How can I talk to my friends about an addiction?

I have a cocaine addiction, I need to talk to my friends about it but the problem is, one of my friends mother and father died from the very same addiction. I watched his mother slowly and painfully die. I can’t figure out a way to bring up a touchy subject like this. Can anyone help me out?
I thought I should mention this one, I already have been through rehab for alcoholism. Witch kind of complicates things for me a little bit more.

More Meth Drug Addiction Info: