Me [22 F] with my sister [25 F], she's addicted to drugs

Hello! I'm really sorry if this is messy or hard to read, I'm finding it hard to express my feelings clearly. I am re-posting this because I formatted the original post wrong.

I'm pretty sure my older sister Kate is addicted to cocaine. She always drank very heavily but for about a year now she has been doing drugs (cocaine, MDMA, ketamine, etc) a lot as well. To give you an idea of how much cocaine she does, the past two or three months she has been going out 4-5 times a week, either staying out all night or coming back at 6am. She's doing it with her boss, co-workers, and her boyfriend (who broke up with her last week because he didn't want to do so much cocaine). She is hardly sleeping since she has a full time job, has spent a lot of her savings, is losing weight, and the other day was complaining of stabbing pains in her brain. She says cocaine is her main hobby in life, she isn't addicted because it's "recreational" and she just does it for fun...

I am very worried and don't know how to help her, one of her friends had a seizure the other month from drugs and is still doing them. I moved out about three years ago whilst she is still living with our parents, so I only see her for a couple of days every few months (during which she is normally out or sleeping). My parents are very anti-drugs but also naive about what someone on drugs looks like. Telling them is not an option at the moment.

I was thinking of telling her that whilst she's still addicted I can't talk to her since my mini-interventions and begging her to stop hasn't worked. But I don't know if this would work and I don't want to upset her, I want to be there for her but it's just really hard watching her throw her life away, ruining relationships and her health. I convinced her to go to therapy because I suspect she has an underlying mental health issue - severely low self esteem, depression? I don't know.

What should I do? Have any of you managed to convince a loved one to give up drugs? Or do I just have to wait for her to get over it herself?

tl;dr: My sister is addicted to cocaine. Is there any way I can convince her to stop?