Caffeine: 3 energy drinks worth. Main ingredient. Not much. You'd likely get a very fast heart rate and high blood pressure. It wouldn't hurt unless you have pre-existing cardiovascular conditions. Then you might get cardiac arrest. Otherwise you'll be irritable, anxious...the stuff you get from downing 3 energy drinks in a day. You might get nauseous if you're not a coffee drinker or be unable to sleep.

Vitamin B: Nothing. Overdose threshold is incredibly high and it's likely just there to make it not seem like caffeine.

Glucose: glucose is just sugar. Probably dissolves the other things to help absorption.

You don't want to do it, but it won't kill you. The LD50 for caffeine is 150-200mg/kg (the amount you need to kill half the population). For an average 70kg man, that's 10.5-14 grams. That'll be about 105 to 140 tablets. But you'll likely suffer a lot in the meantime and might have permanent damage from it.