Ignoring this would be absolutely the worst thing you can do.

In my opinion, you have two action items here.

First, you need to keep your meds where ONLY you can get at them. You cannot and should not leave your meds out knowing that your brother is taking them. Not good for you and not good for him. Those meds are prescribed to you and you alone.

Secondly, it sounds like your brother is very likely addicted to pain medication and if so, he needs professional help, which is even more necessary because of the abusive relationships he has/is experiencing. Someone in your family should talk to him about this in a non-confrontational manner; it can be done. It doesn't have to be done by you if you are uncomfortable with the discussion. Search on the web for tips about how to handle this (I've included a few links below; there are hundreds of web related resources) or talk to your doctor, psychologist, clergy etc. for help in this. Your brother needs help with this; most people cannot deal with addiction on their own.

http://www.hazelden.org/web/public/whatcanisay.page

http://www.drug-addiction-support.or...on-family.html

http://www.drugalcoholaddictionrecovery.com/?p=107