There are vast amounts of references to drugs throughout Neuromancer. It seems they have everything from neurotoxins to awareness boosters in every sense we do now, except considerably more accessable.
The story begins with Case being poisoned [by a drug] and trying to recover from that mess so that he can get back on the matrix to re-live his glory days as a console cowboy. To fix this mess, he goes through some procedures to have the majority of the toxin removed. A simple fix for an elaborate problem, I suppose?
Before all of this mess, Case seemed to be a pretty heavy drug user, dealing with all sorts of wonderful things that can kill the average man with unwatched doses. He's done so much that his organs are starting to fail with irreperable damage. What's the cure? Replacement. However, his new organs were modified in such a way that he was made immune to the effects of the drugs he had previously used. Therefore, there was no reason for him to be taking any of those drugs, as they wouldn't have any effect on him in the future.
I know drug use is pretty serious in some areas now, but will we really get to the point that Neuromancer portrays? What about those who are heavily addicted to things now? I used to smoke pretty heavily for a few years and it's taken me quite a bit of effort to kick the habit. I admit I still have trouble some days and I'm on the verge of beginning again. Perhaps I could just go have some lung surgery done and have my replaced with ones that block out nicotine and remove all the addictive effects of cigarettes? Could those dealing with heavy alcohol addictions simply get a new system that'll nullify the effects of alcohol or prevent it from seeping into the bloodstream?
This presents an interesting (and probably costly) alternative that may be developed sometime in the future, fictional or otherwise. I'm sure at some point we'll be able to grow organs back, prolonging our lives even further than they were originally meant to be. Is this the future we seek, one similar to Gibson's Neuromancer where drugs are abundant, organs are renewable/replacable, and all of the above is considered normal?
Personally, I'd rather live a short but good life than a long and traumatic one... but perhaps that's just me.