What to do about my mom?

My mother is a bad mom. Believe me i do not say this lightly. For as long as i can remember she has been hooked on one drug or another and has a serious problem with alcohol. I constantly get calls from my sisters saying that she got into a bar fight or something to that nature, and its killing me. My sisters and I have tried about everything to help her including but not limited to talking to her, cutting her off completly, getting her sent to a mental health facility, getting her arrested, but no matter what we do it never changes. Now she is about to be 44 if she makes it to that age and I am affraid she is going to kill herself at this rate. It sickens me to think that she will not change but i really just dont know what to do. please help