Its not a great movie but it describe really good how addict behave, how they lie to get a shot. That's only thing what worked in this movie. waiting for shot four days is not realistic. you don't need to be clean to have substitution treatment, and why they just didn't go to some cabins or camping or something like that for four days. many thing that not realistic in movie, but its a movie after all. But like I said, addict behavior is very well pictured in movie. its very much like that