Do you know what kind of drugs the others are using?
I understand where you are coming from. At that age people are quite impressionable and vulnerable to peer pressure. I wasn’t but a lot of my friends were. I would suggest that you do what you can to work on your relationship as a whole and try to do anything to boost her confidence etc… so she is better able to advocate for herself and not submit to peer pressure should she continue to associate with these people at university and possibly end up living with them.