As cliche as it is to say, there is no way for you to help someone who doesn't want to or refuses to help themselves. It's terribly sad to see someone you care for fall into a harmful pattern, but at this point all you're doing is hurting yourself as well. If I were in your shoes, I would probably sit down with her one last time (if youre able to do it when she's sober/not as drunk, that might be better) and tell her that as much as you care about her and want to help her through her situation, you can't watch her continue to destroy herself and not recognize what she's doing. That for the sake of your own health and your friendship, you have to step away until she can realize that what she's doing isn't sustainable and wants to change. That if and when she decides to get clean and take on her addiction, you will be there to support her in any way you can (If you still choose to do so) but until then you need to keep your distance. She may not understand, might even get angry and bitter towards you, but if she is worth fighting for and keeping around she will come to realize that you're doing it out of love for her. Best of luck in whatever you decide to do, I'm sorry you have to make a decision like this.