What to do about a drug addicted family member?

my sister is addicted to painkillers (takes multiple doses of oxycodone a few times a day) and has been taking painkillers for about three years now. she started at vicodin and has made her way up to oxycodone. if she runs out of painkillers she usually goes to the emergency clinic where they dope her up on a few injections of dilaudid or some other strong painkillers. and nobody seems to be doing anything about it. there's no talking to her about it as when i try to talk to her she sweeps it under the rug and acts like it is litterally not a problem at all, when obviously it's not nnormal to take such a high dosage of painkillers so often so many times a day. when she runs out she also complains about "join pains" or a "back ache" but even still, you do not need freaking OXY CODONE for those things. what do i do? she has a family and husband yet nobody seems to be doing anything about it