Supposing you had a syringe filled with the same amount of caffeine as a cup of coffee, and injected it into your blood stream, what would happen medically?

Get it all at once ?: I've had the temptation to do this at starbucks once when the line was too long. You'd likely have supraventricular tachycardia with palpitaions, break out into a sweat, get nauseated, throw up and tbe made to clean up the mess. After you recover from being dizzy you'd probably get a headache and feel awfull for the rest of the day. Better to just order the latte with an extra shot of espresso.