I am an opiate addict and I can't relate to Requiem at all. Panic hit home though.

I agree, in that the film doesn't romanticize heroin addiction, nor does it engage in ham-fisted moralizing about the subject matter.
Panic in Needle Park
is almost documentary-like: it approaches its characters as case studies.
A lot of people compare this film to
Requiem for a Dream
, where the film-maker's camera tricks and artistry make addiction seem stylized and abstract rather than gritty. Both are good films, but this one is probably more honest.

I would agree with you that this film is a masterpiece that portrays heroin addict extremely accurately; the only film that I'd say does it better is Christiane F. This is coming from a recovered addict as well, just so you know that I'm not spouting nonsense, haha.

yea they did a killer job of they're portrayal
"You are the imagination of yourself"-bill hicks

It was sure hard to watch. That first scene with the male addict and the close-up of the bloody needle eeeeek! Had me squirming.