I realize this is a crazy question, and I certainly wouldn’t want anyone (including myself) to try this at home. It’s just that I realized that, in its pure form, caffeine is a white powder and can, apparently, be purchased by the kilogram online.
So, what would happen if someone were to ingest 200 mg of caffeine by snorting it? Would this be any more dangerous than consuming that amount in the form of an energy drink or pill?
It would hit you a lot faster and all at once than it would if taken in pill or drink form. So, depending on the person’s tolerance for caffeine, it could result in anything from a pleasant rush to a racing heart, light-head/dizzyness, cold-sweats, and nausea.
I have tried this, or at least I was told that’s what it was. Not very pleasant - no euphoria, some sleeplessness, and an involuntary flickering of my eyelids.
You can snort pretty much anything that will be absorbed by mucosal membranes in your sinus cavity. See also this wikipedia article: Insufflation (medicine) - Wikipedia
In general drugs will hit you harder (even if their over all bioavaliability is lower) if snorted because they enter the bloodstream and get past the blood-brain barrier quicker.
Some pills I am prescribed are roughly double the strength when insufflated, so sometimes I do this.