Long story short, I decided to take 200 mg caffeine pills to help me stay awake. I ended up taking 1200 mg within a one hour time span. After the first 200-400 mg I was feeling pretty alert and even euphoric. But after the 1200 mg of caffeine had fully absorbed into my body I started to feel bad. I began to feel nauseous and even more weaker and tired than I had before I took the caffeine in the first place. I ended up throwing up all day and all night and felt like I was going to die. I was so dehydrated and delirious and weak that I literally could not move my body. After vomiting numerous times and still not feeling better, I ended up going to the hospital where I vomited some more and was intravenously filled with antiemetic drugs. The drugs helped a lot with my nausea but I was still feeling pretty nauseous and terrible. After spending about 4 hours in the hospital I was discharged and went home where I slept for about 12 hours. When I woke up I was feeling perfectly fine again. I hadn’t eaten or drank anything in over 24 hours, so you can imagine it was heaven when I guzzled down some ice cold sweet Gatorade.
The moral of the story: don’t take too much caffeine. If you plan on supplementing with caffeine to stay awake and alert don’t take more than 200-400 mg at once. That is more than enough to keep you awake for 3-5 hours or so.
Also, some fun facts on caffeine (from http://coffeefaq.com/site/node/12):
The LD_50 of caffeine (that is the lethal dosage reported to kill 50% of the population) is estimated at 10 grams for oral administration. As it is usually the case, lethal dosage varies from individual to individual according to weight. Ingestion of 150mg/kg of caffeine seems to be the LD_50 for all people. That is, people weighting 50 kilos have an LD_50 of approx. 7.5 grams, people weighting 80 kilos have an LD_50 of about 12 grams.
In cups of coffee the LD_50 varies from 50 to 200 cups of coffee or about 50 vivarins (200mg each).
One exceptional case documents survival after ingesting 24 grams. The minimum lethal dose ever reported was 3.2 grams intravenously, this does not represent the oral MLD (minimum lethal dose).
In small children ingestion of 35 mg/kg can lead to moderate toxicity. The amount of caffeine in an average cup of coffee is 50 - 200 mg. Infants metabolize caffeine very slowly.