OOPS! My bad! I had a major brain fart there and confused yazmin with something else that is OTC. However, your friend might still be at risk for pregnancy. She should run this question by the doctor who prescribed the pills.
If yasmin really worked, don't you think it would be a commonly sold, very popular item? NO form of contraception is 100% reliable other than abstinence. Even the birth control pill can fail, although it is the most reliable thing out there. So yes, I suspect your friend is at risk of being pregnant.