I remember him well too, but lost track of him after his loss to Julio Cesar Chavez in 1987. I remember watching his fights in 1986 with Camacho and Livingstone Bramble. He kept on fighting and mixed in some fine wins with disappointing losses:

http://boxrec.com/boxer_display.php?boxer_id=610

There's a good biography of him here:

http://en.wikipedia.org/wiki/Edwin_Rosario

I didn't know anything about his drug problems, only his battles in the ring.