You can't make someone change, i'm all for compassion but a junkie is a junkie anyway you look at it. I don't think I'm gonna "save" them.
You can only help yourself.
Strongly agree balzac, sadly i had an ex addicted to crack and blow, after many failed attempts at begging, yelling, crying i finaly just left, it sucked cause i had been with this guy over 5 years. I blamed myself because We went down to New Brunswick for xmas 2000 and he asked if he could do some blow. I reluctantly said yes but only because it was the holidays, when we got back it took him a few weeks and he was addicted. Lat year i got the call i knew would come from his mom, he had overdosed and passed away. Having to bury someone i thought i would marry sucked but it was all because of the choices he made.
Just be a good friend and tell them how you feel, i'm not so sure about handing out needles, seems kinda like helping them, but i get wanting to prevent them from getting sick.
I hope your friends smarten up, if not maybe you should find new friends buddy, sorry man i know it sucks