amprenavir, hvilket betyder, at det omdannes til amprenavir i kroppen.
The active substance in Telzir, fosamprenavir, is a ‘ prodrug ’ of the protease inhibitor amprenavir, which means that it is converted into amprenavir in the body.