Bem, há um final alternativo, que está disponível no lançamento do DVD.
De Kotaku.com (há um vídeo do final alternativo no site):
In the theatrical version, Eddie has apparently managed to kick the brain-enhancing drug, although we're never entirely sure if he's grandstanding. After Robert De Niro threatens Cooper's new political career, Cooper basically goes full-blown superhero on him and tells him to piss off, because he doesn't need the fancy drug.
In this alternate version, the sentiment is still the same. But we think the underlying message is that Cooper has gone off the rails. Specifically with this line, "Who says I can't ask the drug how to get off the drug... Ask the drug to tell the drug to fuck itself." We know that the director might have been trying to show some sort of self restraint developed over time in Cooper, but honestly we think he's gone off into the deep end. Talk to the pills? No thanks.
Em TVTropes :
However, in the alternate ending of the film, things are less upbeat. In this ending, it turns out Eddie is still on NZT and his stash isn't going to last forever, which makes Carl's ownership of the supply a lot more threatening in the future. It ends with Eddie telling himself he needs to find a way to get off the drug.