Might be just a local or regional thing up here but my local big box pharmacy is carrying Coca-Cola infused with Caffeine and in enough of a percentage that you can taste it! So you brew up a cup of Joe and dump the Cola-caffiene in it and badda-boom/badda-bing you've about doubled the caffiene you're about to ingest.
Best stuff ever was an Aussie product called JOLT Cola. Twice the caffiene and three times the sugar of normal. Three cans of that you are guaranteed to be awake for 24+ hours and twitchin' and jivin' for most of it. Haven't seen it in decades and kind of miss it...........Hee, Hee, Hee, Hee, Hee, Hee. Hee, Hee....................................🤣
Nick